Title: Performance optimization of a bendable parabolic cylinder collimating X-ray mirror for the ALS micro-XAS beamline 10.3.2

Abstract

The Advanced Light Source (ALS) beamline (BL) 10.3.2 is an apparatus for X-ray microprobe spectroscopy and diffraction experiments, operating in the energy range 2.4–17 keV. The performance of the beamline, namely the spatial and energy resolutions of the measurements, depends significantly on the collimation quality of light incident on the monochromator. In the BL 10.3.2 end-station, the synchrotron source is imaged 1:1 onto a set of roll slits which form a virtual source. The light from this source is collimated in the vertical direction by a bendable parabolic cylinder mirror. Details are presented of the mirror design, which allows for precision assembly, alignment and shaping of the mirror, as well as for extending of the mirror operating lifetime by a factor of ~10. Assembly, mirror optimal shaping and preliminary alignment were performedex situin the ALS X-ray Optics Laboratory (XROL). Using an original method for optimalex situcharacterization and setting of bendable X-ray optics developed at the XROL, a root-mean-square (RMS) residual surface slope error of 0.31 µrad with respect to the desired parabola, and an RMS residual height error of less than 3 nm were achieved. Once in place at the beamline, deviations from the designed optical geometry (e.g.due to themore » tolerances for setting the distance to the virtual source, the grazing incidence angle, the transverse position) and/or mirror shape (e.g.due to a heat load deformation) may appear. Due to the errors, on installation the energy spread from the monochromator is typically a few electron-volts. Here, a new technique developed and successfully implemented for at-wavelength (in situ) fine optimal tuning of the mirror, enabling us to reduce the collimation-induced energy spread to ~0.05 eV, is described.« less

Authors:

Yashchuk, Valeriy V. ^[1]; Morrison, Gregory Y. ^[1]; Marcus, Matthew A. ^[1]; Domning, Edward E. ^[1]; Merthe, Daniel J. ^[1]; Salmassi, Farhad ^[1]; Smith, Brian V. ^[1]

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+ Show Author Affiliations

1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Publication Date:

Wed Apr 08 00:00:00 EDT 2015

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1213436

Alternate Identifier(s):

OSTI ID: 1512145

Grant/Contract Number:  

AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Synchrotron Radiation (Online)

Additional Journal Information:

Journal Name: Journal of Synchrotron Radiation (Online); Journal Volume: 22; Journal Issue: 3; Journal ID: ISSN 1600-5775

Publisher:

International Union of Crystallography

Country of Publication:

United States

Language:

English

Subject:

43 PARTICLE ACCELERATORS; X-ray mirrors; bendable mirrors; at-wavelength metrology; optimal surface shaping