AMS-02 INTERNATIONAL SPACE STATION. on the. Kate Scholberg, MIT, for the AMS collaboration

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1 AMS-02 on the INTERNATIONAL SPACE STATION Kate Scholberg, MIT, for the AMS collaboration

2 AMS Overview OUTLINE AMS-01, the Shuttle Precursor Mission AMS-02, Basic Instrumentation Indirect DM Detection with AMS-02 Positrons Instrumentation focus: TRD, ECAL Antiprotons γ-rays Summary Magnet, tracker, TOF

3 The ALPHA MAGNETIC SPECTROMETER A charged particle detector in space to study cosmic rays up to 1 TeV NASA-DOE collaboration, plus Asia, Europe led by Prof. S. C. C. Ting

4 Physics Motivations Search for ANTIMATTER (antinuclei) original motivation Search for DARK MATTER Indirect detection via χχ annihilation signal Search for OTHER EXOTIC MATTER e.g. strangelets (anomalous Q/M) COSMIC RAY studies

5 Basic idea: magnetic spectrometer magnet tracker time of flight time of flight p = γmv from curvature v from time of flight q magnitude from energy loss q sign from direction of curvature m,q identifies particle

6 The AMS-01 Precursor Mission D on the Space Shuttle DOE/NASA International Collaboration Permanent magnet, 0.15 T Si tracker, TOF, Cherenkov Flew June 2-12, 1998 on Discovery, STS degree orbit km ~100 hours of data 100 million particles

7 The AMS-01 Detector Scale: ~ 1 m 3

8 Food for MIR astronauts AMS-01

9 Results of AMS-01 He search Z =2 Events He 0 events nothing!! AMS STS - 91 He events Also, no antinuclei found with Z > GV (Rigidity = p/z) Sign Rigidity

10 AMS-02 on ISS Launch 2006 for 3 year exposure Now with a SUPERCONDUCTING magnet, 0.9 Tesla, allowing tracking up to ~ TeV Acceptance ~0.5 m 2 sr 8 layers of Si strip tracker planes Time of Flight scintillator counters Transition Radiation Detector Rich Imaging Cherenkov Detector Electromagnetic Calorimeter

11 AMS-02

12 Requirements for a detector in space Weight Limit: lb Temperature: -180 o to +50 o C Power consumption: 2 kw Data rate: 2 Mbyte/s 9g acceleration during takeoff Must operate in vacuum Must operate without services for 3 years

13 "Basic" spectrometer elements: magnet tracker tof veto

14 AMS-02 Magnet

15 Want no net dipole moment to avoid torque on the Space Station Rare earth magnet Superconducting magnet NbTi Al-stabilized superconductor Cooled by superfluid helium Central field 0.87 T, operating current 450 A

16 AMS-02 Silicon Tracker Measure curvature of track in B field to get momentum Also measure energy deposition to get charge (de/dx q 2 ) 8 double-sided planes 192 ladders 7 square meters 196,000 channels MDR ~ 3 TeV (protons)

17 AMS-02 Time of Flight (TOF) Velocity measurement Alternate de/dx Provides fast trigger 4 planes of scintillator viewed by photomultiplier tubes 120 ps time-of-flight resolution

18 AMS Overview OUTLINE AMS-01, the Shuttle Precursor Mission AMS-02, Basic Instrumentation Indirect DM Detection with AMS-02 Positrons Instrumentation focus: TRD, ECAL Antiprotons γ-rays Summary Magnet, tracker, TOF

19 Signature of neutralino dark matter: Look for ANNIHILATION PRODUCTS χχ gauge bosons quarks leptons e + p d γ... Here, have background of SECONDARIES from CR collisions look for ANOMALIES in the energy distribution "bump in the spectrum"

20 Look for anomalous POSITRONS Positron fraction background from secondaries should be smooth χχ annihilation would give bump around ~ GeV

