EURORIB'12

20 May 2012, 13:00 → 25 May 2012, 16:00 Europe/Rome

Centro Congressi delle Venezie, Hotel Alexander Palace - Abano Terme (Padova) - Italy

Giovanni La Rana (NA)

EURORIB 2012 - European Radioactive Ion Beam Conference 2012.
The third international EURORIB conference “EURORIB’12” will be held from May 21 to May 25, 2012 at Abano Terme (Padova), Italy.

Our nuclear physics community is eagerly awaiting the construction of the next generation of Radioactive Ion Beam (RIB) facilities in Europe: HIE-ISOLDE@CERN, NUSTAR@FAIR, SPES@LNL, SPIRAL2@GANIL and the future EURISOL. The collaborations built around these facilities are exploring new experimental and theoretical ideas that will advance our understanding of nuclear structure through studies of exotic nuclei. Following in the spirit of the conference held in Lamoura in 2010, EURORIB’12 will provide the opportunity for the different collaborations to come together and present these ideas, and explore the synergies between the research programmes based around the different accelerator projects.

The main topics to be discussed at the conference are:
• Future RIB facilities
• At and beyond the dripline and new modes of radioactivity
• Nuclear structure far from stability
• Heavy and superheavy nuclei
• Dynamics and Thermodynamics of exotic nuclear systems
• Nuclear astrophysics
• Fundamental interactions
• Applications to other fields
• Production and manipulation of RIB
• Instrumentation

Sponsored by:

 

Conference Poster INFN_EURORIB_2012.jpg

First Circular EURORIB12_First_Circular.pdf

Second Circular EURORIB12_Second_Circular.pdf

Third Circular EURORIB12_third_Circular.pdf

Sunday, 20 May

13:00 → 14:00 Bus from Venice Airport

16:30 → 18:30 REGISTRATION

17:00 → 18:00 Bus from Venice Airport

18:30 → 19:30 Welcome Cocktail

Monday, 21 May

08:00 → 09:00 REGISTRATION

09:00 → 09:15 Welcome

09:15 → 09:30 The 50 years of the Legnaro Laboratory in the history of nuclear physics in Italy

Speaker: Renato Angelo Ricci (LNL)

Slides LEGNARO_50_YEARS_Ricci.pdf

09:30 → 11:10 Nuclear Structure far from Stability

09:30 Nuclear structure of exotic neutron-rich nuclei with AGATA

The European project AGATA is the result of a combined effort of many different countries and institutions to serve the future needs of the challenging experiments at new radioactive ion beam facilities. The new concept of the gamma-ray tracking spectrometer AGATA bases its excellences in being capable of identifying the gamma interaction points (pulse shape analysis) and via software in reconstructing the trajectories of the individual photons (gamma-ray tracking). This leads to abandon the Compton suppression concept and to build therefore an array where the full 4π solid angle is covered by germanium detectors, thereby obtaining much larger photopeak efficiency and peak-to-totalratio. AGATA in its first implementation (the AGATA Demonstrator) has been coupled to the large-acceptance magnetic spectrometer PRISMA from 2009 until the end of 2011 at the Laboratori Nazionali di Legnaro (LNL) in a experimental campaign aimed, mainly, at the study of the properties of neutron-rich nuclei populated via multinucleon transfer or deep inelastic reactions. The experiments spanned from the Si neutron-rich isotopes nearby the island of inversion up to the heavy shapetransitional neutron-rich osmium isotopes. For many exotic nuclei, lifetime measurements were possible by using the differential Recoil Distance Doppler Shift method developed for multinucleon-transfer reactions in combination with the AGATA and PRISMA spectrometers. In this presentation, some selected results on neutron-rich nuclei studied with the AGATA Demostrator at LNL together with fort-coming implementation at GSI and SPIRAL2 radioactive ion beam facilities will be discussed.

Speaker: Javier Valiente Dobon (INFN LNL, Italy)

Slides EURORIB2012-Valiente.pdf

10:00 Recent results using VAMOS spectrometer

In addition to new facilities producing more intense radioactive ion beams, the resurgence of “classical” techniques using stable beams with state of art detection systems offer hope towards uncovering new signatures of both single particle and collective motion. Transfer and fission reactions are two such processes that facilitate studies of the evolution of nuclear structure as a function of isospin. In this talk recent work done at GANIL exploiting such “old” reactions and selective “new” tools will be presented. Spectroscopy of neutron rich nuclei studied with high intensity stable beams and radioactive re-accelerated beams, using the highly selective and large acceptance VAMOS spectrometer coupled with the efficient EXOGAM gamma-array and/or charged particle arrays MUST2 and TIARA will be exemplified.

Speaker: Maurycy Rejmund (GANIL, Caen Cedex, France)

Slides Rejmund_EURORIB12.pdf

10:30 Lifetimes of excited states in neutron-rich Zn isotopes using the AGATA demonstrator

The spectroscopy of exotic nuclei offers the opportunity to investigate the isospin dependence of the nuclear structure. The structure of N=40 nuclei away from stability is currently questioned [1]. Even though 68Ni shows signs of magic nucleus with a large first 2+ excitation energy and a small transition probability B(E2; 2+->0+), recent experiments point towards a rapid onset of collectivity and deformed shapes for Cr, Fe, Zn and Ge isotopes. The description of collectivity in this mass region seems to require the g9/2 and d5/2 orbits in the valence space in case of shell model calculations [2]. In neutron-rich copper isotopes 73,75Cu excitations have been shown to contain both single-particle and collective components [3]. In this context, lifetime measurement of the first excited states in 70,72,74Zn have been performed through a recoil-distance Doppler shift method (RDDS). The experiment, carried out at the Laboratori Nazionali di Legnaro in Italy, is one of the first performed with the AGATA demonstrator, first stage of the AGATA new-generation germanium array. A 76Ge beam at 577 MeV impinging on a 238U target has been used to produce the Zinc isotopes from deep-inelastic scattering. Results suggest a maximum of collectivity at N=42 and an unexpectedly long lifetime is measured for the 4+ state in 74Zn leading to a very small ratio of B(E2; 4+->2+)/B(E2; 2+->0+). This could be link to an onset of single-particle components in the excitation. The comparison with theoretical calculations will be discussed in the presentation. [1] J. Ljungvall et al, Phys. Rev. C 81, 061301 (R) (2010) [2] K. Sieja and F. Nowacki, Phys. Rev. C 81, 061303 (R) (2010) [3] J.M. Daugas et al, Phys. Rev. C 83, 054312 (2011)

Speaker: Ms Corinne Louchart (CEA Saclay, Service de Physique nucléaire)

Slides eurorib_louchart.pdf

10:50 Evolution of the structure of neutron rich calcium isotopes with microscopic two- and three-body forces

Three-body (3N) forces have been shown to be essential to the description of light nuclei. For instance, exact ab-initio methods such as no-core shell model (NCSM) or Green Function Monte Carlo (GFMC) need to include 3N forces in order to reproduce the spectra of light nuclei. Recent NCSM calculations showed that 3N forces are also needed to explain the beta-decay lifetime of 14C. However, most of the studies that include microscopic 3N forces are restricted to very light systems. Recently, chiral effective field theory (EFT) nucleon -nucleon (NN) and 3N interactions have been applied in shell model calculations of medium-mass nuclei. They have succeeded to explain, from a microscopic point of view, features such as the oxygen dripline at O24, or the very existence of the magic number N=28. To the moment, these could only be explained through phenomenology. I will present new results obtained within this framework, regarding the ground and excited states of neutron rich calcium isotopes. In particular, I will focus on the importance of including 3N forces in the calculation of binding energies and excitation spectra. Our theoretical results nicely compare to experiments for the isotopes for whom experimental information is available, both for masses and spectra. In particular, we agree with the new trend of the two-nucleon separation energies between Ca50 and Ca52 (the mass of Ca52 was recently re-measured). The theoretical spectra reasonably agree with experiment, in many cases with the same level of agreement as calculations based on phenomenological interactions. This is very encouraging because there are no phenomenological or fitted parameters in our approach. When going to exotic systems, we expect our calculations, based directly on the microscopic chiral EFT, to give more reliable predictions than standard phenomenological approaches. Based on our results, I will also explore the existence (or not) of non-standard magic numbers N=32,34 or 40.

Speaker: Dr Javier Menendez (Technical University Darmstadt)

Slides jmenendez_abano12.pdf

11:10 → 11:30 Coffee break

11:30 → 13:00 Nuclear Structure far from Stability

11:30 Shape coexistence at the neutron rich edge; The cases of N=20, 28 and 40.

I will discuss the mechanisms responsible for the shape transitions and coexistence in the very neutron rich regions around the magic neutron closures N=20, 28 and 40. I will show that the islands of inversion/deformation at N=20 and 28 merge in the Magnesium isotopes

Speaker: Dr Alfredo Poves (Institute the Theoretical Physycs, Madrid, Spain)

Slides A_Poves.pdf

12:00 Study of nuclei north-east of 48Ca with realistic effective hamiltonians

Shell-model calculations for nuclei with valence nucleons outside 48Ca are presented, wherein a fully microscopic approach is adopted. Namely, the single-particle energies and the matrix elements of both the two-body interaction and the electromagnetic multipole operators are derived theoretically starting from the high-precision CD-Bonn nucleon-nucleon potential, renormalized by way of the V-low-k approach. The results compare satisfactorily with a large amount of experimental data. Some remarks are made about the onset of the quadrupole collectivity at N=40.

Speaker: L. Coraggio (Istituto Nazionale di Fisica Nucleare – Sezione di Napoli (Italy))

Slides Coraggio_Eurorib12.pdf

12:20 Shell evolution and effective three-body forces in the newly-explored neutron-rich region around Z=82 and far beyond N=126

The study of exotic nuclei has shown that significant changes of the well known shell structure along the stability valley occur. However, little is known on the neutron-rich nuclei around 208Pb, because of the experimental difficulties to reach such nuclei. The study of these heavy nuclei is relevant also for the understanding of the r-process stellar nucleosynthesis in heavy nuclei. Neutron-rich nuclei around 208Pb were populated by using a 1 GeV*A 238U beam at GSI. The resulting fragments were separated and analysed with the FRS-Rising setup. Many neutron-rich isotopes were identified for the first time and a significant number of new isomers were hence discovered, enabling to study the structure of these isotopes. The new exotic isotopes observed, extend up to 218Pb along the Z=82 shell closure and up to N=134 and N=138 for the proton-hole and proton-particle Tl and Bi nuclei, respectively. The very exotic 210Hg nucleus was also produced and studied: its unexpected structure will be discussed. In our talk, the experimental results will be presented within state-of-the-art shell-model calculations. The significant discrepancies between the experimental findings and the behaviour expected from the usual seniority scheme will be pointed out, showing how the inclusion of effective three-body interactions (and the related two-body transition operators) helps to improve the agreement between theory and experiment.

Speaker: Mr Andrea Gottardo (INFN - LNL)

Slides Gottardo.pdf

12:40 Study of quadrupole collectivity in neutron-rich 128Cd

The neutron-rich isotope 128Cd is only two proton and two neutron holes away from the doubly-magic nucleus 132Sn. It is famous for the irregular behaviour of the excitation energy of the first 2+ state, a feature which cannot be explained even by recent shell model calculations. Currently, only a beyond-mean-field approach is capable to reproduce the anomaly. However, it predicts a considerable prolate deformation next to the N=82 shell closure. Astrophysical interest in this particular isotope arises from the proximity to the r-process waiting-point nucleus 130Cd. We investigated the exotic isotope 128Cd for the first time by safe Coulomb excitation. The beam was delivered at an energy of about 2.85 MeV/u by the REX-ISOLDE facility at CERN. Scattered beam particles as well as recoiling target nuclei were detected by a segmented Si detector in coincidence with gamma-rays measured by the MINIBALL array. From the differential excitation cross section electric matrix elements were deduced. In previous experiments, the isotopes 122,124,126Cd have been investigated in a similar way and evidence for a larger quadrupole collectivity compared to predictions from the shell model has been found. Additionally, the isotope 126Cd has been studied in a lifetime measurement employing the Doppler shift attenuation method (DSAM). In this contribution we will present first new results for 126,128Cd and discuss the evolution of the quadrupole collectivity along the Cd isotopic chain towards N=82. This work is supported by BMBF (No. 06DA9036I), EU through ENSAR (No. 262010), HIC for FAIR, and the MINIBALL and REX-ISOLDE collaborations.

