Cross sections for the production of x rays from heavy ion collisions at MeV energies

X-rays which are emitted in heavy ion collisions have been systematically investigated. Absolute cross-sections, sigma, are reported for the production of Cl-K x-rays in collisions of 30- to 120-MeV chlorine ions with various thin solid targets ranging from Z/sub T/ = 6 (carbon) to Z/sub T/ = 92 (uranium). Surprisingly pronounced oscillations are found in the dependence of sigma on Z/sub T/; in contrast to general expectations these oscillations (i) are very sharp, (ii) tend to increase with increasing energy of the projectile, and (iii) can not, at present, be satisfactorily explained by Coulomb excitation or molecular orbital considerations. Furthermore, we present some detailed results on the newly discovered phenomenon of radiative electron capture (REC); the mechanism to produce REC, line position and width of REC are discussed. (5 figs, 13 refs) (U.S.)