GEM-based beam profile monitors for the antiproton decelerator

TL;DR

This paper presents a new lightweight GEM-based beam profile monitor for CERN's Antiproton Decelerator, overcoming previous issues with MWPC detectors and demonstrating successful deployment and potential for widespread upgrade.

Contribution

Introduction of a novel GEM-based detector for low-energy antiproton beam profiling, replacing aging MWPC systems with improved performance and minimal beam disturbance.

Findings

Successful prototype testing in 2010

Installation of five detectors in beam lines

Potential for widespread CERN upgrade

Abstract

The new beam profile measurement for the Antiproton Decelerator (AD) at CERN is based on a single Gas Electron Multiplier (GEM) with a 2D readout structure. This detector is very light, ~0.4% X0, as required by the low energy of the antiprotons, 5.3 MeV. This overcomes the problems previously encountered with multi-wire proportional chambers (MWPC) for the same purpose, where beam interactions with the detector severely affect the obtained profiles. A prototype was installed and successfully tested in late 2010, with another five detectors now installed in the ASACUSA and AEGIS beam lines. We will provide a detailed description of the detector and discuss the results obtained. The success of these detectors in the AD makes GEM-based detectors likely candidates for upgrade of the beam profile monitors in all experimental areas at CERN. The various types of MWPC currently in use are aging and becoming increasingly difficult to maintain.