High-energy-resolution x-ray optics with refractive collimators

Abstract

We have tested the concept of a high-resolution x-ray monochromator with a refractive collimator as an optical element. Two options were examined, where the refractive collimator was included either instead of, or in addition to the first crystal of the high-resolution monochromator. The first approach offers an easy means of improving the energy resolution of conventional optical schemes by few orders of magnitude while still accepting the entire angular divergence of the primary beam. The second approach improves the performance of existing devices with very high-energy resolution and simplifies the design of future optical schemes.

Nanofocusing with aberration-corrected rotationally parabolic refractive X-ray lenses

“…Compound refractive X-ray lenses (CRLs) (Snigirev et al, 1996;Lengeler et al, 1998) made of beryllium (Schroer et al, 2002) are widely used at synchrotron storage ring sources and X-ray free-electron lasers (XFELs) as beamline optics in order to transport and condition the beam (Chumakov et al, 2000;Vaughan et al, 2011;Polikarpov et al, 2014;Heimann et al, 2016). Their advantages arise from their large geometric aperture, ranging from 300 mm up to several millimeters, their ability to withstand intense radiation due to a low absorption coefficient and good thermal conductivity, and coherencepreserving quality.…”

Using angular dispersion and anomalous transmission to shape ultramonochromatic x rays

“…This is an unusually large number. Typically, the angular acceptance of high-resolution x-ray monochromators is in a 10 to 20 µrad range, often requiring collimating optics, such that the x rays from the source to be fully accepted by the monochromator [2,[4][5][6][7][8][9]21]. The only exception to this rule are single bounce monochromators [22], which, however, have a disadvantage of long Lorentzian tails in the spectral resolution function.…”

“…The intrinsic Bragg bandwidth can be reduced [2][3][4][5][6][7][8][9] by using the so-called asymmetric x-ray diffraction, diffraction from atomic planes at nonzero angle η to the crystal face - Fig. 1.…”

Dynamics of metal centers monitored by nuclear inelastic scattering

“…For this reason, the HS isomer has -in comparison to the LS isomer -many more vibrational states that are thermally accessible, and the vibrational entropy contribution of the HS isomer is significantly higher than the corresponding value of the LS isomer (some 10 J mol −1 K −1 in case of Fe(II) SCO complexes). First NIS experiments have been performed on samples of [Fe(tpa)(NCS) 2 ] (tpa = tris(2-pyridylmethyl)amine) and [Fe(bpp) 2 ](BF 4 ) 2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) [3,37,38]. Subsequent measurements on a single crystalline sample of [Fe(tptMetame)](ClO 4 ) 2 (tptMetame = 1,1,1-tris((N-(2-pyridylmethyl)-N-methylamino)methyl)ethane) yielded angular resolved NIS spectra [4].…”