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Diego Bettoni (FE)08/10/2018, 09:30Perspective of thin film cavities in international projects
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Cristian Pira (LNL)08/10/2018, 09:40Perspective of thin film cavities in international projects
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Dr Anne-Marie Valente-Feliciano (Jefferson Lab)08/10/2018, 09:50Perspective of thin film cavities in international projects
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Dr Oleg Malyshev (STFC Daresbury Laboratory)08/10/2018, 10:20Perspective of thin film cavities in international projectsThe ARIES H2020 collaboration has started in May 2017. One of the main goals of ARIES is to developing and demonstrating novel concepts and further improving existing accelerator technologies. A successful proposal for a work package on systematic studying and developing the superconducting thin film for superconducting RF cavities joint a team of 8 partners (research groups) from 7 countries....Go to contribution page
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Dr Oliver Kugeler (Helmholtz-Zentrum-Berlin)08/10/2018, 10:45Perspective of thin film cavities in international projectsThe greatest challenges for wide-spread adoption of new applications of superconductivity remain the limited understanding of how to apply the fundamental principles on an engineering level and the capability to deploy the technology cost effectively on a large-scale. EASITrain offers a cross-sectoral training program that is a fine blend of engineering, fundamental research and the...Go to contribution page
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Dr Anne-Marie Valente-Feliciano (Jefferson Lab)08/10/2018, 12:00Nb thin film technologyWith the development of energetic vacuum deposition techniques, high quality Nb films have been produced supporting the promise of high RF performance. In energetic condensation, the controlled incoming ion energy enables a number of processes such as desorption of adsorbed species, enhanced mobility of surface atoms and sub-implantation of impinging ions, thus producing improved film...Go to contribution page
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Vanessa Andreina Garcia Diaz (LNL)08/10/2018, 12:25Nb thin film technologyThick films shows the possibility to obtain a mitigation of a Q-slope in Nb on Cu superconductive resonant cavities. In the framework of EASITrain project and CERN-INFN-STFC collaboration, the multilayer technique was applied in order to deposit a 70-microns thick film of Niobium onto 6 GHz seamless copper cavities. In this contribution, we report the results and challenges of the RF...Go to contribution page
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Dr Fabio Avino (CERN)08/10/2018, 12:50Nb thin film technologyThe Wide Open Waveguide (WOW) Crab cavity [1] has been designed in the framework of the Future Circular Collider study. It features a thin Nb film sputtered on bulk copper [2]. The main advantages with respect to bulk Nb include the improved thermal stability, and the reduction of the cavity frequency sensitivity to the external liquid He bath pressure variations as well as to the Lorentz...Go to contribution page
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Dr Alban Sublet (CERN)08/10/2018, 14:30Nb thin film technologySuperconducting thin film coatings offer a valuable alternative to conventional bulk niobium cavities mainly by reducing the cost of raw material and enhancing the heat exchange efficiency thanks to the copper substrate thermal conductivity. The current and future superconducting radiofrequency (SRF) cavities designs and working frequencies lead to a variety of shapes and sizes to be coated....Go to contribution page
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Dr Teng Tan (IMP, CAS)08/10/2018, 14:55Nb thin film technologyThe possibility that CIADS uses only Nb/Cu cavities has been discussed at IMP. A 325 MHz dummy QWR cavity has been fabricated at IMP for technique demonstration. The cavity has been coated for a few runs, with small samples attached to the inner surface and bare cavity only. The small samples manifested a complete superconducting coverage. Vertical testing results suggested the Nb/Cu technique...Go to contribution page
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Giorgio Keppel (LNL)08/10/2018, 15:20Nb thin film technologyIn the framework of the ALPI Upgrade for SPES project, new cryostats with 8 new high beta QWR cavities needed to be produced. In order to carry out this upgrade, a refurbishing of the sputtering system for QWR coating was performed. Now the sputtering system is working and first test coating on quarts’ substrate are in progress. Simultaneously the chemical plant and QWR cold test facility...Go to contribution page
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Ruggero Vaglio (NA)08/10/2018, 16:15Theoretical modelling of RF behaviorRecently, the improvement of RF superconducting cavities performances has motivated a considerable research effort to elucidate the effect of trapped magnetic flux. Here we will show that by introducing a non-linear pinning force in the Gittleman-Rosenblum equations for the RF power dissipation due to an external trapped magnetic field in a superconductor, we can describe most of the common...Go to contribution page