21 A hint from a balloon experiment, HEAT? Positron fraction vs energy hep-ph/ Bump at ~10 GeV seen with different instruments

22 Interpretation in terms of SUSY DM Baltz et al. astro-ph/ N Fits require "boost factor" to enhance signal (plausible for clumpy DM)

23 What do you need to see an anomalous positron signal? At ~ 10 GeV, get 1 e - for ~100 p, get few e + for 100 e - => need excellent e + /p separation Misidentification rate must be < 1 in 10 5 To achieve this: TRANSITION RADIATION DETECTOR (TRD) ELECTROMAGNETIC MCALORIMETER (ECAL) proton rejection ~10 3 proton rejection ~10 3

24 Focus on instrumentation needed for SUSY DM search

25 AMS-02 Transition Radiation Detector Transition radiation is produced when particles cross boundaries between materials with different dielectric properties Significant for relativistic γ =E/m >~ 1000 At >~ GeV energies, electrons produce TR x-rays; protons do not

26 The AMS-02 TRD 20 layers of fleece radiators (many dielectric interfaces) 50% probability of TR photon per layer for ~GeV electrons carbon fiber octagonal structure 20 layers of Xe/CO 2 filled straw tubes for de/dx, TR x-ray detection Expect proton rejection ~10 3

27 AMS-02 Electromagnetic Calorimeter (ECAL) 3D sampling calorimeter Protons and electrons create showers with different shapes, so they can be distinguished

28 AMS-02 ECAL 9 superlayers of 10 fiber/lead planes each, alternate in x and y Scintillating fibers viewed by PMTs Total radiation lengths: 15 X 0 Expect proton rejection ~10 3

29 Prospects for AMS-02 positrons Following Baltz et al. Will measure positron spectrum precisely to ~300 GeV/c

30 Look for anomalous ANTIPROTONS background from secondaries In this case, low energies may have less background A But: geomagnetic cutoff, solar wind effects...

31 AMS-02 prospects for antiprotons SUSY DM signal most likely at low energy, mostly below geomagnetic cutoff (few to ~10 GeV) 3 years possibly some distortion... but at the least, will better understand CR bg models

32 Another possibility: ANTIDEUTERONS Even more kinematic suppression of secondary background at low energy than for p AMS-02 expects a handful of secondary d

33 Can also look for χχ annihilation via γ-ray products χχ gauge bosons quarks leptons hadronize γ's in showers Continuum emission at ~1/10 m χ (Possibly, spectral line from direct χχ γγ, Ζγ) AMS-02 has some γ-ray detection capability

34 See γ's via pair production in material above the tracker ("conversion mode") γ event from AMS-01 e + γ e - γ Also: γ em shower in ECAL ("single photon mode")

35 AMS-02 Gamma Ray Capabilities Angular resolution Energy resolution χχ annihilation γ's (some SUSY parameters) Astronomy: blazars, GRB's, diffuse flux Note: can't point actively G. Lamanna

36 Sensitivity to msugra parameters: example R0 = 8.0 kpc, r0 = 0.3 GeV/cm 3, a = 20 kpc A. Jacholskowska et al. Look at Galactic center, where χ may be trapped

37 Summary of AMS-02 DM Search AMS-02 will be sensitive to non-baryonic dark matter (e.g. χ) via χχ annihilation products Positrons in >~ 10 GeV range Need good proton rejection (TRD, ECAL) Antiprotons in ~< 1 GeV range Gamma rays in few-100 GeV range (plus astrophysics) using tracker, ECAL 3 year run on ISS starting 2006 to explore new territory

Cosmic Ray Astrophysics with AMS-02 Daniel Haas - Université de Genève on behalf of the AMS collaboration

Cosmic Ray Astrophysics with AMS-02 Daniel Haas - Université de Genève on behalf of the AMS collaboration Overview of AMS-02 Cosmic ray studies p/he, Z>2, p/e +, γ-rays Comparison AMS vs. GLAST AMS vs.