may, 18. 2007 ppc07, college station, w. de boer, univ. karlsruhe1 the ams experiment

May, 18. 2007 PPC07, College Station, W. de Boer, Univ. Karlsruhe 1

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,(1) Pulsar,(2) Microwave,(3) Microwave(4) Binary Pulsars,(5) Solar neutrino

X Ray sources


International commitments to AMSInternational commitments to AMS

USAA&M FLORIDA UNIV.JOHNS HOPKINS UNIV.MIT - CAMBRIDGENASA GODDARD SPACE FLIGHT CENTERNASA JOHNSON SPACE CENTERUNIV. OF MARYLAND-DEPRT OF PHYSICSUNIV. OF MARYLAND-E.W.S. S.CENTERYALE UNIV. - NEW HAVEN

MEXICO

UNAM

DENMARKUNIV. OF AARHUS

FINLAND

HELSINKI UNIV.UNIV. OF TURKU

FRANCEGAM MONTPELLIERLAPP ANNECYLPSC GRENOBLE

GERMANYRWTH-IRWTH-IIIMAX-PLANK INST.UNIV. OF KARLSRUHE

ITALYASICARSO TRIESTEIROE FLORENCEINFN & UNIV. OF BOLOGNAINFN & UNIV. OF MILANOINFN & UNIV. OF PERUGIAINFN & UNIV. OF PISAINFN & UNIV. OF ROMAINFN & UNIV. OF SIENA

NETHERLANDSESA-ESTECNIKHEFNLR

ROMANIAISSUNIV. OF BUCHAREST

RUSSIAI.K.I.ITEPKURCHATOV INST.MOSCOW STATE UNIV.

SPAINCIEMAT - MADRIDI.A.C. CANARIAS.

SWITZERLANDETH-ZURICHUNIV. OF GENEVA

CHINA BISEE (Beijing)IEE (Beijing)IHEP (Beijing)SJTU (Shanghai)SEU (Nanjing)SYSU (Guangzhou)SDU (Jinan)

KOREA

EWHAKYUNGPOOK NAT.UNIV.

Y96673-05_1Commitment

PORTUGAL

LAB. OF INSTRUM. LISBON

ACAD. SINICA (Taiwan)CSIST (Taiwan)NCU (Chung Li)NCKU (Tainan)

NCTU (Hsinchu)NSPO (Hsinchu)

TAIWAN


Particle identification = the name of the game

• 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


G.F. 5000 cm2 srExposure > 3 yrs

dP/P2 ~ 0.004 2.5 TV, h/e = 10-6 (ECAL +TRD); Δx=10µm; Δt=100ps

3x3x3m, 7 t


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


Alpha Magnetic Spectrometer - AMS-01

First flight, STS-91, 2 June 1998 (10 days)

TOFTOF

TrackerTracker

MagnetMagnet

TOFTOF

Cerenkov CounterCerenkov Counter

AMS


Flux Return Coils

DipoleCoils

He Vessel

B

B

2500 Liters superfluid He

Superconducting Magnet

Analyzing power

BL2 = 0.8 Tm2


The coils completed


Now inside the cryostat


: 3 –300GeV •e+/p rejection102 –103 in1.5 – 300 GeV

• with ECALe+/p rejection >106

TRD detector to separate e+ from protons


TRD detector

• 20 layers,328 chambers,5248 tubes•Mechanical accuracy <100μm•Assembly ready

CERN beamtest with TRD prototype: proton rejection > 100 up to 250 GeV at electron efficiency 90% reached

Single tube spectra for p+/e separation.


Silicon Tracker

•Rigidity (R/R 2% for 1

GeV Protons) with Magnet•Signed Charge (dE/dx)•8 Planes, ~6m2

•Pitch (Bending): 110 m (coord. res. 10 m )•Pitch (Non-Bending): 208m (coord. res. 30 m )•Charge measurent up Z ~ 26


Aerogel Radiator(n=1.03, 3cm)NaF radiator (n=1.33, 0.5cm)

Mirror

Cerenkov Cone

Photomultipliers

Ring Imaging Cerenkov Counter

•Accurate Velocity

/ = (0.670.01)*10-3% (test beam)

• Isotopic Separation.

• |Q| measurements up

Z~ 30

8.5 x 8.5 mm2 spatial pixel granularity


• 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


Lead foil(1mm)

Fibers(1mm)

y x

z particle direction1.73mm

p e

FIBER

LEAD

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

Electromagnetic calorimeter


2007

2008

Thermal vacuum test at ESA, Holland

2007 Assembly at CERN

Final integration in 2007 at CERNFinal testing in ESA vacuum chamber (NL)


Charge measurements

B

Ne

P

Ca

Fe

ToF, Tracker, RICH performance verified at heavy ion test beam (CERN,GSI)


He

CNCharge measurement:

TOF, Tracker and RICH

Verified by heavy ion beam tests at CERN & GSI.

TOF

LiHe

Be

CO

N

Si

Test Results from Tracker detector

Nuclei separation


6 months 1 day1 year

10Be (t1/2=1.5Myr) / 9Bewill allow to estimate thepropagation time andsize of the ISM

B is secondary produced in nuclear interaction, C is primary produced in stars. B/C is sensitive tothe diffusion constant

3He/4He ratio is sensitive to the density of the ISM

AMS-02 capabilities

Beryllium Boron Helium

6 months1 year

1 day


One propagation model of our Galaxy


it is shown that Galactic cosmic rays can be effectively confined throughmagnetic reflection by molecular clouds,

Another propagation model including static magnetic fields and gas clouds

Integral excess of positrons in bulge because positrons are trapped in magnetic mirrors between gas clouds


Magnetic fields observed in spiral galaxies

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

disk

fieldline


Antiprotons B/C ratio

Preliminary results from GALPROP with isotropic and anisotropic propagation

Summary: with anisotropic propagation you can send charged particleswhereever you want and still be consistent with B/C and 10Be/9Be


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

Summary

may, 18. 2007 ppc07, college station, w. de boer, univ. karlsruhe1 the ams experiment

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