THE AMS RICH COUNTER AMS M Bunerd ISN
THE AMS RICH COUNTER AMS M. Buénerd ISN Grenoble May 5 -10, 2002 Plan • AMS project • RICH counter • Prototype RICH 2002@Pylos The AMS RICH collaboration: Bologna, Grenoble, Lisbon, Madrid, Maryland, Mexico 1
The AMS collaboration UNAM S. C. C. TING (MIT), PI May 5 -10, 2002 RICH 2002@Pylos 2
AMS Scientific Program on the ISS • High statistics study of Cosmic Ray particles: Allowing sensitive search for : • Primordial antimatter (primary goal of the project): • Dark matter (neutralino annihilation): • High energy gamma ray astronomy May 5 -10, 2002 RICH 2002@Pylos 3
The AMS & RICH calendar • 1994 Approval of the project by NASA/DOE • June 1998: Instrumental flight on the space shuttle DISCOVERY, 10 days • 1999 -2004: AMS 02 design & construction for ISS phase: SC magnet+ECAL+RICH+TRD • 2005: AMS 02 launch & installation on the International Space Station • ~2005 -2008: Data taking May 5 -10, 2002 RICH 2002@Pylos 4
THE AMS SPECTROMETER TRD e+/p - TOF Hodoscopes & e-/p Discrim P<300 Ge. V/c (TOF & d. E/d. X) Cryostat & SC Magnet (B = 1 T) VETO Tracker (P & d. E/d. X measurement) RICH (particle ID A<~25, Z<~25) EMC (ID em particles) May 5 -10, 2002 RICH 2002@Pylos 5
THE AMS RICH COUNTER Rôle in AMS: • Ion identification (A & Z) _ • p/e- and p/e+ discrimination • Albedo particle rejection May 5 -10, 2002 RICH 2002@Pylos 6
RICH design history • 1997 -99 : - First simulation works to evaluate the possible performances: see NIM A 454(2000)476 - Study prototype, construction and operation (T. Thuillier et al. , NIM A, in press, astro-ph/0201051) • 2000 -2002 : - (Iterations to) final design - Second generation prototype May 5 -10, 2002 RICH 2002@Pylos 7
Imaging technique & main design features Design drastically constrained by: - Volume - Weight (currently ~190 kg) - Power consumption - Long term reliability of components - Magnetic field in the photodetector region è • Proximity focusing counter, photomultipliers • 2 radiators for a maximum momentum range for particle identification (~1 -13 Ge. V/c/nucleon) May 5 -10, 2002 RICH 2002@Pylos 8
Simulation of 7 Be 9 Be 10 Be 6 weeks counting è ~ 200000 events ! May 5 -10, 2002 10 Be detection A. Bouchet et al, Nucl. Phys A 668(2000) The isotopic abundance ratio 10 Be/ 9 Be depends on: - Time of confinement of CRs in galaxy - ISM density and galactic halo size RICH 2002@Pylos 9
ECAL hole The RICH architecture Radiator(s) Conical mirror Photodetectors May 5 -10, 2002 RICH 2002@Pylos 10
Rich assembly AEROGEL radiator plane. Produced in Japan, Characterized in Mexico Support structure Madrid (exploded view) Na. F radiator ? Photon drift space Photodetector plane 680 PMTs ~104 pixels of photosensors (Japan) Mech Design from Gavazzi Co, Italy Structure Assembly (Bologna/Gavazzi) LOWER PANEL May 5 -10, 2002 Mirror made in USA (~13 kg) Resp. Bologna RICH 2002@Pylos 11
Shielding Grid Structure Courtesy G. Sardo, Gavazzi Space Co End beam Support beam Bottom skin May 5 -10, 2002 Th. = 0. 8 mm Th. = 1. 0 mm Th. = 1. 2 mm RICH 2002@Pylos 12
Photomultipliers Requirements: • Must stand high magnetic field (>~100 G) • Multianode ~5 x 5 mm pixels è May 5 -10, 2002 RICH 2002@Pylos Hamamatsu R 7600 -M 16 13
RICH photodetector and front end electronics assembly PMT Hamamatsu R 7600 -M 16 16 anodes~4. 5 x 4. 5 mm 2 PC Boards, RO and HVD Flex(ible) support Integrated Circuit: Austria. Mikro. System Technology May 5 -10, 2002 RICH 2002@Pylos 14
Front end electronics Principle: Spectroscopy type charge preamplifier, 16 multiplexed channels, 2 gain (x 1 & x 5) modes May 5 -10, 2002 RICH 2002@Pylos 15
