The Astro-H Soft X-ray Spectrometer (SXS)

The Soft-X-ray Spectrometer (SXS) is a high spectral resolution, cryogenic x-ray spectrometer that will fly on the Japan/U.S. Astro-H observatory in 2014. The SXS is composed of a 36 pixel, imaging, x-ray calorimeter array that will operate at 0.05 K utilizing a 2-stage adiabatic demagnetization refrigerator and a redundant pre-cooler design using both a 40 liter liquid helium tank and a 1.7 K Joule-Thomson (JT) cryocooler. Additional redundant Stirling cycle coolers provide pre-cooling for the (JT) and cool the outer thermal shields for the JT and the helium tank. The detector system, while similar to that flown on Suzaku, is composed of larger 0.81x0.81 mm pixels, but has significantly better performance, currently predicted to be better than 4 eV FWHM at 6 keV with 95% quantum efficiency. This instrument is the result of a close collaboration between many institutions in the U.S. and Japan over the last 25 years. Here we will present an overview of the SXS instrument, the SXS cooling system, and recent laboratory improvements to the detector system.