1. XX ECRS ,Lisbon, 5th September, 2006
Detection and measurement of g rays with the AMS02 detector
Simonetta Gentile
Università di Roma La Sapienza, INFN
on behalf of AMS Collaboration
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

2. XX ECRS ,Lisbon, 5th September, 2006
Outline
AMS detector
g detection performances:
Energy resolution
Angular resolution
Physics: Dark matter g
Minimal Supersymmetric Standard Model
Conclusions
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

3. XX ECRS ,Lisbon, 5th September, 2006
The Alpha Magnetic Spectrometer
Designed to take data on International Space Station for more than 3 years.
Full assembled in 2008
Study of charged particles and nuclei with rigidity 0.5 GV– few TV
Direct search for antimatter (antihelium)
Indirect search for
Dark Matter .
Total statistics expected above events
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

4. XX ECRS ,Lisbon, 5th September, 2006
Dimensions 3m x 3mx3m,7 t
Large acceptance ~ 0.5m2sr.
Transition Radiation Detector
Time of Flight scintillator counters
8 layers of Si strips on 5 supporting planes in superconducting magnet
Rich Imaging Cerenkov detector
Electromagnetic calorimeter
M.L. Arruda
Poster
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

5. XX ECRS ,Lisbon, 5th September, 2006
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

6. XX ECRS ,Lisbon, 5th September, 2006
Superconducting Magnet
Flux Return Coils B B
Dipole
Coils
He Vessel
2500 Liters Superfluid He
BL2 = 0.9 Tm2
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

7. XX ECRS ,Lisbon, 5th September, 2006
Silicon Tracker
Rigidity (DR/R < 2% up 20
GeV Protons) with Magnet
Signed Charge (dE/dx)
8 Layers in 5 planes, ~6.7m2
Pitch (Bending): 110 mm (coord. res. 10 mm )
Pitch (Non-Bending): 208mm (coord. res. 30 mm )
Charge magnitude up Z ~ 26
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

8. XX ECRS ,Lisbon, 5th September, 2006
Electromagnetic Calorimeter
3D sampling calorimeter
9 superlayers of 10 fiber/lead planes each alternate in x and y scintillating fibers viewed by PMT
16.4 X0 radiation length
Measure energy (few % resolution) and angle (1° - 0.5° angular resolution) of g, e+,e- e p
10-3 p Rejection with 95% e Efficiency Via Shower Profile
1 GeV - 1 TeV
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

9. Electromagnetic Calorimeter
ECAL
(E)/E ~ 100 GeV e-
Speak also about Charge-Id up to Z=26, sign from TOF/Tracker, e/p separation between (TOF) and (ECAL)
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

10. Photons in AMS: Two complementary modes
Single photon mode: detection
In the electromagnetic calorimeter.
Criteria: “electromagnetic shape”
No activity in the rest of detector
Conversion mode: g conversion
In upstream layers of the detector
Criteria:very small invariant mass, no TRD
Activity in top layer, no particle activity
in the rest of detector
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

11. Performances -rays detection
Single Photon Mode
  EM Shower
θ ~ 0.02 GeV
E/E~ GeV
  EM Shower
  e+ + e- 3% 6%
0.02o
1.0o
2 complementary modes for photon detection
Conversion Mode
  e+ + e-
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

12. Performances -rays detection
Effective Area of Tracker and ECAL
Tracker
Tracker
ECAL
ECAL
Cos(incident angle)
Acceptance ECAL (TRK) ~ 5 (3)·10-2 m2·sr from 10 GeV.
Proton rejection 105 ; e - ~ 104
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

13. Test beam (conversion mode)
Test beam with electrons (producing g up to 7 GeV).
Dominant systematic multiple scattering of electrons
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

14. XX ECRS ,Lisbon, 5th September, 2006
 Origin
Energy range : GeV
Sources in scope of AMS:
Galactic : pulsars, nebulas (VELA, CRAB,…)
Extra-Galactic : GRBs
Diffuse  emission : interaction of Charged rays with galactic medium produce  (0)
Dark Matter
R. Pereira
Poster
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

15. Cosmic Ray Fluxes Cosmic Rays Composition :
AMS ~1/s
AMS ~1/hour
AMS ~1/day
Cosmic Rays Composition :
p : 88 %
He nuclei : 9 %
e- : 2 %
 : < 1%
Standard CR spectra follows a "power law" E- with  = 2-3
DM signal : exponential cut-off in the spectra
Number of particles inside geometrical acceptance
( assuming 0.45 m2sr )2.8
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

