Upgraded hard x-ray telescope with multilayer supermirror for the InFOCμS balloon experiment

Abstract

Hard X-ray focusing observation is important to reveal non-thermal emission mechanism and origin in active galaxies and clusters of galaxies. We have carried out the hard X-ray observation throughout the InFOCµS program, which is an international balloon-borne experiment in collaboration with NASA/GSFC and Nagoya University. The telescope is conical approximation of Wolter-I optics with 8 m focal length and 40 cm diameter. It consists of 255 nested thin (0.17 mm thickness) reflectors with incidence angles of 0.10 • to 0.36 • . Reflectors are coated with depth-graded platinum-carbon (Pt/C) multilayers, so-called supermirrors, with periodic length of 2.6 to 13 nm and bi-layer number of 28 to 79, depending on incidence angles. We are now continuously fabricating advanced next hard X-ray telescope for the second InFOCµS flight in 2004. Compared with the first telescope, the following improvements have been made on the second one. Supermirror reflectors have wider sensitivity in energy band of 20 − 60 keV adopting optimum supermirror design for balloon observation, and smaller interfacial roughness owing to complete replication technique. For upgrading of the image quality, we then adopted stiffer reflector substrate, selected replication mandrel with better shape, and the modified telescope housing with higher alignment accuracy for reflectors. The performance of the new hard X-ray telescope was measured in X-ray beamline facility in ISAS/JAXA and synchrotron radiation facility SPring-8. The effective area and image quality are obtained to be 45 cm 2 at 30 keV and 23 cm 2 at 40 keV, and 2.5 arcmin in half power diameter, respectively. In this paper we report our development of the upgraded hard X-ray telescope for the second balloon flight experiment.

Development of n-type CCDs for the NeXT, a next Japanese x-ray astronomical satellite mission

“…1 Although the X-ray telescopes onboard previous X-ray astronomical satellites could focus X-rays up to 10 keV, the hard X-ray telescope (HXT) onboard the NeXT satellite can focus X-rays in the 0.1−80 keV band, thanks to the multilayer-coated mirror technology, called supermirror. [2][3][4] The NeXT satellite will obtain X-ray image of non-thermal emission above 10 keV which will enable us to investigate various acceleration phenomena in the universe in detail with significantly higher sensitivity than any previous and current X-ray astronomical satellites.…”

Characterization of a Hard X-ray Telescope at Synchrotron Facility SPring-8

“…17,18) Scientific instruments aboard the InFOCS 2001 campaign have been described by Okajima et al, 3) Berendse et al, 4) and Baumgartner et al 19) InFOCS was launched two more times in 2004 and observed several astronomical objects in the 20 to 50 keV region. 20,21) The next InFOCS flight is scheduled in 2009. Another balloon experiment SUMIT has been developed by Nagoya University, Osaka University, ISAS/JAXA, and other Japanese member institutes.…”

Thin Shell, Segmented X-Ray Mirrors

“…A graded Pt/C multilayer was transferred via epoxy replication onto each substrate. In the most recent mirror upgrade, the substrates were divided into 12 groups by radius, with the same multilayer prescription applied to each substrate in a group [26]. The block prescription introduced by Yamashita et al [23] was used to determine the number of layers and the thickness of each [27].…”