The WFI instrument of ATHENA will provide large field of view in combination with high count-rate capability to address key questions of modern astrophysics. It will utilize a DEPFET based active pixel sensor as focal plane detector. To achieve fastest timings, these sensors can be operated by addressing a region of interest. While this window mode operation enhances time resolution, the probability to collect events during signal processing will become non negligible. Due to the incomplete signal evaluation, these so called misfit events cause an additional background contribution, which will be dominant at very fast timings as required for ATHENA. To sustain the spectral performance a built-in electronic shutter and an intermediate storage can be implemented into each pixel. While the shutter is capable to effectively suppress misfit collection and thus maintains the spectral performance, the implementation of a storage region diminishes possible dead times and improves throughput. We will present measurements on prototype devices demonstrating the bene fi t of a fast built-in shutter for DEPFET devices operated at high frame rates. Furthermore we will show results of first measurements on structures that combine a built-in shutter with an intermediate storage, obviating dead times and simultaneously improving the spectral response.

Development of DEPFET active pixel sensors to improve the spectroscopic response for high time resolution applications

Porro, M;
2014-01-01

Abstract

The WFI instrument of ATHENA will provide large field of view in combination with high count-rate capability to address key questions of modern astrophysics. It will utilize a DEPFET based active pixel sensor as focal plane detector. To achieve fastest timings, these sensors can be operated by addressing a region of interest. While this window mode operation enhances time resolution, the probability to collect events during signal processing will become non negligible. Due to the incomplete signal evaluation, these so called misfit events cause an additional background contribution, which will be dominant at very fast timings as required for ATHENA. To sustain the spectral performance a built-in electronic shutter and an intermediate storage can be implemented into each pixel. While the shutter is capable to effectively suppress misfit collection and thus maintains the spectral performance, the implementation of a storage region diminishes possible dead times and improves throughput. We will present measurements on prototype devices demonstrating the bene fi t of a fast built-in shutter for DEPFET devices operated at high frame rates. Furthermore we will show results of first measurements on structures that combine a built-in shutter with an intermediate storage, obviating dead times and simultaneously improving the spectral response.
Proceedings Volume 9144, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10278/5008770
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