The Alpha Magnetic Spectrometer on the International Space Station

1. The Alpha Magnetic Spectrometer on the International Space Station Carmen Palomares CIEMAT (Madrid) On behalf of the AMS Collaboration XXXXth RENCONTRES DE MORIOND

2. AMS is a magnetic spectrometer to be installed on ISS ( 450 km) The aim of AMS is the direct detection of primary cosmic rays below the knee (NO UHECR): Determination of energy with high resolution Large statistics Very good particle identification XXXXth RENCONTRES DE MORIOND

3. AMS-02 • Large geometrical acceptance: 0.45 m2 sr • Long exposure: 3 years • Redundant measurements of the main parameters • Operational conditions: • High vacuum • High radiation levels • Strong gradients of temperature : • -60°C — +40°C • Weight < 7 Tons • Acceleration 3g (6g) launch (landing) • Power consumption < 3 kW XXXXth RENCONTRES DE MORIOND

4. 1 year AMSGoals Antimatter search ( ) with a sensitivity 103 better than current limits Dark matter search. Non-baryonic DM: WIMP (LSP) Signatures: e+, • High statistics study of • the cosmic ray spectrum • Isotope separation • Antiparticle spectrum XXXXth RENCONTRES DE MORIOND

5. AMS detector Set of sub detectors devoted to the measurement of energy and particle identification: Z, mass,… XXXXth RENCONTRES DE MORIOND

6. AMS detector Energy( , ) Tracker (R)/R = 1.5% for 10 GV Max. Dynamic Range 1 TV ECAL (E)/E ~ 3% for 100 GeV electrons XXXXth RENCONTRES DE MORIOND

7. AMS detector Particle Identification Charge (Z): Tracker, ToF and RICH Z  26 (small charge confusion) Tracker + ToF  sing(Z) Electron/hadron separation: TRD: p/e rejection factor 102 - 103 in the range 1.5 – 300 GeV ECAL: Hadron rejection factor 104 for E<1TeV Test-beam results • (Mass) : ToF: ()/ = 3.5% (for =1) RICH: ()/ ~ 0.1%for protons (m)/m = 2% XXXXth RENCONTRES DE MORIOND

8. AMS detector status • The sub-detectors have been tested: • Test-beams at CERN using prototypes of the final detectors • Qualification tests of the flight elements • Currently, they are being assembled and qualified • Integration and functional tests of the whole detector at CERN (2006) Magnet: coils already done ToF XXXXth RENCONTRES DE MORIOND

9. Galactic Cosmic Rays The high energy CR are produced, accelerated and propagated in the Galaxy and provide information about the sources and the matter content and magneto- hydrodynamical properties of our Galaxy • Current critical measurements that can be achieved by AMS are: • Very accuracy measurements of the spectrum of H & He (R 1 TV) • Chemical abundances (from H to Fe) • The ratio of spallation products such as Boron to the primary nuclei • such as Carbon as a function of energy (E  1 TeV) • The energy dependence of the fraction of antiparticles (E100GeV) • Isotopic ratios of elements (E  10 GV) XXXXth RENCONTRES DE MORIOND

10. Energy Spectrum Protons and Helium:The most abundant elements Spectral index: Origin and acceleration, differences between both species Used to determine the expected fluxes of and e+ , atmospheric neutrinos, etc… protons AMS-02 expectations Helium AMS-02 expectations XXXXth RENCONTRES DE MORIOND

11. Hadrons Z>2 In addition to the information provided by primary CR such as C, N and O, secondary CR (produced by spallation) are used to estimate the amount of matter traversed by the CR (confinement volume and time) AMS-02 expectations XXXXth RENCONTRES DE MORIOND

12. Radiactive Isotopes: Provide information about the confinement time of CR in the Galaxy 10Be is specially interesting for its half time (t1/2 = 1.51 106 years) of the same order than the confinement time of the CR in the Galaxy AMS-02 expectations • After 3 years, AMS will collect ~10510Be • (m)/m = 2% XXXXth RENCONTRES DE MORIOND

13. Antiparticles Pure secondary CR from interactions with the ISM Exotic origin: A very good understanding of the expected CR fluxes Antiprotons Positrons Data consistent with secondary CR No conclusive data XXXXth RENCONTRES DE MORIOND

14. Antiparticles AMS will measure the flux up to 400 GeV After 3 years will collect 106 AMS will collect 106 e+ and 107 e- These fluxes provide sensitivity to darkmatter in several scenarios AMS-02 expectations AMS-02 expectations XXXXth RENCONTRES DE MORIOND

15. Summary • AMS will be the first large acceptance magnetic spectrometer • to operate in space for a long period of time • Precise experimental measurements provided by AMS would • yield information about the galactic properties, constraining • propagation models • AMS will be able also to discover some evidence for new • physics (dark matter) or new objects (e.g. stars made of • antimatter) • Currently, AMS-02 is in the construction phase. • The detector must be ready for the launch by the end of 2007 XXXXth RENCONTRES DE MORIOND

16. More Slides XXXXth RENCONTRES DE MORIOND

17. 1 day 6 hours Light Isotopes D and 3He are secondary particles coming from nuclear interactions with the ISM and provide a description of the propagation of p and He AMS-02 expectations AMS-02 expectations XXXXth RENCONTRES DE MORIOND

18. Search of antimatter XXXXth RENCONTRES DE MORIOND

19. Good understanding of GCR origin and propagation will be used to discover some evidence for new physics (dark matter) or new objects (e.g. stars made of antimatter) XXXXth RENCONTRES DE MORIOND

20. ECAL XXXXth RENCONTRES DE MORIOND

21. Ring Imaging Cerenkov Detector Radiator (aerogel) ()/ ~ 0.1%para =1 Charge determination up to Z~26 mirror PMT Plane XXXXth RENCONTRES DE MORIOND

22. Transition Radiation Detector 20 layers XXXXth RENCONTRES DE MORIOND