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The AMS experiment

The AMS experiment. The purpose of the AMS experiment is to perform accurate, high statistics, long duration measurements in space of energetic (0.1 GV - few TV) charged CR including particle identification - energetic gamma rays. Nobel Prizes, Pulsar, Microwave, Microwave

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The AMS experiment

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  1. The AMS experiment

  2. The purpose of the AMS experiment is to perform accurate, high statistics, long duration measurements in space of energetic (0.1 GV - few TV) charged CR including particle identification - energetic gamma rays. Nobel Prizes, Pulsar, Microwave, Microwave Binary Pulsars, Solar neutrino X Ray sources

  3. FINLAND RUSSIA HELSINKI UNIV. UNIV. OF TURKU I.K.I. ITEP KURCHATOV INST. MOSCOW STATE UNIV. DENMARK UNIV. OF AARHUS NETHERLANDS GERMANY ESA-ESTEC NIKHEF NLR RWTH-I RWTH-III MAX-PLANK INST. UNIV. OF KARLSRUHE KOREA USA EWHA KYUNGPOOK NAT.UNIV. A&M FLORIDA UNIV. JOHNS HOPKINS UNIV. MIT - CAMBRIDGE NASA GODDARD SPACE FLIGHT CENTER NASA JOHNSON SPACE CENTER UNIV. OF MARYLAND-DEPRT OF PHYSICS UNIV. OF MARYLAND-E.W.S. S.CENTER YALE UNIV. - NEW HAVEN FRANCE ROMANIA CHINA BISEE (Beijing) IEE (Beijing) IHEP (Beijing) SJTU (Shanghai) SEU (Nanjing) SYSU (Guangzhou) SDU (Jinan) GAM MONTPELLIER LAPP ANNECY LPSC GRENOBLE ISS UNIV. OF BUCHAREST SWITZERLAND ETH-ZURICH UNIV. OF GENEVA TAIWAN SPAIN CIEMAT - MADRID I.A.C. CANARIAS. ITALY ACAD. SINICA (Taiwan) CSIST (Taiwan) NCU (Chung Li) NCKU (Tainan) NCTU (Hsinchu) NSPO (Hsinchu) ASI CARSO TRIESTE IROE FLORENCE INFN & UNIV. OF BOLOGNA INFN & UNIV. OF MILANO INFN & UNIV. OF PERUGIA INFN & UNIV. OF PISA INFN & UNIV. OF ROMA INFN & UNIV. OF SIENA MEXICO UNAM PORTUGAL LAB. OF INSTRUM. LISBON Y96673-05_1Commitment International commitments to AMS

  4. For every antiproton at some energy there are 10,000-100,000 protons For every positron at some energy there are ~10,000 protons which have same charge sign Secondary particles (long and short lived) are locally produced Single scatters change apparent particle charge sign in simple trackers Particle identification = the name of the game

  5. G.F. 5000 cm2 sr Exposure > 3 yrs dP/P2 ~ 0.004  2.5 TV, h/e = 10-6 (ECAL +TRD); Δx=10µm; Δt=100ps 3x3x3m, 7 t

  6. Contraints for a Space Experiment • Thermal Environment (day/night: T~100oC) • Vibration (6.8 g RMS) and G-Forces (17g) • Limitation : Weight (14 809 lb) and Power (2000 W) • Vacuum: < 10-10 Torr • Reliable for more than 3 years – Redundancy • Radiation: Ionizing Flux ~1000 cm-2s-1 • Orbital Debris and Micrometeorites • Must operate without services and human Intervention • Superconducting Magnet

  7. TOF Tracker Magnet TOF Cerenkov Counter Alpha Magnetic Spectrometer - AMS-01 First flight, STS-91, 2 June 1998 (10 days) AMS

  8. Superconducting Magnet Flux Return Coils B B Dipole Coils He Vessel 2500 Liters superfluid He Analyzing power BL2 = 0.8 Tm2

  9. The coils completed

  10. Now inside the cryostat

  11. TRD detector to separate e+ from protons • e+/prejection • 102 –103 in • 1.5 – 300 GeV • with ECAL • e+/p rejection • >106 : 3 –300GeV

  12. TRD detector CERNbeamtest with TRD prototype: proton rejection > 100 up to 250 GeV at electron efficiency 90% reached • 20 layers,328 chambers,5248 tubes • Mechanical accuracy <100μm • Assembly ready Single tube spectra for p+/e separation.

