THE AMS RICH COUNTER

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


The AMS collaboration

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

UNAM


• 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


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


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


THE AMS RICH COUNTER

Rôle in AMS:

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

• Albedo particle rejection

_


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


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)


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


The RICH architecture

ECAL hole

Photodetectors

Radiator(s)

Conical mirror


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 ?


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


Photomultipliers

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

Hamamatsu R7600-M16


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


Front end electronics

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


Prototype of detector module

(16 pixel)PMT

Readout electronics

(16)Light guides

Housing (half) shell


RICH prototype (2nd generation)


Rich detector plane Prototype

96 PMTs, 1536 pixels

Prototype = ~½ module of final counter


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


PMT array before light guide Installation

Light guides installed

Detection plane


Back view of proto 2

Readout lines(9 PMTs/line)


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


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


Prototype performancesin Cosmic Ray tests

Example of (muon) event measured in CR tests

Particle hit on LG+PMT


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


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.


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.


• 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%


Electronics settings

PMTs grouped by 11 (10) / flex

ped ~ 4.3

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


Raw data vs simulation


Noise

Aerogel 1.03 run 3 s delayed trigger

El noise ~ 8 10-5 hit/chan

DC ~ 4 10-5 hit/chan


Proto_1 Z separation

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


Proto_1 (z) resolution

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


Field map at PMTs


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 ?

THE AMS RICH COUNTER

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