M. Sarkar

Analytical expression for the L3 subshell fluorescence yield in the range Z = 23–96

Abstract All the available data on L 3 subshell fluorescence yields, ω 3 , have been collected. Suitably chosen criteria were used to select a reliable data set and these were then fitted to a polynomial of the 7th degree. The fitted values are then compared with the other fitted, semi-empirical and theoretical values.

Importance of subshell coupling in L-shell ionization by low-velocity heavy ions

Abstract Data for available L-subshell ionization caused by slow and heavy ions (Z 1 = 6, 7 and 8) are compiled and compared with the prdictions of the ECPSSR theory with and without the intra-shell (IS) coupling. It has been observed that the standard ECPSSR without Is is inadequate to predict quantitatively the L-subshell cross section data at low projectile velocities. The inclusion of the IS effect somewhat worsens agreement with experiment for the L 1 -subshell ionization, substantially improves it for the L 2 subshell, and plays essentially no role in an analysis of L 3 -subshell data which are fairly well predicted by the standard ECPSSR theory. The quantitative validity of such conclusions may be questioned because they rely on an approximate treatment of the IS effect.

Kα X-ray satellite of Si and P induced by photons

Abstract K α satellite lines of Si from pure Si, SiO 2 , SiC and of P from NH 4 H 2 PO 4 have been measured using a curved PET crystal. The samples were excited with X-rays from a tube. The peak positions, shifting of peaks and their intensities were measured and compared with other available measurements and theoretical predictions. Our measured values agree well with other data.

Measurement of photon-induced L shell fluorescence cross-sections of gold and lead at 21.6, 23.7 and 25.8 keV

Abstract L shell X-ray fluorescence cross-sections of gold and lead have been measured at 21.6, 23.7 and 25.8 keV photon energies. Cross-sections thus obtained were then compared with theoretical predictions using two different sets of atomic parameters.

Angular distribution of Au and U L x rays induced by 22.6-keV photons

The angular distribution of the L x-ray fluorescent lines from Au and U induced by 22.6-keV x rays from a {sup 109}Cd has been measured. A Si(Li) detector having a resolution of 160 eV at 5.90 keV was used to detect these L lines over the angular range of 70 degree sign -150 degree sign . No strong anisotropy was observed as mentioned by some groups. In the case of Au, a maximum anisotropy of 5% was observed while for U it was within experimental errors (2%). From the angular distribution of the L1 line of Au, the alignment parameter was obtained and its value was found to be 0.10{+-}0.14.

K X-RAY PRODUCTION CROSS SECTION OF GE AND AG BY 3.7-11.1 MEV CARBON IONS

Abstract K X-ray production cross sections of Ge and Ag by 3.7–11.1 MeV carbon ions have been measured. After necessary corrections for projectile slowing down and X-ray self absorption, the data have been compared with the theoretical predictions of the ECPSSR and of the 1s σ molecular orbital theory.

Reduction of scattered bremsstrahlung in a secondary target energy dispersive system

Abstract The intensity of the scattered bremsstrahlung in an Energy Dispersive X-ray Fluorescence system comprising of an X-ray tube and a secondary exciter has been studied using a Si(Li) detector, and the optimal geometry for minimum background level has been experimentally determined.

M X-ray production cross-sections of gold and lead by 4 to 12 MeV carbon ions

Abstract M shell X-ray production cross-sections of Au and Pb induced by 0.33–1.0 MeV/u C2,3,4+ ions are reported. The results are compared with the predictions of the first Born and ECPSSR theories. The first Born predictions are in fair agreement with the measured values, while the ECPSSR calculations are by a factor of 2–5 lower than the data.

Measurement of the anisotropy parameters for the M X-rays of gold induced by 3–9 MeV carbon ions

Abstract The angular distribution of Au M X-rays induced by 3–9 MeV carbon ions has been measured with a Si(Li) detector and found to be strongly anisotropic. The measured values of the anisotropy parameters range between 10% and 38%. The implication of such high values of the anisotropy parameter for M X-ray production cross section measurements has been discussed.

L subshell ionisation cross section of gold by 8–15 MeV Si ions

Abstract L subshell ionisation cross section of Au induced by 8–15 MeV Si 2+,3+,4+ ions have been measured. The data are compared with the theoretical predictions of the ECPSSR, and efficacy of incorporating the intra shell (IS) coupling into ECPSSR is examined. The effect of simultaneous multiple ionisation on the data is discussed qualitatively.