APA
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Noda, H., Aoyagi, M., Mori, K., Tomida, H., Nakajima, H., Tanaka, T., … Hayashida, K. (2025). CCD driving technique to suppress anomalous charge intrusion from outside the imaging area for soft X-ray imager of Xtend onboard XRISM. Journal of Astronomical Telescopes Instruments and Systems.
Chicago/Turabian
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Noda, H., Mio Aoyagi, K. Mori, H. Tomida, Hiroshi Nakajima, Takaaki Tanaka, Hiromasa Suzuki, et al. “CCD Driving Technique to Suppress Anomalous Charge Intrusion from Outside the Imaging Area for Soft X-Ray Imager of Xtend Onboard XRISM.” Journal of Astronomical Telescopes Instruments and Systems (2025).
MLA
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Noda, H., et al. “CCD Driving Technique to Suppress Anomalous Charge Intrusion from Outside the Imaging Area for Soft X-Ray Imager of Xtend Onboard XRISM.” Journal of Astronomical Telescopes Instruments and Systems, 2025.
BibTeX Click to copy
@article{h2025a,
title = {CCD driving technique to suppress anomalous charge intrusion from outside the imaging area for soft X-ray imager of Xtend onboard XRISM},
year = {2025},
journal = {Journal of Astronomical Telescopes Instruments and Systems},
author = {Noda, H. and Aoyagi, Mio and Mori, K. and Tomida, H. and Nakajima, Hiroshi and Tanaka, Takaaki and Suzuki, Hiromasa and Murakami, Hiroshi and Uchida, H. and Tsuru, T. and Miyazaki, Keitaro and Kusunoki, Kohei and Kanemaru, Y. and Aoki, Y. and Nobukawa, K. and Nobukawa, M. and Shima, Kohei and Yoshimoto, M. and Asakura, K. and Matsumoto, Hironori and Yoneyama, T. and Kobayashi, S. and Hagino, Kouichi and Uchiyama, H. and Hayashida, K.}
}
Abstract. The Soft X-ray Imager (SXI) is an X-ray charge-coupled device (CCD) camera of the Xtend system onboard the X-Ray Imaging and Spectroscopy Mission (XRISM), which was successfully launched on September 7, 2023 (JST). During ground cooling tests of the CCDs in 2020/2021, using the flight-model detector housing, electronic boards, and a mechanical cooler, we encountered an unexpected issue. Anomalous charges appeared outside the imaging area of the CCDs and intruded into the imaging area, causing pulse heights to stick to the maximum value over a wide region. Although this issue has not occurred in subsequent tests or in orbit so far, it could seriously affect the imaging and spectroscopic performance of the SXI if it were to happen in the future. Through experiments with non-flight-model detector components, we successfully reproduced the issue and identified that the anomalous charges intrude via the potential structure created by the charge injection (CI) electrode at the top of the imaging area. To prevent anomalous charge intrusion and maintain imaging and spectroscopic performance that satisfies the requirements, even if this issue occurs in orbit, we developed a new CCD driving technique. This technique is different from the normal operation in terms of potential structure and its changes during imaging and CI. We report an overview of the anomalous charge issue, the related potential structures, the development of the new CCD driving technique to prevent the issue, the imaging and spectroscopic performance of the new technique, and the results of experiments to investigate the cause of anomalous charges.