Isotopic mass separation with the RICH detector of the AMS Experiment

TL;DR

This paper discusses the use of a RICH detector in the AMS experiment on the ISS for precise isotopic mass separation, including methods for velocity and charge reconstruction.

Contribution

It introduces a likelihood-based method for Cerenkov angle reconstruction and demonstrates isotopic separation of helium and beryllium.

Findings

Velocity resolution around 0.1% for protons

Effective charge reconstruction using photoelectron counting

Successful isotopic separation of helium and beryllium

Abstract

The Alpha Magnetic Spectrometer (AMS) to be installed on the International Space Station (ISS) will be equipped with a proximity focusing Ring Imaging Cerenkov detector (RICH). Reconstruction of the Cerenkov angle and the electric charge with RICH are discussed. A likelihood method for the Cerenkov angle reconstruction was applied leading to a velocity determination for protons with a resolution around 0.1%. The electric charge reconstruction is based on the counting of the number of photoelectrons and on an overall efficiency estimation on an event-by-event basis. The isotopic mass separation of helium and beryllium is presented.