Measurement of β − end-point energies using a Ge detector with Monte Carlo generated response functions

Abstract

A β-γ coincidence spectrometer has been developed, in association with the INEL ISOL facility, to allow β − end-point energies to be measured for short-lived fission-product isotopes. In this spectrometer a 200 mm 2 × 10 mm planar intrinsic Ge detector, in a cryostat with a thin Be window and integrally mounted into the ISOL vacuum system, is used to measure the β − spectra. A feature of the analysis codes used to unfold these measured β − spectra is the use of a complete library of electron response functions generated with a Monte Carlo electron and photon transport code. With this system, β − end-point energies have been measured and Q β values deduced, for 32P, 90Y, 140Cs, 151Pr, 153Nd, 153Pm, 154Pm (1.7 min), 155Nd, 155Pm, 155Sm, 157Sm and 158Sm.