Determination of the absolute alpha-particle emission probabilities of Np-237

In the framework of the EUROMET project No. 416, decay scheme data of Np-23 7 were measured by alpha-particle spectrometry. Emission probabilities of a lpha-particles and gamma-rays were determined in the past at IRMM. After im provements of the detector system and the electron bending magnet the alpha -particle measurements have been repeated. As a result, the absolute emissi on probabilities of 20 alpha-particle transitions were obtained with a sign ificant lower uncertainty. Among those transitions already known, five new were found. (C) 2000 Elsevier Science Ltd. All rights reserved.