Thorium and uranium M-shell x-ray production by 0.4–4.0 MeV protons and 0.4–6.0 MeV helium ions

Abstract

M-shell x-ray production cross sections for thorium and uranium have been determined for protons of energies 0.4–4.0 MeV and helium ions of energies 0.4–6.0 MeV. The M-shell line and total M-shell x-ray production cross sections are compared to the predictions of the first Born approximation and ECUSAR ionization theory using recently recommended atomic parameters. Both theories are in good agreement with the data for protons and He ions above 1 MeV. The data of others for energies above 1 MeV protons on uranium, however, fall significantly under the present measurements. Below 1 MeV, with decreasing energy of these projectiles, the first Born approximation increasingly overestimates our measurements while the ECUSAR theory underestimates them to a similar degree. The same trends are seen versus the data of others.

Polynomial approximation to universal M‐shell ionisation cross‐sections induced by H+ and He2+ ions

“…The same does not hold true in the case of the M γ X‐ray production cross‐sections. A possible explanation for the differences observed is that the experimental M γ values presented by Phinney correspond to the sum of the X‐ray production cross‐sections for the transitions M 3 –N 4 (M γ 2 ) and M 3 –N 5 (M γ 1 ) plus those for the transitions M 4 –O 3 and M 5 –P 3 . On the other hand, the calculated M γ values do not include the M 4 –O 3 and M 5 –P 3 contributions, which should be, nevertheless, small contributions according to the atomic parameters present in literature.…”

“…Experimental M‐shell X‐ray production cross‐sections data found in literature are mostly presented as the total M‐shell X‐ray production cross‐sections . Only a few references present experimental results for the M α , M β and M γ X‐ray productions cross‐sections determined for H and/or He ions impact, which are the ones of interest for this comparison.…”

“…In Figs and , the comparison between calculated and experimental M α , M β and M γ X‐ray production cross‐sections for H + and He 2 + ions impacting on Th and U are presented. The experimental M‐shell X‐ray production cross‐sections for Th and U, represented as black squares, were taken from Phinney et al . The X‐ray production cross‐sections calculated using the form factors functions are represented as white squares, and the polynomial approximation to the universal ionisation cross‐sections are represented as grey circles.…”

“…Comparison between experimental Th and U M α , M β and M γ X‐ray production cross‐sections for the impact of He ions (black squares) from Phinney et al . and calculated X‐ray production cross‐sections using the form factors (white squares) and the polynomial approximation to the universal ionisation cross‐sections (grey circles).…”

Z-dependence analysis of M x-ray production cross sections for heavy elements with 60≤Z≤90 by protons impact

“…In addition to the semi-empirical cross sections previously calculated [5], we tried, in the present work, to investigate our previous procedure, noted as 'Z-dependence', to deduce a new empirical M-shell x-ray production cross sections for a wide range of elements (60≤Z≤90) by proton impact (0.1-4.0 MeV). Moreover, the present calculation is done by using the updated experimental data collected from different sources [6][7][8][9][10][11][12][13][14][15]. Then, the obtained results have been compared with other earlier works.…”