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Dr Akira Miyazaki (CERN and the University of Manchester)08/10/2018, 16:40Theoretical modelling of RF behaviorSince their invention, the performance of Nb film cavities has always been limited by a strong Q-slope. Recent tests at CERN of the newly developed seamless Quarter-Wave Resonator (QWR) showed an interesting decomposition of the Q-slope, which might help to explain/cure this limitation. One is caused by non-linear trapped flux oscillation in the residual component, whose surface resistance...Go to contribution page
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Dr Mattia Checchin (Fermilab)08/10/2018, 17:05Theoretical modelling of RF behaviorIn this study, the radio-frequency complex response of trapped vortices in superconductors calculated for small values of applied radio-frequency field, will be presented. In agreement with experimental data on bulk niobium radio-frequency cavities, the calculated surface resistance shows a non-monotonic trend as a function of the mean-free-path and a sigmoidal-like trend as a function of the...Go to contribution page
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Dr Takayuki Kubo (KEK and ODU)08/10/2018, 17:30Theoretical modelling of RF behaviorWe propose a theory of the nonlinear surface resistance of a dirty superconductor in a strong RF field, taking into account realistic materials features, such as magnetic and nonmagnetic impurities, subgap states originating from finite quasiparticle lifetimes, and a proximity-coupled normal layer at the surface. The Usadel equations with the RF pair-breaking current are solved to obtain the...Go to contribution page
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A.V. Butenko (JINR, Dubna, Russia)08/10/2018, 17:55Perspective of thin film cavities in international projectsThe New Injector Linac for Nuclotron-Nica is the proposed replacement for LU-20 accelerator. The possibility of old DTL LU-20 replacement by the new superconducting (SC) linac of 30 MeV energy for protons and ≥7.5 MeV/nucleon for deuterium beam is discussed now. The development of the SRF technologies is the key task of new Russian - Belarusian collaboration. The collaboration of JINR, NRNU...Go to contribution page
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Prof. Xiaoxing Xi (Temple University)09/10/2018, 09:00Other superconducting materials beyond niobiumMgB2 is a promising superconductor to replace Nb for SRF cavities. Clean MgB2 thin films have a low residual resistivity (<0.1 µΩcm) and a high Tc of 40 K, promising a low BCS surface resistance. Its thermodynamic critical field Hc is higher than Nb, potentially leading to a higher maximum accelerating filed. The lower critical field Hc1 of MgB2 is lower than Nb, but it can be enhanced by...Go to contribution page
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Mr Stewart Leith (Universität Siegen)09/10/2018, 09:25Other superconducting materials beyond niobiumConsiderable research is currently underway to utilise alternative materials to bulk Nb in SRF cavities. This is with the aim to increase their performance to that required by future accelerators. In this contribution, the results of two investigations into dc magnetron sputtered Nb thin films on Cu substrates are summarized, as well as initial results from research which has been conducted...Go to contribution page
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Mr David Beverstock (Jefferson Lab)09/10/2018, 09:50Other superconducting materials beyond niobiumFurther enhancement of superconducting accelerating cavity performance calls upon the development of materials beyond bulk niobium (Nb). Superconducting RF (SRF) is a surface phenomenon; for most superconducting materials the RF penetration depth is in the range of hundreds of nanometers. Due to the field penetration enhancement occurring in films with a thickness smaller than their nominal...Go to contribution page
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Mr Thomas Oseroff (Cornell University)09/10/2018, 10:15Other superconducting materials beyond niobiumA TE mode niobium sample host cavity was used to characterize the RF performance of large 5” diameter thin film samples at 4 GHz. Exciting results were obtained from industry partner Ultramet’s CVD Nb3Sn grown on a copper substrate. These results indicate that slight alterations to the deposition process and use of higher purity precursors could lead to high-performance Nb3Sn coatings on...Go to contribution page
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Mr Sebastian Keckert (Helmholtz-Zentrum Berlin)09/10/2018, 10:40Other superconducting materials beyond niobiumRF-surface resistance measurements have been performed on an S-I-S multilayer sample. The sample was prepared at JLab using DC-magnetron sputtering of a 75 nm NbTiN layer on a 15 nm AlN insulator layer on bulk niobium. The sample (and sputtered area) was a circular disc of 75 mm diameter, welded on an 85 mm high Nb pipe of the same outer diameter. This geometry allowed performing RF...Go to contribution page
