Abstract
The Astro-H (Hitomi) Soft X-ray Spectrometer (SXS) was a pioneering imaging x-ray spectrometer with 5 eV energy resolution at 6 keV. The instrument used a microcalorimeter array at the focus of a high-throughput soft x-ray telescope to enable high-resolution nondispersive spectroscopy in the soft x-ray waveband (0.3 to 12 keV). We present the suite of ground calibration measurements acquired from 2012 to 2015, including characterization of the detector system, anti-coincidence detector, optical blocking filters, and filter-wheel filters. The calibration of the 36-pixel silicon thermistor microcalorimeter array includes parameterizations of the energy gain scale and line-spread function for each event grade over a range of instrument operating conditions, as well as quantum efficiency measurements. The x-ray transmission of the set of five Al/polyimide thin-film optical blocking filters mounted inside the SXS dewar has been modeled based on measurements at synchrotron beamlines, including with high spectral resolution at the C, N, O, and Al K-edges. In addition, we present the x-ray transmission of the dewar gate valve and of the filters mounted on the SXS filter wheel (external to the dewar), including beryllium, polyimide, and neutral density filters.
Highlights
The Hitomi mission,[1,2] formerly known as Astro-H, was launched from Tanegashima Space Center, Japan, on February 17, 2016
We describe the calibration approach and ground calibration measurements: Sec. 2 provides an overview, Sec. 3 presents measurements related to the effective area, Sec. 4 discusses the detector system calibration, Sec. 5 describes the anti-coincidence detector calibration, Sec. 6 provides an overview of the timing calibration, and Sec. 7 provides a summary
Because the HgTe absorbers were hand placed on the array, and had some variation in their positioning, we provided the positions of each pixel corner instead of an average fill fraction for the mission pipeline processing software calibration database.[17]
Summary
The Hitomi mission,[1,2] formerly known as Astro-H, was launched from Tanegashima Space Center, Japan, on February 17, 2016 It carried the Soft X-ray Spectrometer (SXS),[3] a microcalorimeter array cooled to 50 mK to provide highresolution nondispersive spectroscopy from 0.3 to 12 keV. The SXS microcalorimeter array[6] consisted of ion-implanted silicon thermistors and HgTe thermalizing x-ray absorbers that operate at a heat-sink temperature of 50 mK. Because of this low operating temperature, the optical path of the SXS included a set of five thin-film aluminized polyimide filters anchored to nested temperature stages. Eckart et al.: Ground calibration of the Astro-H (Hitomi) soft x-ray spectrometer
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
