Measurement of the x-ray mass attenuation coefficients of gold in the38–50-keV energy range

Abstract

We used synchrotron x rays to measure the x-ray mass attenuation coefficients of gold at nine energies from 38 to 50 keV with accuracies of 0.1%. Our results are much more accurate than previous measurements in this energy range. A comparison of our measurements with calculated mass attenuation coefficients shows that our measurements fall almost exactly midway between the XCOM and FFAST calculated theoretical values, which differ from one another in this energy region by about 4%, even though the range includes no absorption edge. The consistency and accuracy of these measurements open the way to investigations of the x-ray attenuation in the region of the L absorption edge of gold.

Approximating the near-edge mass absorption coefficients for Ni using an ultra-thin bimetal foil

“…Contact with the foil edges, even with careful handling, would easily distort those edges, making the desired measurement error of less than 1% virtually impossible. What became clear was that the foil was globally uniform but locally distorted, characteristics similar to what was reported by Chantler et al (2012) and Islam et al (2010) for a thin foil of similar thickness. Edge thickness measurements could be made very precisely, but these varied greatly depending upon the local point of measurement.…”

“…been outlined (Tran et al, 2004) which allows the comparison of a thicker foil and a thinner foil without having to rely on measuring the thickness of the thin foil directly. This transference technique was demonstrated by Islam et al (2010), who accurately measured a very thick reference sample (275 mm) in order to achieve sufficient accuracy to crosscalibrate a thinner (9.3 mm) foil using comparative absorption measurements.…”

“…On the basis of the above methods, no tool-based measurement was considered reliable for determining the nominal 8 mm foil thickness at the desired 1% uncertainty level. Because the focused beam is quite small at 19BM (less than 50 mm FWHM), there was no advantage to averaging several areas and creating an average profile of the foil, as was done by Islam et al (2010), who employed a very large foil with a much larger (2 Â 2 mm) incident beam shape. Instead, highprecision mechanical reproducibility combined with visual surface examinations were used to position the same area of the sample in the beam for all measurements.…”

Measuring the linearity of X-ray detectors: consequences for absolute attenuation, scattering and absolute Bragg intensities

“…So far we have used the above linearity tests mostly in the course of absolute intensity measurements of the X-ray attenuation, including measurements in the XAFS region (e.g. de Jonge et al, 2005de Jonge et al, , 2007Glover et al, 2008;Islam et al, 2010;Rae et al, 2010), using a suite of techniques collectively referred to as the X-ray extended range technique, which makes it possible to measure X-ray absorption down to an accuracy of better than 0.05%. There is, however, considerable further scope for absolute X-ray intensity measurements that can be applied to other interesting problems, in particular to the absolute measurement of integrated Bragg intensities, whose great importance was recognized very early (see, for example, Bragg & West, 1928;Lipson & Cochran, 1957).…”

Collision-induced amplification of radiation in inversionless two-level systems

“…A recent and extensive set of synchrotron radiation measurements has appeared [20][21][22][23][24][25][26][27][28] in which the authors demonstrated painstaking effort to eliminate systematic errors identified in earlier measurements [15][16][17]. They examined attenuation coefficients for elements Si, Cu, Zn, Ag, Mo, Sn and Au with generally an overall five-fold improvement in measurement accuracy (typically to within 0.1-0.2%) with respect to earlier work.…”