TRDs for the third Millennium
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Europe/Rome
Bari (Italy)
Bari (Italy)
Università degli studi di Bari
Description
4th Workshop on Advanced Transition Radiation Detectors for Accelerator and Space Applications
Support
Participants
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Opening Session
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Registration
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Welcome
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Physics with the ALICE Transition Radiation DetectorALICE (A Large Ion Collider Experiment) is the dedicated heavy-ion experiment at the LHC. It is believed that in nucleus-nucleus collisions at LHC energies a Quark-Gluon-Plasma (QGP) is formed. ALICE is designed to measure a large set of observables in order to study the properties of the QGP. The Transition Radiation Detector (TRD) provides electron identification in the ALICE central barrel at momenta p > 1 GeV/c, where pions cannot be rejected anymore sufficiently via energy loss measurements in the Time Projection Chamber. Thus the TRD significantly enlarges the scope of physics observables. These include measurements of semi-leptonic decays of heavy flavour hadrons (charm and beauty), di-electron mass spectra of heavy quarkonia states, e.g. J/ψ, Ψ', Y, Y', and jet spectra. For reference the corresponding studies have to be performed in pp and p-nucleus collisions. We present the electron identification and its performance in pp collisions also in context of the analysis of electrons from heavy flavour hadron decays. Further case studies will be shown as well.Speaker: Dr Yvonne Pachmayer (University of Heidelberg)
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Running TRDs
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Commissioning and performance of the ALICE TRDThe Transition Radiation Detector (TRD) of ALICE at the CERN-LHC is designed to provide electron identification and an online trigger on high-pt tracks of electron candidates. It consists of 6 layers of drift chambers, covering a pseudo-rapidity range of |eta| < 0.9. In its current configuration, 10 out of 18 sectors in azimuth are installed. The completion of the detector is planned for the LHC shut down in 2013/14. We will give an overview on the setup and working principle of the TRD and summarize experiences from the commissioning phase. Results on the achieved detector performance, such as the pion suppression factors and the tracking resolution, will be discussed. Also, we will report on online and offline calibration procedures and their performance.Speaker: Mr Christoph Blume (University of Heidelberg)
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10:55
Coffee break
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Energy Loss Signals in ALICE TRD and Application in Particle IdentificationThe ALICE experiment is one of the four major experiments at the LHC at CERN. The ALICE TRD is a cylindrical detector system located in radius between 2.9 and 3.7 meters from the beamline and segmented in 6 layers. Each layer consists of a radiator and a drift chamber with pad readout of very good granularity, optimized for Pb-Pb operation. Employing a cosmic-ray trigger and taking advantage of the reconstruction in the complete ALICE setup, we have measured the energy loss of cosmic muons in the TRD in the momentum range 1 to 300 GeV/c, with and without the contribution of transition radiation. Together with the energy loss signals from protons and pions measured in proton-proton collisions, the TRD energy loss spectra are extended down to Lorentz factor $\beta\gamma$ below 1. In this talk, I will present the details of the measurements and the particle identification using the TRD.Speaker: Mr Xianguo Lu (University of Heidelberg)
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Gain Calibration of the ALICE TRD using a Krypton SourceThe TRD is an important subsystem of the ALICE experiment at the LHC at CERN. Segmented into 18 super modules, each consisting of 30 readout drift chambers filled with Xe-CO2 [85-15], the ALICE TRD is designed to be an effective tool in terms of separation of electrons and pi- ons, reconstruction of tracks of charged particles and fast trigger capabilities. Each readout chamber consists of a radiator and a multi-wire proportional chamber, which is segmented into either 16x144 or 12x144 readout pads, giv- ing a total number of 1,118,952 pads. For an early and effective calibration at the level of individual pads, which is crucial for a good particle identification, a dedicated calibration run with a Krypton source has been carried out. We have recorded 2.1 billion decays of metastable 83mKr in the 10 super modules presently installed. We present an overview of the obtained results in terms of gain uniformity over chambers and energy resolution. The obtained gain factors can be used in the front-end electronics, an important ingredient for the TRD trigger.Speaker: Johannes Stiller (Physikalisches Institut Ruprecht-Karls-Universität Heidelberg)
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13:00
Lunch
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"In memoriam of Boris Dolgoshein": free commemorating speeches
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Session dedicated to Boris Dolgoshein
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17:05
Coffee break
