30-METER X-RAY PENCIL BEAM LINE AT THE INSTITUTE OF SPACE AND ASTRONAUTICAL SCIENCE

A 30-m-long X-ray beam line has been built at the Institute of Space a nd Astronautical Science (ISAS) to evaluate the performance of X-ray o ptical instruments for space programs, in particular for the X-ray tel escope on-board the Astro-D (Asca) satellite. This beam line consists of an X-ray generator, a 30-m-long vacuum duct, and measuring chambers . Strong and stable X-ray pencil beams from Al, Ti, Cu, Mo and W targe ts are available with the parallelism of several arcs [full width at h alf maximum (FWHM)]. Three kinds of detectors are prepared: a conventi onal gas proportional counter equipped with a thin plastic window, a o ne-dimensional position-sensitive proportional counter with a Be windo w, and a charge-coupled device (CCD) modified for X-ray measurements. At the present compact beam line, instead of giant systems of hundreds of meters, the combination of a strong X-ray (0.2-10 keV) pencil beam and translation stages enables us to examine the entire aperture of l arge X-ray optical instruments of up to 40 cmphi and 1 m in length.