Abstract:
The recent progress in the development of multilayer mirrors has revolutionized the
field of astronomical X-rays optics. A variety of multilayer mirrors are now being
developed for several unique applications such as hard X-ray imaging telescopes
and soft X-ray polarimeters. Technology development to fabricate good quality
multilayer mirrors carries a significant importance for realization of next generation
X-ray instruments. In this thesis, we have presented our progress in fabricating
and characterizing high quality W/B4C multilayer mirrors for various applications.
We have also discussed the design and development of two X-ray instruments using
the combination of grazing incidence X-ray concentrator and multilayer mirrors.
We fabricated W/B4C multilayer mirrors with varied design parameters using
magnetron sputtering technique. We studied the performance and structural sta-
bility of these mirrors over time and by subjecting these mirror to the temperature
variation analogous to the satellite in low earth orbit using soft X-ray, hard X-ray
reflectivity as well as scanning electron microscopic studies for estimating the con-
tamination and surface quality. We observed that multilayers with small thickness
are more stable than the large thickness multilayers.
We designed a multilayer mirror based soft X-ray polarimeter to operate at
energies less than 1 keV. We proposed this design coupled with a hard X-ray
polarimeter as a simultaneous back-end instrument to a hard X-ray telescope.
For this application, to make multilayer mirrors transparent to hard X-rays, we
etched the Silicon substrate of the mirrors to reduce the absorption. We observed
that the etching process significantly degraded the performance of large thickness
multilayers (> 5 nm) while the process did not affect the performance of short
thickness multilayers (< 3 nm).
