Active shape correction of a thin glass/plastic x-ray mirror

Abstract

Optics for future X-ray telescopes will be characterized by very large aperture and focal length, and will be made of lightweight materials like glass or plastic in order to keep the total mass within acceptable limits. Optics based on thin slumped glass foils are currently in use in the NuSTAR telescope and are being developed at various institutes like INAF/OAB, aiming at improving the angular resolution to a few arcsec HEW. Another possibility would be the use of thin plastic foils, being developed at SAO and the Palermo University. Even if relevant progresses in the achieved angular resolution were recently made, a viable possibility to further improve the mirror figure would be the application of piezoelectric actuators onto the non-optical side of the mirrors. In fact, thin mirrors are prone to deform, so they require a careful integration to avoid deformations and even correct forming errors. This however offers the possibility to actively correct the residual deformation. Even if other groups are already at work on this idea, we are pursuing the concept of active integration of thin glass or plastic foils with piezoelectric patches, fed by voltages driven by the feedback provided by X-rays, in intra-focal setup at the XACT facility at INAF/OAPA. In this work, we show the preliminary simulations and the first steps taken in this project

Manufacturing and testing a thin glass mirror shell with piezoelectric active control

“…In this paper we describe last year's activities carried out in the AXYOM (Adjustable X-raY optics for astrOnoMy) project involving INA F/OAB, Università di Palermo, and INAF/OAPA, to study the possibility to act ively correct the shape of thin glass X-ray mirrors [9] . While other groups [8] have selected the approach of depositing patches of piezoelectric thin films on slu mped glassed, we have adopted piezoelectric elements available co mmercially, to be fed by a system of metallic electrodes deposited by photolithography on the non -optical side of the foil.…”