Characterisation of the NewAthena WFI's DEPFET Flight Production's Operational Parameters

Abstract

NewAthena's Wide Field Imager (WFI) uses detectors made up from Depleted P-Channel Field Effect Transistor (DEPFET) pixels operated in rolling shutter mode. The Large Detector Array (LDA) contains a 2 $\times$ 2 array of 512 $\times$ 512 pixels Large Detectors (LDs) allowing for a field of view of 40' $\times$ 40' with a frame time of 2 ms while the 64 $\times$ 64 pixels Fast Detector (FD) can observe very bright X-ray sources due to a faster frame time of 0.08 ms. Prototype sensors (64 $\times$ 64 pixels) were used to analyse the sensor's operational range and to optimise the ASIC and DEPFET parameters i.e. current and voltage settings, as well as the DEPFET read-out timing parameters, resulting in an improved energy resolution, reduced noise and otherwise improved sensor characteristics.