Particle tracking with a Timepix based triple GEM detector

S.P George,F Murtas,A Curioni,M Silari,J Alozy,A.B Rosenfeld

doi:10.1088/1748-0221/10/11/p11003

S.P George, F Murtas + Show 4 more

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https://doi.org/10.1088/1748-0221/10/11/p11003

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Abstract

This paper details the response of a triple GEM detector with a 55 μmetre pitch pixelated ASIC for readout. The detector is operated as a micro TPC with 9.5 cm3 sensitive volume and characterized with a mixed beam of 120 GeV protons and positive pions. A process for reconstruction of incident particle tracks from individual ionization clusters is described and scans of the gain and drift fields are performed. The angular resolution of the measured tracks is characterized. Also, the readout was operated in a mixed mode where some pixels measure drift time and others charge. This was used to measure the energy deposition in the detector and the charge cloud size as a function of interaction depth. The future uses of the device, including in microdosimetry are discussed.

Highlights

This paper details the response of a triple GEM detector with a 55 μm pitch pixelated ASIC for readout
The GEMPix is based on coupling a small triple GEM detector (3 × 3 × 1.2 cm3) to a quad Timepix ASIC with 262,144 pixels of 55 μm × 55 μm area for readout
A photograph of the detector is shown in figure 1(a) and a diagram of the principal dimensions, components and electrical fields used in the detector are shown in figures 1(b) and 1(c)

Summary

Introduction

This paper details the response of a triple GEM detector with a 55 μm pitch pixelated ASIC for readout. The readout was operated in a mixed mode where some pixels measure drift time and others charge. The GEMPix is based on coupling a small triple GEM detector (3 × 3 × 1.2 cm3) to a quad Timepix ASIC with 262,144 pixels of 55 μm × 55 μm area for readout. Small holes are etched in this foil and a voltage applied across it as shown in figure 1(b) This produces electrical fields as high as 100 kV cm−1 inside the holes. Except where otherwise noted the chamber is operated at a gain of G = 2.104 corresponding to a total applied voltage to the GEM foils of 1.35 kV (450 V per foil) [12] and a drift field of 0.66 kV cm−1. The quad Timepix is mounted on a bespoke quad PCB, and read out using the FITPix system [13] and accompanying Pixelman [14] software developed by CTU Prague

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