Vulcano Workshop 2004

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AMS a Cosmic Ray spectrometer on the ISS
Davide Grandi INFN Milano ITALY On behalf of the
AMS Collaboration

• Vulcano Workshop 2004

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Davide Grandi
Vulcano Workshop 2004
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Outline of the talk

• AMS physics goals
• AMS-02 detector
• AMS-01 measurements and near Earth Environment
• CR Astrophysics
• CR isotopes and propagation (RICH subdetector)
• Conclusions
• Next talk of E. Fiandrini focused on AM and DM
  (and different subdetectors)

Davide Grandi
Vulcano Workshop 2004
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AMS physics goals

• CR Astrophysics
• Primary CR flux precise measurements
• Measurements of CR (e , g, 3,4He, B, C 9,10Be,
  Zlt26) composition in the GeV-TeV region
• Search for Cosmic Antimatter
• Search for Dark Matter
• Gamma Rays astrophysics

Davide Grandi
Vulcano Workshop 2004
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Antimatter search AMS-01
AMS-01 measured spectrum
Davide Grandi
Vulcano Workshop 2004
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TRD (foam straw drift tubes Xe/CO2) separate
e/p up to 300 GeV
TOF (2x2 planes of scintillator hodoscopes) Dt
120 ps, b and Z
Superconducting magnet BL20.85 Tm2 for sign(Z)
Silicon Tracker (8 layers double sided) for
p,Z and sign(Z)
RICH (radiator Aerogel/NaF) b Z and sign(Z)
ECAL (Lead Scintillator fibers) e/p separation
Davide Grandi
Vulcano Workshop 2004
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New detector

• Superconducting magnet in space (cooled to 1.8 oK
  by 3000 l superfluid He)
• Large acceptance (0.5 m2sr)
• Long time exposure (3-5 years) and ionizing flux
  max rate 2 kHz
• Separate light isotopes for Elt10 GeV/n
• B lt 300 G at 2 m
• All coils already built

Davide Grandi
Vulcano Workshop 2004
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Primary CR fluxes

• Protons (88 of total spectrum)
• He (? 9)
• Electrons (2 )
• Antiprotons and D
• Power spectra E-g where g ?2-3 for acceleration
  mod.
• Propagation the magnetic field (galactic,
  heliospheric and Earth)
• Background for DM measure p- ? 10-3 p, e-, He

p
He
e
g
e-
g
Davide Grandi
Vulcano Workshop 2004
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AMS-01 CR measurements

• 108 CR events measured in 10 days
• 3He and 4He measured
• D spectrum
• Positrons and electrons measured (and ratio
  e/(ee-))
• Undercutoff Secondary CR

Davide Grandi
Vulcano Workshop 2004
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Magnetic field and Secondary CR
Origin and sink of secondary CR (e and e-) in
atmosphere
Davide Grandi
Vulcano Workshop 2004
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Separation of Primary and Secondary CR

• Reconstruction of particle trajectory using the
  last model of magnetic field (IGRF and
  Tsyganenko)
• backtracing and forward tracing technique
• nature of the CR and
• nature (trapping) and origin of secondary CR
• TF calculation evaluation of magnetosphere
  transmissivity (Proc. ICSC 2003 ESA SP-533)
• Adiabatic analysis of undercutoff leptons and
  protons (Jour. Geoph. Res., 108 A11, 2003)
• MC of secondary CR production in atmosphere
  (Phys. Lett., B489, 2000)

Davide Grandi
Vulcano Workshop 2004
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Separation of Primary and Secondary CR
The TF calculation (based on the backtracing) for
the AMS geomagnetic region can separate the
primary CR component from the total measured flux

Davide Grandi
Vulcano Workshop 2004
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SOLAR Modulation

• Solar cycle (22 years)
• Magnetic field polarity (drift in the heliosphere
  important for the ratio p/antip) in year 2012
  will change polarity (from Alt0 to Agt0)

• 3-5 years of data taking (2008-2013) important
  test of external magnetic field models
  (Tsyganenko) and heliospheric diffusion models
  for Galactic CR

Davide Grandi
Vulcano Workshop 2004
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CR propagation

• Propagation models of CR in the galaxy
  diffusion, convection and reacceleration
• Nuclear interaction of Primary CR with the ISM
  
• abundance of elements
• Local modulation effects (the Sun..)
• Primary CR (acceleration mech.)
• Secondary CR B/C ratio is sensitive to diffusion
  (B secondary while C primary)
• Radioactive nuclei 10Be/9Be (t 10Be 1.5x106 y)
  estimate propagation time and size of ISM
• 3He/4He sensitive to the density of ISM

Davide Grandi
Vulcano Workshop 2004
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Ratios of abundances RICH
Cerenkov Cone

• Accurate velocity measurement via the opening
  angle of the Cerenkov cone
• Isotope separation
• Resol. D b/b 0.1 (p)
• Test of CR propagation
• Measure charge
• up to Z 30
• Measure the value Z

Aerogel Radiator
Mirror
Photomultipliers
RICH gives additional particle identification
capability
Davide Grandi
Vulcano Workshop 2004
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AMS-02 RICH
Without mirror
Be
Fe
With mirror in
SPS beam A/Z 2
Reconstructed charge spectrum
Davide Grandi
Vulcano Workshop 2004
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AMS-02 capabilities
Unstable isotopes are very sensitive of the
conditions of the solar system neighborhood
Davide Grandi
Vulcano Workshop 2004
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AMS-02 capabilities
Davide Grandi
Vulcano Workshop 2004
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AMS-02 capabilities
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Vulcano Workshop 2004
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CONCLUSIONS

• AMS-02 mission starting 2008 accurate new data
  from GeV to TeV
• CR measurements for 3-5 year
• Long term study of Solar modulation and
  geomagnetic field effect on CR flux
• Test of CR propagation (radioactive nulcei) ISM
  density (isotopes secondary CR)
• Secondary CR creation (important for
  atmospheric n fluxes) and near Earth radiation
  environment

Davide Grandi
Vulcano Workshop 2004