Differential gain stability of a microchannel plate detector dedicated to a neutral particle instrument (JENI) of the JUICE space mission

A. Grigoriev; A. Fedorov; N. André; O. Chassela; E. Le Comte

doi:10.1117/12.2536153

12 July 2019 Differential gain stability of a microchannel plate detector dedicated to a neutral particle instrument (JENI) of the JUICE space mission

A. Grigoriev, A. Fedorov, N. André, O. Chassela, E. Le Comte

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Proceedings Volume 11180, International Conference on Space Optics — ICSO 2018; 111806I (2019) https://doi.org/10.1117/12.2536153
Event: International Conference on Space Optics - ICSO 2018, 2018, Chania, Greece

Abstract

The Jupiter Icy moon Explorer (JUICE) is a long-life ESA mission to be working in extremely harsh space environment. The energetic neutral atoms imager (JENI), designed as a Time-of-Flight (TOF) spectrometer, contains microchannel plate (MCP) detectors to register start and stop secondary electrons produced by incident neutrals atoms. Due to rather severe mass and power constraints this spectrometer uses a single MCP assembly to detect both Start and Stop electrons, to define their detection time and then calculate an incident particle velocity. Thus one MCP is divided in several sectors. One of them is dedicated to detect Start electrons and another sector is detecting Stop electrons. Since the load of the Start sector can be higher than the load of the Stop sector by a factor of 10, it is important to know how does the MCP sectoral gain (Differential Gain) change during the MCP lifetime. Since the JUICE mission is a long-time mission it is important to be sure the MCP gain changes evenly along the active surface. To characterize the MCP overall gain uniformity we have combined the gain uniformity measurement and differential gain stability measurement into a single experiment of the MCP aging. A differential gain stability test has been performed on a representative MCP assembly using a uniform UV light source. The differential UV exposure has been achieved using an attenuation mask provided ~10% exposure of a majority of the MCP surface and full exposure of a small area. Differential gain versus the MCP bias voltage has been characterized every 0.5 C/cm² of the charge extracted out of the MCP. We have shown the spatial gain variations and the differential degradation of the MCP sectors are acceptable for JENI experiment.

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A. Grigoriev, A. Fedorov, N. André, O. Chassela, and E. Le Comte "Differential gain stability of a microchannel plate detector dedicated to a neutral particle instrument (JENI) of the JUICE space mission", Proc. SPIE 11180, International Conference on Space Optics — ICSO 2018, 111806I (12 July 2019); https://doi.org/10.1117/12.2536153

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