Glass Technology for the next generation X-ray optics: Shell#4 grinding and polishing @LT-Ultra (2017)

The scope of the document is to summarize the activity performed during the first phase of the grinding and polishing campaign in 2017 for shell#4 (until the interruption of the activities at LT-Ultra in consequence of the shell breakage

Glass Technology for the next generation X-ray optics: Preliminary optical design for Lynx (based on full shell in fused silica)

The scope of the document is to illustrate the three preliminary optical designs for the mirror module of the Lynx mission. They were the baseline configurations for mechanical evaluation of the Lynx Mirror Assembly. The framework of the activities is the Lynx mission study. The design is based on direct polishing of thin fused silica shells. It has been prepared in response of the request by the Lynx OWG Co-Chairs: Lester Cohen/SAO & Mark Schattenburg/MIT, 16 August 2017). After the selection of the best mechanical configuration, a new design has been realized. The final design for the Lynx Mirror Assembly is presented

Tecnologie Avanzate per Ottiche in raggi-X (TAO-X ). Technical report on the opto-mechanical design of the telescope based on thin monolithic shells, including supporting systems, jigs and integration scheme and expected performance

The scope of the document is to report on the opto-mechanical design of the telescope based on thin monolithic shells, including supporting systems, jigs and integration scheme and expected performance

Glass Technology for the next generation X-ray optics: Report on polishing tests on Shell#4 with INAF-OAB Zeeko machine

The scope of the document is to report the activities performed on the Shell#4 in INAF-OAB after the breakage. After the breakage of the shell#4 in LT-Ultra, for opportunity reasons it has been decided to continue the polishing work on this shell instead of starting a new one from integration phase. Given that the resources to restart the grinding campaign in LT-Ultra were not available, the results to be presented in the Lynx trade off selection process were judged primary

Tecnologie Avanzate per Ottiche in raggi-X (TAO-X ). Report on the shell design, tolerances definition and manufacturing plan, including the description of the figuring and polishing assessment, the shell integration process and report of the performances for the developed shells.

The scope of the document is to report Report on the shell design, tolerances definition and manufacturing plan, including the description of the figuring and polishing assessment, the shell integration process and report of the performances for the developed shells

Glass Technology for the next generation X-ray optics: Report on Bonnet test for polishing procedure definition

The scope of the document is to report the activities performed in preparation of the Bonnet polishing on board of LT-Ultra lathe. This activity replaces the chemical etching tests, initially foreseen to study the SSD removal from the raw fused silica material. As the procurement chain for the new shells was not yet fixed, a standard polishing procedure for the SSD removal has been preferred, as the results could be used in more independent way

Glass Technology for the next generation X-ray optics: Report on polishing tests

The scope of the document is report the tests performed to characterize the polishing process by means of 3M™ Trizact™ Hookit™ Film Disc 568XA and 3M™ Trizact™ Hookit™ Film Disc 268XA. The tests were part of the optimization of the polishing process, to increase the speed and to reduce the costs of shell production]. They were carried out on fused silica samples prepared with a starting micro-roughness of the order of 50 - 70 nm rms (equivalent to the initial status of the shell under manufacturing). We characterized the removal rate and the micro-roughness improvement rate in dependence of several parameters as amount of water, pH, velocity and pressure, taking care also of the wear rate of the pads

Evaluation of deflectometry for E-ELT optics

A deflectometrical facility was developed at Italian National Institute for Astrophysics-OAB in the context of the ASTRI project to characterize free-form segments for Cherenkov optics. The test works as an inverse Ronchi test in combination with a ray-tracing code: the under-test surface is illuminated by a known light pattern and the pattern warped by local surface errors is observed. Knowing the geometry of the system it is possible to retrieve the surface normal vectors. This contribution presents the analysis of the upgrades and of the configuration modifications required to allow the use of deflectometry in the realization of optical components suitable for European Extremely Large Telescope and as a specific case to support the manufacturing of the Multi-conjugate Adaptive Optics Relay (MAORY) module. <P /

Thin glass shells for active optics for future space telescopes

We present a method for the manufacturing of thin shells of glass, which appears promising for the development of active optics for future space telescopes. The method exploits the synergy of different mature technologies, while leveraging the commercial availability of large, high-quality sheets of glass, with thickness up to few millimeters. The first step of the method foresees the pre-shaping of flat substrates of glass by replicating the accurate shape of a mold via hot slumping technology. The replication concept is advantageous for making large optics composed of many identical or similar segments. After the hot slumping, the shape error residual on the optical surface is addressed by applying a deterministic sub-aperture technology as computer-controlled bonnet polishing and/or ion beam figuring. Here we focus on the bonnet polishing case, during which the thin, deformable substrate of glass is temporary stiffened by a removable holder. In this paper, we report on the results so far achieved on a 130 mm glass shell case study.Comment: This is a pre-print of an article published in CEAS Space Journal. The final authenticated version is available online at: http://link.springer.com/article/10.1007/s12567-019-00259-

Ray-tracing of displaced SPO mirror modules

The report includes a description of the method used for simulating the effects of SPO MM rotations in the Athena geometry. The main results are also included