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From the ideas to the ATLAS TRTOverview of the R&D work related to the development of the ATLAS Transition Radiation Tracker (TRT) is presented. Significant part of the report will be dedicated to the ideas and aside R&D work, which were not necessary realised in the final TRT design, but were directed to find appropriate solutions and might still be interesting for the developments of the transition radiation detectors and gaseous detectors in general.Speaker: Dr Anatoli Romaniouk (MEPHI/CERN)
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18:35
End of session
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Running TRDs
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11:00
Coffee break
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TRDs for space applications
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The PERDaix detectorThe PERDaix (Proton Electron Radiation Detector Aix-la-Chapelle) detector is designed to measure charged particles in cosmic rays. It can distinguish particle species up to 5 GV rigidity. PERDaix was flown on the BEXUS-11 balloon on 23rd November 2010. The detector dimensions are 60 x 60 x 85 cm3, the weight is 40 kg, the power consumption 65 W and the geometrical acceptance 32 cm2sr. PERDaix is divided into three subdetectors: a spectrometer, a time-of-flight (TOF) system and a transition radiation detector (TRD). The spectrometer consists of four double layers of scintillating fiber tracker arranged around a permanent magnet. The scintillating fibers are read out with 32 channel MPPC arrays produced by Hamamatsu. The channels are 1.1 mm high and have a 250 um pitch. They are read out with VA_32/75 chips. The time-of-flight system is made of scintillator bars arranged in two double layers. It measures the velocity of charged particles, provides the main trigger for other subdetectors and distinguishes downward from upward (Albedo) flying particles. Each scintillator bar is read out with four MPPCs type Hamamatsu S1 0362-33-100C. The MPPC signals are feat into NINO discriminator chips followed by a HPTDC based digitizing board. TOF and tracker used a passive compensation circuit to deal with the temperature dependence of the operation voltage of the MPPCs during the balloon flight. The TRD has 8 layers of radiator fleece followed by proportional counters. The proportional counters are made of straw tubes filled with a Xe/CO2 (80/20)-mixture at 1.1 bar. A tungsten wire running through the tubes serves as anode operated at 1.5 kV. The TRD is used to discriminate electrons from protons. Characterization measurements will be presented as well as the detector performance as a whole.Speaker: Dr Thomas Kirn (RWTH Aachen University, I. Physikalisches Institut B)
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13:30
Lunch
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Novel TRDs development
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16:10
Coffee break
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Recent advancements in the Micro Pattern Detector TechnologySpeaker: Leszek Ropelewski (CERN)
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TRD based on the usage of thin scintillators.Detector based on the usage of thin scintillators is proposed for particle identification by TRD. Such type of TRD may be especially interesting for space experiments because of no gas. The detector is based on the thin transparent films with incorporated micro-granules of LuBO3:Ce scintillator. Scintillation signal produced by absorbed gammas is registered by vacuum PMT or by SiPM connected to WLS fibers. Results of measurements with different samples of such films are presented. The clear signals from Fe55 (5 keV) and Am241 (16 keV) gamma sources were observed. The detailed Monte Carlo simulations of such kind of TRD are also presented.Speaker: Dr Vladimir Tikhomirov (P.N.Lebedev Physical Institute of the Russian Academy of Science)
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Electron identification with help of silicon transition radiation detector based on DEPFET pixel matrices.Transition Radiation Detectors (TRD) have the attractive features of being able to separate particles by their gamma factor. Replacing the Xenon based gaseous detectors by modern silicon detectors is complicated by the large energy losses of charged particles in 300-700 um of silicon. A silicon pixel detector - DEPFET - has features which allows to overcome the existing limitation on detecting transition radiation photons with an energy losses from a charged particle in the same pixel. The tests of DEPFET with fiber radiator have been carried out at CERN SPS and DESY beams. The results of test beam measurements and Monte Carlo simulation are presented.Speaker: Dr Sergey Furletov (University of Bonn)
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Possible applications of the SiTRD technique in the next generation collider experimentsThe Silicon Transition Radiation Detector (SiTRD) combines the excellent space resolution of a silicon tracker with the particle identification capability of a conventional TRD. The detector consists of multiple modules, each composed by a radiator and a tracker plane, separated by an air gap and immersed in a magnetic field. This layout allows to separate the TR photons possibly produced by radiating particles from their trajectories. Provided that the separation in the tracker plane is larger than the granularity of the tracker, the SiTRD can identify radiating particles from non radiating ones. Moreover, the small amount of materials encountered by the particles along their path, does not significantly affect the momentum reconstruction performance of the tracker. These features make the SiTRD an attractive option when designing the inner tracker of a collider experiment. We have studied a possible SiTRD layout for the inner tracker of a collider experiment at LHC. The detector parameters have been optimized taking into account the geometry constraints derived from an upgrade proposal of the ATLAS inner tracker. A Monte Carlo simulation has been also developed in which the detector performances have been investigated.Speaker: Dr Francesco Loparco (BA)