Speaker: Prof. Thorsten Kröll (TU Darmstadt)

Slides tkroell_EURORIB12.pdf

13:00 → 14:30 Lunch

14:30 → 16:30 Future RIB Facilities

14:30 Physics case and status of the HIE-ISOLDE project

The High Intensity and Energy ISOLDE (HIE-ISOLDE) project is a major upgrade of the existing ISOLDE and REX-ISOLDE facilities at CERN. The project contains three major elements: higher energies, improvements in beam quality and flexibility, and higher beam intensities. This requires developments in radioisotope selection, improvements in charge-breeding and target-ion source development, as well as construction of the new injector for the PS Booster, LINAC4. The most significant improvement will come from replacing most of the existing REX accelerating structure by a superconducting (SC) linear accelerator with a maximum energy of 10 MeV/u. This would allow all ISOLDE beams to be accelerated to energies well below and significantly above the Coulomb barrier, facilitating a broad programme of nuclear structure and nuclear astrophysics studies using different classes of nuclear reactions. An overview of the status and the time line of the project will be given followed by a number of physics cases becoming possible. Also the required instrumentation will be discussed

Speaker: Mark Huyse (KU Leuven, Belgium)

Slides 2012_EURORIB_Mark_Huyse_short.pdf

15:00 Physics opportunities with SPIRAL2

The SPIRAL 2 facility [1], an ambitious extension of the GANIL accelerator complex, has entered recently in the construction phase. In the frame of this project, a new superconducting linear accelerator delivering high intensity, up to 40 MeV, light (proton, deuteron, 3-4He) beams as well as a large variety of heavy-ion beams with mass over charge ratio equal to 3 and energy up to 14.5 A.MeV will be constructed in the coming two years (SPIRAL2 Phase 1). Using a dedicated converter and the 5 mA deuteron beam, a neutron-induced fission rate is expected to approach 1014 fissions/s for high-density UCx target. The versatility of the SPIRAL 2 driver accelerator will also allow using fusion-evaporation, deep-inelastic or transfer reactions in order to produce very high intensity Rare Isotope Beams and exotic targets. The energies of accelerated RIB will reach up to 7-8 A.MeV for fission fragments and 20 A.MeV for neutron-deficient nuclei (SPIRAL2 Phase 2). The physics case of SPIRAL 2 based on the use of high intensity Radioactive Ion Beams and stable light- and heavy-ion beams as well as on possibilities to perform several experiments simultaneously will be discussed and illustrated with recent high-light results obtained at GANIL/SPIRAL. In particular, it will be shown that a use of these beams at the low-energy ISOL facility (DESIR) and their acceleration to several A.MeV as well as of high neutron flux at the n-tof like facility will open new possibilities in study of heavy and super-heavy nuclei, in nuclear structure physics and nuclear astrophysics and in reaction dynamics studies. This exciting scientific program as well as relatively moderate intensities and high cost of radioactive beams impose a use of the most efficient and innovative detection systems as the magnetic spectrometer VAMOS, the 4P gamma-array EXOGAM2 and AGATA as well as charged particle detectors like MAYA, MUST 2 and TIARA. Several new concepts of the detection systems (ACTAR TPC, DESIR, FAZIA, GASPARD, PARIS) and a new separator/spectrometer S3 located in dedicated experimental halls are currently under construction or design. References: [1] 1. http://pro.ganil-spiral2.eu/

Speaker: Hervé Savajols (GANIL, Caen Cedex, France)

15:30 THE SPES PROJECT AT THE INFN-LEGNARO NATIONAL LABORATORIES

ABSTRACT The SPES Radioactive Ion Beam (RIB) facility at INFN-LNL is now in the construction phase. The aim of the SPES project is to provide high intensity and high-quality beams of neutron-rich nuclei to perform forefront research in nuclear structure, reaction dynamics and interdisciplinary fields like medical, biological and material sciences. The SPES project is supported by the INFN national laboratories LNL (Legnaro) and LNS (Catania). It is based on the ISOL method with an UCx Direct Target able to sustain a power of 10 kW. The primary proton beam is delivered by a high current Cyclotron accelerator with energy of 35-70 MeV and a beam current of 0.2-0.5 mA. Neutron-rich radioactive ions will be produced by UCx target at an expected fission rate in the target in the order of 1013 fissions per second. The exotic isotopes will be re-accelerated by the ALPI superconducting LINAC at energies of 10 AMeV and higher, for masses in the region of A=130 amu, with an expected rate on the secondary target of 107 – 109 pps. The general overview and the status of the project will be presented.

Speaker: Gianfranco Prete (LNL)

Slides Prete.pdf

16:00 Towards Eurisol

In the NuPECC long range plan published in 2010, the construction of the next generation ISOL facility EURISOL was recognized as one of the main long-term priorities for European Nuclear Physics. After a brief review of the results of the EURISOL Design Study, which defined the layout and main components of the facility, this talk will focus on the ongoing initiatives to further the EURISOL concept. The goals and achievements of the following work packages will be presented: • EURISOL Project Office: Oversees and orients the EURISOL related activities • EURISOL User Group: Represents the community backing EURISOL • EURISOL-NET (Network of the ENSAR contract): Disseminates R&D performed at the current large scale facilities and updates the EURISOL physics case through the organization of topical and town meetings • EMILIE (promoted by the NuPNET contract): Conducts R&D on charge breeding methods • TIPHAC (workpackage of the TIARA contract): Designs R&D installations for cryomodules and high power targets • Pb-Bi loop: Construction and beam test of a Pb-Bi loop target. Finally future plans for moving towards EURISOL will be discussed. We acknowledge the financial support of the European Community under the FP6 “Research Infrastructure Action—Structuring the European Research Area” EURISOL DS Project Contract no. 515768 RIDS and the FP7 ENSAR contract no 262010. * On leave from IPN Orsay, France Finally future plans for moving towards EURISOL will be discussed. We acknowledge the financial support of the European Community under the FP6 “Research Infrastructure Action—Structuring the European Research Area” EURISOL DS Project Contract no. 515768 RIDS and the FP7 ENSAR contract no 262010. * On leave from IPN Orsay, France

Speaker: Yorick Blumenfeld (CERN, Geneva, Switzerland)

Slides EURORIB12_EURISOL_Blumenfeld.pdf

16:30 → 17:00 Coffee break

17:00 → 18:10 Future RIB Facilities

17:00 Radioactive Beams at FAIR - the NUSTAR programme

The FAIR (Facility for Antiproton and Ion Beams) installations, to be constructed at the GSI site in Darmstadt, will be addressing a wealth of outstanding questions within the realm of subatomic, atomic and plasma physics through a combination of novel accelerators, storage rings and innovative experimental set-ups. One of the key installations is the fragment separator Super-FRS that will be able to deliver an unprecedented range of radioactive ion beams (RIBs) in the energy range of 0-1.5 GeV/u. These beams will be distributed to three branches, each with its unique domain with respect to beam energies and properties. The high-energy branch will permit reactions with radioactive beams at relativistic energies, whereas the low-energy branch will supply decelerated beams for high-resolution spectroscopy, traps and laser spectroscopy. Finally, the ring branch will uniquely permit stored and cooled exotic beams for a range of methods only possible in a storage ring. This ambitious programme is exploited within the NUSTAR (Nuclear Structure, Astrophysics and Reactions) programme. Consequently, a broad experimental programme utilising these beams are envisaged, under the umbrella of the NUSTAR (Nuclear Structure, Astrophysics and Reactions) collaboration. The FAIR facility will be presented with emphasis on the NUSTAR programme in the _rst part to be realized, the modularized start version (MSV) but with an outlook towards intermediate opportunities and short- and long-term extensions. The experimental methods and the associated instrumentation are currently being constructed and/or developed, partially through combining prototype tests and pilot experiments with the running scienti_c programme at GSI.

Speaker: Thomas Nilsson (Fundamental Physics, Chalmers University of Technology, Gothenburg, Sweden)

Slides T_Nilsson.pdf

17:30 LONG RANGE PLANE WITH RADIACIVE BEAMS AT DUBNA

The new project of the in-flight fragment separator ACCULINNA-2 [1] at U-400M cyclotron in Flerov Laboratory of Nuclear Reaction, JINR is proposed as the third generation of the Dubna Radioactive Ions Beams complex, briefly DRIBs [2]. It is expected to be a more universal and powerful instrument in comparison with existing separator ACCULINNA [3]. The RIBs intensity should be increased by factor 15 (factor 6 - via angular acceptance and factor 2.5 – via more intensive primary beams of upgraded cyclotron), the beam quality greatly improved and the range of the accessible secondary radioactive beams broadened up to Z~20. The new separator will provide high intensity RIBs in the lowest and wide energy range attainable for in-flight separators, i.e. E ≈ 5÷50 MeV/nucleon. The prime objectives of ACCULINNA-2 are to provide good energy resolution and high efficiency for correlation measurements. Extensive research program which could be carried out at this facility as from 2015 and its operating principle are foreseen. 1. A.S. Fomichev et al., JINR Communication E13-2008-168, Dubna (2008) 2. http://159.93.28.88/flnr/dribs.html; http://159.93.28.88/dribs/publ.html 3. A.M. Rodin et al., Nucl. Instr. and Meth. B 204 (2003) 114-118; http://aculina.jinr.ru/

Speaker: Dr Andrey Fomichev (FLNR JINR)

Slides Eurorib2012_Fomichev.pdf

17:50 The ISOL@MYRRHA project at SCK•CEN

The idea of ISOL@MYRRHA was born 5 years ago, when a feasibility study was initiated within the “Belgian Research Initiative on eXotic nuclei” network project. This facility should use up to 5% of the 2-4 mA proton beams delivered by the MYRRHA linac, for the production of Radioactive Ion Beams (RIBs) via the Isotope Separator On Line method. By combining the high primary-beam intensity (up to 200 uA) with selective ionization and a beam purification system with high mass-resolving power, it will be possible to produce intense RIBs with high purity. ISOL@MYRRHA aims to be complementary to existing facilities, focusing on experimental programs requiring long uninterrupted beam times. These are experiments which • hunt for very rear phenomena, • need high statistics, • need many time-consuming systematic measurements, • have inherent limited detection efficiency. Based on the feasibility study, the detailed technical design is now in preparation. In this presentation, I intend to introduce the ISOL@MYRRHA project and to discuss its status and perspectives.

Speaker: Dr Lucia Popescu (SCK-CEN)

Slides LPopescu_EURORIB_May2012_v1.pdf

Tuesday, 22 May

09:00 → 11:00 Nuclear Structure far from Stability

09:00 Perspectives for laser spectroscopy at the next generation of European RIB facilities

The last 10 years have witnessed significant advances in field of laser spectroscopy. Leaps in detection sensitivities through continued development at existing on-line facilities have pushed measurements towards fringes of the nuclear chart. The application of laser probing for rare isotope production and purification has established itself as a mature field in its own right. Synergy between the fields of nuclear spectroscopy and laser spectroscopy is helping to further refine existing techniques and provide new tools to probe nuclear structure even further from stability. This talk will consider compelling regions of the nuclear chart that will be accessible at the next generation of RIB facilities and the spectroscopic tools required to study them.

Speaker: Kieran Flanagan (CERN, Geneve, Switzerland)

Slides Eurorib2012_Flanagan.pdf

09:30 Ground States and Isomers of Cadmium by High-Resolution Laser Spectroscopy

We report on the first hyperfine-structure study of cadmium by high-resolution laser spectroscopy. The goal is to determine nuclear spins, electromagnetic moments and root mean square charge radii of ground and isomeric states along the chain, ultimately reaching the neutron 50 and 82 shell closures. In the first part of the program we studied the intense beams of 106-124,26Cd by fluorescence spectroscopy, which also covered the b-decaying isomers in the odd 111-123Cd. The measurements determined the ground-state spins as being 1/2, 3/2, and 5/2 in close relation with the corresponding single-particle orbitals. Evidence is found whether the isomeric configuration is 11/2- in all isotopes. The data is sensitive to the changes in the degree of collectivity between the ground states and the isomers, not only from their quadrupole moments, but also through their charge radii. This enable a discussion in therms of shape coexistence. In this contribution we will present the preliminary results and their interpretation.

Speaker: Dr D. T. Yordanov (Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany)

Slides EURORIB_Yordanov-1.pdf

09:50 The observation of a strong E0 component in the 2+2-->2+1 transition in 184Hg from the beta-decay of laser-ionized thallium isotopes: a strong signature for shape coexistence.

