Production of DT neutrons by means of TiT targets and analyzed atomic deuteron beams

Abstract

The behaviour of TiT targets during irradiation with a pure beam of atomic deuteron ions was investigated. The dependence on time of the absolute DT neutron yield and the build-up of DD neutron intensity was determined at a constant current density of 0.3 mA/cm 2 for both a 2 Ci and 5 Ci/sq-inch TiT target. Half-lives of 12 mAh/cm 2 and 18 mAh/cm 2 for the DT neutron yield were observed in these two cases. These half-lives are more than an order of magnitude longer than those observed using TiT targets in low-energy accelerators with unanalyzed beams. The DD neutron intensity rises approximately proportional with the irradiation time and reaches a saturation value of about 0.3% of the initial DT yield or 30% of the yield of a TiD target at the end of one half-life. The results suggest that the effect of replacement of tritium by the implanted deuteron is less than hitherto assumed and most of the deuterons are capable of diffusing out of the target without interaction with the tritium. It appears that the short half-lives observed with the use of unanalyzed beams are mainly due to sputtering and radiation damage caused by heavy-ion contaminants always present in unanalyzed beams.