K-vacancy production by 3.6-, 4.75-, and 5.9-MeV/amu238U Ions

Abstract

Projectile (Zl) and target (Z2) K-vacancy production cross sections induced by 3.6-, 4.75-, and 5.9-MeV/amu 2asU ions in selected targets between C and U are reported. The cross sections are discussed within the context of the molecular model of inner-shell vacancy production in heavy-ion-atom collisions. The measured l sa and 2pa excitation cross sections are compared with semiempirical formulas, and with the perturbed-stationarystates calculations of Betz et al. The dependence of these cross sections on Z, =Z 1 +Z 2 agrees well with the Betz calculations. However, the measured cross sections are factors of 2 to 4 (1so-) and 4 to 5 (2p~r) larger than the theoretical values.

The quasimolecular 1s? orbital in collision systems?(Z 1+Z 2)?1, its excitation and spectroscopy

“…to [18]. Since both systems are measured at four different projectile velocities, one gets for (20) agree fairly well with those from theory. Certainly, the variation of the theoretical energies within the whole covered Ro-range amounts only to ~40 keV and is even smaller than the statistical errors of the "measured" binding energies.…”

“…Some methods based on the encouraging agreement with experimental results are proposed in order to extract from measured P~(b)-data or mean impact parameters <b> the binding energy of the quasimolecular lso-state as function of R o ( (20,22,27)). Looking to the assumptions made when deriving these analytical expressions one finds that the basic physical quantity entering into these formulae is the energy transferred to the ls a electron in the collision.…”

“…3 we show the values for Elso(Ro) extracted from the experiments acc. to (20), whereas the full curve gives the calculated values acc. to [18].…”

“…Concerning the total lsa excitation cross section for ctZ > 130, a lot of experimental data are available [19,20]. From the measured lso-cross sections, D(Z) can be determined in the following way: Starting with an arbitrary value for <Ro> one calculates acc.…”

K-vacancy production in high-energy U+U and U+Pb collisions at small impact parameters

“…To determine the intensity of 72, we used the measured intensity of the other 7-ray lines in the spectra to normalize theoretical calculations [10] of nuclear Coulomb excitation [11]. Figure 4 shows the number of 7-rays from both contributing center-of-mass angles compared with theoretical predictions.…”