Electron peaks ine++Th,U,andTainteractions

Abstract
Th, U, and Ta targets were irradiated by positrons from Te−118Sb−118Sn−118 β+ sources. Electron spectra were taken by means of an electron spectrometer and a position-sensitive electron counter. We have observed an electron line located at 328.6 ± 0.4 keV in the spectra from Th and U targets, but not in the Ta target. The kinetic energy and the intrinsic full widths at half maximum of the line were deduced to be 330.8 ± 1.0 keV and 3.7 ± 0.5 keV, respectively. The cross section was estimated to be 28 ± 10 mb/sr and 34 ± 13 mb/sr for Th and U, respectively.