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Title: Operation of a dynamically bent sagittally focusing double crystal monochromator for XAFS studies

Abstract

The X-11A beamline at the NSLS has been upgraded to include a dynamic sagittally focusing second crystal in the monochromator, currently operating in the range 5.5--11 keV. The monochromator maintains a constant focus at the sample by adjustment of the bent crystal radius during the XAFS scan. The monochromator accepts 3.3 mrad of horizontal radiation and a spot size of {similar to}1.5 mm{sup 2} is achieved at the sample. The sagittally focusing mechanism in the monochromator is described and the results are presented of intensity profiles, spatial stability, and energy resolution between the energy ranges 6 and 10 keV, where the system performs most favorably. Intensity gains over unfocused operation are substantial and XAFS studies of dilute fluorescence samples reveal the expected {ital S}/{ital N} improvements, without any introduction of additional noise from the bending process. The mechanism operates with close to 100% efficiency between the energy ranges 6 and 8 keV. Bending errors hinder the performance at higher energies and also preclude effective harmonic rejection, by piezocrystal detuning, over the entire energy range.

Authors:
;  [1]
  1. Brookhaven National Laboratory, Upton, New York 11973 (United States)
Publication Date:
OSTI Identifier:
5520607
DOE Contract Number:  
FG05-89ER45384; AC02-76CH00016
Resource Type:
Journal Article
Journal Name:
Review of Scientific Instruments; (United States)
Additional Journal Information:
Journal Volume: 63:1; Journal ID: ISSN 0034-6748
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; 47 OTHER INSTRUMENTATION; MONOCHROMATORS; OPERATION; FOCUSING; GAIN; NSLS; PERFORMANCE; SIGNAL-TO-NOISE RATIO; ACCELERATORS; AMPLIFICATION; CYCLIC ACCELERATORS; RADIATION SOURCES; SYNCHROTRON RADIATION SOURCES; SYNCHROTRONS; 430303* - Particle Accelerators- Experimental Facilities & Equipment; 440600 - Optical Instrumentation- (1990-)

Citation Formats

Lamble, G M, and Heald, S M. Operation of a dynamically bent sagittally focusing double crystal monochromator for XAFS studies. United States: N. p., 1992. Web. doi:10.1063/1.1142634.
Lamble, G M, & Heald, S M. Operation of a dynamically bent sagittally focusing double crystal monochromator for XAFS studies. United States. doi:10.1063/1.1142634.
Lamble, G M, and Heald, S M. Wed . "Operation of a dynamically bent sagittally focusing double crystal monochromator for XAFS studies". United States. doi:10.1063/1.1142634.
@article{osti_5520607,
title = {Operation of a dynamically bent sagittally focusing double crystal monochromator for XAFS studies},
author = {Lamble, G M and Heald, S M},
abstractNote = {The X-11A beamline at the NSLS has been upgraded to include a dynamic sagittally focusing second crystal in the monochromator, currently operating in the range 5.5--11 keV. The monochromator maintains a constant focus at the sample by adjustment of the bent crystal radius during the XAFS scan. The monochromator accepts 3.3 mrad of horizontal radiation and a spot size of {similar to}1.5 mm{sup 2} is achieved at the sample. The sagittally focusing mechanism in the monochromator is described and the results are presented of intensity profiles, spatial stability, and energy resolution between the energy ranges 6 and 10 keV, where the system performs most favorably. Intensity gains over unfocused operation are substantial and XAFS studies of dilute fluorescence samples reveal the expected {ital S}/{ital N} improvements, without any introduction of additional noise from the bending process. The mechanism operates with close to 100% efficiency between the energy ranges 6 and 8 keV. Bending errors hinder the performance at higher energies and also preclude effective harmonic rejection, by piezocrystal detuning, over the entire energy range.},
doi = {10.1063/1.1142634},
journal = {Review of Scientific Instruments; (United States)},
issn = {0034-6748},
number = ,
volume = 63:1,
place = {United States},
year = {1992},
month = {1}
}