The mass region of neutron-deficient mercury and lead isotopes near the midshell (N=104) is well known for the phenomenon of shape coexistence. In neutron-deficient, even-even 180-188Hg isotopes an oblate (beta2~-0.15) ground state band is found to coexist with an excited prolate (beta2~0.25) band at low spin and low-excitation energies. This band is built on top of a deformed excited 0+ state, which is interpreted as resulting from proton excitations across the Z=82 closed shell. Such intruder states have been found to be a widely occurring structural feature of nuclei at and near closed shell. The low-lying coexisting states in 180,182,184Hg have been studied at ISOLDE, CERN through the beta+/EC decay of 180,182,184Tl as part of a systematic alpha, beta, and beta-delayed fission study of neutron-deficient thallium isotopes. The beta+/EC decay is a very simple but still powerful tool which allows to effectively populate low-lying not-yrast states in the daughter nucleus, normally not easily accessible with other techniques, thus providing complementary information to the ones from in-beam gamma-spectroscopy studies and from alpha-decay studies from the Pb parent nuclei. Mass-separated Tl beams, produced at ISOLDE, CERN, in the bombardment of 238U by 1.4 GeV protons and selectively laser ionized, were implanted on a carbon foil mounted on a rotating wheel. The implantation foil was surrounded by two Si detectors for alpha, and electron detection while gamma rays were detected with two high-resolution Ge detectors. By means of unambiguously Si-gamma and gamma-gamma coincidences, a detailed level scheme of the coexisting states has been built-up as well as a detailed description of their decay properties (gamma intensities, E0 component of 2+ -->2+ transitions). The newly observed or better energy-determined 02+, 22+, 23+ states in 180,182Hg follow well the general trend of the prolate band. They confirm that the minimum of the parabolic behavior in excitation energy of the prolate band occurs in 182Hg, as expected. The exceptionally large E0 component observed in the 21+ -->22+ transition in 184Hg (23+/-5) confirm that the two states are strongly mixed and they have different deformation. Isomerism is well-known in the heavier thallium isotopes and the population of low-spin states as well as high-spin states (up to 8+ in 182,184Hg) in the beta decay points to similar features in the lighter thallium isotopes. The information gathered can be combined with the ones obtained with different techniques, such as in-beam gamma and conversion-electron spectroscopy, Coulomb excitation on post-accelerated radioactive ions (recently performed at ISOLDE), lifetime measurements and laser spectroscopic studies to get a deeper knowledge of the shape-coexistence phenomenon.

Speaker: Ms Elisa Rapisarda (IKS Katholieke Universiteit Leuven)

Slides Rapisarda.pdf

10:10 A diynamical model for halo nuclei and two-nucleon transfer reaction

The peculiar properties of the halo nuclei 11Li and 12Be can be successfully interpreted in the framework of a dynamical model based on the interweaving of single-particle levels with the collective vibrations of the system, leading to a substantial admixture of phonons in the ground state. This interweaving induces an attractive interaction between the two-halo neutrons that in the model is crucial to reproduce quantitatively the position of the single-particle levels and the two-neutron separation energy. A recent two-neutron transfer experiment, performed with a beam of 11Li and populating both the ground and the first excited state of 9Li showed evidence for the quadrupole mixing in the ground state wave function. A second-order DWBA calculation based on our microscopic wavefunction for 11Li is able to reproduce both the angular distribution and the absolute value of the cross section.

Speaker: Enrico Vigezzi (INFN Milano, Italy)

Slides eurorib_2012_vigezzi_web.pdf

10:40 Ab-initio Green's function calculations of medium-mass open-shell nuclei

Ab-initio approaches - starting from the sole knowledge of a realistic nuclear force - aim at eventually achieving parameter-free predictions of nuclear properties. Although considerable progress has been made in recent years, e.g. using couple-cluster or self-consistent Dyson-Green's function methods, ab-initio nuclear structure calculations of medium-mass and heavy nuclei are still restricted to a limited number of (doubly-magic) nuclei. Besides the challenging numerical scaling, one reason is the inadequate account of pairing correlations that is essential to any realistic treatment of single- and doubly-open shell nuclei. We are currently developing an ab-initio many-body method based on Green's function theory in the Gorkov formalism that allows for an explicit treatment of pairing correlations. Such approach is therefore applicable to a much larger set (~500) of semi-magic nuclei, including systems up to, e.g., the tin isotopic chain. The talk will introduce the context within which such nuclear calculations take place, describe the many-body method and present the first results in the oxygen and calcium isotopes.

Speaker: Dr Vittorio Somà (EMMI/TU-Darmstadt)

Slides Soma_Eurorib12.pdf

11:00 → 11:30 Coffee break

11:30 → 13:00 Instrumentation

11:30 Novel large scintillator arrays for RIB facilities

The advent of radioactive ion beam facilities, both in Europe (FAIR, SPIRAL2, SPES, HIE-ISOLDE and, in the future, EURISOL) and worldwide (e.g. FRIB, RIKEN) is expecting to give access to unreachable so far exotic nuclei and exotic processes. This in turn demands development and usage of highly efficient and dedicated instrumentation. For gamma ray detection with high-energy resolution large germanium arrays, possessing tracking capabilities, are being constructed (AGATA or GRETA). But recent progress on scintillator materials, offering medium energy resolution and very good timing resolution (e.g. LaBr3), allowed to design and start constructing novel large scintillator arrays. They may be complementary to the germanium arrays, and replaced them in physics cases where highest energy resolution is not priority (very exotic nuclei or fast beams), but the highest efficiency or time resolution are a must. In the talk the development of large scintillator arrays aiming at specific physics cases will be overviewed, starting from the Milano-Copenhagen-Krakow HECTOR+HELENA array, via new projects as HECTOR+, PARIS, SHOGUN and others, and finishing with the CALIFA project. Also the synergies between those projects will be discussed, exemplified by the recent GANAS@NUPNET project.

Speaker: Adam Maj (IFJ PAN Krakow, Poland)

Slides AMaj_Eurorib2012.pdf

12:00 TRACE status and perspective for the new RIB facilities

Various physics themes have been addressed, during the AGATA Demonstrator experimental campaign at LNL, by exploring different mass regions in the nuclear landscape, ranging from the study of the hydrogen burning CNO cycle in the light 15O nucleus to the non-yrast octupole-deformed bands expected in the moderately p-rich 222Th,220Ra heavy nuclei. In this such campaign the complementary detectors had a prominent role, making possible, by increasing the sensitivity of the gamma-tracking spectrometer, the study of both proton- and neutron-rich nuclei away from the valley of beta stability. In particular the light-charged-particle detector TRACE has been used in the study of the origin of cluster-bands in 21Ne and of high-collective dipole and quadruple modes in 208Pb and 90Zr. In addition the use of digital pulse shape analysis recently revealed to be an efficient technique for the discrimination of low-energy charged particles. The present contribution focuses, a the end of a succesful AGATA campaign at LNL, on the status of the highly segmented silicon array TRACE in the context of the European partner projects, like GASPARD(SPIRAL2) and HYDE(FAIR), and in view of the construction of the radioactive beam facility SPES at LNL (Italy).

Speaker: Dr Daniele Mengoni (PD)

Slides Mengoni.pdf

12:20 Experiments with stored ions at ISOLDE: TSR@HIE-ISOLDE proposal

Experiments with exotic nuclei stored in a ring have shown a huge potential in the last years. Such experiments profit from high revolution frequencies of stored beams, which allows one to 'recycle' the exotic nuclei, and from low background conditions. Well-established scientific programs on mass and half-life measurements are pursued at such facilities [1], and new ones are being tested on proton- and alpha- induced reactions in inverse kinematics at low energies [2]. We propose to store the ISOL-produced beams from HIE-ISOLDE in a ring, to perform precision experiments in nuclear and atomic physics and astrophysics. The Test Storage Ring (TSR) at MPIK Heidelberg [3] is well-suited for this purpose. The envisaged physics programme is rich and varied, spanning from investigations of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR can also be used to remove isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. In this contribution we will present the proposal, outline the physics cases and give the present status of the project. [1] Franzke B, Geissel H and Münzenberg G 2008 Mass Spectr. Rev. 27 428–469 [2] Zhong Q et al. 2010 J. Phys. Conf. Series 202 012011 [3] Ion Storage Ring TSR, http://www.mpi-hd.mpg.de/blaum/storage-rings/tsr/index.en.html

Speaker: Riccardo Raabe (Instituut voor Kern- en Stralingsfysica, KU Leuven)

Slides Raabe_Eurorib12.pdf

12:40 Resonance Ionization Laser Spectroscopy with the Leuven gas cell-based Laser Ion Source

After almost two decades of operation purified radioactive ion beams of more than 15 different elements, mainly devoted to decay studies, have been obtained by resonant laser ionization with the Leuven Isotope Separator Online (LISOL) facility, at the Cyclotron Research Center (CRC), Louvain-la-Neuve. Production and thermalization of radioactive species in a cell filled with ultra-pure buffer gas is used in combination with resonant laser radiation for selective ionization of the isotopes of interest in the Leuven gas cell-based laser ion source. These ions are extracted from the cell in a supersonic free jet and are transported by a radio frequency ion guide up to the mass separator, where they are segregated from non-isobaric contamination. Ion beams of high purity can then be sent to the detector station for the study of their characteristic decay radiation. In addition to the routinely performed nuclear-decay-spectroscopy studies the recent implementation of a new concept gas cell [1] in the LISOL setup has allowed to perform in-source laser spectroscopy studies of neutron deficient 57-59Cu [2] and 97-102Ag [3] isotopes. These measurements have become feasible owing to the enhanced selectivity and sensitivity of the apparatus, which has allowed spectroscopic studies on exotic species with count rates as low as 6 ions/s for 57Cu (T1/2 =200 ms) or 1 ion/s for 97Ag, both semimagic nuclei. Online experiments are currently being carried out to pursue similar results on the actinium isotopes, where preliminary results were obtained for 212,213Ac. In spite of the good results obtained by in-gas-cell laser spectroscopy the inherent pressure broadening makes this technique to be inapplicable to those elements with reduced hyperfine parameters and/or high sensitivity to atomic collisions, as observed in practice, for instance, in the tin isotopes around A= 100. For the successful study of the atomic properties of these species in-gas-jet laser spectroscopy would be the technique of choice. In parallel to the online runs we are developing this technique, new for the study of rare isotopes, which will improve the resolution and efficiency of the present method. The proof of principle of in-gas-jet laser spectroscopy has previously been demonstrated at LISOL [4] and the full benefits of it recently evaluated with a high-repetition laser system [5]. Currently, we are constructing a laser laboratory at the K.U. Leuven to further develop and apply in-gas-jet laser spectroscopy for the study of heavy elements. Implementation of this technique will allow high sensitivity, high efficiency, and high resolution laser spectroscopy experiments on low-production-rate species using the Leuven gas cell-based laser ion source at S3 (GANIL) and GSI. The necessary reduction of the existing laser linewidth (1.5 GHz) has been demonstrated lately by amplification of single mode cw diode laser light in a pulse dye amplifier resulting in a spectral resolution of 150 MHz in the reference cell. In my presentation I will report on the results obtained in the last online runs performed on the production of Ac beams and on the different tests carried out to accomplish in-gas-jet laser spectroscopy at LISOL in view of a full implementation of this technique in the future low energy branch facility S3, at SPIRAL2 or at GSI. [1] Yu. Kudryavtsev et al. Nucl. Instr. and Meth. B 267 (2009) 2908 [2] T.E. Cocolios et al Phys. Rev. Lett. 103 (2009) 102501 [3] I. Darby et al. In preparation [4] T. Sonoda et al., Nucl. Instr. and Meth. B 267 (2009) 2918 [5] R. Ferrer, V. T. Sonnenschein et al. In preparation

Speaker: Dr Rafael Ferrer-Garcia (IKS-KU Leuven)

