THE CHERENKOV IMAGER of the AMS02 EXPERIMENT
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Transcript of THE CHERENKOV IMAGER of the AMS02 EXPERIMENT
Nov 30-Dec 5, 2004 RICH2004 Int. Workshop, Playa Del Carmen, Mexico M. Buénerd 1
THE CHERENKOV IMAGER of THE CHERENKOV IMAGER of the AMS02 EXPERIMENTthe AMS02 EXPERIMENT
The AMS RICH collaboration: Bologna, Grenoble, Lisbon, Madrid, Maryland, Mexico
M. BuénerdM. BuénerdLPSC GrenobleLPSC Grenoble
AMS
Nov 30-Dec 5, 2004 RICH2004 Int. Workshop, Playa Del Carmen, Mexico M. Buénerd 2
PLAN
The AMS02 spectrometer
Physics program
The Cherenkov imager
In-beam test results
Nov 30-Dec 5, 2004 RICH2004 Int. Workshop, Playa Del Carmen, Mexico M. Buénerd 3
Capabilities of the spectrometer
Measure particle energy from ~ 0.4 GeV/n up to ~ 1 TeV/n
Discriminate lepton-hadron
HE ray measurement
Identify ions or elements
over the largest possible energy range
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AMS Scientific Program on the ISS
• High statistics study of the Cosmic Ray particles flux:
Allowing sensitive search for :
• Primordial antimatter (primary goal of the project):
• Dark matter (neutralino annihilation):
• High energy gamma ray astronomy
,...)C,He( 124
)X.... X,e X,p
nuclei) Antimatter Be,unstable 30, Z& 16A ions p, ,p ,(e 10
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Main purpose:
• The only AMS detector dedicated to
Isotope identification (A & Z)
Also (redundant) :• p/e- and p/e+ discrimination
• Albedo particle rejection
_
The AMS Cherenkov imager
Nov 30-Dec 5, 2004 RICH2004 Int. Workshop, Playa Del Carmen, Mexico M. Buénerd 6
The isotopic abundance ratio 10Be/ 9Be depends on:
- Time of confinement of CRs in galaxy- ISM density and galactic halo size
6 weeks counting ~ 200000 events !
A.Bouchet et al,Nucl.Phys A668(2000)7Be 9Be 10Be
Simulation of 10Be detection
isomax
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The RICH inside AMS
ECAL
Photodetectorplane (680 PMTs)
Radiator(s)
Conical mirror
AMS spectrometer NaF aerogelCherenkovRadiator
Photo- detectors
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Sodium Fluoride
NaF, n = 1.33 thickness 5 mm
Aerogel n = 1.05 thickness 30 mm
Radiator plane
P range ~ 3-10GeV/c/n
P range ~ 1-4 GeV/c/n
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4x4 Light Guides7.5x7.5mm2
PMT Hamamatsu R7900_M164x4 pixels (4.5x4.5mm2)
Front End Electronics: Charge preamplifier Track&hold +MPX 16 chan (x2gains)
ADC High voltage divider
Magnetic Shielding profile(Stray field up to 300G)
Photodetector cell
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½ module of final detector
96 PMTs (1536 pixels) Light Guides FE+DAQ Radiators:
AGL 1.03 < n < 1.05 NaF n=1.33 (CR only)
The RICH prototype
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with HE ion beam at CERNwith HE ion beam at CERN
Tests of the AMS RICH prototypeTests of the AMS RICH prototype
• Beam production principle*• Measurements • Results
* M. Buénerd and I. Efthymiopoulos, CERN report AB-2003-052
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Multi-ion beam production
Incident SPS
- Pb ion beam(20GeV/c/n)- In ion beam(158GeV/c/n)
Productiontarget
Momentumanalysis
B
BCte x A/Z
Beam fragmentation BCte x beam A/Z
Example: A/Z=2 D, He, Li, Be, B, C,…, Si,.., Ca,…, 52Fe, ..
and beyond, but….
Testingdetector
Fewmrad
500m beam line
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Intensity of ion beam fragments vs
Cosmic Ray flux
Cosmic Ray flux J.A. Simpson ARNS 33(1983)323
Beam fragments (A/Z=2)(From dE/dX scintillator ) Similarity of
the 2 spectra
controllableCR equivalent flux
~Nuclear charge Z
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2 Runs
• October 2002: 20 GeV/nucleon 208Pb fragments A<~60 (z~30) 5 million events collected
• October 2003 : 158 GeV/nucleon 115Cd fragments A<115 (z=49)11 million events collected
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Experimentalsetup
Prototype & RO electronics
MWPC
MWPC
dE/dXScintillatorsor Cherenkov
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Close-up view of matrix with mirror
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20GeV/n Cherenkov rings
Z2
3 6
>~16
>16
He
Li C
Si-P ?
~Fe ?
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Velocity reconstruction 2002
spectra fittingRing fitting
nc 1 cos
Z=1 particlesZ=1 particlesAerogelRadiator Index Resol (x10- 3) Clarity (x10- 3)
Matsushita 1.03 0.71 7.9Matsushita 1.05 0.98 9.5Novosibirsk1.03 0.67 5.9
CIEMAT Madrid analysis
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(Z) resolution 2002
Nγ in the ring ~
Z2
Limit set by pixel size
24
2
)10 8.0()1( )(
ZZ
Aerogel 1.03
CIEMAT Madrid analysis
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Charge resolution 2002
(Z) < ~.2 up to Z=26
(n=1.05)
cZdxddN
sin 2 2
)1(exp ZN
NZ pe
Combining RICH+TRCKR
Courtesy M.Pohl, Geneva U.
