Decay spectroscopy with Solenogam at the ANU Heavy Ion Accelerator Facility

Solenogam is a recoil spectrometer designed and constructed for use at the Australian National University (ANU) Heavy-Ion Accelerator Facility (HIAF). The design enables the study of nuclear excitations populated by the decay of long-lived states such as isomers and radioactive ground states. Solenogam is comprised of high-sensitivity gamma-ray and electron detector arrays coupled to a new 8-T solenoid. While the installation of the 8-T solenoid proceeds, off-line measurements have been made to characterise Solenogam's performance. Gamma-electron coincidences in the electron capture decay of Re-182 into W-182 were used to investigate conversion coefficients and gamma-e(-) angular correlations. The measured conversion coefficients show good agreement with theoretical calculations and have been used to extract E0/ E2 mixing ratios for a number of J -> J transitions. The angular correlations measured by the array are in qualitative agreement with theoretical calculations. However, the magnitudes of the correlations are attenuated by approximately 40% for reasons unknown at present. These results are the first full use of the Solenogam system for gamma-e(-) coincidence measurements and have proven that the system is capable of highly-sensitive internal conversion analysis of complex decays.