Slides EuroRIB12_FerrerGarcia.pdf

13:00 → 14:30 Lunch

14:30 → 16:30 Nuclear Astrophysics

14:30 Nucleosynthesis: a field with still many open nuclear physics questions

Stellar nucleosynthesis is a vastly interdisciplinary field. There is a large number of different problems invoked calling for a variety of different and complementary research fields. Impressive progress has been made for the last decades in the various fields related to nucleosynthesis, especially in experimental and theoretical nuclear physics, as well as in ground-based or space astronomical observations and astrophysical modellings. In spite of that success, major problems and puzzles remain. As far as nuclear physics is concerned, good quality nuclear data is known to be a necessary condition for a reliable modelling of stellar nucleosynthesis. Important effort has been devoted to measure reaction cross sections, but still nuclear astrophysics requires the use of theoretical predictions to estimate experimentally unknown rates. Most of the nuclear ingredients in the calculations of reaction cross sections need to be extrapolated in an energy or/and mass domain out of reach of laboratory simulations. In addition, some nucleosynthesis applications often involve a large number of unstable nuclei, so that only global approaches can be used. For these reasons, when the nuclear ingredients to the reaction models cannot be determined from experimental data, it is highly recommended to consider preferentially microscopic global predictions based on sound and reliable nuclear models which, in turn, can compete with more phenomenological highly-parametrized models in the reproduction of experimental data. However, such microscopic models need to reproduce as accurately as possible all available experimental data of relevance. Through some selected examples, the need for further theoretical or experimental developments is critically discussed in view of their impact on nucleosynthesis predictions

Speaker: Stephane Goriely (Universitè Libre de Bruxelles,Belgium)

Slides goriely.pdf

15:00 What Masses Can Teach Us About Stellar Evolution

The origin of elements from iron to uranium is considered to be one of the 11 greatest unanswered questions in physics published by the magazine Discover. Today, the rapid neutron-capture process of stellar nucleosynthesis is held responsible for their production. Although more sophisticated astrophysical models for the r-process have evolved in recent years, the astrophysical conditions for a successful r-process have not been identified yet, and r-process model predictions still suffer from large uncertainties. An alternative theory is the process of neutronization occurring in the high-density crust of neutron stars, which shifts the valley of stability towards neutron-rich nuclei. Thus, exotic rare isotopes become so-called equilibrium nuclei and can contribute to the elemental abundance. In both cases, precise mass values are important input parameters to constrain models of stellar element composition and to test their predictive power in comparison with observations. Whenever masses are not (yet) available, mass models are used to deliver required masses of nuclei participating in the astrophysical creation process. A third mechanism of stellar nucleosynthesis is the rp-process, rapid proton-capture process, which takes place on the proton-rich side of the valley of stability and originates in x-ray bursts. In this contribution, recent mass measurements in the context of stellar nucleosynthesis are presented and possible measurements at future facilities will be discussed.

Speaker: Susanne Kreim (CERN, Geneva, Switzerland and Max Planck Institute for Nuclear Physics, Heidelberg, Germany)

Slides 2012_EURORIB_S_Kreim_online.pdf

15:30 JYFLTRAP Penning trap - a tool to study isomers for nuclear structure and astrophysics

JYFLTRAP is a double Penning trap at the Ion-Guide Isotope Separator On-Line (IGISOL) facility. A large variety of nuclei can be produced with the fast and chemically non-selective IGISOL method for JYFLTRAP experiments. Thus far, around 270 atomic masses have been measured with a typical precision of around 10 ppb. In this contribution, mass measurements of isomeric states will be discussed. JYFLTRAP is capable of measuring excitation energies of isomeric states with a precision of better than 10 keV provided that the excitation energy is high enough (> 100 keV) and the half-life long enough (> 100 ms). Mass-excess values of around 25 isomers have been measured with JYFLTRAP. The method is particularly important for beta-decaying isomers for which the excitation energies can be difficult to measure accurately by other means. In addition, JYFLTRAP has been used for in-trap conversion electron spectroscopy of isomeric states [1]. Isomers provide relevant information for nuclear structure and shell-model studies. They can also play a role in astrophysical processes. For example, the excitation energies of the proton-emitting high-spin isomer in 53Co [2] as well as 90Tcm (1+) [3] in the region relevant for the astrophysical rp-process have been measured at JYFLTRAP. Isomers close to doubly magic 132Sn located at the path of astrophysical r-process have also been investigated with JYFLTRAP [4]. The measured excitation energies of the 11/2- isomers in 121,123,125Cd and and 1/2- isomers in 129,131In yield new information on single-particle energies near 132Sn. A good agreement has been found between the JYFLTRAP results and the well-known excitation energies of the 7- isomers in 130Sn and 134Sb. [1] J. Rissanen et al., Eur. Phys. J. A 34 (2007) 113. [2] A. Kankainen et al., Phys. Rev. C 82 (2010) 034311. [3] A. Kankainen, submitted to Eur. Phys. J. A [4] A. Kankainen et al., to be published

Speaker: Dr Anu Kankainen (University of Jyväskylä)

Slides Kankainen_EURORIB12.pdf

15:50 Beta decay and isomeric studies of proton-rich nuclei near the endpoint of the rp-process

Neutron-deficient nuclei in the vicinity of the N = Z = 50 doubly-magic shell closure were produced at the National Superconducting Cyclotron Laboratory to study their structure and their relevance in the astrophysical rp-process. The 100Sn nucleus is the heaviest particle-stable N = Z nucleus, and it is also thought to be doubly magic. Additionally, 100Sn and its closest neighbours lie in the path of rp-process, therefore, the production and study of the decay properties of these nuclei are of great interest for the experimental and theoretical nuclear physics and astrophysics community. Previous attempts to produce these nuclei were hampered by large amounts of contaminants produced with higher abundances than those of the nuclides of interest. The Radio Frequency Fragment Separator was designed and built at the NSCL in order to purify rare neutron-deficient secondary beams. The implementation of this device has made a number of β-decay experiments feasible at the NSCL, including the present work. The nuclei of interest were produced at NSCL via fragmentation of a 112Sn primary beam accelerated to 120 MeV/nucleon, impinging on a 9Be target. The secondary beam was first selected by the A1900 Fragment Separator and purified further with the RFFS. The N = Z nuclei 100Sn, 98In and 96Cd were produced and their β decay was studied. The experimental determination of the half-life of 96Cd was of special interest as it was the last rp-process waiting point to be measured. The effect of the half-life of 96Cd on the nuclear abundances produced by an rp-process and the origin of the light-p nucleus 96Ru was explored. Other exotic nuclei produced include 102 − 101Sn, 100, 99In, 98, 97Cd, 96 − 94Ag, 94 − 92Pd, 92, 91Rh and 90, 91Ru. Several isomeric states were found and their decay modes analysed. The experimental results will be presented and compared to shell model calculations. Also, the impact of our measurements on the astrophysical rp-process will be discussed.

Speaker: Dr ANA BECERRIL (INSTITUTO DE ESTRUCTURA DE LA MATERIA CSIC)

16:10 Experimental study of the 60Fe destruction using the d(60Fe,pg)61Fe transfer reaction.

Observations of 60Fe are crucial for several astrophysical studies: (i) characteristic gamma-ray lines of 60Fe decay are observed in our galaxy confirming nucleosynthesis processes are still active nowadays, (ii) detection of 60Fe in marine sediment has been interpreted as a close-by supernova explosion 2 million years ago and (iii) observation of 60Fe in presolar grains is used to constraint the astrophysical environment of solar system formation. However the interpretation of these observations rely on 60Fe yields, presently very uncertain, obtained from stellar models. One key ingredient in such models are the cross-sections of the production [59Fe(n,g)60Fe] and destruction [60Fe(n,g)61Fe] of 60Fe and current nuclear uncertainties on these reactions translate into a factor of 5 uncertainty in the 60Fe yield. We report here on the study of the direct component of the 60Fe(n,g)61Fe reaction using the one neutron transfer reaction d(60Fe,pg)61Fe performed in LISE at GANIL. Protons were detected with the MUST2 array in coincidence with the gamma-rays detected in the EXOGAM array. Beam-like nuclei were identified with an ionization chamber and a plastic at zero degree. Excitation energy spectra will be presented as well as angular distributions for the known and new populated levels observed in 61Fe. Spectroscopic factors and transferred angular momentum will be presented as well as comparison with shell-model calculations will be presented.

Speaker: Dr Nicolas de Sereville (IPNO / CNRS)

Slides desereville.pdf

16:30 → 18:30 Poster session

Paper LIST_of_POSTERS.pdf

17:00 → 19:00 ECOS Steering Committee

Wednesday, 23 May

09:00 → 11:00 Production and Manipulation of RIB

09:00 Charge breeding of Radioactive Ion Beams: status and perspectives

Charge breeding, which transforms the charge state of ions from 1+ to an n+ charge state, is a key technology for nuclear facilities aiming at reaccelerating Radioactive Ion Beams (RIB’s). It has to meet the following challenges: high charge states for high energies, high efficiency, rapidity and purity. In the past few years, remarkable progresses were made with the two techniques of charge breeding which employ either an ECRIS or an EBIS as charge breeder. However both techniques still require dedicated R&D to overcome their present limitations. This talk will present the status of the field, and the efforts that are undertaken in particular in the frame of the NuPNET funded EMILIE project to provide future facilities with a new generation of state-of –the-art charge breeders.

Speaker: Pierre Delahaye (GANIL, Caen Cedex, France)

Slides Delahaye.pdf

09:30 Heavy ion induced degradation of carbon materials

At FAIR, the production target and the beam catchers at the planned Super-FRS fragment separator will have to withstand large amounts of thermal and mechanical stress. To minimize the energy deposited by heavy ions, graphite, a low-Z material has to be chosen. The properties as well as the structure and dimensional stability of the target and beam catcher material are affected by the temperature and the absorbed irradiation dose. Failure of these components due to irradiation-induced damage are related to dimensional changes, embrittlement, reduction of the thermal conductivity, degradation of the thermal shock response and fatigue resistance in the fast-extraction regime. To evaluate the ion beam- induced structural and dimensional changes and the degradation of material properties involved in the thermo-mechanical response of the target and beam catcher material, in-situ and post-irradiation investigations of graphite samples exposed to large swift heavy- ions doses were performed at GSI. Experimental data for thermal conductivity and elastic modulus of irradiated material provide realistic input parameters for the irradiated material in the thermo-mechanical simulations.

Speaker: Marilena Tomut (GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany)

Slides Tomut-Eurorib2012.pdf

10:00 Recent results on R&D of the SPES production target

The SPES project at Laboratori di Legnaro of INFN (Italy) is concentrating on the production of neutron-rich radioactive nuclei by the Uranium fission at a rate of 1013 fission/s . The emphasis to neutron-rich isotopes is justified by the fact that this vast territory has been little explored, at exceptions of some decay and in-beam spectroscopy following fission.. The Rare Ion Beam (RIB) will be produced by ISOL technique using the proton induced fission on a Direct Target of UCx. The most critical element of the SPES project is the Multi-Foil Direct Target. Up to day the proposed target represents an innovation in term of capability to sustain the primary beam power. The design is carefully oriented to optimise the radiative cooling taking advantage of the high operating temperature of 2000oC. During the talk will be presented the recent developments on the fabrication, characterization, and on-line testing of uranium carbide targets. Also developments related to the ion-source activities using the surface ion source, plasma ion source, laser ion source techniques it will be reported. Finally test e results on handling of the target system it will be shown.

