Radiative electron capture at ultrarelativistic energies: 33-TeV Pb82+ ions - art. no. 010701

Cross sections for radiative electron capture (REC) by 33-TeV Pb82+ ions in Be and C targets have been extracted from an analysis of measurements of t otal electron capture by these ions in Be, C, Al, Cu, Sn, and Au targets. T he REC cross sections in the Be and C targets, when REC is significant, wer e obtained by subtracting cross sections for electron capture from pair pro duction (ECPP), the only other significant capture process at these energie s. The ECPP contributions in Be and C were determined from extrapolations o f measured cross sections in the heavier targets where the ECPP process dom inates, with suitable accounting for slightly decreased screening effects f or the light targets. We obtain an experimental K-REC cross section (0.010 +/- 0.002b per electron per Pb K vacancy), which agrees with a calculation of REC made by applying detailed balance to the corresponding process of ra diative recombination and using tabulated photoelectric effect cross sectio ns. A comparison is also presented of the present experimental result with other heavy-ion measurements made at lower energies, and with nonrelativist ic and relativistic calculations, which differ considerably in this energy regime.