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Dr Emanuela Barzi (Fermi National Accelerator Laboratory)09/10/2018, 11:30
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Md Nizam Sayeed (Old Dominion University)09/10/2018, 11:55Other superconducting materials beyond niobiumNb3Sn-coated Nb SRF cavities are studied due to their potential of providing a higher accelerating gradient over Nb SRF cavities. Magnetron sputtering can be a feasible alternative to conventional tin vapor diffusion process to fabricate Nb3Sn for SRF cavities. By depositing Nb and Sn layers separately and annealing afterward, the stoichiometry of the coated films can be controlled to create...Go to contribution page
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UTTAR PUDASAINI (College of William and Mary)09/10/2018, 12:20Other superconducting materials beyond niobiumNb3Sn-coated SRF cavities can potentially achieve superior performance in terms of quality factor, accelerating gradient, and operating temperature. Tin vapor diffusion process of Nb3Sn coating on Nb is a simple, yet efficacious technique to fabricate Nb3Sn-coated SRF cavities. The process comprises two¬ steps: “nucleation” followed by “deposition”. The crucible with Sn/SnCl2 and the substrate...Go to contribution page
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Dr reza valizadeh (ASTeC, STFC)09/10/2018, 12:45Other superconducting materials beyond niobiumNb3Sn alloy is a type II superconductor with maximum Tc of 18 K and predicted superheating field of 400 mT and potentially may offer improvements in both cryogenic efficiency and maximum accelerating field. Hence, Nb3Sn thin film can be an alternative superconducting coating either as a single or multilayer for SRF cavity production. Nb3Sn has been deposited from stoichiometric alloy target...Go to contribution page
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Dr Marco Arzeo (CERN)09/10/2018, 13:10Other superconducting materials beyond niobiumSuperconducting radio frequency (SRF) cavities, made of niobium films on copper (Nb/Cu), are currently employed for a large variety of particle accelerators. At the same time, the Nb/Cu technology, being very cost effective, also represents one of the main options for upcoming machines like the future circular collider (FCC). While research and development continue on the Nb/Cu...Go to contribution page
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Cristian Pira (LNL)09/10/2018, 14:40Advanced preparation of substrates and atmospheric plasmasThin film technology moves the surface preparation from Nb to Cu, because the Nb thin film cannot be chemical treated. For the Nb on Cu resonant cavities two principal copper cleaning and polishing treatments were studied: one is the electropolishing (EP) and the other one is the chemical polishing with SUBU solution. The influence of surface preparation is deeply studied in bulk Nb cavities...Go to contribution page
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Martina Martinello (Fermilab)09/10/2018, 15:05Advanced preparation of substrates and atmospheric plasmasField emission is one the major limitations to the maximum usable accelerating gradient of SRF cavities in cryomodules. Taking advantage of the plasma chemistry, field emitting and decreasing the field emission. A collaboration between FNAL, SLAC and ORNL was established to develop a plasma processing system capable to minimize and overcome the problem of field emission in LCLS-II cryomodules....Go to contribution page
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Mr Oleksandr Hryhorenko (IPNO)09/10/2018, 15:30Advanced preparation of substrates and atmospheric plasmasThe reduction of construction and operation costs are major aims for future superconducting radio-frequency (SRF) applications. So as to reduce the construction cost of the particle accelerators, the standard expensive chemical treatments (electropolishing (EP) or buffered chemical polishing (BCP)) of bulk Niobium (Nb) cavities can be significantly reduced or even suppressed thanks to...Go to contribution page
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Prof. Arturs Medvids (Riga Technical University)09/10/2018, 15:55Advanced preparation of substrates and atmospheric plasmasThe properties of Nb thin films deposited on planar Cu substrate were studied after its laser annealing. Five samples were prepared employing different substrate preparation techniques and were subsequently coated with 3-µm thick Nb film with the same deposition parameters. Afterwards, the Nb films were irradiated using Nd:YAG laser in order to increase crystallinity and improve adhesion of...Go to contribution page
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Oscar Azzolini (LNL)09/10/2018, 16:50Advances in cavity substrate fabricationIn the framework of the FCC study, niobium-coated copper cavities are considered to operate at 400 MHz. Spinning is a potential alternative to conventional shaping methods of copper half cells. A step by step presentation of the complete spinning process will be explained, observing the effects of the stresses induced by the forming and the actions chosen to fight this specific behaviour of...Go to contribution page