Speaker: Alberto Andrighetto (LNL)

Slides Eurorib12_-_Andrighetto.pdf

10:20 Uranium Carbide Target Material Development for the Production of Exotic Radioisotopes at ISOLDE-CERN

ISOLDE is known to produce a large variety of more than 1000 radioisotopes of 73 different chemical elements throughout the chart of nuclides. Therefore a number of not less than 30 different target materials are currently in use or under intense development. Especially targets based on uranium and thorium refractory compounds have been at the heart of the ISOL technique since its first pioneer experiment in 1951, nowadays producing over 60% of the radioisotopes delivered at ISOLDE. Different developments took place along the years in the various facilities, and today porous uranium carbides with excess graphite phase are used throughout the different operating facilities. However little is known about the influence of their microstructure, crystallography, porosity and chemistry on the isotope release properties. Recently submicron, porous SiC [1], CaO and Y2O3 materials with improved exotic sodium, magnesium, krypton and argon yields [2] could be used without significant degradation over extended periods at ISOLDE, providing the first direct evidence that such kind of matrices can be used to improve the ISOL beam performance for exotic beams. Within the framework of ActILab in FP7-ENSAR: Integrating R&D on ISOL UC targets, several uranium carbide target materials are now under development with the objective to translate these recent findings. This is done by systematic investigations of the impact of phase composition, nano- or submicro-metric grain size, and porosity on their performance and stability [3,4]. This contribution will summarize recent investigations and major achievements in this field at ISOLDE. [1] S. Fernandes, PhD thesis EPFL (2011), http://cdsweb.cern.ch/record/1312950/ [2] J. P. Fernandez Ramos, Nanostructured Calcium Oxide Targets for the Production of Argon Beams, ISOLDE Workshop and Users Meeting, CERN (2011) [3] A. Gottberg, Online Tests of a High Density UC target at CERN-ISOLDE, ARIS (2011) [4] A. Gottberg, Uranium Carbide Material Developments at CERN-ISOLDE, EURISOL-NET (ENSAR/NA03) Working Group Meeting (2011)

Speaker: Dr Alexander Gottberg (CERN, CH-1211 Genève 23, Switzerland / Université Bordeaux 1, 351 cours de la libération 33405 Talence Cedex, France)

Slides Gottberg_2012-05-23_EURIB12.pdf

10:40 Production of radioactive ion beams at ISOLDE with the dual dye and titanium:sapphire RILIS

The Resonance Ionization Laser Ion Source (RILIS) of the ISOLDE radioactive ion beam facility at CERN has been in operation since 1992 and used for the on-line production of ion beams of 27 different elements. The high efficiency, combined with the inherent selectivity of the multi-step resonance ionization process used is essential for many of the experiments conducted at ISOLDE. For this reason the RILIS is the most commonly used ion source, with a typical annual operating time of more that 2000 hours for on-line physics. Following a recent upgrade of the dye laser system, the reliability and overall performance of the RILIS has increased to a degree where such intense use is reliably sustainable but remains limited by the complexity of switching from one ionization scheme to another. Amongst other benefits, the final stage of the RILIS upgrade: the installation of an independent laser system of Nd:YAG pumped titanium:sapphire (Ti:Sa) lasers, largely addresses this issue. The two laser systems, which each have complementary wavelength tuning ranges can operate in parallel and therefore offer a new set of RILIS operating modes. Depending on the requested elements it is possible to tune one laser system whilst another is in use, use ionization schemes which rely one a mixture of Ti:Sa and dye tuning ranges or use one laser to supplement or backup another. This added flexibility enabled RILIS use for over 2500 hours during the 2011 on-line period, which was the first year of operation of the Ti:Sa system. The specifications of the complete RILIS system will be presented and the various benefits of the dual laser system will be described.

Speaker: Dr Bruce Marsh (CERN)

Slides Marsh.pdf

11:00 → 11:30 Coffee break

11:30 → 12:30 Future RIB Facilities

11:30 FRIB - Facility for Rare Isotope Beams at MSU

FRIB, the US’s “Facility for Rare Isotope Beams” at Michigan State University (MSU), will be based on a 400 kW, 200 MeV/u heavy ion driver linac and use in-flight rare isotope production. FRIB will provide a wide variety of high-quality beams of unstable isotopes at unprecedented intensities, opening exciting research perspectives with fast, stopped, and reaccelerated beams. This talk will give an overview of FRIB and its science opportunities, and summarize the status of the project.

Speaker: Georg Bollen (Michigan State University, East Lansing, USA)

Slides Bollen_FRIB_EuroRibs(post).pdf

12:00 The RI Beam Factory at RIKEN: Status and Prospects

A number of new rare isotope facilities are in the planning or under construction worldwide. Often referred to as next-generation RIB facilities, major effort is being made towards bringing into operation RIB drivers with hundreds of kilowatt to megawatt primary beam powers. What could be considered the first such a facility, the RI Beam Factory (RIBF) at RIKEN was completed and brought into operation a few years ago. Its initial phase of operation and research represents a test bed for the opportunities, but also the challenges of a high-power facility. The talk will attempt to summarize the experiences made. Design values for beam intensities have been fully achieved for light heavy-ion beams and used in experiments approaching new frontiers. Efforts are now directed towards the design goals that have been set for the heavier beams, where stripping and beam dynamic challenges are more formidable. Examples will be given of some major research achievements during the initial phase of operation. The present status of the accelerators, the experimental facilities, RI beam properties, and of the next steps in terms of research programs and accelerator improvements will be summarized

Speaker: W. F. Henning (RIKEN Nishina Center; TU Munich and Argonne National Laboratories, USA)

Slides EURORIB_2012_website_Henning_31may2012.pdf

12:30 → 14:00 Lunch

14:00 → 19:00 Social Excursion and/or visit to LNL

Social Excursion and visit to LNL

Thursday, 24 May

09:00 → 11:00 Nuclear Structure far from Stability

09:00 Perspectives in transfer reactions at next generation European RIB facilities

Transfer reactions are known to represent a powerful tool for investigating the structure of atomic nuclei in detail. In the last 15 years, new instrumentation and methodologies have been developed for efficient study of these reactions when performed with radioactive ionbeams. Based on recent transfer reaction experiments performed at GANIL and RIKEN, and on existing projects of detectors aiming to replace the present generation of detector arrays, I will present some perspectives in transfer reactions studies with radioactive beams in view of the next generation European RIB facilities.

Speaker: Didier Beaumel (RIKEN Nishina center, Saitama, Japan)

Slides EURORIB12-DBeaumel.pdf

09:30 Shell structure far off stability studied via high-energy reactions

A highly interesting topic of modern nuclear structure research is to explore the evolution of the nuclear shell far from the valley of β-stability. The nuclear shell model, being so successful in stable nuclei, relies on the prevalence of a static nuclear potential and the dominance of the mean-field dynamics. It is an open question to what extent that concept is still valid in nuclei with large neutron to proton ratio. With this talk we intend to contribute to this central question by presenting a review of recent experimental studies of exotic nuclei produced at the present in-flight RIB facilities, selecting those that highlight the studies of the structures of light nuclei with 6≤Z≤13: a) direct reactions in inverse kinematics performed at high energies via nuclear [1] and electromagnetic probes [2], which contribute to give specific information on the single particle occupancy and correlation effects in drip line nuclei [3, 4]; b) interaction cross section measurements and experiments of proton scattering [5], well suitable to derive the density distribution and root mean square radii of the nucleon distribution in nuclei providing access to the nuclear skin along the isotopic chains [6, 7]; c) charge-changing cross sections, which show sensitivity to the proton distribution opening a new approach to explore the structure of exotic nuclei [8]. [1] A. Gade and T. Glasmacher, Prog. Part. Nucl. Phys. 60, 161 (2008). [2] T. Nakamura, et al., Phys. Rev. Lett. 103, 2625 (2009). [3] R.V.F. Janssens, Nature 459,1096 (2009). [4] R. Kanungo, et al., Phys. Lett. B 685, 253 (2010). [5] S. Ilieva, et al., Nucl. Phys. A 875, 8 (2012). [6] R. Kanungo, et al,, Phys. Rev. C 83, 021302 (2011). [7] M. Takechi, et al., Phys. Lett. B 707, 357 (2012). [8] T. Yamaguchi, et al., Phys. Rev. Lett. 107, 032502 (2011).

Speaker: Chiara Nociforo (GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany)

Slides C_NOCIFORO.pdf

10:00 Isomeric beams: population of high-spin states in projectile fragmentation

Fragmentation (including spallation) is the main reaction mechanism used to produce exotic nuclei in the majority of the present and future radioactive beam facilities. However the understanding of the reaction mechanism is still not good enough to predict accurately the yields of exotic nuclei. The situation is worse in the case of isomeric states. The main experimental observables to test the theory of peripheral fragmentation are the production cross sections, the longitudinal momenta of the fragments and isomeric ratios. Experimentally we cannot determine the population of a single state with a given angular momentum, but only the total population of all the states decaying into a long-lived isomeric state. Therefore, the study of the population at high angular momentum provides a much more stringent test of the theory than populations at lower angular momenta. An earlier study based on two data points suggested that for spin I ≥ 17ћ there is a higher population than predicted by theoretical models [1,2]. Recently, new experimental results were obtained on a large number of high-spin states (I ≥ 17ћ) in nuclei in the vicinity of the N=126 line, from the fragmentation of 238U [3,4]. The experimental results will be compared with models. The standard abrasion-ablation model based on macroscopic, geometrical approach in which the momentum of the fragments originate from the angular momenta of the removed nucleons is the most widely used; both cross section and isomeric ratio calculations are usually done with the ABRABLA code [5]. In addition the microscopic IntraNuclear Cascade model [6] will be employed. This model considers the individual nucleon-nucleon collisions, and the angular momentum originates from both single-particle removals and collective effects. The talk will discuss the population of high-spin states in the light of the newly obtained results. [1] Zs. Podolyák et al., Phys. Lett. B 632, 203 (2006). [2] S. Pal and R. Palit, Phys. Lett. B 665, 164 (2008). 3] A. M. Denis-Bacelar et al., to be published. [4] M. Bowry et al. , to be published. [5] M. De Jong et al., Nucl. Phys. A 613, 435 (1997). [6] A. Boudard et al., Phys. Rev. C 66, 044615 (2002).

Speaker: Dr Zsolt Podolyak (University of Surrey)

10:20 Spectroscopic factors far from stability

Nucleon transfer reactions have been for years a powerful tool to investigate the filling of orbitals issued from the nuclear shell model. Even for stable magic nuclei, spectroscopic factors deviate from unity. It is understood as the result of short and long-range correlations. In the case of exotic nuclei, the variation of spectroscopic factors with the difference in separation energy ΔS = |Sn - Sp| is still an open question, but no strong effect was shown from transfer reaction [1]. However available data are restricted to a limited range in ΔS values. A different picture arises from the one nucleon knock-out performed at higher incident energy where a strong asymmetry is found [2] for the reduction factor of spectroscopic factors versus ΔS. Although not observables, spectroscopic factors may be relevant provided they do not depend on the incident energy and on the reaction mechanism: it is crucial to disentangle structure from reaction mechanism effects. To investigate that issue, we performed one nucleon transfer and knock-out experiments on the same nucleus 14O corresponding to large positive and negative ΔS values, large enough to significantly test the asymmetry. Results will be shown and compared to previous data obtained for (d,p) transfer and Ar isotopes [1]. [1] J. Lee et al., Phys. Rev. C 83 (2011) 014606 [2] A. Gade et al., Phys. Rev. C 77 (2008) 044306

Speaker: Dr Alain GILLIBERT (CEA/IRFU/SPhN)

10:40 Isomer and ground-state properties of stored exotic nuclei

The ILIMA (Isomeric states, Lifetimes and Masses) collaboration at FAIR builds on experiences at GSI with the combination of the in-flight separator (FRS) [1] and the storage-cooler ring (ESR) [2] for the measurement of masses, lifetimes and decay modes of nuclear isomers and ground states. The two complementary techniques of isochronous mass spectrometry (IMS) and Schottky mass spectrometry (SMS) [3] enable masses to be measured for nuclear lifetimes below 0.1 ms (with IMS) and with an uncertainty that can be as low as 10 keV (with SMS). The decay mode of a single ion can be characterised through accurate mass determination before and after the decay event. Recent highlights include the mass of 208Hg [4] determined from a single stored ion; the direct observation of a high-spin, shell-model isomer in 133Sb [5]; and the discovery of long-lived high-K isomers in neutron-rich Hf and Ta isotopes [6]. The ILIMA collaboration is developing the next generation of experiments, based on the Super-FRS [7] separating and injecting exotic nuclei into new storage rings, with the overall capability to improve access to stored fragments by a factor of at least one thousand. The first new ring to be commissioned (CR) [8] will focus on measurements of the masses and lifetimes of the most-exotic proton- and neutron-rich nuclides, along the rp- and r-process nucleosynthesis pathways. Recent results and future plans will be presented. [1] H. Geissel et al., Phys. Rev. Lett. 68 (1992) 3412. [2] B. Franzke et al., Mass Spectr. Rev. 27 (2008) 428. [3] Yu.A. Litvinov and F. Bosch, Rep. Prog. Phys. 74 (2011) 016301. [4] L. Chen et al., Phys. Rev. Lett. 102 (2009) 122503. [5] B. Sun et al., Phys. Lett. B688 (2010) 294. [6] M.W. Reed et al., Phys. Rev. Lett. 105 (2010) 172501. [7] H. Geissel et al., Nucl. Instr. Meth. B204 (2003) 71. [8] F. Nolden et al., Proceedings of EPAC-2006.

