STUDY OF THE BEAM-FOIL EXCITATION MECHANISM USING CARBON PROJECTILES

Beam-foil excitation functions have been measured for some optical transitions in C II-C IV in the projectileenergy range 100-450 keV, and in C IV-C VI from 4 to 20 MeV. The full set of population functions, representing eightdifferent classes of core-outer shell arrangements, are reproduced by three parameters accounting for 1s vacancies, 2s vacancies, and outer shell populations according to the independent-electron model. The excitation functions at 4-20 MeV were measured with foils tilted 0°, 30° and 45° and the photon yields for C III-C VI lines found to depend substantially upon the foil tilt angle. Relative level populations were measured for some C IV levels. The results show that the relative level population within the same term series decreases slightly faster than n-3. The relative population for fixed principal quantum number increases from s to p levels, decreases to d levels, and shows another increase from d to g levels. This relative level population picture is independent of foil tilt angle. © 1979 IOP Publishing Ltd.