Measurement of K fluorescence yields of niobium and rhodium using monochromatic radiation

Abstract

Both reactions Nb-93(n,n 0 )Nb-93 m and Rh-103(n,n 0 )Rh-103 m are of particular importance for dosimetry in reactor, and the measurement of the activity of Nb and Rh dosimeters provides the basic data that can be traced back to the reactor operating information. These radionuclides emit only X-rays of which emission intensities in recommended data are determined thanks to the γ-ray transition probabilities and fluorescence yield values. In general, the knowledge of fluorescence yields is rather poor and based on old measurements. Nowadays, the use of tunable monochromatic X-ray sources allows performing optimized measurements. In a first step, accurate values of the attenuation coefficients are measured at the metrology beam line of the SOLEIL synchrotron, using procedures such as optimized for similar measurements. In a second step, the fluorescence yields are determined using experimental approaches in a traditional experimental configuration. For both materials, several incident energies are used to get experimental spectra with energy-dispersive spectrometer. The peaks of interest are processed using the COLEGRAM software, which allows detailed fitting of the peak shape. The K fluorescence yields are derived with about 2% relative uncertainty.

Selective Thermal Evolution of a Native Oxide Layer in Nb and Nb3Sn-Coated SRF Grade Nb: An In Situ XPS Study

“…The measurements were acquired to a maximum energy of 15 keV to avoid the Nb Kα fluorescence signal (Nb: 20−25 keV). 32 The calculated depth penetration for λ = 0.826 Å and 1°degree of incidence angle is about ∼1 μm using Parratt's equation. 33 The patterns were indexed with the Dicvol method in conjunction with a crystalline phase identification using Match!…”

Precise measurement of αK and αT for the 39.8-keV E3 transition in Nica1, Hardy2, Iacob3 et al. 2018Phys. Rev. C6000View full textAdd to dashboardCite

“…The fluorescence yield for rhodium has been measured a number of times (see summary in Ref. [20]) but with rather modest precision. However, world data for fluorescence yields have been evaluated [21] systematically as a function of Z for all elements with 10 ≤ Z ≤ 100, and ω K values have been recommended for each element in this range.…”

Improvement of 93mNb and 103mRh activity measurement methodology for reactor dosimetry

“…The knowledge of the fluorescence yields for 93m Nb is rather poor and based on old experiments [10]. All data for 103m Rh, are not well known and leading to high uncertainties on emission intensities [10].…”

“…The knowledge of the fluorescence yields for 93m Nb is rather poor and based on old experiments [10]. All data for 103m Rh, are not well known and leading to high uncertainties on emission intensities [10]. Two experiments were performed to measure the K fluorescence yields of Nb and Rh and the emission intensities of K X-rays of 103m Rh, in order to improve the knowledge of the decay data.…”

“…New measurements of the K fluorescence yields of niobium and rhodium were performed, taking advantage of optimized experimental facilities, using tunable monochromatic X-rays [10]. The experiment included two steps:…”