Paper
6 July 2018 A magnetic electron repeller to improve the ATHENA/WFI background level
E. Perinati, D. Spiga, A. Santangelo, C. Tenzer
Author Affiliations +
Abstract
The WFI is a DEPFET-based device developed at MPE as one of the two focal plane instruments for the next large ESA’s mission for high energy astrophysics ATHENA. The expected level of instrumental background induced by the radiation environment in space is one of the parameters driving the camera design and it is required to be below 5•10-3 cts/cm2 /sec/keV to enhance some of the unique observing capabilities of this detector. Background reduction can be obtained in a passive way by optimizing the detector shielding specifications (e.g. materials, thicknesses) and discarding frame regions affected by X-ray-like counts. In principle a higher rejection efficiency could be achieved with an active anticoincidence system surrounding the detector, in practice this cannot be done as it would make very complicated the camera readout and introduce dead-time. In this proceeding we discuss how a passive shielding against soft electrons with efficiency comparable to that of an active anticoincidence and no dead-time issue could be obtained by means of permanent magnets. We present results of a very preliminary feasibility study conducted in the framework of AHEAD and demonstrate theoretically the effectiveness of this solution. Nevertheless, an actual implementation would have as drawbacks an increased mass of the camera due to the presence of magnets and a potentially disturbing residual field in the detector environment.
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
E. Perinati, D. Spiga, A. Santangelo, and C. Tenzer "A magnetic electron repeller to improve the ATHENA/WFI background level", Proc. SPIE 10699, Space Telescopes and Instrumentation 2018: Ultraviolet to Gamma Ray, 106994B (6 July 2018); https://doi.org/10.1117/12.2312699
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KEYWORDS
Sensors

Magnetism

Cameras

High energy astrophysics

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