THE AMS RICH COUNTER G. BOUDOUL ISN Grenoble ISN-GRENOBLE 1 The AMS RICH collaboration: Bologna, Grenoble, Lisbon, Madrid, Maryland, Mexico
2 The AMS collaboration UNAM S.C.C. TING (MIT), PI
3 AMS Scientific Program on the ISS High statistics study of Cosmic Ray particles: (e ±, p, p, ions A < 25 & Z < 25, unstable nuclei 10 Be, 26 Al,..) Allowing sensitive search for : Primordial antimatter (primary goal of the project): ( 4 He, 12 C,...) Dark matter (neutralino annihilation): (χ + χ + p + X, e + X, γ + X...) High energy gamma ray astronomy (?): (~1-2 GeV- ~1 TeV) effective upper limit ~100 GeV due to statistics
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: AMS02 design & construction for ISS phase: SC magnet+ecal+rich+srd+trd 2005: AMS02 launch & installation on the International Space Station ~2005-2007: Data taking ISN-GRENOBLE 4
5 THE AMS SPECTROMETER SRD TRD e + /p & e - - /p Discrim P<300GeV/c Cryostat & SC Magnet (B = 1T) Tracker (P & de/dx measurement) EMC (ID em particles) TOF Hodoscopes (TOF & de/dx) VETO RICH (particle ID A<~27, Z<~26)
6 THE AMS RICH COUNTER Role in AMS: Ion identification Antiproton-electron and positron-proton discrimination Albedo particle rejection
7 RICH design history 1997-99 : - First simulation works to evaluate the possible performances: see NIM A454(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
8 Imaging technique & main design features Design drastically constrained by: - Magnetic field in the photodetector region - Volume - Weight (currently ~190kg) - Long term reliability Proximity focusing counter, photomultiplier detectors 2radiatorsfor a maximummomentumrange for particle identification (~1-13 GeV/c/nucleon)
Simulation of 10 Be detection 7 Be 9 Be 10 Be A.Bouchet et al,nucl.phys A668(2000) 6 weeks counting ~ 200000 events! The isotopic abundance ratio 10 Be/ 9 Be depends on: - Time of confinement of CRs in galaxy - ISM density and galactic halo size ISN-GRENOBLE 9
10 The RICH ECAL hole architecture Radiator(s) Conical mirror Photodetectors
11 Rich assembly (exploded view) AEROGEL radiator plane. Produced in Japan, Characterized in Mexico Support structure Madrid NaF radiator? Mirror made in USA (~13kg) Resp. Bologna Photon drift space Photodetector plane 680 PMTs ~10 4 pixels of photosensors (Japan) Mech Design from Gavazzi Co, Italy LOWER PANEL Structure Assembly (Bologna/Gavazzi)
Shielding Grid Structure Courtesy G. Sardo, Gavazzi Space Co End beam Support beam Bottom skin Th. = 0.8 mm Th. = 1.0 mm Th. = 1.2 mm ISN-GRENOBLE 12
13 Photomultipliers Requirements: Must standhigh magnetic field (>~100 G) Multianode ~5x5mm pixels Hamamatsu R7600-M16
RICH photodetector and front end electronics assembly PMT Hamamatsu R7600-M16 16 anodes~4.5x4.5mm 2 PC Boards, RO and HVD Flex(ible) support Integrated Circuit: AMS Technology (or DMILL) ISN-GRENOBLE 14
15 Front end electronics Principle: Spectroscopy type charge preamplifier, 16 multiplexed channels, 2 gain (x1 & x5) modes
Photodetector module (16) Light guides (16 pixel) PMT Readout electronics Housing (half) shell ISN-GRENOBLE 16
17 RICH prototype (2nd generation)
18 Prototype = ~½ module of final counter Rich detector plane Prototype!96 PMTs, 1536 pixels
Prototype experimental set-up (Cosmic ray configuration) Scintillators MWPCs Cosmic µ Trigger electronics and MWPC readout Vacuum chamber Radiator PMT Matrix 3 Radiators tested aerogels 1.03, 1.05, NaF AMS Proto DAQ ISN-GRENOBLE 19
20 Detection plane PMT array before light guide Installation Light guides installed
21 Back view of proto 2 Readout lines (9 PMTs/line)
22 Top view of the set-up PMT matrix LED Scintillators RO electronics Vacuum chamber MWPC tracker Chamber lid
RICH prototype DAQ setup P S Tracker : MWPCs + delay line RO [CAMAC] Trigger : scintillators + PMTs [CAMAC] PC2 VME BUS SUN Station ISN-GRENOBLE 23
24 Readout and DAQ Each board (33PMTs): 1 DSP controlled FPGA + memory buffer 3 DAQ modes controlled by DSP: - calibration: pedestal calibrated and tabulated -RAW: 2 gainsandallchannels stored - REDUCED : gain mode selection and channel reduction
25 Prototype performances in Cosmic Ray tests Particle hit on PMT Example of (muon) event measured in CR tests
Velocity resolution Reconstructed β spectrum Aerogel radiator n=1.03 Only a resolution estimate since no measurement of the incident momentum of particles. Data Resolution per hit: Measured: 3.2 10-3 MC : 2.5 10-3 MC simulation ( β/β) event 10-3 (Z=1) Contribution from mwpc tracker being reduced ISN-GRENOBLE 26
27 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.
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 GeV/c) Identify nuclei or elements: Isotopes A < ~30 Elements Z < ~25 Current knowledge E kin <500MeV/n P < 35GeV/c/n AMS P < 13-20GeV/c/n P < 1 TeV/c/n Assuming P/P~1% ISN-GRENOBLE 28
29 Conclusion The AMS RICH is fully designed End-to-end tests of the prototypes have been performed successfully Radiators (aerogels 1.03/05, NaF), PMTs, Light guides, FE and RO electronics, processing algorithms, provide the expected results The forthcoming in-beam tests with ions at CERN on october will complete the tests. The AMS RICH is on the tracks. for flying on the ISS.
Electronics settings <G(x5)> = 69 <σ/q> ~ 0.47 <σ ped > ~ 4.3 PMTs grouped by 11 (10) / flex ISN-GRENOBLE 30
Raw data vs simulation ISN-GRENOBLE 31
32 Noise Aerogel 1.03 run 3 µs delayed trigger El noise ~ 8 10-5 hit/chan DC ~ 4 10-5 hit/chan
33 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 GeV/c Assuming P/P~1% The upper bounds quoted for A and Z are asymptotic limits