Attenuation studies near K-absorption edges using Compton scattered 241Am gamma rays

Abstract

We have carried out photon attenuation measurements at several energies in the range from 49.38 keV to 57.96 keV around the K-absorption edges of the rare earth elements Sm, Eu, Gd, Tb, Dy and Er using 59.54 keV gamma rays from 241 Am source after Compton scattering from an aluminium target. Pellets of oxides of the rare earth elements were chosen as mixture absorbers in these investigations. A narrow beam good geometry set-up was used for the attenuation measurements. The scattered gamma rays were detected by an HPGe detector. The results are consistent with theoretical values derived from the XCOM package.

Differential scattering cross sections for elements with 13 ⩽Z⩽ 50 using 59.54 keV gamma rays

“…The signals from the detector were processed by the standard ORTEC modules and are then fed to a CAMAC (computer automated measurement and control)-based data acquisition system. The data analysis software PAW developed by CERN laboratories 5 has been used for data analysis in the present studies. A representative spectrum recorded with 59.54 keV gamma rays scattered at 90 • by an Ag scatterer is shown in figure 2.…”

“…where N Al is the count rates for aluminum under the Compton peak, N T is the count rate for the target under the corresponding (coherent or incoherent) peak, n Al is the number of scattering centres of aluminum, n T is the number of scattering centres of the target, n = N A ρm A (A is the mass number, N A the Avagadro number, ρ the density of the target material and m the mass per unit area of the target. ), T Al and T T represent the transmission factors which account for the 5 CERN laboratory in Geneva, Switzerland. absorption of the incoming and scattered photon beams while traversing the targets, η is the efficiency of the coherent or incoherent photon beam, T is the solid angle subtended by the target at the centre of the source and D is the solid angle subtended by the detector at the target centre.…”

“…Good agreement with theoretical values based on XCOM [4] was observed by them. Subsequently, Abdullah et al [5] carried out attenuation studies near the K absorption edges in rare earth elements using 241 Am gamma rays, Compton scattered at various angles by an aluminum scatterer. More recently, Abdullah et al [6] conducted similar studies with the elements Zr, Nb, Mo and Pd.…”

X-ray attenuation around K-edge of Zr, Nb, Mo and Pd: A comparative study using proton-induced X-ray emission and 241Am gamma rays

“…Budak and Polat [17] and Polat et al [18] have applied this technique for the measurement of the K-shell absorption jump factors and jump ratios in some rare earth elements in the energy range 48-59 keV. Again, very recently, we have carried out similar measurements [19] using Compton scattered 241 Am γ-rays for the rare earth elements Sm, Eu, Gd, Tb, Dy and Er.…”

“…A large number of measurements have been reported over the years on the experimental determination of attenuation coefficients [19,22,23]. On the theoretical side, several compilations are available for obtaining theoretical values of the attenuation coefficients with which the experimental values can be compared.…”