AMS-02: Anti-Coincidence-Counter

The ACC detects unwanted particle tracks running through the tracker volume outside the main acceptance mimicking anti-nuclei.

Requirements:• High detection efficiency • operational in high field• fast response for trigger

Stefan Schael, RWTH Aachen

ACC System

Panel: Bicron BC414 826.5mm x 230mm x 8mmWLS: Kuraray Y-11(200)MCLF: Bicron BCF-98PMT’s: Hamamatsu R5946

ACC AMS-01 ETH Zürich July 1997

machining (grooves) all (16+2) done

Panel machining

Fibres are thermally preconditioned=> less mechanical stress during insertion and hence less damages, => more homogeneous light transport

First flight panel in cosmic test stand

0 missed out of 25977 triggers and still running ...

ACCT1

T2

T3

Attenuation LengthWLS Fibers

PMTPMT

10 - 185 cm

LED (λ=375 nm)

λ=398±33 cm

Attenuation Lengthclear fibers

PMTPMT

LED (λ=375 nm)

λ=659±101 cm

Clear fiber cable in test

WLS (from ACC panel)matching end PMT

matching end

PMT

matching end

ACC System Status

• All flight componentsin hand

• Assembly of flightpanels has started(1 week/panel)

• Optimization ofclear fiber cableis ongoing tillend Oct. 06

• Production of PMTboxes start Dec. 06

• ACC System will bedelivered June 07 toCERN for integrationinto AMS-02.

BackupTransparencies