Alpha Magnetic Spectrometer AMS on International Space Station ISS

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Alpha Magnetic Spectrometer (AMS) on
International Space Station (ISS)

• Behcet Alpat
• I.N.F.N. Perugia
• Frontier Detectors for Frontier Physics
• 8th Pisa Meeting on Advanced Detectors
• May 21-27, 2000 La Biodola, Isola dElba, Italy

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The AMS Physics

• To search for Antimatter (He,C) in space with a
  sensitivity of 103 to 104 better than current
  limits.
• To search for dark matter
• High statistics precision measurements of e?, ?
  and p spectrum.
• To study Astrophysics.
• High statistics precision measurements of D, 3He,
  4He, B, C, 9Be, 10Be spectrum
• B/C to understand CR propagation in the Galaxy
  (parameters of galactic wind).
• 10Be/9Be to determine CR confinement time in the
  Galaxy.

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AMS-01 Configuration on STS-91 Flight

• STS-91 Flight, June 2-12th, 1998

• Magnet Nd2Fe14B, BL2 0.15 TM2
• T.o.F Four planes of scintillators
• ? and Z measurements, up/down separation
• Tracker Six planes of ds silicon detectors
• Charge sign, dE/dX up to Z8, Rigidity (p/Z)
• Anticounters
• Veto stray trajectories and bckgnd particles from
  magnet walls
• Aerogel Threshold Cerenkov
• ? measurements (1?3 GeV/c) for better e/p
  separation
• Low Energy Particle Shielding (LEPS)
• Carbon fibre, shield from low energy (lt5MeV)
  particles

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AMS-01 STS-91 Flight Results
G.F. ? 3000 cm2.sr MDR ? 400 GV Energy Range
100 MeV/nltEklt 300 GeV/n Electronics channels ?
70000 Power ? 1 kW

• ?30 hours before and ?105 hours after rendezvous
  with MIR (total of ?135 hours including ?11 hours
  of albedo measurements)
• Shuttle altitude ranged from 320 to 390 km
• Latitudes ?51.7, All longitudes (except S.A.A.)
• A total of 100 million events recorded with event
  rates ranging from 100 Hz to 700 Hz
  (corresponding to 95?40 DAQ livetime)

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AMS-01 on Discovery during STS-91 Flight
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AMS-01 STS-91 Flight Results (2)

• It was a successful flight !!
• Detector test in actual space conditions
• Good performance of all subsystems
• Physics results
• Antimatter search
• Charged cosmic ray spectra (p,?,e?,D,He,N)
• Geomagnetic effects on cosmic ray

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AMS-01 STS-91 Flight Physics Results (1)
NHe/NHe 1.110-6 Same spectrum for He,
He (Ref. Phys. Lett. B461(1999)387-396)
Any Spectrum from He
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AMS-01 STS-91 Flight Physics Results (2)
(Ref. Phys. Lett. B472(2000)215-226)
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AMS on ISS ? AMS-02
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AMS-02 on ISS
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AMS-02 on ISS
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AMS-02 Superconducting Magnet (1)
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AMS-02 Superconducting Magnet (2)Critical
Parameters

• Nominal Bending Power 0.85 Tm2
• Stray field _at_ radius of 230 cm lt 15.2 mT
• Peak in coil 6.6 T
• N. of Coils 2 Dipoles, 20 racetracks
• Magnetic Torque 0.272 Nm
• Conductor NbTi wire, Aluminum stabilized
• Operating Temperature 1.8 K _at_ 20 mbar (2600 lt
  superfluid Helium)
• Operating Current 450 A
• Power 1.5 kW (peak, during ramp), 400 W
  (maintenance)
• Endurance 27 to 33 months (w cryocoolers)
• Weight about 3 tons (whole magnetic system)
• Dimensions 2.7 m of diameter and 1.5 m of max
  height

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AMS-02 Synchrotron Radiation Detector

• Aim
• Identify the charge of TeV electrons and PeV
  nuclei using their synchrotron radiation in the
  earths magnetic field by observing synchrotron
  photons (Ethr KeV and eV respectively) in
  detector (2x3 m2).
• Photons position, counting and energy
  measurements give info on
• Particles charge sign, estimation on primary
  electron momentum hence distinguish electrons
  from nuclei.
• April 2001, a small stand-alone detector (PSRD)
  will fly as secondary payload on the Space
  Shuttle.
• For this flight, 16 YAlO3Ce(YAP) scintillating
  crystals of size 25x25x2 mm3 will be coupled
  directly to Hamamatsu R5900U PMTs.
• SRD will be installed on AMS-02 if PSRD will give
  good results

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AMS-02 Transition Radiation Detector (1)

• (Straw Drift Tube System), Aim
• Non-destructive information for particle
  identification in addition to electromagnetic
  calorimeter
• Identification of hadrons (?s against Ks and
  ps) and electrons
• Final goal is good e/h separation between 1-2
  (TRthr) GeV to about 100 GeV (hadrons start to
  radiate)
• e/p Rejection 1.5 to 4 10-3 with ? 90?95
  electron efficiency
• 6 mm diameter, 1.3 to 2 m long straw tubes
• Radiators Foam (Airex) or (10 ?m or 16 ?m)
  fibre (0.06 g/cm3)
• Gas mixture Xe/CO2 80/20, gain ? 2.5 104
• Operating temperature interval 10 C to 25 C
  (gradient ? 1 K)
• Weight 484 kg (350 kg detector)
• Test beam with e? and p (3.5 to 15 GeV)
• Tests and studies are underway for the final
  choice of radiator, gas mixture and GCPS, vacuum
  properties of straw tubes, radiator
  outgassing,mechanical stability etc.

