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Solid-State Imaging Spectrometer (SIS)

NSSDCA ID: 1993-011A-01

Mission Name: ASCA
Principal Investigator:Dr. George R. Ricker, Jr.


Two identical Solid-state Imaging Spectrometer (SIS) detectors were carried by the ASCA spacecraft. The SIS detectors were located in the focal plane of the X-Ray Telescopes (XRT). Each CCD camera head was based around four 420 x 422 pixel MIT Lincoln Laboratory CCD chips abutted side by side, with four preamplifiers, front-side illuminated. The SIS had an energy resolution of 2 percent at 5.9 keV at launch. Between about 1.5 and 5 keV the SIS had an effective area of about 150-200 cm**2. Below 1.5 keV the SIS had more effective area than the ASCA Gas Imaging Spectrometer (GIS) experiment while above 5 KeV the GIS had more effective area. The GIS could observe brighter sources and had better temporal resolution than the SIS but the GIS had poorer angular resolution. The SIS was better suited to the study of small-scale structure (about 1 arcmin). The field-of-view of each SIS camera was 22 x 22 arcmin square. The SIS CCDs could be operated in four clocking modes: a 4-CCD mode with a time resolution of 16 s (at the high bit rate); 2-CCD mode with a time resolution of 8 s; 1-CCD mode with a time resolution of 4 s; and parallel sum mode with a time resolution of 15.625 ms. In addition, the SIS detectors could be operated in three data modes, "faint", "bright", and "fast", which corresponded to three different ways of telemetering to the ground the photon spread produced by an incoming X-ray photon.

Alternate Names

  • SIS

Facts in Brief

Bit rate (avg): 15.2 kbps

Funding Agencies

  • Institute of Space and Aeronautical Science, U of Tokyo (Japan)
  • NASA-Office of Space Science Applications (United States)


  • Astronomy: X-Ray

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Dr. George R. Ricker, Jr.Principal InvestigatorMassachusetts Institute of

Selected References

  • Tanaka, Y., The ASTRO-D mission, in Observatories in Earth Orbit and Beyond, edited by Y. Kondo, IAU Colloq. 123, Kluwer, 81-87, 1990.
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