Transcript Folie 1 - Texas A&M University

The AMS experiment
May, 18. 2007
PPC07, College Station, W. de Boer, Univ. Karlsruhe
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May, 18. 2007
PPC07, College Station, W. de Boer, Univ. Karlsruhe
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Nobel Prizes,
(1) Pulsar,
(2) Microwave,
(3) Microwave
(4) Binary Pulsars,
(5) Solar neutrino
X Ray sources
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.
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PPC07, College Station, W. de Boer, Univ. Karlsruhe
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International commitments to AMS
FINLAND
RUSSIA
HELSINKI UNIV.
UNIV. OF TURKU
I.K.I.
ITEP
KURCHATOV INST.
MOSCOW STATE UNIV.
DENMARK
NETHERLANDS
USA
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
UNIV. OF AARHUS
ESA-ESTEC
NIKHEF
NLR
GERMANY
RWTH-I
RWTH-III
MAX-PLANK INST.
UNIV. OF KARLSRUHE
FRANCE
ROMANIA
GAM MONTPELLIER
LAPP ANNECY
LPSC GRENOBLE
ISS
UNIV. OF BUCHAREST
SPAIN
CIEMAT - MADRID
I.A.C. CANARIAS.
MEXICO
UNAM
PORTUGAL
LAB. OF INSTRUM. LISBON
KOREA
EWHA
KYUNGPOOK NAT.UNIV.
CHINA BISEE (Beijing)
SWITZERLAND
ETH-ZURICH
UNIV. OF GENEVA
ITALY
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
IEE (Beijing)
IHEP (Beijing)
SJTU (Shanghai)
SEU (Nanjing)
SYSU (Guangzhou) TAIWAN
SDU (Jinan)
ACAD. SINICA (Taiwan)
CSIST (Taiwan)
NCU (Chung Li)
NCKU (Tainan)
NCTU (Hsinchu)
NSPO (Hsinchu)
Y96673-05_1Commitment
May, 18. 2007
PPC07, College Station, W. de Boer, Univ. Karlsruhe
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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
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PPC07, College Station, W. de Boer, Univ. Karlsruhe
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3x3x3m, 7 t
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
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PPC07, College Station, W. de Boer, Univ. Karlsruhe
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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
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Alpha Magnetic Spectrometer - AMS-01
First flight, STS-91, 2 June 1998 (10 days)
TOF
Tracker
Magnet
AMS
TOF
Cerenkov Counter
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Superconducting Magnet
Flux Return Coils
B
Dipole
Coils
B
He Vessel
2500 Liters superfluid He
Analyzing power
BL2 = 0.8 Tm2
May, 18. 2007
PPC07, College Station, W. de Boer, Univ. Karlsruhe
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The coils completed
May, 18. 2007
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Now inside the cryostat
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TRD detector to separate e+ from protons
: 3 –300GeV •e+/p rejection
102 –103 in
1.5 – 300 GeV
• with ECAL
e+/p rejection
>106
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PPC07, College Station, W. de Boer, Univ. Karlsruhe
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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.
May, 18. 2007
PPC07, College Station, W. de Boer, Univ. Karlsruhe
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Silicon Tracker
•Rigidity (R/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
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PPC07, College Station, W. de Boer, Univ. Karlsruhe
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Ring Imaging Cerenkov Counter
•Accurate Velocity
Aerogel Radiator(n=1.03, 3cm)
NaF radiator (n=1.33, 0.5cm)
/ = (0.670.01)*10-3%
Cerenkov
Cone
Mirror
(test beam)
• Isotopic Separation.
• |Q| measurements up
Z~ 30
Photomultipliers
8.5 x 8.5 mm2 spatial pixel granularity
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PPC07, College Station, W. de Boer, Univ. Karlsruhe
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Calorimetry in space
• 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
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
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Electromagnetic calorimeter
p
Sampling calorimeter with lead foils
and scintillating fibers
e
Lead foil
(1mm)
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
Fibers
(1mm)
Total weight 634 kg
z
1.73mm
particle direction
FIBER
LEAD
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y
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x
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Final integration in 2007 at CERN
2007
Final testing in
ESA vacuum chamber (NL)
2008
Thermal vacuum test at ESA, Holland
2007 Assembly at CERN
May, 18. 2007
PPC07, College Station, W. de Boer, Univ. Karlsruhe
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Charge measurements
ToF, Tracker, RICH performance verified
at heavy ion test beam (CERN,GSI)
Fe
Ca
P
Ne
B
May, 18. 2007
PPC07, College Station, W. de Boer, Univ. Karlsruhe
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Nuclei separation
He Li
He
Charge measurement:
Be
Test Results from Tracker detector
C
C
N
N
O
Si
TOF, Tracker and RICH
Verified by heavy ion
beam tests at CERN &
GSI.
TOF
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PPC07, College Station, W. de Boer, Univ. Karlsruhe
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AMS-02 capabilities
Boron
Beryllium
1 year
1 year
Be (t1/2=1.5Myr) / 9Be
will allow to estimate the
propagation time and
size of the ISM
10
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months
66months
Helium
1 day
1 day
B is secondary produced 3He/4He ratio is sensitive
in nuclear interaction, C to the density of the
is primary produced in
ISM
stars. B/C is sensitive to
the diffusion constant
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One propagation model of our Galaxy
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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
May, 18. 2007
PPC07, College Station, W. de Boer, Univ. Karlsruhe
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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
May, 18. 2007
PPC07, College Station, W. de Boer, Univ. Karlsruhe
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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
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PPC07, College Station, W. de Boer, Univ. Karlsruhe
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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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