Integral shell mirrors for the Constellation X-ray Mission Hard X-ray Telescope

Estimates of background in CZT detectors(1) indicate that even with the beneficial concentration of a focussing telescope measurements in the 20 to 100 keV band of the Constellation X-ray Mission's HXT will become background limited after several thousand seconds of observing. This time is less than the expected exposure of most measurements. Consequently the sensitivity of most if not all observations of the HXT will be background limited. Therefore, the angular resolution should be as good as possible as long as the effective area remains high. We are pursuing a method for fabricating telescopes for the twelve units of HXT that consists of electroforming integral shell substrates, a process that has been highly developed for XMM. We are attempting to adapt this method to higher energy X-rays by employing multilayer coatings, and smaller graze angles, and also reduce the mass of the telescopes from the XMM prescription by employing stronger, lighter alloys. The resolution that XMM has achieved, 15 " HPW is an indication of the resolution we can expect.