The AMS Transition Radiation Detector and the Search for Dark Matter Gianpaolo Carosi Lab for...
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Transcript of The AMS Transition Radiation Detector and the Search for Dark Matter Gianpaolo Carosi Lab for...
The AMS Transition Radiation Detector and the Search for Dark Matter
Gianpaolo Carosi Lab for Nuclear Science, MIT The AMS Collaboration Lake Louise Winter Institute 2/23/05
Outline• Signatures of dark matter in cosmic rays
• Overview of the AMS-02 detector
• Principles of Transition Radiation
• Construction of the AMS TRD system
• Physics reach of AMS-02 detector with the TRD
The Problem of Dark Matter• What is it?
-Matter which appears to not interact electromagnetically.
-Observed from gravitational interactions only!
v2
v1
Galactic Rotation Curves
R1
R2
R2R1
v1 v2
00 SUSY Dark Matter
• Neutralino – majorana particles
Direct searches: Scattering off nuclei
Indirect searches: Look for annihilation products.
Positrons: low intrinsic background
Energy correlated to WIMP mass
X 0
X 0
e+
e-
HEATBalloon Experiment
ve
ve
_
AMS-02 experimentConstraints:•9 g at takeoff/landing.•Weight < 14809 lbs•Power = 3 kW•Temperature: -40˚ - +65˚ C•Date rate = 2 Mb/sec•3 year remote operation without servicing
Operational ExperienceAMS-01 engineering test flight10 days: ~ 100 Million events
ISS
The Experiment
TRD: p+ rejection 102-103
ECAL: p+ rejection 103-104
Principle of Transition RadiationHigh energy charged particles crossing boundary between materials of different dielectric constants gives off X-rays.
Detection possible with Lorentz boosts > 300.
Discriminate e+ (TR) / p+ (no TR)
AMS TRD: Proportion tubes and fleece radiator
Construction of AMS TRDTRD Octagon/straw tubesRWTH Aachen
TRD Gas Supply/Circulation SystemMIT – Design CERN & MIT - Construction
TRD Slow Control SystemMIT & INFN Rome
TRD DAQTH Karlsruhe
DAQ Electronics Slow Control and Monitoring
50 liter/hr
DetectorVolume
DistributionSystem
CirculationSystem
Supply/MixingSystem
Vibration TestsThermal Vacuum Tests
Leak Tests
Extensive Testing
328 Modules (5248 straw tubes) Lengths: 0.8 – 2.0 m and 100 μm tolerance
Straw tube walls
Carbon Fiber Structure
Aachen
328 straw modules have been produced:
Gas System: Box S
• Mix Gas:
Xe:CO2 80:20
(to 1% accuracy)
• Refresh Supply Daily:
max 7 liter/day
Engineering model: CERN Flight system: ARDE Corp.
Xe49.5 kg
CO2
4.5 kg
Gas System:Box C• Circulate Gas:
50 liter/hr through Octagon• Monitor gas gain:
Calibration tubes coated with Fe55
Spirometer: Measures CO2 fraction
TRD Gas Slow Control/Monitoring
TRD DAQTRD FE-electronics: 20 Watt for 5248 channels => multiplexed pulse height only
• 20 layer TRD detector in the test beam at CERN in 2000• we have recorded 3 million events providing signals for protons, electrons,
muons and pions at energies from 5-250 GeV
HEAT experiment(experimental data + DM model)
AMS-02 experiment(simulated data + DM model)
Physics Reach
TRD + ECAL
Paolo Maestro: SIENA
AMS on the ISS: 2008
AMS TRD currently under constructionBeam tests: achieve 102-103 p+ rejection to 300 GeVCombined with ECAL will obtain precise e+ spectrum
Summary