16. XX ECRS ,Lisbon, 5th September, 2006
 rays
EGRET map E>100 MeV
Cygnus
Region
3C279
Geminga
Vela
Cosmic Ray
Interactions
With ISM
LMC
PKS
PKS
Crab
PSR B
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

17. AMS exposure to galactic g
Revolution : 90’
51º latitude
Conversion mode (sel. acc.)
Calorimeter mode (geom. acc.= area x t obs)
Larger Field of view: 43⁰ GC : ~ 40 days
Field of View : 23º GC : ~ 15 days
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

18. Astrophysical g sources
AMS expectations
Measurements and model
prediction for diffuse g rays
from central part of galaxy
rays emission from Vela Pulsar
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

19. XX ECRS ,Lisbon, 5th September, 2006
Dark Matter
One of the most popular candidates for Dark matter is the neutralino 0, the Lightest Supersymmetric Particle (LSP), neutral, weak-interacting and stable in R-parity conserving SUSY models.
NOT YET OBSERVED!
Mixture of superpartners of Higgs boson and W-boson and Z/ bosons (B)
Direct detection – elastic interaction on nucleus (CDMS, DAMA, EDELWEISS)
Indirect detection - Neutralino annihilation
0101  qq , W+W-, ZZ, ...
 p ,D ,  (continuum), e+
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

20. Indirect searches with AMS: detection channels
Possible detectable products from: xx with
small physical backgrounds
Gamma rays:
They are originated either from annihilation into a final state containing Zγ or γγ (line signal) or from the decay of other primary annihilation products (continuum signal).
Positrons:
Primarily from the decay of gauge bosons (e.g.,W+W-) as primary annihilation products; or from heavy quark/lepton decay
Antiprotons and antideuterons:
Production in WIMP annihilations by hadronization of quark and gluon subproducts.
 ray telescopes
and satellites
AMS
Balloons
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

21. XX ECRS ,Lisbon, 5th September, 2006
Dark Matter -  ray case
Detection rate (source) :
N v 2 (r) dl() d
m2
 
  
LoS
SUSY
Astrophysics
• source D M : g Galactic Centre (G. C.)…..
Nuclear recoils in the dense center
Mass density
Profile in our Galaxy
NFW : Navarro-Frenk-White (, , ) = (1, 2, 1)
Moore et al. : (, , ) = (1, 1.5, 1.5)
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

22. Gamma sensitivity to different DM halo profilesB B
Gamma rays
Many experiments will be covering the little known GeV range in the next decade.
Case considered: Galactic center treated as point source. Favorable conditions to detect or exclude AMSB scenarios; benchmark points of parameter space accesible in case of cuspy profile as well as several KK candidates.
MSSM = Minimal SuperSymetric Model
mSUGRA = Minimal SUGRA model
SUGRA = SuperGravity grand unified models
AMSB = Anomaly Mediated SUSY Breaking
A.Jacholkwska et al. Astro-ph/ ,
Phys. Rev D.74 vol 2
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

23. XX ECRS ,Lisbon, 5th September, 2006
CONCLUSIONS
AMS02 is magnetic spectrometer on International Space Station, ready in 2008:
Large Acceptance
Long term operation
AMS02 will provide:
Precise Cosmic Ray elemental and isotopic fluxes in a wide energy range
Direct search for antimatter (antihelium)
Indirect search for Dark Matter (positrons, antiprotrons, gamma).
Good g performance detection through conversion and and calorimetric mode:
Angular resolution under ~3º (~0.1º) over 10 GeV.
Energy resolution ~3 % over 10 GeV
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

24. XX ECRS ,Lisbon, 5th September, 2006
CONCLUSIONS
Using Si-Tracker and EM Calorimeter, AMS-02 will provide new  measurements in the range GeV .
AMS-02 will study several galactic and extragalactic  sources as Pulsars, GRBs…
(At least) constraints in various Cold Dark Models will be provided.
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006

25. XX ECRS ,Lisbon, 5th September, 2006
-rays - AMS vs. GLAST
Similarities: Silicon for Tracker, Coverage GeV
GLAST: quasi-independent detector operation, charged particle vetoing, conversion-optimized
Before I come to my conclusions
Simonetta Gentile
XX ECRS ,Lisbon, 5th September, 2006