International Workshop on Astronomical X–Ray Optics
Prague 2011
Presentation details
X-ray mirror development at Brera: hot slumping of glass plates and thin monolithic glass shells
Presentation duration: 30 minutes
Presenter: Gianpiero Tagliaferri
We will present two technological projects in the field of X-ray mirrors development that we are pursuing at the Brera Astronomical Observatory (INAF-OAB). The “Hot slumping technology with pressure” allow us to properly shape glass plates to be used in grazing incidence segmented optics. Following this replication approach, it is possible to obtain, with the same mould, a number of equal mirror segments to be integrated and aligned in a Wolter I X-ray telescope. To this end a study, financed by ESA, started in 2009 at INAF-OAB and it is scheduled to finish in 2012 with the production of representative module prototypes, named POC and XOU_BB. To be effective a mission dedicated to deep survey the X-ray sky, after the advent of eRosita, needs to have a wide-field X-ray telescopes with an angular resolution of 5-10 arcsec constant across a wide field of view (1 deg^2 diameter). A significant increase of effective area and grasp with respect to eRosita must also be achieved. This is possible with high precision but at the same time thin glass mirror shells, in particular we are considering quartz glass (fused silica). To bring the mirror shells to the needed accuracy, we are developing a deterministic direct polishing method. This method has already been used for past missions (as Einstein, Rosat, Chandra). The technological challenge now is to apply it for almost ten times thinner shells. We will describe the results achieved so far for both projects.
S. Basso, O. Citterio, M. Civitani, P. Conconi, M. Ghigo, G. Pareschi, L. Proserpio, B. Salmaso, G. Sironi, D. Spiga