Medipix3 Demonstration and understanding of near ideal detector performance for 60 & 80 keV electrons

TL;DR

This paper quantitatively evaluates Medipix3 hybrid pixel detector's imaging performance at 60 and 80 keV, demonstrating near-ideal MTF and DQE in different modes, and models its response to optimize electron imaging in microscopy.

Contribution

It provides the first quantitative analysis of Medipix3's performance as a direct electron detector and introduces an empirical model to predict its imaging capabilities.

Findings

Medipix3 achieves near-ideal MTF and DQE in charge summing mode.

Energy threshold tuning can optimize either MTF or DQE.

The empirical model accurately predicts detector performance based on energy threshold.

Abstract

In our article we report first quantitative measurements of imaging performance for the current generation of hybrid pixel detector, Medipix3, as direct electron detector. Utilising beam energies of 60 & 80 keV, measurements of modulation transfer function (MTF) and detective quantum efficiency (DQE) have revealed that, in single pixel mode (SPM), energy threshold values can be chosen to maximize either the MTF or DQE, obtaining values near to, or even exceeding, those for an ideal detector. We have demonstrated that the Medipix3 charge summing mode (CSM) can deliver simultaneous, near ideal values of both MTF and DQE. To understand direct detection performance further we have characterized the detector response to single electron events, building an empirical model which can predict detector MTF and DQE performance based on energy threshold. Exemplifying our findings we demonstrate the Medipix3 imaging performance, recording a fully exposed electron diffraction pattern at 24-bit depth and images in SPM and CSM modes. Taken together our findings highlight that for transmission electron microscopy performed at low energies (energies <100 keV) thick hybrid pixel detectors provide an advantageous and alternative architecture for direct electron imaging