Cosmic-ray acceleration in Cassiopeia A and grazing-incidence multilayer X-ray mirrors

This dissertation consists of two separate, but complementary parts. The first part is a search for evidence of cosmic-ray acceleration in the newly-discovered forward shock of the young shell-type remnant Cassiopeia A. Spectra extracted around the entire circumference of the forward shock are best fitted by a two-component model: a nonequilibrium ionization model assuming nonequipartition between electrons and ions and an additional nonthermal component interpreted as synchrotron radiation. The maximum electron energy is estimated to be ∼10 TeV assuming a magnetic field of 0.08–0.16 μG. A population of regions showing very little thermal line emission exists between the forward and reverse shock. These regions can be interpreted either as thermal forward shock emission seen in projection or as synchrotron emission. The search for x-ray synchrotron emission can be facilitated by imaging x-rays above 20 keV where thermal emission is negligible. The focus of the second part of this dissertation is the production of a grazing-incidence multilayer mirror for the International Focusing Optics Collaboration for μCrab Sensitivity hard x-ray balloon-borne telescope. The 40-cm diameter, 8 m focal-length mirror is composed of 2040 aluminum foils coated with a platinum/carbon graded multilayer. The mirror consists of 255 concentric shells of a conic approximation to a Wolter Type I geometry. Reflectivity measurements of sample foils give a mean multilayer interface width of 0.5 nm. The on-axis effective area of the mirror is 78 cm2 at 20 keV to 22 cm2 at 40 keV. The mirror produces an on-axis image half-power diameter (HPD) of 1.9&feet; ± 0.5&feet;. The combined mirror/detector HPD is 2.8&feet; ± 0.5&feet; due to large detector pixels (54&inches;). The mirror was tested in-flight using the x-ray binary Cygnus X-1 on 4–5 Jul 2001. The balloon experienced unexpectedly large stochastic motions exceeding the design limits of the pointing system. As a result, an image HPD of 7.2&feet; ± 1.0&feet; was obtained during the flight. An image during a brief time interval with steady pointing has a HPD of 4.0&feet; ± 0.5&feet;.