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18:45
End of session
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20:30
Social dinner
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Advanced R & Ds for radiation and particle detection
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Triggering with the ALICE TRDThe Transition Radiation Detector (TRD) in A Large Ion Collider Experiment (ALICE) at the LHC consists of 6 layers of tracking chambers and covers a pseudo-rapidity range of eta < 0.9. At the moment 10 out of 18 azimuthal sectors are installed. The completion is planned during the long LHC shutdown in 2013/14. We will discuss how a hardware Level-1 trigger, about 7 us after an interaction, can be derived from this detector. Chamber-wise track segments from fast on-detector reconstruction are readout with position, angle and PID information. In the Global Tracking Unit these tracklets are matched and used for the reconstruction of transverse momenta and electron identification of individual tracks. These tracks form the basis for versatile and flexible trigger conditions, s.a. single high-pt hadron, single high-pt electron, di-electron (J/\Psi, Upsilon) and at least n high-pt tracks (jet). The need for low-latency on-line reconstruction poses challenges on the detector operation. The calibration for gain (pad by pad) and drift velocity must be applied already in the front-end electronics and cannot be calculated off-line based on the recorded data. Due to pressure changes an on-line monitoring and control loop for these parameters is required. After a long period of minimum bias data-taking in ALICE rare triggers are now used in ALICE. We will discuss the tracking performance at the local and global reconstruction stages and report on first experiences with the TRD based triggers.Speaker: Jochen Klein (Physikalisches Institut, University of Heidelberg)
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The MRPC-based ALICE Time-Of-Flight detector: status and performanceThe large Time-Of-Flight (TOF) array is one of the main detectors devoted to charged hadron identification in the mid-rapidity region of the ALICE experiment at the LHC; it will allow separation among pions, kaons and protons up to few GeV/c, covering the full azimuthal angle and -0.9 < η < 0.9. The TOF exploits the innovative MRPC technology capable of an intrinsic time resolution better than 50 ps with an overall efficiency close to 100% and a large operation plateau; the full array consists of 1593 MRPC chambers covering a cylindrical surface of around 150 m2. The TOF detector is efficiently taking data since the first pp collisions recorded in ALICE in December 2009. In this report, the status of the TOF detector and the performance achieved both with pp and PbPb collisions are shown.Speaker: Dr Andrea Alici (BO)
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11:00
Coffee break
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Test beam studies of the GasPixel Transition Radiation detector prototype.F. Hartjes, M.Fransen, W. Koppert, S.Konovalov, S.Morozov, N. Hessey, A.Romaniouk, M. Rogers, H. van der Graaf. A combination of a pixel chip and a gas chamber opens new opportunities for particle detectors. These “GasPix” detectors have vector tracking features offering at the same time L1 track trigger and particle identification using transition radiation and dE/dX measurements. Test beam and MC studies of tracking and particle identification properties have been performed with a GridPix prototype. The properties of the detector very much depend on the gas mixture. For one layer of the GasPix detector one can obtain a special accuracy down to 11 μm and a vector angular accuracy of about 10 mrad for a beam incident angle of 10o. For particle identification studies the detector was filled with a Xe/CO2(70/30) mixture. A block of transition radiation radiator of 18 cm was installed in front of the detector. The pion rejection power using both cluster counting and full dE/dX methods was studied. It was shown that for 5 GeV particles a single layer of the detector gives a pion suppression by about a factor of 7 at an electron efficiency of 90%. Two layers of this detector provide a pion rejection factor of 50 at 90% electron efficiency. A detailed comparison with MC is presented.Speaker: Dr Anatoli Romaniouk (MEPHI/CERN)
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13:00
Lunch
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Software development and DAQ
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16:10
Coffee break
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18:30
Concert (<a href="http://agenda.infn.it/getFile.py/access?resId=5&materialId=2&confId=3468">leaflet</a>)
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