X-Ray Telescope for 20 to 100 Kev Using Multilayer Optics

Radiation Science proposes to design and build a prototype, broad band hard X-ray telescope for flight on a balloon payload. The telescope will focus X-rays with energies between 10 and 100 keV. The reflecting surfaces will consist of multilayer diffractors composed of bilayers whose period varies as a function of depth. The diffractors will be deposited on smooth, flat substrates arranged as a planar approximation to a Kirkpatrick-Baez grazing incidence telescope. To our knowledge, this will be the first focussing telescope in this energy range. Phase I will be a conceptual design study of the telescope. The design will be based on previous Kirkpatrick-Baez telescope designs and on prior work on depth-graded multilayers. The energy range, focal length, and image scale of the telescope will be chosen to interface with the balloon payload and the spectroscopic imaging detector. We will consider the specification of the multilayer coatings, the selection of an appropriate substrate material, and the design of the mirror mount and the optical bench. The spatial resolution and effective area will be estimated as a function of energy. The size, weight, and cost of the telescope will be estimated.