Precise conversion electron intensities of low energy gamma transitions for efficiency calibration of electron detectors.

Precise energies and relative intensities of gamma transitions and conversion electrons in the electron capture decay of Gd have been determined independently with our well-tested and optimized gamma and electron spectrometers - a large-volume (60 cc) HPGe detector and a mini-orange electron transporter paired to a Si(Li) detector, respectively. The experimental internal conversion coefficients of the gamma transitions in Eu have been determined using Normalized Peak to Gamma method and compared with the theoretical values adopted by Nuclear Data Sheets to assign multipolarities of all the transitions. The precise internal conversion electron intensities of the low energy transitions can be used as standards for calibration purposes of electron detectors and spectrometers.

Electron-gamma spectroscopic measurements in 131 Cs.

The decay of 131 Ba to levels of 131 Cs has been studied using an HPGe detector for gamma-ray and a mini-orange electron spectrometer for conversion electron measurements. Our experiment identifies 76 gamma transitions in this decay, including 15 new gamma rays and 6 new K-conversion electron lines. The results also include M2 multipolarity assignment for the 269 keV transition, E2 assignment to two newly observed transitions, M1 + E2 for the 406 and 417 keV transitions and M3 for the 533.