TY - JOUR
T1 - Absolute x-ray energy calibration over a wide energy range using a diffraction-based iterative method
AU - Hong, Xinguo
AU - Chen, Zhiqiang
AU - Duffy, Thomas S.
N1 - Funding Information:
We would like to acknowledge C. Koleda, L. Ehm, and D. Weidner for useful discussions, and X. M. Yu, Z. Zhong, L. P. Huang, and S. Lin for their help in the experiments. Assistance from M. Abeykoon, P. Gao, and T. Dykhne on PDF analysis are also acknowledged. This work was supported by COMPRES, the Consortium for Materials Properties Research in Earth Sciences under National Science Foundation (NSF) Cooperative Agreement No. EAR 10-43050. The use of NSLS was supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-98CH10886.
PY - 2012/6
Y1 - 2012/6
N2 - In this paper, we report a method of precise and fast absolute x-ray energy calibration over a wide energy range using an iterative x-ray diffraction based method. Although accurate x-ray energy calibration is indispensable for x-ray energy-sensitive scattering and diffraction experiments, there is still a lack of effective methods to precisely calibrate energy over a wide range, especially when normal transmission monitoring is not an option and complicated micro-focusing optics are fixed in place. It is found that by using an iterative algorithm the x-ray energy is only tied to the relative offset of sample-to-detector distance, which can be readily varied with high precision of the order of 10 -5 -10 -6 spatial resolution using gauge blocks. Even starting with arbitrary initial values of 0.1 Å, 0.3 Å, and 0.4 Å, the iteration process converges to a value within 3.5 eV for 31.122 keV x-rays after three iterations. Different common diffraction standards CeO 2, Au, and Si show an energy deviation of 14 eV. As an application, the proposed method has been applied to determine the energy-sensitive first sharp diffraction peak of network forming GeO 2 glass at high pressure, exhibiting a distinct behavior in the pressure range of 2-4 GPa. Another application presented is pair distribution function measurement using calibrated high-energy x-rays at 82.273 keV. Unlike the traditional x-ray absorption-based calibration method, the proposed approach does not rely on any edges of specific elements, and is applicable to the hard x-ray region where no appropriate absorption edge is available.
AB - In this paper, we report a method of precise and fast absolute x-ray energy calibration over a wide energy range using an iterative x-ray diffraction based method. Although accurate x-ray energy calibration is indispensable for x-ray energy-sensitive scattering and diffraction experiments, there is still a lack of effective methods to precisely calibrate energy over a wide range, especially when normal transmission monitoring is not an option and complicated micro-focusing optics are fixed in place. It is found that by using an iterative algorithm the x-ray energy is only tied to the relative offset of sample-to-detector distance, which can be readily varied with high precision of the order of 10 -5 -10 -6 spatial resolution using gauge blocks. Even starting with arbitrary initial values of 0.1 Å, 0.3 Å, and 0.4 Å, the iteration process converges to a value within 3.5 eV for 31.122 keV x-rays after three iterations. Different common diffraction standards CeO 2, Au, and Si show an energy deviation of 14 eV. As an application, the proposed method has been applied to determine the energy-sensitive first sharp diffraction peak of network forming GeO 2 glass at high pressure, exhibiting a distinct behavior in the pressure range of 2-4 GPa. Another application presented is pair distribution function measurement using calibrated high-energy x-rays at 82.273 keV. Unlike the traditional x-ray absorption-based calibration method, the proposed approach does not rely on any edges of specific elements, and is applicable to the hard x-ray region where no appropriate absorption edge is available.
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U2 - 10.1063/1.4722166
DO - 10.1063/1.4722166
M3 - Review article
C2 - 22755637
AN - SCOPUS:84863518383
SN - 0034-6748
VL - 83
JO - Review of Scientific Instruments
JF - Review of Scientific Instruments
IS - 6
M1 - 063901
ER -