Simulation Method for Investigating the Use of Transition-Edge Sensors as Spectroscopic Electron Detectors

Transition-edge sensors (TESs) are capable of highly accurate single particle energy measurement. TESs have been used for a wide range of photon detection applications, particularly in astronomy, but very little consideration has been given to their capabilities as electron calorimeters. Existing electron spectrometers require electron filtering optics to achieve energy discrimination, but this step discards the vast majority of electrons entering the instrument. TESs require no such energy filtering, meaning they could provide orders of magnitude improvement in measurement rate. To investigate the capabilities of TESs in electron spectroscopy, a simulation pipeline has been devised. The pipeline allows the results of a simulated experiment to be compared with the actual spectrum of the incident beam, thereby allowing measurement accuracy and efficiency to be studied. Using Fisher information, the energy resolution of the simulated detectors was also calculated, allowing the intrinsic limitations of the detector to be separated from the specific data analysis method used. The simulation platform has been used to compare the performance of TESs with existing X-ray photoelectron spectroscopy (XPS) analysers. TESs cannot match the energy resolution of XPS analysers for high-precision measurements but have comparable or better resolutions for high count rate applications. The measurement rate of a typical XPS analyser can be matched by an array of 10 TESs with 120 microsecond response times and there is significant scope for improvement, without compromising energy resolution, by increasing array size.