Fine-pitch semiconductor detector for the FOXSI mission

S. Ishikawa, S. Saito, H. Tajima, T. Tanaka, S. Watanabe, H. Odaka, T. Fukuyama, M. Kokubun, T. Takahashi, Y. Terada, S. Krucker, S. Christe, S. McBride, L. Glesener

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


The Focusing Optics X-ray Solar Imager (FOXSI) is a NASA sounding rocket mission which will study particle acceleration and coronal heating on the Sun through high sensitivity observations in the hard X-ray energy band (5-15 keV). Combining high-resolution focusing X-ray optics and fine-pitch imaging sensors, FOXSI will achieve superior sensitivity; two orders of magnitude better than that of the RHESSI satellite. As the focal plane detector, a Double-sided Si Strip Detector (DSSD) with a front-end ASIC (Application Specific Integrated Circuit) will fulfill the scientific requirements of spatial and energy resolution, low energy threshold and time resolution. We have designed and fabricated a DSSD with a thickness of 500 μm and a dimension of 9.6 mm × 9.6 mm, containing 128 strips with a pitch of 75 μm, which corresponds to 8 arcsec at the focal length of 2 m. We also developed a low-noise ASIC specified to FOXSI. The detector was successfully operated in the laboratory at a temperature of -20°C and with an applied bias voltage of 300 V. Extremely good energy resolutions of 430 eV for the p-side and 1.6 keV for the n-side at a 14 keV line were achieved for the detector. We also demonstrated fine-pitch imaging successfully by obtaining a shadow image. Hence the implementation of scientific requirements was confirmed.

Original languageEnglish (US)
Article number5876284
Pages (from-to)2039-2046
Number of pages8
JournalIEEE Transactions on Nuclear Science
Issue number4 PART 2
StatePublished - Aug 1 2011


  • Astrophysics
  • Silicon radiation detectors
  • X-ray detectors
  • high-resolution imaging
  • low-noise amplifiers
  • sun

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