Diamond crystal optics for self-seeding of hard X-rays in X-ray free-electron lasers

• Published in: Diamond and related materials Vol. 33; pp. 1 - 4
• Main Authors: Stoupin, S., Blank, V.D., Terentyev, S.A., Polyakov, S.N., Denisov, V.N., Kuznetsov, M.S., Shvyd'ko, Yu.V., Shu, D., Emma, P., Maj, J., Katsoudas, J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-03-2013
• Subjects: Assemblies; Coherence; Coherent light; Crystal defects; Crystals; Defects; Diamond crystal; HPHT; Plates; Strain; X-ray optics; X-ray topography; X-rays; XFEL; Diamond crystal; XFEL; HPHT; X-ray optics; Strain; Defects
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2012.12.009

We report design, fabrication, and results of X-ray topography characterization of thin synthetic type IIa diamond crystal plates and crystal-holder assemblies developed for the Hard X-ray Self-Seeding project at the Linac Coherent Light Source. The goal of the project was to achieve generation of fully coherent hard X-rays using the self-seeding concept and the single-crystal diamond wake monochromator [Geloni et al., J. Mod. Opt. 58, 1391 (2011)]. High crystal quality, crystal thickness of ≈0.1–0.2mm and strain-free crystal mount were the main requirements. Nearly defect-free diamond plates of (001) orientation, with thicknesses of 0.1mm and 0.15mm, and of a trapezoidal shape were fabricated and preliminarily evaluated. The plates were further characterized using X-ray topography. These tests helped to minimize strain in crystals induced by mounting in crystal holders and to determine defect-free crystal regions. Self-seeding experiments were conducted at the Linac Coherent Light Source using the diamond plates and crystal-holder assemblies selected by our studies. Fully coherent 8.33-keV X-rays with 5×10−5 relative bandwidth were produced [Amann et al., Nat. Photonics 6, 693 (2012)].
► 100-μm-thick type IIa HPHT diamond crystal plates fabricated and characterized using X-ray topography ► Defect-free regions and strain-free plate mounting conditions identified ► Selected plates were found to be suitable for applications in X-ray optics enabling new sources of coherent hard X-rays.