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Detection & Measurement of gamma rays in the AMS-02 Detector. J. Bolmont - LPTA - IN2P3/CNRS Montpellier - France On behalf of AMS collaboration. Outline. Detecting with AMS-02 Conversion Mode Single Photons Cosmic Ray Fluxes Various sources Pulsars, GRBs Cold Dark Matter.
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Detection & Measurement of gamma rays in the AMS-02 Detector J. Bolmont - LPTA - IN2P3/CNRS Montpellier - France On behalf of AMS collaboration Lake Louise - February 20-26 2005
Lake Louise - February 20-26 2005 Outline • Detecting with AMS-02 • Conversion Mode • Single Photons • Cosmic Ray Fluxes • Various sources • Pulsars, GRBs • Cold Dark Matter
Lake Louise - February 20-26 2005 AMS-02 Launch scheduled in 2008
g g e+ e- Lake Louise - February 20-26 2005 Detecting with AMS • Two complementary modes • Tracker mode : e+e-conversion in TRD • ECAL mode : single no hit in TOF & Tracker • Completeness of AMS-02 : overall proton to gamma supression factor 104 - 105
Lake Louise - February 20-26 2005 Detecting with AMS : e+e- • The Si Tracker : charged track reconstruction & identification • 8 layers • Double sided silicon strips • Total area : 7 m2 • 200000 channels A layer completely equipped
Lake Louise - February 20-26 2005 Tracker Resolutions Beam test results • Angular resolution ~0.02° when E > 100 GeV. • Energy resolution at high energy affected by the leptons trajectory reconstruction errors. Angular Resolution Energy Resolution
Lake Louise - February 20-26 2005 Detecting with AMS : single showers • The Electromagnetic Calorimeter • SPACAL calorimeter (Pb + Scintillating fibers) • 9 superlayers (~16 X0), X-Y sampling • 324 PMTs with 4 pixels 1296 channelshigh granularity 3 Superlayers
Lake Louise - February 20-26 2005 EM Calorimeter Resolutions Beam test results Energy Resolution Angular Resolution
Lake Louise - February 20-26 2005 Acceptance / Effective Area • Monte Carlo simulations + Preliminary analysis Cos(incident angle)
Lake Louise - February 20-26 2005 Cosmic Ray Fluxes • Cosmic Rays Composition : • p : 88 % • He nuclei : 9 % • e- : 2 % • : < 1% • Standard CR spectra follows a "power law" E- with = 2-3 • DM signal : exponential cut-off in the spectra
Lake Louise - February 20-26 2005 Various sources • Energy range : 1-300 GeV • Sources in scope of AMS: • Galactic : pulsars, nebulas (VELA, CRAB,…) • Extra-Galactic : GRBs • Diffuse emission : interaction of Charged Rays with galactic medium produce (0)
Lake Louise - February 20-26 2005 Some Results Of Simulations • Using a fast simulation tool with parametrizations of ECAL & Tracker acceptances and resolutions One year of operation
Lake Louise - February 20-26 2005 Some Results Of Simulations : CRAB nebula+pulsar • Results in 5 energy bands for 1 year of operation : • 1-2 GeV • 2-5 GeV • 5-20 GeV • 20-50 GeV • > 50 GeV
Lake Louise - February 20-26 2005 Predictions for GRBs • GRBs : the most explosive cosmological events after Big Bang : ~5x1051 erg released in • Taking into acount the most luminous GRBs observed by EGRET & BATSE, we expect a few GRBs per year in AMS detector. • Big uncertainties: processes of production at high energies not known !
Lake Louise - February 20-26 2005 Cold Dark Matter The matter content of the Universe is 90% dark and non-baryonic. Astrophysical measurements of the star rotation velocities in the galaxies, of the large structures, gravitational arc phenomena confirm the CDM paradigm. Hypotheses : • Dark Matter is Cold (CDM) and weakly interacting (WIMPs) • Exotic – Supersymmetry (Particle Physics) offers an excellent WIMP candidate – the LSP as neutralino : 01 • The WIMPs interact in the underground detectors with nucleons and annihilate in the halo of the Dark Matter and produce stable particles : , neutrinos, e+, anti-p, …
Lake Louise - February 20-26 2005 Predictions for benchmark fluxesGalactic Centre • mSUGRA models MC simulation • Accelerators & WMAP constraints • Various DM halo profiles J. Ellis et al. Eur. Phys. J. C24 (2002) 311 One year of operation
Lake Louise - February 20-26 2005 Predictions for fluxes from the Galactic Centre : DarkSUSY + Suspect MC • Different Models : • SUSY conventional(MSSM, mSUGRA) • Non thermal (AMSB) • Kaluza-Klein scenario MSSM = Minimal SuperSymetric Model mSUGRA = Minimal SUGRA model SUGRA = SuperGravity grand unified models AMSB = Anomaly Mediated SUSY Breaking
Lake Louise - February 20-26 2005 Summary • Using Si-Tracker and EM Calorimeter, AMS-02 will provide new measurements in the range1-300 GeV during 3 to 5 year mission. • AMS-02 will study several galactic and extragalactic sources as Pulsars, GRBs… • (At least) constraints in various Cold Dark Models will be provided.