Quantifying the Performance of a Hybrid Pixel Detector with GaAs:Cr Sensor for Transmission Electron Microscopy

TL;DR

This study evaluates the performance of a hybrid pixel detector with a GaAs:Cr sensor in transmission electron microscopy, demonstrating its superiority over silicon sensors at high electron energies through MTF and DQE measurements.

Contribution

It provides a comparative analysis of GaAs:Cr and Si sensors in HPDs, highlighting the advantages of GaAs:Cr for high-energy electron detection in TEM.

Findings

GaAs:Cr sensor outperforms Si sensor at high electron energies

MTF and DQE measurements confirm superior performance of GaAs:Cr

GaAs:Cr sensor enables better resolution in high-energy TEM applications

Abstract

Hybrid pixel detectors (HPDs) have been shown to be highly effective for diffraction-based and time-resolved studies in transmission electron microscopy, but their performance is limited by the fact that high-energy electrons scatter over long distances in their thick Si sensors. An advantage of HPDs compared to monolithic active pixel sensors (MAPS) is that their sensor does not need to be fabricated from Si. We have compared the performance of the Medipix3 HPD with a Si sensor and with a GaAs:Cr sensor using primary electrons in the energy range of 60 - 300keV. We describe the measurement and calculation of the detectors' modulation transfer function (MTF) and detective quantum efficiency (DQE), which show that the performance of the GaAs:Cr device is markedly superior to that of the Si device for high-energy electrons.