Performance evaluation of the high-voltage CMOS active pixel sensor AstroPix for gamma-ray space telescopes

• Published in: arXiv.org 2024-08
• Main Authors: Suda, Yusuke, Caputo, Regina, Steinhebel, Amanda L, Striebig, Nicolas, Jadhav, Manoj, Fukazawa, Yasushi, Hashizume, Masaki, Kierans, Carolyn, Leys, Richard, Metcalfe, Jessica, Negro, Michela, Perić, Ivan, Perkins, Jeremy S, Taylor, Shin, Tajima, Hiroyasu, Violette, Daniel, Nakano, Norito
• Format: Article
• Language: English
• Subjects: Active pixel sensors; CMOS; Dynamic range; Energy resolution; Gamma rays; High voltages; Observatories; Performance evaluation; Pixels; Radiation tolerance; Space telescopes
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2408.12891

AstroPix is a novel monolithic high-voltage CMOS active pixel sensor proposed for next generation medium-energy gamma-ray observatories like the All-sky Medium Energy Gamma-ray Observatory eXplorer (AMEGO-X). For AMEGO-X AstroPix must maintain a power consumption of less than \(1.5~\rm{mW/{cm}^2}\) while having a pixel pitch of up to \(500~\rm{\mu m}\). We developed the second and third versions of AstroPix, namely AstroPix2 and AstroPix3. AstroPix2 and AstroPix3 exhibit power consumptions of \(3.4~\rm{mW/{cm}^2}\) and \(4.1~\rm{mW/{cm}^2}\), respectively. While AstroPix2 has a pixel pitch of \(250~\rm{\mu m}\), AstroPix3 achieves the desired size for AMEGO-X with a pixel pitch of \(500~\rm{\mu m}\). Performance evaluation of a single pixel in an AstroPix2 chip revealed a dynamic range from 13.9 keV to 59.5 keV, with the energy resolution meeting the AMEGO-X target value (\(