Simulation and optimization of the NSLS-II SRX beamline combining ray-tracing and wavefront propagation

Abstract

The Sub-micron Resolution X-ray spectroscopy (SRX) beamline will benefit from the ultralow emittance of the National Synchrotron Light Source II to address a wide variety of scientific applications studying heterogeneous systems at the sub-micrometer scale. This work focuses on the KB branch (ΔE: 4.65-28 keV). Its main optical components include a horizontally focusing mirror forming an adjustable secondary source, a horizontally deflecting monochromator and two sets of Kirkpatrick-Baez mirrors as focusing optics of two distinct inline stations for operations requiring either high flux or high resolution. In the first approach, the beamline layout was optimized with ray-tracing calculations involving Shadowvui computer codes. As a result, the location and characteristics of optics were specified for achieving either the most intense or the smallest monochromatic beam possible on the target (10 13 ph/s or 10 12 ph/s respectively in a 500 nm or 65 nm focal spot). At the nanoprobe station, the diffraction limited focusing of X-rays is governed by the beam coherence. Hence, a classical geometric approach is not anymore adapted. To get reliable estimates of the Nanoprobe performances, a wavefront propagation study was performed using Synchrotron Radiation Workshop (SRW) code. At 7.2 keV, calculations show an intense (10 12 ph/s) 67 nm wide diffraction limited spot achieved with actual metrological data of mirrors.

A new SHADOW update: integrating diffraction effects into ray-tracing

“…4(a)] and parameters are extracted from reference. 17 One should note that the parameters may not be the final design values of the NSLS-II storage ring and the SRX beamline. The source is a 1.5 m long in-vacuum IVU21 undulator with the period of 21 mm and a K value of 1.79.…”

“…The HFM is assumed to be an ideal elliptical cylinder, while both the VKB and HKB contain figure errors with profiles extracted from the mirrors used in reference 17 [cf. Fig.…”

Recent updates in the “Synchrotron Radiation Workshop” code, on-going developments, simulation activities, and plans for the future

“…the electron beam. Despite of this issue, the partiallycoherent simulations are now routinely performed using SRW for beamlines 15,[19][20][21][22][23][24][25] of the National Synchrotron Light Source II (NSLS-II), which has been recently constructed in the Brookhaven National Laboratory (BNL). Typically, such calculations are performed using a parallel version of SRW code, on a 16-or 32-core server or on a small cluster, with one isolated simulation "from source to sample" lasting from minutes to hours.…”

Nanoscale 3D imaging at the Advanced Photon Source

“…Over the past decade, technology breakthroughs in the field of x-ray optics have enabled the development of advanced imaging nanoprobes at third-generation synchrotrons. [1][2][3][4][5][6][7][8][9][10][11] X-rays have unique capabilities in terms of resolution, sensitivity, and speed, and by combining these properties with their ability to penetrate matter, these new instruments have played an important role in the recent advent of nano-material-related research. 12 The gapin terms of spatial resolution-between such x-ray instruments and electron microscopes, however, still needs to be reduced.…”