The principal GIS calibrations are the Gain, Point-Spread Function and Energy Resolution.
The response of the GIS is expected to be relatively stable. For each observation mode, a response function will be created by the instrument team following ground testing. After launch, these response functions will be adjusted and calibrated, and their temporal behavior monitored. As with the SIS, all these calibration data will be available to Guest Investigators if requested, although normally just those data which will enable the appropriate responses for each observation to be constructed will be supplied.
The calibration of the GIS in air has begun at the University of Tokyo. From March the GIS will be calibrated in vacuo at ISAS, and, if possible, will undergo additional calibration at a Japanese synchrotron facility in June 1992.