Development of hard X-ray imaging detectors for the High Energy Focusing Telescope

The High Energy Focusing Telescope (HEFT) is a balloon-borne instrument carrying one of the first focusing telescopes for the hard X-ray band (20-70 keV). It makes use of tungsten-silicon multilayer coatings to extend the reflectivity of nested grazing-incidence mirrors beyond 10 keV. It also carries novel semiconductor pixel detectors on its focal planes to match the capabilities of the multilayer mirrors. After a decade of research and development, we achieve with HEFT an angular resolution of 1.5 arcminutes in half-power diameter, and an energy resolution of 1.0 keV full width at half maximum at 60 keV. We launched HEFT for a 25-hour balloon flight in May, 2005; the instrument performed within specification, and observed Cyg X-1, the Crab Nebula, and other celestial hard X-ray sources.In this thesis, I lay out the scientific motivations for HEFT, and give an overview of the experiment. I report on our detector development effort in depth, and document the balloon flight of 2005. I also describe a study of two relic radio sources, 0917+75 and 1401-33, with data from the soft X-ray XMM-Newton observatory. With a hard X-ray focusing telescope like HEFT, one can improve the sensitivity and extend the scope of such studies to other classes of objects.