A study of the effects of accelerating voltage,detector layer thickness,and processing method on imaging with hybrid pixel detectors
The high detection efficiency of hybrid pixel detectors(HPD)at low voltages compensates for the suboptimal imaging capabilities of monolithic active pixel sensors(MAPS)when applied to radiation-sensitive materials.However,HPD imaging is constrained by challenges in electron counting,such as identifying single-electron signal clusters and localizing events.Clustering,which is primarily influenced by detector hardware and imaging conditions,lacks comprehensive systematic studies.This paper examined the effects of varying accelerating voltages,detector layer thicknesses,and event localization method on the MTF through both experimental and Monte Carlo simulations approaches,and calculates the relative energy loss.The findings revealed that Timepix detectors with thicknesses of 300 µm and 500 μm exhibited the lowest relative energy loss at low and medium high voltages,respectively.The centroid localization method performed similarly to the CNN method at low voltage,but the latter's localization advantage increased with higher voltages.Additionally,for Timepix,the MTF was positively correlated with detector thickness at low voltages,whereas the relationship reversed at high voltages.These insights are valuable for the future application of HPD cameras in single particle Cryo-electron microscopy.
hybrid pixel detectorsMonte Marlo simulationevent localizationmodulation transfer functionrelative energy loss