The measurement of subnanosecond lifetimes using a rotating target systems

Abstract

A rotating target system has been developed for use in the measurement of lifetimes of excited nuclear states by a direct timing technique using a pulsed proton or deuteron beam. The target system which is capable of speeds up to 7 000 r.p.m. can be used with two targets simultaneously. The system has the electronics capable of routing into two separate regions of the on-line computer the information obtained from each target. The technique has a distinct advantage over most previous centroid shift delayed-coincidence methods in that data are obtained at the same time for both the prompt and delayed time distribution curves. Thus errors that may occur due to electronic drifts and shifts between alternate experimental runs to obtain the prompt and delayed time distribution curves separately are avoided. As an illustration of the use of the rotating target system, the lifetime of the first excited state of 47Ti at 160 keV was measured to be (295 ± 24) ps.