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THE CHERENKOV IMAGER of the AMS02 EXPERIMENT

THE CHERENKOV IMAGER of the AMS02 EXPERIMENT. AMS. M. Buénerd LPSC Grenoble. The AMS RICH collaboration: Bologna, Grenoble, Lisbon, Madrid, Maryland, Mexico. PLAN. The AMS02 spectrometer Physics program The Cherenkov imager In-beam test results. Capabilities of the spectrometer.

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THE CHERENKOV IMAGER of the AMS02 EXPERIMENT

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  1. THE CHERENKOV IMAGER of the AMS02 EXPERIMENT AMS M. Buénerd LPSC Grenoble The AMS RICH collaboration: Bologna, Grenoble, Lisbon, Madrid, Maryland, Mexico RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  2. PLAN • The AMS02 spectrometer • Physics program • The Cherenkov imager • In-beam test results RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  3. Capabilities of the spectrometer • Measure particle energy from ~ 0.4 GeV/n up to ~ 1 TeV/n • Discriminate lepton-hadron • HE g ray measurement • Identify ions or elements over the largest possible energy range RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  4. AMS Scientific Program on the ISS • High statistics study of the Cosmic Ray particles flux: • Allowing sensitive search for : • Primordial antimatter(primary goal of the project): • Dark matter (neutralino annihilation): • High energy gamma ray astronomy RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  5. The AMS Cherenkov imager • Main purpose: • The only AMS detector dedicated to Isotope identification (A & Z)Also (redundant) : • p/e- and p/e+ discrimination • Albedo particle rejection _ RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  6. Simulation of 10Be detection 10Be 9Be 7Be A.Bouchet et al,Nucl.Phys A668(2000) isomax The isotopic abundance ratio 10Be/ 9Be depends on: - Time of confinement of CRs in galaxy - ISM density and galactic halo size 6 weeks counting è ~ 200000 events ! RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  7. The RICH inside AMS CherenkovRadiator AMS spectrometer aerogel NaF Photo- detectors ECAL Radiator(s) Conical mirror Photodetectorplane (680 PMTs) RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  8. Radiator plane Aerogel n = 1.05 thickness 30 mm P range ~ 3-10GeV/c/n Sodium Fluoride NaF, n = 1.33 thickness 5 mm P range ~ 1-4 GeV/c/n RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  9. Photodetector cell 4x4 Light Guides7.5x7.5mm2 Front End Electronics: Charge preamplifier Track&hold +MPX 16 chan (x2gains) ADC High voltage divider Magnetic Shielding profile (Stray field up to 300G) PMT Hamamatsu R7900_M16 4x4 pixels (4.5x4.5mm2) RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  10. The RICH prototype ½ module of final detector • 96 PMTs (1536 pixels) • Light Guides • FE+DAQ • Radiators: • AGL 1.03 < n < 1.05 • NaF n=1.33 (CR only) RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  11. with HE ion beam at CERN Tests of the AMS RICH prototype • Beam production principle* • Measurements • Results * M. Buénerd and I. Efthymiopoulos, CERN report AB-2003-052 RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  12. Multi-ion beam production Example: A/Z=2 èD, He, Li, Be, B, C,…, Si,.., Ca,…, 52Fe, .. and beyond, but…. 500m beam line Incident SPS - Pb ion beam (20GeV/c/n) - In ion beam (158GeV/c/n) Productiontarget Br Fewmrad Momentumanalysis Br = Cte xgA/Z Testingdetector Beam fragmentation è Br = Cte x gbeam A/Z RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  13. Intensity of ion beam fragments vs Cosmic Ray flux Beam fragments (A/Z=2) (From dE/dX scintillator ) Similarity of the 2 spectra _ controllableCR equivalent flux Cosmic Ray flux J.A. Simpson ARNS 33(1983)323 ~Nuclear charge Z RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  14. 2 Runs • October 2002: 20 GeV/nucleon 208Pb_ fragments A<~60 (z~30)5 million events collected • October 2003 : 158 GeV/nucleon 115Cd_ fragments A<115 (z=49)11 million events collected RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  15. Experimentalsetup Prototype & RO electronics MWPC dE/dXScintillators or Cherenkov MWPC RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  16. Close-up view of matrix with mirror RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  17. 20GeV/n Cherenkov rings C Li Si-P ? 6 He ~Fe ? 3 >~16 Z 2 >16 RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  18. Velocity reconstruction 2002 Ring fitting spectra fitting Z=1 particles Aerogel CIEMAT Madrid analysis RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  19. b(Z) resolution 2002 CIEMAT Madrid analysis Aerogel 1.03 Nγ in the ring ~ Z2 Limit set by pixel size RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  20. Charge resolution 2002 Individual Element separation a (Z) < ~.2 up to Z=26 (n=1.05) Combining RICH+TRCKR Courtesy M. Pohl et al. Courtesy M.Pohl, Geneva U. RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  21. 