  13. Silicon Tracker • Rigidity (DR/R 2% for 1 • GeV Protons) with Magnet • Signed Charge (dE/dx) • 8 Planes, ~6m2 • Pitch (Bending): 110 mm(coord. res. 10 mm) • Pitch (Non-Bending): 208mm (coord. res. 30 mm ) • Charge measurent up Z ~26

  14. Ring Imaging Cerenkov Counter • Accurate Velocity • / = (0.670.01)*10-3% • (test beam) • Isotopic Separation. • |Q| measurements up • Z~ 30 Cerenkov Cone Aerogel Radiator(n=1.03, 3cm) NaF radiator (n=1.33, 0.5cm) Mirror Photomultipliers 8.5 x 8.5 mm2 spatial pixel granularity

  15. due to limitations in weight, space experiments have an ECAL section, normally with limited thickness Standard measurement for “thickness” is the radiation length (X0) which is related to the development of the energy deposition a detector with high X0 has a good energy and angular resolution and it is capable of measuring particles in the energy range 10GeV-1TeV with good accuracy (<5%) AGILE : 1.5X0 GLAST 10X0 AMS-02 : 16.1 X0 Calorimetry in space AMS: 3D sampling calorimeter: measure energy (few % resolution) and angle (1° - 0.5° angular resolution) 10-3 p rejection at 95% e efficiency via shower profile 1 GeV - 1 TeV

  16. Electromagnetic calorimeter Sampling calorimeter with lead foils and scintillating fibers Basic block is superlayer: 11 lead and 10 fiber layers 9 superlayers with alternating x and y readout Total thickness is 166mm, corresponding to 16.2 X0 Total weight 634 kg p e Lead foil (1mm) Fibers (1mm) z 1.73mm particle direction FIBER LEAD y x

  17. 2007 Assembly at CERN Final integration in 2007 at CERN Final testing in ESA vacuum chamber (NL) 2007 2008 Thermal vacuum test at ESA, Holland

  18. ToF, Tracker, RICH performance verified at heavy ion test beam (CERN,GSI) Fe Ca P Ne B Charge measurements

  19. Test Results from Tracker detector He Li C O N Be Si TOF Nuclei separation He Charge measurement: TOF, Tracker and RICH N C Verified by heavy ion beam tests at CERN & GSI.

  20. 1 day 6 months 1 year AMS-02 capabilities Boron Beryllium Helium 1 year 6 months 1 day 10Be (t1/2=1.5Myr) / 9Be will allow to estimate the propagation time and size of the ISM B is secondary produced in nuclear interaction, C is primary produced in stars. B/C is sensitive to the diffusion constant 3He/4He ratio is sensitive to the density of the ISM

  21. One propagation model of our Galaxy

  22. Another propagation model including static magnetic fields and gas clouds it is shown that Galactic cosmic rays can be effectively confined through magnetic reflection by molecular clouds, Integral excess of positrons in bulge because positrons are trapped in magnetic mirrors between gas clouds

  23. Magnetic fields observed in spiral galaxies fieldline disk A few uG perpendicular to disc: Strong convection to disc? A few µG in the disc: can lead to slow radial diffusion Isotropic diffusion assumes randomly oriented magnetic turbulences. Preferred magnetic field directions -> anisotropic diffusion

  24. Preliminary results from GALPROP with isotropic and anisotropic propagation Antiprotons B/C ratio Summary: with anisotropic propagation you can send charged particles whereever you want and still be consistent with B/C and 10Be/9Be

  25. Summary • AMS is a High Energy Physics detector in space foreseen to operate on the ISS for 3 years • Asked by NASA to be Ready For Flight end 2008 • The cosmic rays, including gamma rays, will be measured with a high accuracy from the GeV to the TeV range • Unique opportunity to study properties of our Galaxy and its dark matter, including how particles propagate

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