A magnetic electron repeller to improve the ATHENA/WFI background level
Date Issued
2018
Author(s)
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 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.
Coverage
Space Telescopes and Instrumentation 2018: Ultraviolet to Gamma Ray
All editors
den Herder, Jan-Willem A.; Nikzad, Shouleh; Nakazawa, Kazuhiro
Series
Volume
10699
Start page
106994B
Conferenece
Space Telescopes and Instrumentation 2018: Ultraviolet to Gamma Ray
Conferenece place
Austin, Texas, United States
Conferenece date
10-15 June, 2018
Issn Identifier
0277-786X
Ads BibCode
2018SPIE10699E..4BP
Rights
open.access
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