Mid Term Review

Gamma-electron spectroscopy with Solenogam

Mr Matthew Gerathy
Department Nuclear Physics

Solenogam is a recoil spectrometer designed and constructed for use at the ANU Heavy Ion Accelerator Facility. The design enables the study of nuclear excitations populated in the decay of long-lived states such as isomers and radioactive ground states. First used on a 6.5-T gas-filled solenoid for the study of isomeric decays in 189Pb, Solenogam is now installed on an 8-T gas-filled solenoid and preliminary results for this configuration have been reported. The solenoid is used to transport the products of fusion-evaporation reactions to a focal plane where Solenogam is situated, consisting of high-sensitivity gamma-ray and electron detector arrays for singles and coincidence measurements.

The ability to measure gamma-gamma, electron-electron and gamma-electron coincidences has increased the sensitivity and enables the study of weak decays and complex level schemes. A number of systems have been studied during implementation and testing, including the electron capture decay of 182Re into 182W, and the beta-decay of both 190Au and 184Au into 190Pt and 184Pt, respectively. More recently, we have studied the decay of the high-spin, T1/2=0.96-microsecond isomer in the N=83 nucleus, 145Sm, using the 124Sn(26Mg,5n) reaction at a beam energy of 115 MeV. Microsecond chopped beams were used to isolate the isomeric decay resulting in a (longer) revised lifetime, while conversion coefficients were also measured to confirm the isomer spin and parity for the first time. The new results for 145Sm, as well as other results that demonstrate the measurement capabilities of Solenogam, will be presented.

Updated:  15 January 2019/ Responsible Officer:  Director, RSPE/ Page Contact:  Physics Webmaster