X-ray telescope onboard Astro-E. II. Ground-based x-ray characterization

R. Shibata et al., X-ray telescope onboard Astro-E. II. Ground-based x-ray characterization, APPL OPTICS, 40(22), 2001, pp. 3762-3783
Citations number
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Optics & Acoustics
Journal title
ISSN journal
0003-6935 → ACNP
Year of publication
3762 - 3783
SICI code
X-ray characterization measurements of the x-ray telescope (XRT) onboard th e Astro-E satellite were carried out at the Institute of Space and Astronau tical Science (Japan) x-ray beam facility by means of a raster scan with a narrow x-ray pencil beam. The on-axis half-power diameter (HPD) was evaluat ed to be 1.8 ' -2.2 ', irrespective of the x-ray energy. The on-axis effect ive areas of the XRTs for x-ray imaging spectrometers (XISs) were approxima tely 440, 320, 240, and 170 cm(2) at energies of 1.49, 4.51, 8.04, and 9.44 keV, respectively. Those of the x-ray spectrometer (YRS) were larger by 5- 10%. The replication method introduced for reflector production significant ly improved the imaging capability of the Advanced Satellite for Cosmology and Astrophyics (ASCA) XRT, whose HPD is similar to3.6 '. The increase in t he effective area by a factor of 1.5-2.5, depending upon the x-ray energy, compared with that of the ASCA, was brought about by mechanical scale up an d longer focal lengths. The off-axis HPDs were almost the same as those obt ained on the optical axis. The field of view is defined as the off-axis ang le at which the effective area becomes half of the on-axis value. The diame ter of the field of view was similar to 19 ' at 1.49 keV, decreasing with i ncreasing x-ray energy, and became similar to 13 ' at 9.44 keV. The intensi ty of stray light and the distribution of this kind of light on the focal p lane were measured at the large off-axis angles 30' and 60 '. In the entire XIS field of view (25.4 mm X 25.4 mm), the intensity of the stray light ca used by a pointlike x-ray source became at most 1% of the same pointlike so urce that was on the optical axis. (C) 2001 Optical Society of America.