EXCITATION-FUNCTIONS OF SE-74(D,XN)BR-75,BR-74M REACTIONS - COMPARATIVE-EVALUATION OF POSSIBLE ROUTES FOR THE PRODUCTION OF BR-75 AT A SMALL CYCLOTRON

Excitation functions were measured for the first time for Se-74(d,n)Br -75 and Se-74(d,2n)Br-74m reactions from threshold to 23 MeV. Use was made of the stacked-foil technique, and thin samples were prepared by electrolytic deposition of 31.4% enriched Se-74 on Al-backing. Differe ntial and integral yields of Br-74m and Br-75 were calculated from the measured excitation functions. The optimum energy range for the produ ction of Br-75 via the Se-74(d,n)-process was found to be E(d) = 12 -- > 8 MeV, with Br-75-yield amounting to 509 MBq (13.75 mCi)/muAh and th e Br-74m impurity to < 1%. A comparative evaluation of the two routes, namely Kr-78(p,alpha)Br-75 and Se-74(d,n)Br-75, suggested for the pro duction of Br-75 at a small cyclotron is given. The (d,n) reaction giv es higher yield than the (p,alpha) process and is preferable at cyclot rons with E(d) greater-than-or-equal-to 10 MeV. In general, at a small cyclotron the achievable batch yields of Br-75 via both the processes are limited.