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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A Novel Approach to X-ray Mirror Bending Stability and Control

Weinbaum, Michael 22 October 2010 (has links)
A novel, no-contact approach to X-ray mirror bending control is presented here, proposed for use on the beamlines of the European X-ray Free Electron Laser (XFEL) project. A set of mirrors with tunable bending radii are desired, that will maintain their optical properties even as the beam incidence causes local heating. Various mechanical bending mechanisms have been proposed and used on other beamlines, which can take up a lot of physical space, demanding more vacuum power, while using expensive high precision servomotors. Rather than bend the mirror by mechanical means, it is proposed to heat the mirror to produce the desired bending. This could work two ways. One scenario calls for a finely tunable heat lamp to irradiate the back surface of the mirror while the X-ray laser heats the front side. With appropriate tuning, simulations show that this approach can keep the mirror flat, and perhaps produce a circular profile. The second scenario is similar to the first, but a thin film of tungsten is added to the back of the silicon mirror. This scenario calls for the temperature of the mirror to change homogenously to affect the desired bending, and in this case the profile should be cylindrical. In both scenarios the uneven nature of the incident radiation causes distortions that may be undesirable. Both scenarios are simulated and it is shown that the stress produced by a metal film may minimize this distortion. The response time of the mirror and configuration of both the heating and cooling mechanism are also considered.

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