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AMS-02 Time of Flight System (1)

• Aim
• Fast Trigger (L1) to the experiment
• ToF measurements of the particles w up/down
  resolution _at_ 10-8 level
• e/p separation up to about 1.5 GeV
• Absolute charge determination (in addition to
  tracker)
• Total Surface 8 m2
• Four layers each composed by 11cm wide (1cm
  thick) scintillator paddles
• Each paddle seen by 2 PMT at both ends
• Total PMT 224 (Hamamatsu fine-mesh tubes, space
  qualified, operates in B of 1?3 kGauss, _at_ 2kV, 2
  PMT/ counter-end)
• The angle between the field and PMT axis should
  be lt45
• Total weight 250 kg
• INFN Bologna

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AMS-02 Time of Flight System (2)
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AMS-02 Time of Flight System (3) (T.o.F.
Resolution from AMS-01)
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AMS-02 Tracker (1)

• Aim
• Rigidity (P/Ze) measurements
• Sign of Charge
• Absolute Charge (dE/dX , in addition to ToF
  system)
• Tracker detector based on 8 thin layers of
  double-sided silicon microstrips, with a spatial
  resolution better than 10 mm, ? 200.000 of
  electronics channel and ? 800 W of power.
• A complex detector, qualified for operation in
  space, with its ? 6 m2 of active surface will be
  the largest ever built before the LHC _at_ CERN.

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AMS-02 Tracker (2)

• Operating Temperature -10/25 C
• Power Dissipation on the Detector 1 W/ladder, in
  total 192 ladders
• dP/P ? 2 _at_ 1 GeV (? 8 in AMS-01) (for
  protons)
• The planes alignment will be monitored by a IR
  laser alignment system (as in case of AMS-01).
• INFN Perugia

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AMS-02 Tracker (3)(from AMS-01)
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AMS-02 Tracker (4)
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AMS-02 Tracker (5)
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AMS-02 Tracker (6)
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AMS-02 Ring Imaging Cerenkov Detector (1)

• Aim
• High efficiency rejection of albedo particles for
  momenta above threshold
• Measurement of particle velocity, mass
  determination (with P measurement from Tracker)
• dM/MdP/P ?2 d?/?
• Isotope identification below masses up to A ?25
  (10Be/9Be, 3He/4He etc.) and identification of
  chemical elements up Z ? 26 (up to Tracker
  rigidity limit)
• High level redundancy for e/p separation

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AMS-02 Ring Imaging Cerenkov Detector (2)

• Acceptance ? 0.4 m2.sr
• Radiator (NaF) n1.15 (2 cm thick) or n1.34 (1
  cm)
• Light Yield (N?) ? 50
• PMTs are pixelized version of Hamamatsu R5900 (16
  pixels, 0.45x0.45 cm2 each)
• Goal is
• d?/ ? ? 0.1 , p1.7 to 7.3 GeV/c/amu (for
  n1.15)
• 9Be and 10Be separation w Mass Resolution of ?
  0.2 up to 10 GeV
• INFN Bologna and ASI

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AMS-02 Ring Imaging Cerenkov Detector (3)
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AMS-02 Ring Imaging Cerenkov Detector (4)
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AMS-02 Ring Imaging Cerenkov Detector (5)
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AMS-02 Electromagnetic Calorimeter (1)

• Aim
• e/h separation _at_ 10-4 level in 1 ? 1000 GeV range
• High energy ? detection w good angular and energy
  resolution
• Distinct signature for antinuclei
• Measurement of neutral (albedo) particles (?,n,n)
• Energy Resolution (Simul.) ? 6.1 ? 3.1 _at_
  1 GeV
• ?
  4.4 ? 1.2 _at_ 10 GeV
• ?
  1.46 ? 0.2 _at_ 100 GeV
• INFN Pisa

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AMS-02 Electromagnetic Calorimeter (1)
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AMS-02 Electromagnetic Calorimeter (2)
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AMS-02 Electromagnetic Calorimeter (3)
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AMS-02 DAQ System (1)

• Link Speed
• Max raw link speed is 100 Mbps
• Max raw data transfer rate is ? 10 Mbytes/sec
• Data transfer rate w overhead is ? 5 Mbytes/sec
• Input data rate
• Max event rate is ? 2 kHz
• Average data size is ? 2 Kbytes
• Max input data rate is ? 4 Mbytes/sec
• Total 20-24 crates , max input data rate from
  each crate is ? 2 Kbytes/sec
• Output data rate
• Max output data rate is 100 Mbps
• Two links for data transfer
• Further data reduction on board with Level-3
  algorithm (Solutions DSP or PowerPC750 from
  Lockheed Martin)
• IEEE1355 (Space Wire) standard at all board and
  crate level communications

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AMS-02 DAQ System (2)
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AMS-02 Physics on ISS (1)
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AMS-02 Physics on ISS (2)
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AMS-02 Physics on ISS (3)
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AMS-02 on ISS
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Conclusions

• AMS-01 has successfully been tested during STS-91
  flight providing important information on
  operating in actual space conditions
• AMS-01 data allows to study the primary and
  trapped CR fluxes in the energy range from 100
  MeV to about 100 GeV
• AMS-02 is being built for the launch with the UF4
  during fall 2003
• AMS-02 will extend the accurate measurements of
  CR spectra to unexplored TeV region opening a new
  window for the search for Antimatter and
  Darkmatter.