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Mr Jean-Francois Croteau (I-Cube)09/10/2018, 17:15In the framework of CERN’s Future Circular Collider (FCC), fabrication of high-performance superconducting radiofrequency (SRF) cavities is crucial to attain energy levels relevant for breakthrough research in particle physics. Damage to the inner surface of copper and niobium cavities must be minimized to ensure proper growth of the superconducting film and prevent quenching during operation....Go to contribution page
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Dr Claire Z. Antoine (CEA)10/10/2018, 09:00RF and material characterization for SRF filmsDeveloping thin films deposited with complex superconductors like Nb3Sn or multilayers requires being able to test the maximum field achievable on numerous samples. In classical magnetometer where the sample is immersed in homogenous field, there is always some ambiguity resulting from the fact that the penetration of field can start on the back or the edges of the samples. We have tried to...Go to contribution page
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Mr Thomas Proslier (Commissariat de l'énergie atomique)10/10/2018, 09:25RF and material characterization for SRF filmsI will present recent analysis of tunneling spectroscopy data measured on cut out samples from a N doped cavity, and from commonly processed hot and cold spot regions of a BCP cavity. The hot spot samples reveal small gap area consistent with a proximity effect model along with spectroscopic signature of magnetic impurities, caracteristic of two level systems. The cold and N doped samples on...Go to contribution page
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Mr Dmitry Tikhonov (Helmholtz-Zentrum Berlin (HZB))10/10/2018, 09:50RF and material characterization for SRF filmsAt the present time more and more low temperature superconducting materials and compounds are being developed around the world for new applications in future accelerators and industry. However, the production processes and recipes are not fully developed and require measurement tools for studies and optimization. The Quadrupole Resonator (QPR) is a cavity that is able to perform the most...Go to contribution page
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Prof. Steven Anlage (University of Maryland)10/10/2018, 10:15RF and material characterization for SRF filmsBased on the needs of the SRF community to identify and evaluate defects on Nb surfaces, a novel near-field magnetic microwave microscope was successfully built using a magnetic writer from a conventional magnetic recording hard-disk drive [1]. This magnetic writer can create an RF magnetic field in the 100 mT range, localized and strong enough to drive Nb into the mixed state, and may have...Go to contribution page
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Dr Alexei Katashev (profesosr)10/10/2018, 11:10RF and material characterization for SRF filmsPhotothermostimulated exoelectron emission (PTSE), being observed when solid specimen is simultaneously heated and excited by photons with energy close to photoemission threshold, often is related to the annealing of structural defects and hereby, could become the tool to test quality, or amount of imperfections, of the superconductive Nb films. The present study explores PTSE of the Nb...Go to contribution page
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Dr sepideh Aliasghari (research fellow)10/10/2018, 11:35RF and material characterization for SRF filmsS. Aliasghari1,2, P. Skeldon2, A. Gholinia2, R. Valizadeh1, 1 ASTeC, STFC Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, UK. 2 Corrosion and Protection Group, School of Materials, The University of Manchester, Manchester M13 9PL, UK. Defects on the niobium superconducting radio frequency (SRF) can have an important impact on quality factor at low accelerating fields....Go to contribution page
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Sergio Calatroni (CERN)10/10/2018, 12:00CERN is studying the feasibility of a new proton-proton collider reaching an unprecedented centre-of-mass energy of 100 TeV, the Future Circular Collider (FCC). The proton beams will be steered by 16 T superconducting magnets cooled at 1.9 K, whose cold bore is protected from the intense synchrotron radiation by a coaxial beam screen maintained at 50 K, temperature which stems from a...Go to contribution page
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Dr antonio cassinese (università di Napoli)Superconducting films beyond SRFWe review r.f. measurements of the surface impedance Zs=Rs+iXs of YBCO films films deposited on sapphire or MgO . The measurements are performed by a microstrip dielectric resonator and cavities techniques using a meander line geometry. The power dependence of Zs is studied at different temperatures and frequencies in the range 1-18 GHz. The effects of a d.c. magnetic field applied with...Go to contribution page
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