The Time of Flight System of the AMS-02 Space Experiment

TL;DR

The paper describes the design and expected performance of the Time-of-Flight system for the AMS-02 space experiment, highlighting its capabilities in particle detection and the technical adaptations for operation in a strong magnetic field.

Contribution

It introduces a new TOF system design for AMS-02, including specialized photomultiplier tubes and electronics optimized for the space environment and magnetic field conditions.

Findings

Time resolution of 150-180 ps achieved

Enhanced charge measurement with new electronics

System designed for operation in 1.0-2.5 kG magnetic field

Abstract

The Time-of-Flight (TOF) system of the AMS detector gives the fast trigger to the read out electronics and measures velocity, direction and charge of the crossing particles. The new version of the detector (called AMS-02) will be installed on the International Space Station on March 2004. The fringing field of the AMS-02 superconducting magnet is $1.0\div2.5$ kG where the photomultiplers (PM) are installed. In order to be able to operate with this residual field, a new type of PM was chosen and the mechanical design was constrained by requiring to minimize the angle between the magnetic field vector and the PM axis. Due to strong field and to the curved light guides, the time resolution will be $150\div180$ ps, while the new electronics will allow for a better charge measurement.