Figure correction of adjustable x-ray optic segments with thin-film PZT actuators

Precisely shaped thin X-ray mirrors that enable high effective area and high angular resolution are required for the mirror assemblies in the next generation of X-ray telescopes. To address this need, the deterministic figure correction capabilities of an adjustable X-ray mirror are reported. This ~ 0.4 mm thick optic segment measures 10.16 cm axially by 10.16 cm azimuthally and employs 288 lead zirconate titanate thin-film actuators. When each actuator is individually addressed with a low DC voltage, it induces a localized figure change to the mirror. The method of using measured actuator responses to simulate correcting low spatial frequency (< 1 mm^(-1)) figure errors is described. The process for filtering high spatial frequency metrology errors from measurements and the figure correction algorithms used are outlined. These corrections are compared with those simulated using a set of finite-element analysis modeled actuator responses.