detection & measurement of gamma rays in the ams-02 detector
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
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Detection & Measurement of gamma Detection & Measurement of gamma rays in the AMS-02 Detectorrays in the AMS-02 Detector
Detection & Measurement of gamma Detection & Measurement of gamma rays in the AMS-02 Detectorrays in the AMS-02 Detector
J. Bolmont - LPTA - IN2P3/CNRS
Montpellier - France
On behalf of AMS collaboration
J. Bolmont - LPTA - IN2P3/CNRS
Montpellier - France
On behalf of AMS collaboration
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OutlineOutline
• Detecting with AMS-02- Conversion Mode- Single Photons
• Cosmic Ray Fluxes• Various sources
- Pulsars, GRBs- Cold Dark Matter
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AMS-02AMS-02
Launch scheduled in 2008Launch scheduled in 2008
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Detecting Detecting with AMS 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
e+ e-
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Detecting Detecting with AMS : with AMS : e e++ee--
• The Si Tracker : charged track reconstruction & identification- 8 layers- Double sided silicon strips- Total area : 7 m2
- 200000 channels
A layer completely equipped
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Tracker ResolutionsTracker ResolutionsBeam test results• Angular resolution ~0.02° when E > 100 GeV.• Energy resolution at high energy affected by the leptons trajectory reconstruction errors.
Energy ResolutionAngular Resolution
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Detecting Detecting with AMS : with AMS : single single showers 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
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EM Calorimeter ResolutionsEM Calorimeter Resolutions
Energy Resolution Angular Resolution
Beam test results
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Acceptance / Effective AreaAcceptance / Effective Area
• Monte Carlo simulations + Preliminary analysis
Cos(incident angle)
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Cosmic Ray FluxesCosmic 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
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Various Various sources 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)
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Some Results Of SimulationsSome Results Of Simulations• Using a fast simulation tool with parametrizations of
ECAL & Tracker acceptances and resolutions
3EG Catalog Other Name N (Tracker) N (ECAL) N (total)
J0210-5055 0208-512 47.0 13.4 60.4
J0530+1323 0528+134 18.7 4.0 22.7
J0534+2200 Crab 102.2 26.6 128.8
J0834-4511* Vela 491.4 203.8 695.2
J1255-0549 3C279 138.6 35.8 138.6
J1409-0745 1406-076 31.7 5.9 37.6
J1635+3813 1633+382 65.5 18.3 83.8
One year of operation
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Some Results Of Simulations : Some Results Of Simulations : CRAB nebula+pulsar 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
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Predictions for GRBsPredictions 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 !
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Cold Dark MatterCold Dark MatterThe 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 : 0
1 •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, …
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Predictions for benchmark fluxesPredictions for benchmark fluxesGalactic CentreGalactic Centre• mSUGRA models MC simulation• Accelerators & WMAP constraints• Various DM halo profiles
Model B G I K L
m 98.3 153.6 143.0 571.5 187.2
m0 59.0 116.0 178.0 999.0 299.0
tan 10. 20. 35. 38.2 47
relic 0.122 0.124 0.122 0.116 0.101
n (NFW) 0.11 0.07 0.47 0.14 1.17
n (NFW cuspy) 4.8 2.8 20.3 6.0 50.5
n (Moore) 14.1 8.2 59.0 17.5 146.7
One year of operation
J. Ellis et al. Eur. Phys. J. C24 (2002) 311
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Predictions for Predictions for fluxes from the fluxes from the Galactic Centre : Galactic Centre : DarkSUSY + Suspect MCDarkSUSY + 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
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SummarySummary
• 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.