Speaker: Prof. Phil Walker (University of Surrey and CERN)

Slides Walker_ILIMA.pdf

11:00 → 11:30 Coffee break

11:30 → 12:30 Heavy and Superheavy Nuclei

11:30 Superheavy Elements – an Island on Quantum Mechanical Grounding

The search for the next closed proton and neutron shells beyond 208Pb has yielded a number of exciting results in terms of the synthesis of new elements [1,2,3] at the upper end of the charts of nuclides, in a region of exotic high-Z nuclear matter. In particular, the results obtained at the Flerov Laboratory of Nuclear Reactions (FLNR) for a rich number of decay patterns for 48Ca induced reactions on actinide targets [2] have by now been confirmed for reactions on 238U and 244Pu at GSI [4,5], and on 242Pu at LBNL [6]. These superheavy elements (SHE), however, are a nuclear structure phenomenon. They owe their existence to shell effects, an energy contribution of quantum mechanical origin to the nuclear potential, without which they would not be bound. Experimental activities in this field, apart from attempts to directly synthesise new elements, have to investigate reaction mechanism studies and, in particular, they have to pursue nuclear structure investigations to study the development of single particle levels towards the expected gap for the proton and neutron shell closure in the region of the spherical SHE. Chemistry studies of SHE provide additional input on chemical properties and the Z assignment. Precision mass measurements yield an important input in terms of nuclear binding energies for theoretical models. In recent years the development of efficient experimental set-ups, including separators and advanced particle and photon detection arrangements, allowed for more detailed nuclear structure studies for nuclei at and beyond Z=100. A review of recent achievements is given in ref. [7]. Among the most interesting features is the observation of K-isomeric states. Experimentally about 14 cases have been identified in the region of Z>96. K-isomers or indications of their existence have been found for almost all even-Z elements in the region Z=100 to 110. We could recently establish and/or confirm such states in the even-even isotopes 252,254No [8]. The heaviest nucleus where such a state was found is 270Ds with Z=110 as we reported in 2001 [9]. In the period August – October 2010, in a period of  40 days of beam on target, we accumulated 25 additional decay chains of 270Ds, for which we measured in addition to the decay pattern observed in the first experiment, also ER-α-sf and (ER)-α-α-α-sf correlations resulting among other in the discovery of a new K-Isomer in 266Hs and the link of the 270Ds mass to the precisely measured mass of 254No via Q values. Precision mass measurements with the SHITRAP set-up are important new source of valuable information. In particular, the successful mass measurements for 252,253,254No performed in 2009 [10] establish together with -decay chains the connection up to Ds isotopes. In this way we are able to lay out the grounds for a detailed understanding of these heavy and high-Z nuclear systems, and contribute at the same time valuable information to the preparation of strategies to successfully continue the hunt for the localisation of the next spherical proton and neutron shells beyond 208Pb. References [1] S. Hofmann and G. Münzenberg, Rev. Mod. Phys. 72, 733 (2000). [2] Yu.Ts. Oganessian, J. Phys. G 34, R165 (2007). [3] K. Morita et al., J. Phys. Soc. Jpn. 73, 2593 (2004). [4] S. Hofmann et al., Eur. Phys. J. A 32, 251 (2007). [5] C.E. Düllman et al, Phys. Rev. Lett. 104, 252701(2010).

Speaker: Dieter Ackermann (GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany)

Slides D_Ackermann_EURORIB2012.pdf

12:00 What can we learn about the shapes of heavy nuclei from Coulex of radioactive beams?

REX-ISOLDE has a unique capability to provide post-accelerated ISOL beams of heavy radioactive nuclei. I will present the latest results from two experimental programmes to measure electric multipole matrix elements in heavy nuclei, from Coulomb excitation of the beam. In these experiments the Coulex yields of nuclear transitions were measured using the MINIBALL germanium detector array and CD silicon detector. These experiments should provide quantitative information about the nature of shape coexistence in Hg-182,-184,-186 and -188, and the nature of octupole correlations in Rn-220 and Ra-224.

Speaker: Peter Butler (University of Liverpool, UK)

Slides Eurorib12_Butler_-_public.pdf

12:30 → 14:00 Lunch

14:00 → 15:10 Fundamental Interactions

14:00 Trends in the study of fundamental interactions with radioactive beams

Precision measurements in nuclear beta decay provide sensitive means to test the foundations and symmetries of the standard electroweak model and allow also the determination of fundamental couplings in processes involving the lightest quarks. The main aim of such measurements is to find deviations from the standard model predictions as possible indications of new physics. These indirect searches for new physics carried out at low energies are complementary to those performed at the highest energies, in collider experiments that look for the direct production of new particles. In this talk I will review selected precision measurements in nuclear beta decay that have recently reported new results and discuss the plans for new studies of fundamental interactions at future facilities.

Speaker: Oscar Naviliat (NSCL - Michigan State University, East Lansing, USA)

14:30 First results on 35Ar obtained at WITCH

Low energy precision experiments for the search of exotic components in the weak interaction are complementary to the high energy experiments at the colliders dedicated to discover new particles. In the case of the WITCH experiment the beta neutrino angular correlation coefficient (a) in nuclear beta decay is studied. A deviation from the distribution predicted by the standard model will reveal the exotic interactions. Experimentally WITCH combines a Penning trap arrangement to provide a scattering free source of beta-decaying nuclides with a MAC-E filter setup to analyze the recoil energy distribution. In the online experiments of last year it was finally possible to acquire the first sets of data, meaning recoil spectra with 35Ar ions [1]. The first measurement resulted in a recoil spectrum with about 5000 events recorded. This first spectrum has been analyzed with the help of simulation programs developed in the collaboration and under consideration of the charge state distribution of the daughter nuclei, which has been determined at LPCtrap/GANIL. The result is a value of a = 1.12(33) which is compatible with the literature value for 35Ar [1]. During the second online experiment in 2011 several more recoil spectra could be acquired, which were obtained using various spectrometer voltage sequences. These data are currently under analysis. A first estimation points for a statistical uncertainty on the value of a in the order of 2%. This will allow the investigation of systematic effects in the data as studied before by numerical simulations [2, 3]. [1] S. van Gorp et al., in preparation [2] M.Tandecki, PhD thesis, University of Leuven, 2011. [3] P. Friedag, Diploma thesis, University of Münster, 2008.

Speaker: Martin Breitenfeldt (Instituut voor Kern- en Stralingsfysica, Katholieke Universiteit Leuven)

Slides 2012_EURORIB_Padova_Breitenfeldt.pdf

14:50 Beta-neutrino correlation measurements with LPCTrap

The precise measurement of the beta-neutrino angular correlation coefficient "a" in nuclear beta decay is a sensitive tool to search for exotic couplings presently excluded by the V-A theory of the weak interaction. For instance, the study of a pure Gamow-Teller (GT) transition enables to probe tensor-type couplings while a pure Fermi (F) transition is sensitive to scalar-type interactions. Moreover, in the case of mirror transitions, a precise measurement of "a" also allows the determination of the mixing ratio between the GT and F contributions. This constitutes an important input for the database of nuclear mirror transitions, leading to the extraction of the Vud element of the CKM matrix [1]. In a beta-neutrino correlation measurement, the most relevant observable is the energy of the recoiling daughter nucleus. In the LPCTrap device, the radioactive nuclei are confined in a Paul trap, allowing the detection of the recoil ions in coincidence with the beta particles [2]. The set-up is presently installed at LIRAT, the low energy beam line of the SPIRAL facility at GANIL. The correlation measurement in the pure GT 6He decay has already reached a relative statistical precision of 0.5%. Particular attention is continuously being devoted to the study of systematic effects. For instance, the detection set-up is sensitive to the charge state distributions of the recoiling ions, allowing the determination of the shake-off probabilities in the decay of 1+ ions. As the Paul trap enables to confine any radioactive species, an experiment with 35Ar, which essentially decays through a mirror transition with a large Fermi component (>90%), is also ongoing. These first experiments have clearly shown that LPCTrap is well suited for precise correlation measurements. The next step is a significant upgrade of the whole set-up to improve, on one hand, the statistical precision to the 0.1% level and, on the other hand, to perform relevant experiments with the future radioactive beams soon available at GANIL in the framework of the SPIRAL/GANISOL initiative, and later at the SPIRAL2/DESIR facility. These different aspects will be discussed during the conference. [1] O. Naviliat-Cuncic and N. Severijns, Phys. Rev. Lett. 102 (2009) 142302 [2] X. Fléchard et al., J. Phys. G: Nucl. Part. Phys. 38 (2011) 055101

Speaker: Dr Etienne Lienard (LPC Caen)

Slides Eurorib12_Lienard.pdf

15:10 → 16:20 Applications to other Fields

15:10 New trends in nuclear physics applications

Nuclear physics applications cover a wide variety of domains such as energy, health, security, environment, material science or cultural heritage. During the last decade, nuclear physicists have demonstrated a growing interest for applications. This interest was driven either by the need of more precise nuclear data for instance for nuclear energy and medical applications, or by new opportunities offered by the availability of new facilities or progress in detection techniques which could be applicable in various fields. In this talk, a review of recent achievements and new trends in applied nuclear physics will be presented with an emphasis on applications related to the use of radioactive isotopes or radioactive-ion beams.

Speaker: Sylvie Leray (CEA Saclay,Gif-sur-Yvette Cedex, France)

Slides EURORIB_Leray.pdf

15:40 Radioisotopes for nuclear medicine

Today a variety of radioisotopes for nuclear medicine applications is available commercially. Still, for some nuclear medicine applications it would be advantageous to use "new" radioisotopes with better decay properties or radioisotopes with higher "quality" (such as high specific activity or non-carrier added quality). When these are not commercially available, or easily producible with in-house means at small cyclotrons, it may hinder promising research directions. Methods are discussed to overcome this particular type of "isotope shortage" by production using high-flux reactors, spallation by high-energy protons, reactions with heavy ion beams, mass separation or other "unconventional" methods. Synergies with existing and upcoming RIB facilities are outlined.

Speaker: Dr Ulli Köster (Institut Laue Langevin)

Slides ulli_Koster-Eurorib-2012.pdf

16:00 Nuclear techniques for studying soft matter at ISOLDE

Due to the complexity of systems in living matter nuclear techniques are not commonly used in biology and biochemistry. The ISOLDE facility is, however, a perfect place for carrying out experiments with perturbed angular correlation of γ-rays (PAC) spectroscopy. This well established technique is suitable for addressing different biological topics, such as metalloprotein structure, dynamics of protein folding or protein – protein interaction, providing information on the molecular and electronic structure at the PAC probe site [1]. By approaching from simple inorganic complexes we aim to elucidate the fundamental chemistry of heavy metal ion interaction with proteins. This involves studies on de novo designed peptides, naturally occurring proteins, plants and recently also bacteria. Currently we are also focused on setting up the first of its kind ßNMR system which will allow to carry out the first measurements ever performed on biological samples. ßNMR is a technique where NMR resonances are observed as changes in the ß decay anisotropy. It has already been successfully applied in solid state and nuclear physics and the technique holds great promise for successful applications in biology as well. The underlying physics of ßNMR is widely comparable to classical NMR using stable isotopes what is a considerable advantage since the large expertise gained within the last decades of using this method in the field of biophysics and chemistry can be easily projected to future ßNMR experiments. Moreover, this technique offers many advantages over NMR spectroscopy. Most notably, it is extremely sensitive, several orders of magnitude in comparison with standard NMR, and it may be applied for elements which are otherwise difficult to explore spectroscopically for certain biologically highly important oxidation states, such as Zn(II) or Cu(I). In this way both, PAC spectroscopy and ßNMR spectroscopy, can contribute to studies of many important biological problems. This contribution will present numerous biological and biochemical applications at ISOLDE during recent years. References: [1] Hemmingsen L.; Sas K. N.; Danielsen E. Chem. Rev. 2004, 104, 4027.

