4 Matching Results

Search Results

Projectile charge state dependence of M-shell ionization of Au, Pb, Bi, and U by 1. 42-MeV/amu fluorine ions

Description: The present study was undertaken to determine the direct ionization and electron capture contributions to vacancy production in the M-shells of /sub 79/Au, /sub 82/Pb, /sub 83/Bi and /sub 92/U for incident /sup 19//sub 9/F ions. M-shell x-ray production cross sections have been measured for 1.42-MeV/amu /sup 19//sub 9/Fq/sup +/ ions for q = 4,5,6,8,9. Enhancements in the target x-ray production cross sections were observed for projectiles with one and two K-shell vacancies over those without K-shell vacancies. Direct ionization and electron capture contributions to the vacancy production were extracted from the data and compared to the plane wave Born approximation and to the Oppenheimer-Brinkman-Kramers calculations of Nikolaev, respectively.
Date: January 1, 1980
Creator: Mehta, R.; Duggan, J.L.; McDaniel, F.D.; Andrews, M.C.; Wheeler, R.M.; Chaturvedi, R.P. et al.
Partner: UNT Libraries Government Documents Department

Implications of heavy-ion-induced satellite x-ray emission. II. Production of K and L x rays by 0. 9 to 2. 6 MeV/u Ar ions in thick targets of V, Cu, Nb, Ta, and Pt

Description: Cross sections are reported for x-ray production in targets of /sup 23/V, /sup 29/Cu, /sup 41/Nb, /sup 73/Ta, and /sup 78/Pt by /sup 40/Ar ions of 36.0, 56.4, 76.6, and 103 MeV. Because the targets were relatively thick, approx. 1 mg/cm/sup 2/, the data were corrected, using a novel approach, for projectile energy loss and x-ray attenuation in the targets. The cross sections so analyzed are compared with the predictions of the first Born approximation as well as with those of a more extensive treatment which includes energy loss, Coulomb deflection, perturbed stationary-state, and relativistic effects. The significant discrepancies between the data and this latter theory are atrributed primarily to the influence of multiple ionization on the x-ray emission probabilities.
Date: January 1, 1983
Creator: O'Kelley, G.D.; Auble, R.L.; Hulett, L.D.; Kim, H.J.; Milner, W.T.; Raman, S. et al.
Partner: UNT Libraries Government Documents Department

L-shell x-ray production cross sections in Nd, Gd, Ho, Yb, Au and Pb for 25-MeV carbon and 32-MeV oxygen ions

Description: L-shell x-ray production cross sections in /sub 60/Nd, /sub 64/Gd, /sub 67/Ho, /sub 70/Yb, /sub 79/Au and /sub 82/Pb have been measured for incident 25 MeV /sub 6//sup 12/C/sup +q/(q = 4,5,6) and 32 MeV /sub 8//sup 16/O/sup +q/(q = 5,7,8) ions. Measurements were made on targets ranging in thickness from 1 to 100 ..mu..g/cm/sup 2/. Echancement in the L-shell x-ray production cross section for projectiles with one or two K-shell vacancies over those for projectiles with no K-shell vacancies is observed. The sum of direct ionization to the continuum (DI) plus electron capture (EC) to the L,M,N ... shells and EC to the K-shell of the projectile have been extracted from the data. Calculations in the first Born approximation are approx. 10 times larger than the data. Predictions of the ECPSSR theory that accounts for the energy-loss, Coulomb deflection, perturbed-stationary state, and relativistic effects are in good agreement with the data for both ions.
Date: January 1, 1984
Creator: Andrews, M.C.; McDaniel, F.D.; Duggan, J.L.; Mehta, R.; Lapicki, G.; Miller, P.D. et al.
Partner: UNT Libraries Government Documents Department

M-shell electron capture and direct ionization of gold by 25-MeV carbon and 32-MeV oxygen ions

Description: M-shell x-ray production cross sections have been measured for thin solid targets of Au for 25 MeV /sup 12/C/sup q+/ (q = 4, 5, 6) and for 32 MeV /sup 16/O/sup q+/ (q = 5, 7, 8). The microscopic cross sections were determined from measurements made with targets ranging in thickness from 0.5 to 100 ..mu..g/cm/sup 2/. For projectiles with one or two K-shell vacancies, the M-shell x-ray production cross sections are found to be enhanced over those by projectiles without a K-shell vacancy. The sum of direct ionization to the continuum (DI) and electron capture (EC) to the L, M, N ... shells and EC to the K-shell of the projectile have been extracted from the data. The results are compared to the predictions of first Born theories i.e. PWBA for DI and OBK of Nikolaev for EC and the ECPSSR approach that accounts for energy loss, Coulomb deflection and relativistic effects in the perturbed stationary state theory. 25 references, 3 figures, 1 table.
Date: January 1, 1984
Creator: Andrews, M.C.; McDaniel, F.D.; Duggan, J.L.; Miller, P.D.; Pepmiller, P.L.; Krause, H. et al.
Partner: UNT Libraries Government Documents Department