May 5-10, 2002 RICH2002@Pylos M. Buénerd 1

THE AMS RICH COUNTER

The AMS RICH collaboration: Bologna, Grenoble, Lisbon, Madrid, Maryland, Mexico

M. BuénerdISN Grenoble Plan

• AMS project• RICH counter• Prototype

AMS

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The AMS collaboration

S.C.C. TING (MIT), PI

UNAM

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• High statistics study of Cosmic Ray particles:

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

Al,..)Be,nuclei unstable 25, Z& 25A ions p, ,p ,(e 2610

AMS Scientific Program on the ISS

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The AMS & RICH calendar

• 1994 Approval of the project by NASA/DOE

• June 1998: Instrumental flight on the space shuttle DISCOVERY, 10 days

• 1999-2004: AMS02 design & construction for ISS phase: SC magnet+ECAL+RICH+TRD

• 2005: AMS02 launch & installation on the International Space Station

• ~2005-2008: Data taking

May 5-10, 2002 RICH2002@Pylos M. Buénerd 5

TOFHodoscopes(TOF & dE/dX)

Cryostat & SC Magnet

(B = 1T)

Tracker(P & dE/dX measurement)

EMC(ID em particles)

RICH(particle ID

A<~25, Z<~25)

TRDe+/p & e-/p

Discrim P<300GeV/c

-

THE AMS SPECTROMETER

VETO

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THE AMS RICH COUNTER

Rôle in AMS:

• Ion identification (A & Z)• p/e- and p/e+ discrimination

• Albedo particle rejection

_

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RICH design history

• 1997-99 :

- First simulation works to evaluate the

possible

performances: see NIM A454(2000)476

- Study prototype, construction and operation

(T.Thuillier et al., NIM A, in press, astro-ph/0201051)

• 2000-2002 :

- (Iterations to) final design

- Second generation prototype

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Imaging technique & main design features

Design drastically constrained by: - Volume - Weight (currently ~190kg) - Power consumption - Long term reliability of components - Magnetic field in the photodetector region

• Proximity focusing counter,

photomultipliers

• 2 radiators for a maximum momentum

range

for particle identification (~1-13

GeV/c/nucleon)

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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

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The RICH architecture

ECAL hole

Photodetectors

Radiator(s)

Conical mirror

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Rich assembly (exploded view)

AEROGEL radiatorplane.Produced in Japan,Characterized in MexicoSupport structure Madrid

StructureAssembly(Bologna/Gavazzi)

LOWER PANEL

Photodetector plane680 PMTs

~104 pixels of photosensors(Japan)

Photondrift space

Mirror made inUSA (~13kg)Resp. Bologna

Mech Designfrom GavazziCo, Italy

NaF radiator ?

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Bottom skin

End beam

Support beam Th. = 0.8 mm Th. = 1.0 mm Th. = 1.2 mm

Shielding Grid StructureCourtesy G. Sardo, Gavazzi Space Co

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Photomultipliers

Requirements:• Must stand high magnetic field (>~100 G)• Multianode ~5x5mm pixels

Hamamatsu R7600-M16

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PMT HamamatsuR7600-M1616 anodes~4.5x4.5mm2

PC Boards, RO and HVD

Flex(ible) support

Integrated Circuit:AustriaMikroSystem Technology

RICH photodetector and front end electronics assembly

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Front end electronics

Principle: Spectroscopy type charge preamplifier, 16 multiplexed channels, 2 gain (x1 & x5) modes

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Prototype of detector module

(16 pixel)PMT

Readout electronics

(16)Light guides

Housing (half) shell

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RICH prototype (2nd generation)

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Rich detector plane Prototype

96 PMTs, 1536 pixels

Prototype = ~½ module of final counter

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Prototype experimental set-up (Cosmic ray configuration)

MWPCs

Scintillators

Radiator

AMSProto DAQ

Vacuumchamber

Triggerelectronicsand MWPCreadout

PMT Matrix

Cosmic

3 Radiators tested aerogels 1.03, 1.05, NaF

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PMT array before light guide Installation

Light guides installed

Detection plane

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Back view of proto 2

Readout lines(9 PMTs/line)

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PMT matrix

RO electronics

Scintillators

MWPCtracker

Vacuum chamber

Chamberlid

LED

Top view of the set-up

May 5-10, 2002 RICH2002@Pylos M. Buénerd 23 SUN Station

VME BUS

Tracker :MWPCs + delay line

RO[CAMAC]

Trigger :scintillators

+ PMTs[CAMAC]

L. Gallin-Martel ISN Grenoble, AMS - CERN October 19th 2001

PS

PC2

RICH prototype DAQ setup

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Readout and DAQ

Each board (33PMTs):

1 DSP controlled FPGA + memory buffer

3 DAQ modes controlled by DSP:

- calibration: pedestal calibrated and tabulated

- RAW: 2 gains and all channels stored

- REDUCED : gain mode selection and channel reduction

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Prototype performancesin Cosmic Ray tests

Example of (muon) event measured in CR tests

Particle hit on LG+PMT

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Velocity resolution

Reconstructed spectrumOnly a resolution estimate since no measurement of the incident momentum of particles.

Aerogel radiatorn=1.03

MC simulation

° Data Resolution per hit: • Measured: 3.2 10-3

• MC : 2.5 10-3

()event 10-3 (Z=1)

Contribution from mwpc tracker being reduced

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Next steps

-Technical tests : Vacuum, thermal,

vibrations

- Ion beam test at CERN on next october

- Detector modules assembly will start on

next January 2003.

- Counter assembly finalized by end of 2003.

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Summary & Conclusion• The AMS RICH is fully designed • End-to-end tests of the prototypes have been performed successfully.• Radiators (aerogels 1.03/05, NaF), PMTs, Light guides, FE and RO electronics, processing algorithms, provide the expected

results (See talk by F. Barao).• The forthcoming in-beam tests with ions at CERN on october will complete the tests. The AMS RICH is on the tracks…. for flying on the ISS.

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• Reject Albedo particles (prototype inefficiency < 10-3 )

• Discriminate e+/p & e-/pbar (p < ~12 GeV/c) • Identify nuclei or elements:

What the RICH will do:

Current knowledge

AMS

I sotopes A < ~30

Ekin <500MeV/n P < 13- 20GeV/c/n

Elements Z < ~25

P < 35GeV/c/n P < 1 TeV/c/n

Cosmic Ray studies with the RICH

Assuming P/P~1%

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Electronics settings

PMTs grouped by 11 (10) / flex

ped ~ 4.3

<G(x5)> = 69 /Q ~ 0.47

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Raw data vs simulation

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Noise

Aerogel 1.03 run 3 s delayed trigger

El noise ~ 8 10-5 hit/chan

DC ~ 4 10-5 hit/chan

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Proto_1 Z separation

Z separation obtainedwith proto 1 at GSI with 1GeV/n 12C beam

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Proto_1 (z) resolution

resolution obtainedwith proto 1 at GSI with 1GeV/n 12C beam.

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Field map at PMTs

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From simulation results:• Mass range A< ~30• Charge range Z< ~25• Momentum range P< ~15 GeV/c

Assuming P/P~1%

The upper bounds quoted for A and Z are asymptotic limits

What ion mass and charge ID range with the RICH ?