Effective area of the AXAF high-resolution camera (HRC)

The Advanced X-Ray Astrophysics Facility High Resolution Camera was calibrated at NASA's X-Ray Calibration Facility during March and April 1997. We have undertaken an analysis of the effective area of the combined High Resolution Mirror Assembly/High Resolution Camera using all data presently available from these tests. In this contribution we discuss our spectral fitting of the beam-normalization detectors, our method of removing higher order contamination lines present in the spectra, and the corrections for beam non- uniformities. Using an approach based upon the mass absorption cross-section of Cesium Iodide, we determine the quantum efficiency in the microchannel plates. We model the secondary electron absorption depth as a function of energy, which we expect to be relatively smooth. This is then combined with the most recent model of the telescope to determine the ensemble effective area for the HRC. The ensemble effective area is a product of the telescope effective are, the transmission of the UV-Ion shield, and the quantum efficiency of the microchannel plates. We focus our attention on the microchannel plate quantum efficiency, using previous result for the UV-Ion shield transmission and telescope effective area. We also address future goals and concerns.