X-Ray Performance of Critical-angle Transmission Grating Prototypes for the Arcus Mission
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- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Izentis LLC, Cambridge, MA (United States)
- Max Planck Inst. fuer Extraterrestrische Physik, Garching (Germany)
- Univ. of Iowa, Iowa City, IA (United States)
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Smithsonian Astrophysical Observatory, Cambridge, MA (United States)
Arcus is a proposed Explorer Class soft X-ray grating spectrometer. It aims to explore cosmic feedback by mapping hot gases within and between galaxies and galaxy clusters and characterizing jets and winds from supermassive black holes and to investigate the dynamics of protoplanetary disks and stellar accretion. Arcus features 12 m focal-length grazing-incidence silicon pore optics (SPO) developed for the Athena mission. Critical-angle transmission (CAT) gratings efficiently disperse high diffraction orders onto CCDs. We report new and improved X-ray performance results for Arcus-like CAT gratings, including a record resolving power for two coaligned CAT gratings. Multiple Arcus prototype grating facets were illuminated by an SPO at the PANTER facility. The facets consist of 32 × 32.5 mm2 patterned silicon membranes, bonded to metal frames. The bonding angle is adjusted according to the measured average tilt angle of the grating bars in the membrane. Two simultaneously illuminated facets show a minor broadening of the Al-Kα doublet in the 18th and 21st orders with the best-fit record effective resolving power of $${R}_{G}\approx {1.3}_{-0.5}^{+\infty }\times {10}^{4}$$ (3σ), about three to four times the Arcus requirement. We measured the diffraction efficiency of quasi-fully illuminated gratings at O-K wavelengths in orders 4–7 in an Arcus-like configuration and compare results with synchrotron spot measurements. After corrections for geometrical effects and bremsstrahlung continuum, we find agreement between full and spot illumination at the two different facilities, as well as with the models used for Arcus effective area predictions. We find that these flight-like gratings meet the diffraction efficiency and greatly exceed the resolving power Arcus requires.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- European Union (EU); National Aeronautics and Space Administration (NASA); National Science Foundation (NSF); USDOE Office of Science (SC), High Energy Physics (HEP)
- Grant/Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1906690
- Journal Information:
- The Astrophysical Journal, Journal Name: The Astrophysical Journal Journal Issue: 2 Vol. 934; ISSN 0004-637X
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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