Development of a reliable gas-jet transport system for use at the Oak Ridge isochronous cyclotron

Abstract

In a previous paper transport yields of recoil nuclei produced in heavy-ion-induced reactions through capillaries were reported. These studies have now been extended to develop a reliable gas-jet-capillary transport system for use in conjunction with the heavy-ion beams available at the Oak Ridge isochronous cyclotron. Several additives to the helium gas were used and tested for their effectiveness to increase the transport efficiency. With water as the additive and a 10 m teflon capillary, i.d. of 1.3 mm, connecting the reaction and collection chambers an efficiency of ≈20% was measured. Under similar conditions an upper limit of ≤10 s was determined for the transport time. [However, with an annular Si(Au) α-detector it was possible to observe 162W, T 1 2 ≤0.25 s .] Also, the efficiency of the system was found to be remarkably constant; during a 7 h period it varied only by about 10%. Most of the tests and developments were made as part of experiments that had to do with short-lived nuclei. As part of this paper, therefore, we describe some of these experiments so as to illustrate the versatility and usefulness of the capillary transport system.