Fe55 calibration - track reconstruction (2 x linear fit) - Herbstschule ...

Hard- Hard and Software 

Development for the 

AMS-02 AMS 02 TRD 

Mike Schmanau 

IEKP - Universität Karlsruhe (TH)

AMS-02 AMS 02 Physics Interest 

• Search for antimatter 

• Search for dark matter annihilation 

• Investigate earths particle environment 

• Determine the age of cosmic rays by Be9 / 

Be10 measurement 

• Gamma-ray astronomy 

• Search for stranglets 

• Investigate characteristic particle radiation of 

microquasars, primordial black holes 

September 2006 Herbstschule Maria Laach Mike Schmanau, IEKP 2

Antimatter production by 

Dark Matter (DM) Annihilation 

• SUSY offers Neutralinos as candidates for Dark Matter 

• A Neutralino as a supersymmetric particle hardly interacts with common 

matter due to R-Parity conservation. 

• But it can annihilate with another Neutralino and create Matter/Antimatter 

e.g. Electrons/Positrons, Gammas, Proton/Antiprotons. 

Diffuse Gamma Rays Positron Fraction Antiprotons 

Annihilation 

Background 

(From: W. De Boer et al. Indirect Evidence for the Supersymmetric Nature of Dark Matter..., hep-ph/0309029.) 


AMS on the International Space Station 

AMS-02 

To perform this search, we have to get rid of the disturbing atmosphere. 

A good place is 400km over ground on the ISS. 


AMS – 02 

General Purpose detector with 

excellent particle identification 


DM detection accurracy 

Primary Sources: Neutralino-Annihilation 

Secondary Sources: fragmentation. 

AMS-02 total acceptance 

• Background: p + /e + = O(10 4 -10 5 ) 

=> proton-rejection >10 5 up to 300 GeV 

(e± efficiency = 90%) 

• Achieved by AMS-02 ECAL (10 -4 ) 

+ TRD (10 -2 –10 -3 ) rejection 


TRD mechanics 

• Conical octagon made of aluminum honeycomb 

• Modules: 16 tubes with 6mm diameter and 30 µm W-Au 

• 20 layers separated by 22 mm fleece-radiator 

• Lengths of tubes between 86 and 201cm 

• Tubewall 72 µm Kapton-Al sandwich 

Capton wall, 72 µm 

• Xe/CO2 (80/20) Pressure 1250mbar, Flow 1 liter/h, Gain 3000 


Principle of transition radiation 

• Highly relativistic particle traverses the 

boundary of two media with different ε. 

• To fulfilling the of continuity at the 

boundary, TR is emitted 

• Probability of emitting a photon: ∼α=1/137 

• In AMS-02 fleece is used as radiator 

• Approxim. 100 transitions 

September 2006 Herbstschule Maria Laach Mike Schmanau, IEKP 8 

22 mm

Test beam and MC Simulation 

MC rejection deviates above 150 GeV 

Proton energy 

Ad hoc solution: 

diffractive proton dissociation 

p + p ⇒ (p + π + + π + + p) + p ; σ = 15 mb 

TRD 20 layer test beam: 

- inter-calibration between TRD modules 

- Fe55 calibration 

- track reconstruction (2 x linear fit) 

- event selection 

Likelihood Analysis 

At 90% e- efficiency 


Requirements for Space Operation 

• TRD Weight limit (480 kg) 

full AMS limit 7t 

• Start Vibrations up to 6.8g. 

• TRD outer casing Temperature 

–180°C...+50°C => insulation 

inner TRD temperature 0..20°C. 

gradient below 1°C. 

• Vacuum operation 

• Outgasing deposition limits on 

ISS < 10 -14 g/s/cm 2 

• EMI limits on ISS 

AMS 

• Maintenance free for > 3 years. 

• Limited power consumption 

(full AMS 2kW) 

September 2006 Herbstschule Maria Laach Mike Schmanau, IEKP 

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TRD(U)-Electronics TRD(U) Electronics Overview 

Ucrate = TRD electronic crate 

UBP = TRD backplane 

UPD = TRD power distribution box 

USCM = TRD power controller 

UPSFE = TRD power supply for front end 

UDR = TRD data reduction board 

JINF = data concentrator and link to higher DAQ for TRD 

UHVG = TRD high voltage generator 

UFE = TRD front end 

UTE = TRD tube end 

UHVD = TRD high voltage distributor 


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TRD Electronic-Facts 

Electronic Facts 

• 82 front end boards (UFE) TRD each with 64 straw tubes => 5248 channels. 

• Data transmission limit => Data reduction by ACTEL FPGA and DSP 

• 2 U-crates with 21 card powered by 2 UPD-Box with 7 DC/DC converters. 

• DC/DC conversion efficiencies up to 80%. 

• Power consumption: 19W Frontends, 41W U-crate, 36 W UPD-Box => P ≈ 100W 

• TRD read-out time ≈ 70 µs. Expected max. trigger rate ≈ 2kHz. 

• VA Input range: 50 Mips, Noise ≈ 1/30 Mip 

• 42 HV channels (0..2kV) with 1V accurracy 


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Space Qualification of electronics 

• Thermo-Vacuum Test (TVT) 

• Vibration-Test 

Requirement: 

Operating Temp.: 

-25°C to +55°C 

Non-operating Temp.: 

-45°C to +85°C 

Requirement: 

Vibration up to 9g. 

Eigenfrequency > 50 Hz 


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Space Qualification of electronics 

• EMI-Tests to assure no EM-pollution of ISS environment is caused. 

Radiated Susceptibility (RS03) 

14 kHz-200 MHz at 5 V/m, 

200 MHz-8 GHz at 60 V/m 

8 GHz-10 GHz at 20 V/m. 

Conducted emissions 

(CE1,CE03) 

30Hz-15kHz, 15kHz-50Mhz 

Conducted susceptibility 

0.15 us spikes, 10 us spikes 

Radiated Emission (RE02) 

14 kHz-20 GHz 


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Electronics Production Steps 

• Engineering Module-Production (EM): Europe 

Purpose: 

FPGA firmware and DSP software development and functional tests 

• Qualification Module 1 - Production (QM1): Europe 

Purpose: 

Small quantity of electronics with space qualification 

• Qualification Module 2 - Production (QM2): 

Purpose: 

CSIST, Taiwan 

Knowledge transfer, Crate quantity of electronics and Crate level space qualification 

Current working step! 

• Flight Module Production (FM): 

Purpose: 

CSIST, Taiwan 

Flight hardware with low stress Crate level space qualification 


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Summary 

• AMS–02 TRD +ECAL provides a p + rejection of 10 -6 up to 300 GeV 

• MC Simulations can can describt beamtest results by adding diffractive 

proton dissotiation (unfortunatly not Geant4, so far) 

• Space qualification tests show that requirements for detector are fulfilled. 

• Electronics development is finished. 

A prototype of each board has been 

tested successfully in a beam test. 

• Space qualification (TVT, vibration ,EMI) for 

flight electronics ongoing 

• Flight-Production finished next year 

• Schedule: 

Complete test of TRD 2007. 


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Fe55 calibration - track reconstruction (2 x linear fit) - Herbstschule ...

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