Effects of high-energy ionizing particles on the Si:As mid-infrared detector array on board the AKARI satellite

TL;DR

This study investigates the impact of high-energy ionizing particles on the Si:As mid-infrared detector aboard AKARI, revealing offset changes mainly due to increased dark current and proposing a correction method to enhance survey data quality.

Contribution

It is the first to quantify ionizing radiation effects on Si:As IBC detectors in orbit and to develop a correction method for improved data accuracy.

Findings

Ionizing particles cause significant offset changes in the detector.

Offset changes are mainly due to increased dark current, not gain.

A correction method improves the AKARI mid-infrared survey data.

Abstract

We evaluate the effects of high-energy ionizing particles on the Si:As impurity band conduction (IBC) mid-infrared detector on board AKARI, the Japanese infrared astronomical satellite. IBC-type detectors are known to be little influenced by ionizing radiation. However we find that the detector is significantly affected by in-orbit ionizing radiation even after spikes induced by ionizing particles are removed. The effects are described as changes mostly in the offset of detector output, but not in the gain. We conclude that the changes in the offset are caused mainly by increase in dark current. We establish a method to correct these ionizing radiation effects. The method is essential to improve the quality and to increase the sky coverage of the AKARI mid-infrared all-sky-survey map.