1/20/2024 0 Comments Xray diffraction gratings thesis![]() ![]() resolve the diffraction satellites, the divergency of the X-ray beam. These contain all the details of our work on 100 nm period gratings. creates a dynamical diffraction grating on the crystal surface, and this can be used. The remainder of this report consists of portions excerpted from Erik Anderson's thesis. Moreover, 100 nm-period gratings produced by achromatic holography are coherent over their entire area whereas gratings produced by e-beam lithography are coherent only over areas /approximately/100. The achromatic holography, on the other hand, should be capable of exposing areas well in excess of 1 cm/sup 2/ in times under 1 hour. However, the e-beam method proved to be highly impractical: exposure times of about 115 days would be required to cover an area of 1 cm/sup 2/. Erik was successful in both the e-beam and more » holographic approaches. This work was pursued by Erik Anderson as a major component of his Ph.D. We explored two approaches: e-beam fabrication of x-ray lithography masks, and achromatic holographic lithography. The major focus of our efforts was to develop a means of fabricating gratings of 100 nm period. These gratings are generally gold transmission gratings with spatial periods of 200 nm or less. This subcontract was initiated in order to facilitate the development at MIT of technologies for fabricating the very fine diffraction grating required in x-ray spectroscopy at Lawrence Livermore Laboratory (LLL). More detailed rf simulation, heat extraction analysis, beam dynamics using a mm-wave structure, and measurements on lOx larger scale models can be found in these proceedings. First harmonic undulator radiation at 5.2 KeV would be possible using the Advanced Photon Source (APS) linac system, which provides a low-emittance electron beam by using an rf thermionic gun with an energy as high as 750-MeV. A mm-wave undulator, which will be discussed later, may have special features compared to the conventional undulator. A more » 30- or 84-cell 108-GHz mm-wave structure can serve as an electromagnetic undulator. Rectangular cavity geometry is best suited to this fabrication technique. Major challenges are: fabrication of the wafers into three-dimensional rf structures alignment and overlay accuracy of structures adhesion of the PMMA on the copper substrate and selection of a developer to obtain high resolution. Highly precise, two-dimensional features can be machined onto wafers using DXRL. The fabrication process includes manufacture of precision x-ray masks, exposure of positive resist by x-ray through the mask, resist development, and electroforming of the final microstructure. He demonstrated the ability of copper sulphate crystals to act as three dimensional diffraction gratings (Deschamps & Flippen-Anderson, n.d.). The possibility of fabricating mm-wave radio frequency cavities (100-300 GHz) using deep x-ray lithography (DXRL) is being investigated.
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