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

Abstract

In an effort to improve the characteristics of a fluorescing metal-foil-based beam position monitor, a new bimetal ultra-thin (0.98/0.67 mm) Ti-Ni foil was introduced to replace an existing single-element ultra-thin 0.5 mm thick Cr foil. During characterization it was determined that absorption measurements on the bimetal foil could be used to fit the Ni mass absorption coefficients accurately in the vicinity of the Ni K edge. Comparison with experimental results from the literature demonstrated that the fitting procedure produced coefficients with uncertainties of the order of AE1%. Once determined, these fit coefficients allowed the thickness of an independently mounted 8 mm thick Ni foil to be computed from absorption measurements instead of relying on a tool-based measurement of the foil thickness. Using the 8 mm thick foil, a continuous map of Ni mass absorption coefficients was produced at 1 eV resolution throughout the near-edge region. This high-resolution map marks a significant improvement over the existing NIST XCOM or FFAST database mass absorption coefficients, which have estimated errors of 10-20% for the near-edge region.

Customisable X-ray fluorescence photodetector with submicron sensitivity using a ring array of silicon p-i-n diodes

“…Hence, the selection of materials becomes a necessity, based on their Kshell values having sufficient separation below the energy of incident X-ray beams. The following is a list of the selection along with respective values of K α and wavelength λ: 22 Ti (K α = 4.511 keV; λ = 2.749Å), 24 Cr (K α = 5.415 keV; λ = 2.290 A), 25 Mn (K α = 5.899 keV; λ = 2.102Å), 26 Fe (K α = 6.404 keV; λ = 1.936Å), 27 Co (K α = 6.930 keV; λ = 1.789Å). The X-ray transmission efficiency and fluorescence signals contend with each other.…”

“…The X-ray transmission efficiency and fluorescence signals contend with each other. The optimal thickness of each of the film materials was determined from the existing experimental data of massabsorption coefficients µ ρ from the literature [20,21,22] and numerical simulations that follow ( Supplementary Fig. 2).…”