E. A. Boughan, J. P. Doty, R. F. Foster
MIT Center for Space Research,
70 Vassar St., Cambridge, MA 02139
Martin Marietta Aerospace Group,
P. O. Box 179, Mail Stop B0560, Denver, CO 80201
An X-ray imaging spectrometer, ACIS (AXAF-I CCD Imaging Spectrometer), which incorporates silicon CCDs as photon counting X-ray detectors, is being designed as a focal plane instrument for the Advanced X-ray Astrophysics Facility - Imaging (AXAF-I). The ACIS instrument will provide both spectral and imaging information of celestial X-ray sources, or when operated with the HETG (High Energy Transmission Grating), ACIS will provide high resolution, dispersed spectra of celestial X-ray sources. The ACIS instrument will also perform the communication, housekeeping, and diagnostic functions required for ground testing and on-orbit operation. Proper operation of the CCD focal plane requires operating temperatures below -100 degrees C. The -100 degrees C focal plane temperature requirement will be achieved through a passive radiator design. A general description of the planned ACIS instrument and its expected performance is provided.
The authors wish to acknowledge the contributions of Stuart E. Schechter of MIT Lincoln Laboratory, and Jeanne Repec of the MIT CSR.