Courtesy M. Pohl et al.
IndividualElement separation
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2003 comparison of Aerogels
H (Nominal = 44 cm)
Test beam 2003 RESULTS (H = 33,5 cm)
TYPE SIZE
(Z=1, = 1) (Z=2, = 1)
PH. YIELD PH. YIELD
MAT 1.03 3 x 1 cm 11,0 ± 0.1 36,0 ± 0.1 (0.487 ± 0.006) x 10-3
NOV 1.03 1 x 3 cm 10,6 ± 0.1 34,7 ± 0.1 (0.468 ± 0.005) x 10-3
NOV 1.05 1 x 2.5 cm 14,6 ± 0.3 47,6 ± 0.1 (0.484 ± 0.007) x 10-3
Specific runs to compare the performances for radiators with different refraction index H = 33.5 cm (full contained rings)
ELECTEDELECTED
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Cells integration
April 2004
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coating
(Spares from the prototype used)
Finally:
680 PMT cellsASSEMBLED
POTTEDCOATEDTESTED SORTED
9 failures (3 due to PMT failure)
Ready for final counter integation
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Summary
The study of the AMS RICH prototype with 20 & 158 GeV/n ions has allowed to:
1. Perform an end-to-end test of the instrument with a broad range of nuclear charges (1<Z<~49).
2. Measure the performances of the prototype:• Velocity resolution : / = 0.7 10-3 for Z=1 particles• Charge resolution : (Z) < 0.2 up to Z>~30
3. All the RICH prototype elements have been thoroughly tested (PMT cells, FE+RO electronics, reconstruction algorithms) and validated .
The final counter integration has started (end Nov 05).
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AMS is an International CollaborationAMS is an International CollaborationNASA provides: Three shuttle flights and Mission Management at JSCNASA provides: Three shuttle flights and Mission Management at JSC
(S. Porter - Project Manager)(S. Porter - Project Manager)
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
PORTUGALLAB. OF INSTRUM. LISBON
ROMANIAISSUNIV. OF BUCHAREST
RUSSIAI.K.I.ITEPKURCHATOV INST.MOSCOW STATE UNIV.
SPAINCIEMAT - MADRIDI.A.C. CANARIAS.
SWITZERLANDETH-ZURICHUNIV. OF GENEVA
CHINABISEE (Beijing)IEE (Beijing)IHEP (Beijing)SJTU (Shanghai)SEU (Nanjing)SYSU (Guangzhou)SDU (Jinan)
ACAD. SINICA (Taiwan)CSIST (Taiwan)NCU (Chung Li)NCKU (Tainan)NCTU (Hsinchu)NSPO (Hsinchu)
KOREAEWHAKYUNGPOOK NAT.UNIV.
50 universities, 500 participants
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TOFHodoscopes(TOF & dE/dX)
Cryostat & SC Magnet
(B = 1T)
Tracker(P & dE/dX measurement)
EMC(ID em particles)
RICH(particle & isotope ID
A<~16 ?, Z<~25)
TRDe+/p & e-/p
Discrim P<300GeV/c
-
VETOskirt
THE AMS2 SPECTROMETER
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2x
Dipole Coils2x6
Racetrack Coils
2,500 l Superfluid He
SC magnet in support structure
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• What for ?• Which imaging technique ?• What radiator(s) ?• What photodetectors ?• What performances ?Prototype and test resultsPrototype and test results
The Cherenkov Imager
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Largely dictated by constraints on: - Volume available (Shuttle cargo bay)- Weight (currently ~190kg) - Power consumption (currently ~150W) - Long term reliability of components - Magnetic field in the photodetector region- Isotropic flux (No point source like in accelerators)
• Proximity focusing counter, photomultipliers• 2 radiators for a maximum momentum range for isotope identification (~1-10 GeV/c/nucleon)
Which imaging technique ?
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AEROGEL radiatorplane.Produced in Japan or Russia,Characterized at UNAM MexicoSupport structure made by CIEMAT Madrid
StructureAssembly(Bologna/Gavazzi)LOWER PANEL
Photodetector plane680 PMTs
~104 pixels of photosensors(Japan)
Photondrift space
Mirror made inUSA (~ 13kg)Resp. Bologna
Mech. Designby GavazziSpace, Italy
NaF radiator
Rich assembly (exploded view)
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Selection of the ion sample
Z=2He
Z=82Pb beam
Z=8O
Z=20Ca
Z=50Zr
N
Z
Selec
tion
line
(A/Z
=Cte)
Changing the magnetic field in the beam line changes the ion mass/charge sampled Chart of the nuclides
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The CERN H8 beam line
Productiontarget
Position (m)
RICH
MomentumAnalysis
Dispersiondipole
AnalysisDipoleAcceptance
collimators Imagecollimators
0-480 -420
-464
-352 -150 -80
TOF1
-26
NA45
Wall
/ /
Experimental area
Tracker
TOF
CREAM
P/P~1%
TOF2
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Front end electronics
Principle: Spectroscopy type charge preamplifier, 16 multiplexed channels, 2 gain (x1 & x5) modes
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To be cross checked with calibration from the ion charge distribution
3 pixels
PMT linearityPMT linearity measurementmeasurement
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Team (night shift) at work
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M.MartonModule coatingCoating
Aug 2004
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Surface scattering