Search

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 is that their sensors do not need to be fabricated from Si. We have compared the performance of the Medipix3 HPD with a Si sensor and a GaAs:Cr sensor using primary electrons in the energy range of 60–300 keV. 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. • Characterisation of a Medipix3 hybrid pixel detector with high-Z sensor for transmission electron microscopy. • MTF and DQE performance of a device with a GaAs:Cr sensor measured using electrons with energies in the range of 60–300 keV and compared with the performance of a standard Si device. • GaAs:Cr sensor significantly improves detector MTF and DQE when using 120 keV and 200 keV electrons compared with the Si sensor. • Investigation into the effects of sensor defects on detector performance. [ABSTRACT FROM AUTHOR]