<title>ASTRO-E high-resolution x-ray spectrometer</title>

Abstract

The Astro-E High Resolution X-ray Spectrometer (XRS) was developed jointly by the NASA/Goddard Space Flight Center and the Institute of Space and Astronomical Science in Japan. The instrument is based on a new approach to spectroscopy, the x-ray microcalorimeter. This device senses the energies of individual x-ray photons as heat with extreme precision. A 32 channel array of microcalorimeters is being employed, each with an energy resolution of about 12 eV at 6 keV. This will provide spectral resolving power 10 times higher than any other non-dispersive x-ray spectrometer. The instrument incorporates a three stage cooling system capable of operating the array at 60 mK for about two years in orbit. The array sits at the focus of a grazing incidence conical mirror. The quantum efficiency of the microcalorimeters and the reflectivity of the x-ray mirror system combine to give high throughput over the 0.3- 12 keV energy band. This new capability will enable the study of a wide range of high-energy astrophysical sources with unprecedented spectral sensitivity. This paper presents the basic design requirements and implementation of the XRS, and also describes the instrument parameters and performance.