Conceptual design for a dispersive XAFS beamline in the compact storage ring MIRRORCLE
Résumé
We present the conceptual design of a dispersive X-ray Absorption Fine Structure (XAFS) beamline for MIRRORCLE [1], a new compact laboratory X-ray source. This machine accelerates electrons up to 1,4,6 or 20 MeV (depending upon the model) in a ring and produces X-rays when the electrons collide onto a thin target. The radiation emitted has a white spectrum due to both synchrotron and bremsstrahlung emission. The electrons are recovered after collisions, and the emitted light has high ux, wide energy spectrum and a large angular dispersion. We opted for a simple beamline design using a collimator, slits, a curved crystal, the sample environment and a CCD. The beamline parameters (position of the mirror, ray of curvature, slit aperture, rejecting angle, etc.) have been optimized by de ning and improving a gure of merit. This optimization allows for room constraints (distances among elements), mechanical constraints (minimum curvature radii available) and optical constraints. Further ray tracing simulations using SHADOW3 have been performed to check all the theoretical results, re fine the fi nal parameters, quantitative flux calculations and for simulating the image on the CCD camera.