Prototype of detector module (16) Light guides May 5 -10, 2002 RICH 2002@Pylos (16 pixel) PMT Readout electronics Housing (half) shell 16
RICH prototype (2 nd generation) May 5 -10, 2002 RICH 2002@Pylos 17
Prototype = ~½ module of final counter Rich detector plane Prototype a 96 May 5 -10, 2002 RICH 2002@Pylos PMTs, 1536 pixels 18
Prototype experimental set-up (Cosmic ray configuration) Cosmic m Scintillators Trigger electronics and MWPC readout MWPCs Vacuum chamber Radiator PMT Matrix 3 Radiators tested aerogels 1. 03, 1. 05, Na. F May 5 -10, 2002 RICH 2002@Pylos AMS Proto DAQ 19
Detection plane PMT array before light guide Installation May 5 -10, 2002 RICH 2002@Pylos Light guides installed 20
Back view of proto 2 Readout lines (9 PMTs/line) May 5 -10, 2002 RICH 2002@Pylos 21
Top view of the set-up PMT matrix LED Scintillators RO electronics MWPC tracker Vacuum chamber Chamber lid May 5 -10, 2002 RICH 2002@Pylos 22
RICH prototype DAQ setup Tracker : MWPCs + delay line RO [CAMAC] P S PC 2 Trigger : scintillators + PMTs [CAMAC] VME BUS SUN Station May 5 -10, 2002 RICH 2002@Pylos 23
Readout and DAQ Each board (33 PMTs): 1 DSP controlled FPGA + memory buffer 3 DAQ modes controlled by DSP: - calibration: pedestal calibrated and tabulated - RAW: 2 gains and all channels stored - REDUCED : gain mode selection and channel reduction May 5 -10, 2002 RICH 2002@Pylos 24
Prototype performances in Cosmic Ray tests Particle hit on LG+PMT Example of (muon) event measured in CR tests May 5 -10, 2002 RICH 2002@Pylos 25
Velocity resolution Reconstructed b spectrum Aerogel radiator n=1. 03 ° Data Only a resolution estimate since no measurement of the incident momentum of particles. Resolution per hit: • Measured: 3. 2 10 -3 • MC : 2. 5 10 -3 MC simulation è(Db/b)event ~ 10 -3 (Z=1) Contribution from mwpc tracker being reduced May 5 -10, 2002 RICH 2002@Pylos 26
Next steps -Technical tests : Vacuum, thermal, vibrations - Ion beam test at CERN on next october - Detector modules assembly will start on next January 2003. - Counter assembly finalized by end of 2003. May 5 -10, 2002 RICH 2002@Pylos 27
Summary & Conclusion • The AMS RICH is fully designed • End-to-end tests of the prototypes have been performed successfully. • Radiators (aerogels 1. 03/05, Na. F), PMTs, Light guides, FE and RO electronics, processing algorithms, provide the expected results (See talk by F. Barao). • The forthcoming in-beam tests with ions at CERN on october will complete the tests. èThe AMS RICH is on the tracks…. for flying on the ISS. May 5 -10, 2002 RICH 2002@Pylos 28
Cosmic Ray studies with the RICH What the RICH will do: • Reject Albedo particles (prototype inefficiency < 10 -3 ) • Discriminate e+/p & e-/pbar (p < ~12 Ge. V/c) • Identify nuclei or elements: May 5 -10, 2002 RICH 2002@Pylos Assuming DP/P~1% 29
Electronics settings <G(x 5)> = 69 <s/Q> ~ 0. 47 May 5 -10, 2002 PMTs grouped. RICH 2002@Pylos by 11 (10) / flex <sped> ~ 4. 3 30
Raw data vs simulation May 5 -10, 2002 RICH 2002@Pylos 31
Noise 3 ms delayed trigger Aerogel 1. 03 run El noise ~ 8 10 -5 hit/chan DC ~ 4 10 -5 hit/chan May 5 -10, 2002 RICH 2002@Pylos 32
Proto_1 Z separation obtained with proto 1 at GSI with 1 Ge. V/n 12 C beam May 5 -10, 2002 RICH 2002@Pylos 33
Proto_1 b(z) resolution b resolution obtained with proto 1 at GSI with 1 Ge. V/n 12 C beam. May 5 -10, 2002 RICH 2002@Pylos 34
Field map at PMTs May 5 -10, 2002 RICH 2002@Pylos 35
What ion mass and charge ID range with the RICH ? From simulation results: • Mass range A< ~30 • Charge range Z< ~25 • Momentum range P< ~15 Ge. V/c Assuming DP/P~1% The upper bounds quoted for A and Z are asymptotic limits May 5 -10, 2002 RICH 2002@Pylos 36
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