2003 comparison of Aerogels H (Nominal = 44 cm) Specific runs to compare the performances for radiators with different refraction index H = 33.5 cm (full contained rings) ELECTED RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  22. Cells integration April 2004 RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  23. coating Finally: 680 PMT cells ASSEMBLED POTTED COATED TESTED SORTED 9 failures (3 due to PMT failure) Ready for final counter integation (Spares from the prototype used) RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  24. Summary • The study of the AMS RICH prototype with 20 & 158 GeV/n ions has allowed to: • Perform an end-to-end test of the instrument with a broad range of nuclear charges (1<Z<~49). • Measure the performances of the prototype: • Velocity resolution :Db/b= 0.7 10-3 for Z=1 particles • Charge resolution :s(Z) < »0.2 up to Z>~30 • 3. All the RICH prototype elements have been thoroughly tested (PMT cells, FE+RO electronics, reconstruction algorithms) and validated . • The final counter integration has started (end Nov 05). RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  25. AMS is an International Collaboration NASA provides: Three shuttle flights and Mission Management at JSC (S. Porter - Project Manager) 50 universities, 500 participants DENMARK ITALY ROMANIA UNIV. OF AARHUS ASI CARSO TRIESTE IROE FLORENCE INFN & UNIV. OF BOLOGNA INFN & UNIV. OF MILANO INFN & UNIV. OF PERUGIA INFN & UNIV. OF PISA INFN & UNIV. OF ROMA INFN & UNIV. OF SIENA ISS UNIV. OF BUCHAREST CHINA FINLAND USA BISEE (Beijing) IEE (Beijing) IHEP (Beijing) SJTU (Shanghai) SEU (Nanjing) SYSU (Guangzhou) SDU (Jinan) ACAD. SINICA (Taiwan) CSIST (Taiwan) NCU (Chung Li) NCKU (Tainan) NCTU (Hsinchu) NSPO (Hsinchu) HELSINKI UNIV. UNIV. OF TURKU RUSSIA A&M FLORIDA UNIV. JOHNS HOPKINS UNIV. MIT - CAMBRIDGE NASA GODDARD SPACE FLIGHT CENTER NASA JOHNSON SPACE CENTER UNIV. OF MARYLAND-DEPRT OF PHYSICS UNIV. OF MARYLAND-E.W.S. S.CENTER YALE UNIV. - NEW HAVEN KOREA I.K.I. ITEP KURCHATOV INST. MOSCOW STATE UNIV. EWHA KYUNGPOOK NAT.UNIV. FRANCE GAM MONTPELLIER LAPP ANNECY LPSC GRENOBLE SPAIN NETHERLANDS GERMANY CIEMAT - MADRID I.A.C. CANARIAS. RWTH-I RWTH-III MAX-PLANK INST. UNIV. OF KARLSRUHE ESA-ESTEC NIKHEF NLR MEXICO SWITZERLAND UNAM ETH-ZURICH UNIV. OF GENEVA PORTUGAL LAB. OF INSTRUM. LISBON RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  26. THE AMS2 SPECTROMETER TRDe+/p & e-/p Discrim P<300GeV/c - TOF Hodoscopes(TOF & dE/dX) Cryostat & SC Magnet(B = 1T) VETOskirt Tracker(P & dE/dX measurement) RICH(particle & isotope ID A<~16 ?, Z<~25) EMC(ID em particles) RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  27. SC magnet in support structure 2x Dipole Coils 2x6 Racetrack Coils 2,500 l Superfluid He RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  28. The Cherenkov Imager • What for ? • Which imaging technique ? • What radiator(s) ? • What photodetectors ? • What performances ? • aPrototype and test results RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  29. Which imaging technique ? è • Proximity focusing counter, photomultipliers • 2 radiators for a maximum momentum range for isotope identification (~1-10 GeV/c/nucleon) • Largely dictated by constraints on: • Volume available (Shuttle cargo bay) • Weight (currently ~190kg) • Power consumption (currently ~150W) • Long term reliability of components • Magnetic field in the photodetector region • Isotropic flux (No point source like in accelerators) RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  30. Rich assembly (exploded view) Mirror made inUSA (~ 13kg) Resp. Bologna NaF radiator AEROGEL radiatorplane. Produced in Japan or Russia, Characterized at UNAM Mexico Support structure made by CIEMAT Madrid Photon drift space Mech. Designby GavazziSpace, Italy Photodetector plane 680 PMTs ~104 pixels of photosensors(Japan) Structure Assembly (Bologna/Gavazzi) LOWER PANEL RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  31. Selection of the ion sample Changing the magnetic field in the beam line changes the ion mass/charge sampled Z Chart of the nuclides Selectionline (A/Z=Cte) Z=50Zr Z=20Ca Z=8O Z=82 Pb beam Z=2He N RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  32. The CERN H8 beam line Tracker CREAM Dispersiondipole Productiontarget AnalysisDipole TOF Acceptancecollimators Momentum Analysis RICH Imagecollimators Wall TOF1 NA45 / / TOF2 Experimental area DP/P~1% -464 -352 0 -480 -420 -80 -26 -150 Position (m) RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  33. Front end electronics Principle: Spectroscopy type charge preamplifier, 16 multiplexed channels, 2 gain (x1 & x5) modes RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  34. PMT linearitymeasurement 3 pixels • To be cross checked with calibration from the ion charge distribution RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  35. Team (night shift) at work RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  36. Module coating Coating Aug 2004 M.Marton RICH2004 Int. Workshop, Playa Del Carmen, Mexico

  37. Surface scattering RICH2004 Int. Workshop, Playa Del Carmen, Mexico

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