Spectroscopic Performance of Detectors for Athena's WFI: Measurements and Simulation

TL;DR

This paper evaluates the spectroscopic performance of depleted p-channel FET detectors for Athena's WFI, combining measurements, simulations, and initial flight data to assess and predict detector capabilities.

Contribution

It introduces a comprehensive measurement and simulation approach for detector performance, including flight data validation and Monte Carlo prediction methods.

Findings

Detectors show excellent performance in initial tests.

Simulation accurately models threshold effects and noise.

Flight data confirms laboratory measurement consistency.

Abstract

The depleted p-channel field effect transistor is the chosen sensor type for the Wide Field Imager of the Athena mission. It will be used in two types of cameras. One will enable observations of a field of view of 40' x 40' by using an array of four 512 x 512 pixel sensors in a 2 x 2 configuration. A second, small one is designed to investigate bright, point-like sources with a time resolution of up to 40 microseconds. Sensors of final size, layout, and technology were fabricated, assembled and characterised. Also, first results from the flight production are available and confirm the excellent performance. In order to be able to estimate the future performance of degraded detectors, a simulation was developed that takes into account the non-analytical threshold effects on the basis of measurement results. We present the measurement analysis and the comparison of simulated and measured values as well as first attempts to use the Monte Carlo simulation to predict performance results based on noise measurements.