Speaker: Monika Stachura (University of Copenhagen, IMG-LIFE, Denmark)

Slides Stachura_Biophysics.pdf

16:20 → 16:40 Coffee break

16:40 → 17:30 At and beyond the Dripline and New Modes of Radioactivity

16:40 Halo nuclei: stepping stones across the drip-line

In my talk I'd like to present recent results obtained at GSI for the halo nucleus 14Be and it's unbound sub-system 13Be. The structure of these nuclei is a prerequisite to understand the observed structure and angular correlations for the heaviest known Lithium system 13Li [1]. 13Li and 13Be can be produced with relativistic beams by proton and neutron knock-out reactions, respectively, where the 14Be properties can be extracted from a comprehensive missing momentum and spectroscopic analysis. Recently, three data sets were published for 13Be, all with different interpretations of its ground-state structure. From the data obtained at GANIL [2] it is a Breit-Wigner l=0 resonance, it is a virtual s-state [3] populated in the one-neutron knockout from 14Be at GSI, and finally it is interpreted as a l=1 resonance from data obtained at RIKEN [4]. We have carried out a study of the root-mean-square (r.m.s) momentum of a fragment+n system after one neutron knockout from the Borrome an halo nucleus as a function of the relative energy between neutron and fragment. Results will be shown and discussed in view of the underlying nuclear structure. [1] H.T. Johansson et al., Nucl. Phys. A847 (2010) 66. [2] J.L. Lecouey, Few-Body Systems, 34 (2004) 21. [3] H. Simon et al., Nucl. Phys. A 791 (2007) 267. [4] Y. Kondo et al., Phys. Lett. B 690 (2010) 245.

Speaker: Haik Simon (GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt)

Slides 20120524-EURORIB-HaikSimon.pdf

17:10 Identification of 10He low-lying states in the 3H(8He,p)10He reaction

The low-lying spectrum of 10He nucleus was studied in the 3H(8He,p)10He transfer reaction. The 0+ ground state was observed at about $2.1\pm0.2$ MeV ($\Gamma \sim 2$ MeV) above the three-body 8He+n+n breakup threshold. Angular correlations observed for 10He decay products show prominent interference patterns allowing us to make conclusions about the structure of low-energy excited states. We interpret the energy spectrum of 10He obtained in the experiment as a result of a coherent superposition of the broad 1- state with a maximum located in the energy range 4-6 MeV and the 2+ state at the energy > 6 MeV on top of the 0+ state ``tail''. This anomalous level ordering indicates that the shell inversion phenomenon observed in 12Be extends also to 10He system as the last known member of N=8 isotone.

Speaker: Dr Sergey Sidorchuk (FLNR, Joint Institute for Nuclear Research, Dubna, Russia)

Slides sidorchuk.pdf

17:30 → 18:30 Poster Prize Presentations

17:30 Investigating shape coexistence in the lead region with in-source laser spectroscopy at ISOLDE-RILIS

The competition between spherical and deformed nuclear shapes at low energy gives rise to shape coexistence in the region of the neutron-deficient lead isotopes with Z~82 and N~104 [1]. In order to determine to which extend the ground-state of those isotopes is affected by this phenomenon, a large campaign of investigation of changes in the mean-square charge radii is on-going at ISOLDE. Using the high-sensitivity of the in-source laser spectroscopy technique, which combines the ISOLDE-RILIS lasers with the Windmill alpha-decay spectroscopy setup, it has been possible to study very exotic isotopes of lead [2-3] and polonium [4-6], down to N=100 and N=107 respectively, and more recently thallium down to N=99. In this contribution, we shall review the experimental observations on lead and polonium and present the first results of the 2011 experiment on thallium. [1] A.N. Andreyev et al., Nature 403(2000)430 [2] H. De Witte et al., PRL 98(2007)112502 [3] M.D. Seliverstov et al., EPJA 41(2009)315 [4] T.E. Cocolios et al., JPG 37(2010)125103 [5] T.E. Cocolios et al., PRL 106(2011)052503 [6] M.D. Seliverstov et al., Letter in preparation On behalf of a CERN-KULeuven-Paisley-Gatchina-Oulu-Orsay-Mainz-Bratislava-Brussels collaboration

Speaker: Dr Thomas Elias COCOLIOS (CERN ISOLDE)

Slides 20120524_EURORIB_TEC_websafe.pdf

17:50 Beta delayed fission studies of the neutron deficient Tl, At and Fr nuclei

Valentina Liberati* University of the West of Scotland, Paisley UK. *On behalf of IS466 Collaboration, the ISOLDE collaboration and Paisley-Leuven-Los-Alamos-Bratislava-Darmstadt-Geneva- Gent-Grenoble-Liverpool-Manchester-Orsay-Tokai. Beta delayed fission (β DF) is a rare nuclear decay process which couples β decay and fission. In this two-step process, a parent nucleus first undergoes β decay, possibly populating states in the daughter nucleus close to the top of the fission barrier, thus allowing the fission of the daughter to be competitive with other decay modes. The occurrence of this process has been previously observed in several heavy nuclei in the actinides region (N/Z ∼ 1.5-1.6) due to the relatively large Qec value of the parent nucleus and the small fission barrier of the daughter. According to semiempirical estimates, β DF is also likely to happen in the neutron- deficient region from Tl(Z=81) to Fr(Z=87), where high Qec values of up to 12 MeV are expected. The uniqueness of β DF in the lead region lies in the possibility of reaching exotic nuclei with an unusual N/Z ratio, e.g. N/Z=1.25 for 180 Hg, the β decay product of 180 Tl, which do not undergo spontaneous fission, and thus, it allows the investigation of their low-energy fission properties. This talk reviews the results of an experimental campaign carried out at the ISOLDE mass-separator at CERN, in which a search for the β DF decay of isotopes 178−184 Tl, 193−196 At and 200−202 Fr has been performed. A novel and key feature of this work was the production of pure sources of the Tl and At isotopes using resonant laser ionization followed by mass separation. A surprising outcome resulted from the β DF study of 180 Tl, where a completely unexpected asymmetrical mass split of the fission products of 180 Hg was observed([1]). Furthermore, evidence for the β DF of 178 Tl, 194,196 At and 202 Fr was obtained and an asymmetrical mass split of the fission products of 178 Tl is suggested. Together with the data for 180 Tl, this has established a new island of asymmetric fission, in addition to the previously known one in the heavy actinides nuclei. The experimental details and the results will be discussed in this contribution. References [1] A. N. Andreyev et al. Phys. Rev. Lett.,105 252502 (2010).

Speaker: Ms Valentina Liberati (University of the West of Scotland)

Slides EURORIB_liberati.pdf

18:10 Precise determination of the ionization potential of astatine by in-source laser spectroscopy

On-line in-source laser resonance ionization spectroscopy of the exclusively radioactive element astatine was performed at CERN/ISOLDE, representing the first ever laser spectroscopy on that heaviest halogen element. An efficient ionization scheme was developed and the first precise determination of the ionization potential of astatine was carried out. Due to the absence of long-lived isotopes of astatine, on-line production at the ISOLDE isotope separator facility at CERN was required. During an initial measurement campaign, the ionization potential was located within a range of 100 cm-1 by photoionization threshold spectroscopy. This work was a prerequisite for the precision spectroscopy of high lying Rydberg states which was performed by scanning one of the RILIS lasers across the corresponding wavelength range. The observed Rydberg levels converge towards the ionization potential which was determined as 75151(1) cm-1. This closes the gap in the list of measured IPs from hydrogen (Z = 1) to rutherfordium (Z = 104). The efficient ionization scheme for astatine will enable further precision in-source spectroscopy of isotope shifts and hyperfine structure as well as the study of beta delayed fission of the isotopes 194-199At.

Speaker: Mr Sebastian Rothe (CERN)

Slides 2012_Eurorib_Astatine_srothe.pdf

19:30 → 23:30 Conference Dinner

Bus to the Restaurant and Conference Dinner at "Ristorante Al Pirio", Torreglia (Padova)

Friday, 25 May

09:00 → 11:00 Dynamics and Thermodynamics of exotic Nuclear Systems

09:00 Perspectives of NUCLEAR DYNAMICS AND THERMODYNAMICS with Radioactive Ion Beams

Modern nuclear dynamics and thermodynamics studies are related to the description of the properties of the nuclear matter under extreme conditions. Among them the dependence of nuclear matter symmetry energy on nuclear density and temperature is one of the most interesting problems. However, the symmetry energy is not a directly measurable quantity and has to be extracted indirectly from observables which are related to it through model predictions. Other microscopic properties, related to the transport theory, like the viscosity parameter and the in medium n-n cross sections can be addressed through dynamical studies. The thermodynamics, especially through the study of the de-excitation of hot nuclear systems, gives access to macroscopic properties like the level density parameter or the limiting Temperature and the maximum Excitation Energy which a nuclear system can sustain. The studies performed with stable beams are the first step in an effort to constrain these properties of the nuclear matter, moving in a region up to extreme values in terms of excitation energy and angular momentum. With the advent of facilities like SPES, SPIRAL2 and ISOLDE new measurements will be carried out with accelerated radioactive beams as a function of extreme values of isospin, in order to gain new insight for nuclear models in the region far from the stability.

Speaker: Fabiana Gramegna (LNL)

Slides eurorib2012_Gramegna_[Ripristinato].pdf

09:30 Influence of neutron enrichment on compound system formation and decay in 78Kr + 40Ca and 86Kr + 48Ca reactions at 10 AMeV

The experiment, named ISODEC, was performed in order to study the de-excitation of medium mass nuclei formed by fusion processes, and to explore the isospin dependence of their decay modes. The nuclei 118,134Ba, produced by bombarding 40,48Ca targets with stable beams of 78,86Kr at 10 AMeV, present a large variation of N/Z, high angular momentum, and similar excitation energy. Indeed, the neutron enrichment of the compound nuclei is expected to play an important role on the various emission mechanisms, providing crucial information on fundamental nuclear quantities such as level density, fission barrier or viscosity, symmetry energy. This experiment, named ISODEC, that complements the results of previous experiment realized at GANIL with INDRA detector, was performed at INFN-LNS with the 4π multidetector for charged particle CHIMERA. For the first time this array was used to work at bombarding energy as low as 10AMeV, thanks to a suitable the Pulse Shape Discrimination method, for charge identification, applied in the Si detectors. This method, combined with the TOF and ΔE-E techniques, provides a complete discrimination in charge and mass of the main reaction products. Preliminary results show a different isotopic composition and relative enrichment for the same Z in the two systems. The yields of the Intermediate Mass Fragments (IMF, 3

Speaker: Prof. Sara Pirrone (INFN Catania - Italy)

Slides EURORIB12-S_Pirrone.pdf

09:50 Dynamical Dipole and EOS in N/Z asymmetric fusion reactions with stable and unstable beams

The study of the collective properties of a nuclear system is a powerful tool to understand the structure of the nucleus. A successful technique which has been used in this field is the measurement of the decay of the Giant Dipole Resonance (GDR) which can be used as probe for hot nuclei and, in addition, constitutes a clock for the thermalization process. Using fusion-evaporation reactions, it has been recently possible to study the yield of the high-energy gamma-ray emission from Dynamical Dipole (DD) mechanism which takes place during fusion processes when there is a N/Z asymmetry between projectile and target. A good understanding of the DD is important because this emission depends on several key parameters like the Nuclear Equation of State (EOS) and the in medium N-N cross sections. This is more relevant using exotic systems which have a large N/Z asymmetry. In addition, the DD yield is expected to depend on the energy of the projectile and on the size of the D(0) parameter defined as weighted difference between the projectile and target N/Z asymmetry [5]. By general arguments it is expected an increase of the DD yield with beam energy (the dynamics in the neck region between projectile and target become faster) followed by a decrease of the yield (because of the damping related to fast processes like pre-equilibrium neutron emission). Similarly, it is expected an increase for the DD yield with D(0). In the framework of a molecular dynamics theoretical model (BNV) is it possible to test the sensitivity of the measurable DD total yield for different nuclear EOS [1]. It has been observed and it will be shown that, using stable projectiles and targets in particular experimental conditions, different EOS produce different DD yield and that this difference increase significantly using to exotic beams like 132Sn. It was found that in reactions with a small impact parameters, the DD centroid energy and yield strongly depends on the used EOS. This effect greatly increases with the N/Z asymmetry and predictions will be given for the extreme case 132Sn+58Ni for different beam energies. From the esperimental side, to validate the theoretical predictions of the BNV model, a campaign focused on the measurement of the total DD yield in the mass region A ≈ 132 has been performed at the Laboratori Nazionali di Legnaro using GARFILED-HECTOR arrays (respectively for light charged particles and gamma-rays detection) coupled to phoswich detectors (for the measurement of fusion residues). In this campaign the DD emission in the fusion reaction 16O (Elab=192 MeV) + 116Sn has been measured in function of beam energy (in particular at 8.1 A MeV/A, at 12 A MeV and at 15.6 A MeV) [2]. The measured DD yields and angular distributions will be compared with the theoretical results and with the already existing experimental data in the same mass region [3], [4]. [1] V. Baran et al. Phys. Rev. Lett. 87 (2001) 182501 [2] A. Corsi et al. Phys. Lett. B 679 (2009) 197 [3] D. Pierroutsakou et al. Phys. Rev. C 80 (2009) 024612 [4] B. Martin et al. Phys. Lett. B 664 (2009) 47 [5] C. Simenel et al. Phys. Rev. Lett. 86 (2001) 2971

