X-Ray Performance of Critical-angle Transmission Grating Prototypes for the Arcus Mission

Abstract 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 galaxy clusters characterizing jets winds from supermassive black holes investigate the dynamics of protoplanetary disks stellar accretion. features 12 m focal-length grazing-incidence silicon pore optics (SPO) developed for Athena mission. Critical-angle transmission (CAT) gratings efficiently disperse high diffraction orders onto CCDs. We report new improved performance results Arcus-like CAT gratings, including record resolving power two coaligned gratings. Multiple prototype facets were illuminated an SPO at PANTER facility. The consist 32 × 32.5 mm 2 patterned membranes, bonded metal frames. bonding angle adjusted according measured average tilt bars in membrane. Two simultaneously show minor broadening Al-K α doublet 18th 21st with best-fit effective R G ≈ 1.3 − 0.5 + ∞ × 10 4 (3 σ ), about three four times requirement. efficiency quasi-fully O-K wavelengths 4–7 configuration compare synchrotron spot measurements. After corrections geometrical effects bremsstrahlung continuum, we find agreement full illumination different facilities, as well models used area predictions. that these flight-like meet greatly exceed requires.