X-Ray Imaging Spectrometer (XIS) on Suzaku

 The X-ray Imaging Spectrometer (XIS) is one of three science instruments aboard Suzaku (formerly Astro-E2), an orbiting X-ray astronomy observatory. Suzaku was developed jointly by the Institute for Space and Astronautical at the Japan Aerospace and Exploration Agency (ISAS/JAXA) and by NASA. The XIS was developed and built by a collaboration between MIT, ISAS and the Universities of Osaka and Kyoto.

There are four independent XIS sensors aboard the spacecraft, each with its own X-ray telescope, and each employing an X-ray sensitive charged coupled device (CCD) that records the location and energy of incident X-ray photons. The CCDs are similar to those used in previous space mission, such as Chandra, but several improvements have been made to increase the energy resolution and mitigate the effects of on-orbit radiation damage.

The XIS CCD detectors were fabricated at MIT's Lincoln Laboratory, and the thermoelectric cooling system and analog electronics were also provided by MIT. The digital electronics, onboard processing software, and certain parts of the sensor housing were developed jointly in Japan by ISAS/JAXA, the University of Kyoto, and the University of Osaka.

The X-ray Imaging Spectrometer (XIS) is one of three science instruments flown on the Suzaku X-ray satellite. There are four independent XIS sensors aboard the spacecraft, each with its own telescope and electronics, and each employing an X-ray sensitive CCD. These sensors are the latest in a line of development that includes the ASCA SIS and Chandra ACIS detectors. Each XIS CCD contains 1024 by 1024 pixels and provides a square field of view 17.8' on a side. Each pixel subtends about 1", and the angular resolution of the XIS is determined by the ~2' half-power diameter of the X-ray Telescopes (XRTs). Energy resolution ranges from 50-180 eV (FWHM) over the 0.2-10 keV energy range. One of the sensors is a thinned backside-illuminated (BI) device, allowing substantially improved sensitivity at energies below 2 kev. The XIS devices are quite similar to the CCDs flown on Chandra ACIS, but various improvements increase the spectral resolution of the BI chip and mitigate the effects of on-orbit radiation damage.