Speaker: Ms Agnese Giaz (MI)

Slides A_Giaz.pdf

10:10 Reaction dynamics with halo nuclei

Huge efforts have been done in the last years in major laboratories around the world to understand the reaction dynamics around the Coulomb barrier with neutron halo nuclei. Reactions induced by n-halo nuclei have been extensively studied, in a wide range of energies and on different targets, in order to understand the role played by the halo on the reaction dynamics (e.g. [1-3]. Owing to the very low binding energy and extended matter distribution, n-halo induced reactions exhibit very large total reaction cross-section. Moreover, an important reaction process in collisions induced by such nuclei is the break-up. In fact, at energies well above the Coulomb barrier a large fraction of the total reaction cross-section is due to break-up. At these energies nuclear and Coulomb break-up have been studied in great detail both experimentally and theoretically and we have now a quite good understanding of the process [4]. At low energies, close to the Coulomb barrier, coupling effects dominate the reaction dynamics. Since the ground state of halo nuclei lies very close to the continuum, coupling with the continuum (break-up) may affect the various reaction processes. Low energy elastic scattering induced by n-halo nuclei shows a suppression of the elastic cross-section in the Coulomb-nuclear interference region. The recent results of 11Be experiment performed at Rex-ISOLDE, have shown a strong suppression of the Coulomb-nuclear interference with a low charge target showing that nuclear as well as Coulomb effects are important at large impact parameters in collisions induced by halo nuclei [5]. The collision dynamics at the barrier with proton-halo nuclei is expected to be different, but almost no experimental data exist. In this contribution recent experimental results on reactions induced by n-halo nuclei will be presented along with the discussion of future perspective with p-halo beams. [1] L.F. Canto et al., Phys. Rep. 424, 1(2006) [2] N. Keeley et al., Prog. Part. Nucl. Phys. 59, 579(2007) [3] N. Keeley et al., Prog. Part. Nucl. Phys. 63, 396(2009) [4] P.G. Hansen and B.M. Sherrill Nucl. Phys. A693(2001)133 [5] A. Di Pietro et al. Phys. Rev. Lett. 105, 022701 (2010)

Speaker: Alessia Di Pietro (INFN Laboratori Nazionali del Sud, Catania)

Slides dipietro_Eurorib.pdf

10:40 Elastic scattering of the halo nucleus 11Li and its core 9Li on 208Pb at energies around the Coulomb barrier

The discovery of the halo nuclei has brought renewed interest in the modeling of nuclear reactions. This structure will affect the reaction properties at near Coulomb barrier energies. Therefore we have studied, for the first time, the dynamics of the halo nucleus 11Li in presence of a strong electric field of 208Pb at energies below, 24.2 MeV, and around, 29.7 MeV, the Coulomb barrier at the ISACII facility at TRIUMF. To disentangle the halo contribution in the scattering we have studied the behavior of the core by measuring the 9Li+208Pb reaction at the same center-of-mass energies of 23.0 and 28.3 MeV. We have compared the elastic differential cross section results of 9Li+208Pb with optical model calculations using the double-folding Sao Paulo Potential (SPP) for the real part and a Woods-Saxon potential for the imaginary part, whose parameters are obtained from the fit of the elastic data. In this contribution the angular distribution of the elastic differential cross section of 11Li+208Pb is presented and compared with Continuum-Discretized Coupled-Channel (CDCC) calculations based on a simple two-body model (2n+9Li) for the 11Li nucleus. The coupling to the breakup channels produces a significant reduction of the elastic cross section below the grazing angle at energies around and below the Coulomb barrier. This effect will be discussed in terms of the strong dipole coupling to the states in the low-lying continuum of 11Li.

Speaker: Mr Mario Cubero (IEM-CSIC)

Slides mcubero_EURORIB2012.pdf

11:00 → 11:30 Coffee break

11:30 → 13:10 Nuclear Structure far from Stability

11:30 Coulomb excitation of 200Po studied at REX-ISOLDE with the Miniball γ spectrometer

The neutron-deficient polonium isotopes with two protons outside the closed Z = 82 shell represent an interesting region of the nuclear chart to study shape coexistence in nuclei. 200Po manifests itself as a transitional nucleus between a general-seniority-type regime in the heaviest polonium isotopes and a shape-coexistence character in the lightest polonium isotopes [1,2]. However, questions remain concerning this transition; the sign of deformation and the magnitude of mixing between the different configurations are still unclear. Coulomb excitation at safe energies serves as a vigorous technique to investigate the magnitude of transitions between low-lying states, revealing information on the deformation of these states and on the mixing of the different bands. Pure 200Po beams were produced and post accelerated to an energy of 2.85 MeV/u at the REX-ISOLDE facility in CERN. The radioactive ion beam was delivered to a stable 104Pd target placed in the middle of the Miniball γ spectrometer to induce Coulomb excitation. The Doppler corrected de-excitation gamma spectrum showed, next to the 200Po de-excitation peak, a big amount of polonium X rays. After taking into account the X rays produced in an atomic process [3], the remaining X rays could be assigned to the E0 transition from the 0+2 state to the ground state. The observed de-excitation rates were included in the Coulomb excitation analysis code Gosia to extract transitional matrix elements connecting the low-lying states in 200Po. These results will be discussed within the framework of shape coexistence and mixing. They will also be compared with recent results from beyond mean-field calculations [4]. These results will be complemented by the rest of the experimental campaign on shape coexistence in neutron-deficient polonium isotopes [5]. [1] R. Julin et al., J. Phys. G 27 (2001) R109. [2] A.M. Oros et al., Nucl. Phys. A 645 (1999) 107. [3] J.D. Garcia et al., Rev. Mod. Phys. 45 No 2 (1973) 111. [4] P.-H. Heenen, private communication (2012). [5] B. Bastin et al., INTC-P-247 (2008).

Speaker: Ms Nele Kesteloot (IKS KU Leuven, SCK Mol)

Slides Eurorib_NeleKesteloot.pdf

11:50 Study of the 84Ga beta-decay at the ALTO facility

There is an increasing interest in studying the evolution of the collectivity of neutron-rich nuclei beyond N=50. Germanium isotopes are well known to undergo collective effects such as vibrations or gamma softness. It is particularly interesting to study 84Ge as it is the first even-even nucleus beyond N=50. The nature of the collectivity can be probed by measuring the excitation energies of the first 2+, 4+, 0+ states. We have studied beta-decay of a neutron rich 84Ga isotope at the ALTO facility in IPN Orsay. The fission fragments were produced with photo-fission reaction induced by 50MeV electron beam in a thick UCx target. For the first time the maximum electron beam intensity at ALTO - 10µA - was used. The gallium atoms were selectively ionized with a newly developed laser ion source. With this ion source the ionization of the gallium was more than ten times higher compared to the surface ion source. The ions were separated with the PARRNe mass separator and implanted on a mylar tape station. Two germanium detectors were used for the detection of gamma-rays and a plastic 4PiBeta detector for beta detection. The improved level scheme for 84Ge will be presented and compared with the shell model calculations performed with ANTOINE code using “ni78-jj4b“ interaction (which is the modified version of the residual interaction developed by K.Sieja et.al. for the 78Ni natural valence space).

Speaker: Ms Karolina Kolos (IPN Orsay, CNRS/Univ. Paris Sud)

Slides KarolinaKolosIPNOrsay-1.pdf

12:10 Hindered proton collectivity in the proton-rich nucleus 28S

The reduced transition probability B(E2) of the 0+ → 2+ transition in 28S was determined experimentally using the Coulomb excitation at 53 MeV/nucleon. The experiment was performed using the RI Beam Factory at RIKEN Nishina Center. The resultant B(E2) value is smaller than the expectation based on an empirical B(E2) systematics. The relative importance of the proton- and neutron- collectivities in the transition is evaluated using the ratio of the neutron/proton transition matrix elements (Mn/Mp) obtained from the present B(E2) value for 28S and the known one for the mirror nucleus 28Mg. The obtained Mn/Mp ratio is much larger than N/Z ratio of 28S, indicating the neutron dominance in the transition and the hindered proton collectivity relative to that of neutrons. These result could be the emergence of Z=16 magicity in the |Tz|=2 nucleus 28S.

Speaker: Dr Yasuhiro Togano (EMMI, GSI)

Slides EURORIB_togano_revised.pdf

12:30 Transfer reaction studies of neutron rich Be isotopes.

On behalf of the MINIBALL and IS430 collaborations. A transfer reaction experiment was performed at ISOLDE in 2010 using a 11Be beam incident on both deuterons and protons. Both one neutron transfer and scattering reactions were detected enabling study of bound states and low lying resonances in 10Be, 11Be and 12Be. The MINIBALL Ge cluster along with the T-REX Si setup were used for particle and gamma detection. The gamma detection and the difference in decay channels for the individual states enabled a complete separation of all known bound states in the three nuclei, including the 2+ and the 1- state in 10Be separated only by 1keV. The primary target of the experiment was to investigate the mixing of the p and the sd shell in 12Be leading to the breaking of the N=8 magic number. Both 11Be and 12Be are known for the mixing of the shells leading to the inversion of states. A previous transfer reaction study of 12Be at TRIUMF showed disagreement between theoretically and experimentally determined spectroscopical factors [1]. Spectroscopical factors determined in the experiment will be presented and compared to the previously determined ones. The differential cross sections of elastic scattering of 11Be, both (d,d) and (p,p), have shown some remarkably features, which is expected to be due to the halo structure of 11Be. The determined differential cross sections are much larger than compared to cross sections of 11B(d,d) and 10Be(d,d). The elastic cross sections will be presented and discussed along with theoretically determined cross sections calculated using FRESCO. Resonances in 11Be and 12Be have been investigated as well. Large backgrounds have complicated the analysis of the resonances, but gamma gates have given a clear signal for the 4.5MeV resonance in 12Be. The investigation of the resonance has led to a new prediction of the spin and parity. Finally some preliminary results of 11Be(d,Xn) reactions, using the MINIBALL as a neutron detector, will be shortly presented and discussed. [1] R. Kanungo et al. Phys Let B682 (2010), 391-395.

Speaker: Mr Jacob Johansen (Aarhus University)

Slides Johansen.pdf

12:50 Study of the weakly bound nucleus 26F

Nuclear forces play a decisive role to account for the creation and modifications of shell gaps, to explain deformed nuclei, to permit the development of halo structures and to fix the limits of particle stability. The determination of nuclear forces inside the nucleus from bare forces is a tedious but important task. The neutron-rich 26F is a benchmark nucleus for studying proton-neutron interaction for different reasons. First, as its neutron binding energy amounts to only 0.80(12) MeV [i], its structure is likely to be influenced by drip-line phenomena. Second, it lies close to the 24O doubly magic nucleus [ii]. Therefore its nuclear structure at low excitation energy is expected to be rather simple. It is mainly provided by the interaction between a deeply proton d5/2 and an unbound neutron d3/2 on top of a closed 24O core, leading to J = 1, 2, 3, 4 positive parity states. The structure of this nucleus has been investigated at GANIL by means of the in-beam γ-ray spectroscopy technique using fragmentation reactions of a cocktail of radioactive nuclei, as by the study of its ground and isomeric beta decay to 26Ne. Combining these pieces of information, as well as those obtained from atomic mass measurement [i] and the discovery of unbound states in 26F [iii], we observe a reduction by about 30% of the proton-neutron forces as compared to those used in the USD interactions [iv] to account for structural evolution closer to the valley of stability. This pinpoints the need of more self-consistent methods to derive nuclear forces for nuclei close to the continuum. i B. Jurado et al. Phys. Lett. B 649 (2007) 43 ii C. Hofmann et al. Phys. Lett. B 672 (2009) 17 iii N. Frank et al., Phys. Rev. C 84 (2011) 037302 iv B. A. Brown and B. H. Wildenthal, Ann. Rev. of Nucl. Part. Sci. 38, 29 (1988)

Speaker: Mr Alexandre Lepailleur (GANIL)

Slides eurorib2010_lepailleur.pdf

13:10 → 14:30 Lunch

15:00 → 16:00 Bus to Venice Airport