Test results for an AOA-Xinetics grazing incidence x-ray deformable mirror

Abstract

X-ray telescopes use grazing incidence mirrors to focus X-ray photons from celestial objects. To achieve the large collecting areas required to image faint sources, thousands of thin, doubly curved mirrors are arranged in nested cylindrical shells to approximate a filled aperture. These mirrors require extremely smooth surfaces with precise figures to provide well-focused beams and small image spot sizes. The Generation-X telescope proposed by SAO would have a 12-meter aperture, a 50 m² collecting area and 0.1 arc-second spatial resolution. This resolution would be obtained by actively controlling the mirror figure with piezoelectric actuators deposited on the back of each 0.4 mm thick mirror segment. To support SAO's Generation-X study, Northrop Grumman used internal funds to look at the feasibility of using Xinetics deformable mirror technologies to meet the Generation-X requirements. We designed and fabricated two 10 x 30 cm Platinum-coated silicon mirrors with 108 surface-parallel electrostrictive Lead Magnesium Niobate (PMN) actuators bonded to the mirror substrates. These mirrors were tested at optical wavelengths by Xinetics to assess the actuator's performance, but no funds were available for X-ray tests. In 2013, after receiving an invitation to evaluate the mirror's performance at Argonne National Laboratory, the mirrors were taken out of storage, refurbished, retested at Xinetics and transported to ANL for metrology measurements with a Long Trace Profilometer, a Fizeau laser interferometer, and X-ray tests. This paper describes the development and testing of the adaptive x-ray mirrors at AOAXinetics. Marathe, et al, will present the results of the tests at Argonne.