Kenneth Saul Krane

Cosmic-ray history derived from the 54Mn, 56Ni and 144Pm chronometers

Sources of 54 Mn, 55 Ni, and 144 Pm were placed at the center of the Gammasphere array and searches were made for the astrophysically interesting β + decay modes of these isotopes. The results of these searches are presented and the implications for cosmic-ray physics are discussed.

An Investigation of 154Eu as a High‐Precision Multi‐γ‐Ray Intensity Calibration Standard for Detector Arrays

The decay of 154Eu has been studied using γ‐ray singles and γ − γ coincidence spectroscopy with an array of Compton‐suppressed Ge detectors. Particular attention to coincidence summing in the analysis, with consideration of detailed decay cascades and angular correlation effects, suggests that previous studies have overlooked necessary corrections. It is concluded that 154Eu provides 26 γ rays that can be used for relative efficiency calibrations from 120 to 1600 keV at the 0.7% precision level and that this precision could be improved in the future.