STUDY OF LOW-LYING 0(-228 AND U-232,U-234,U-236 IN THE (P,T) REACTION()EXCITATIONS IN TH)

The (p, t) reaction was studied at 22 MeV proton energy using targets of Th-230,Th-232 and U-234,U-236,U-238. In Th-228 we observed in addit ion to the 832 keV first-excited 0(+) level a second-excited 0(+) leve l at 939 keV populated with 5% of the ground-state strength. A 0(+) le vel proposed recently in U-232 at 927 keV was not observed in the (p, t) reaction, with an upper limit for its excitation of 0.2% of the gro und-state strength. In U-234 a level at 1045 keV, assigned in the lite rature as second-excited 0(+) level, is weakly populated in the (p, t) reaction but does not show the angular distribution characteristic fo r single-step L = 0 transfer. In U-236 We observed a level at 1036 keV with an angular distribution suggesting that it might be a doublet co mposed of a known 3(-) level and a new 0(+) level. The properties of t he first two excited 0(+) bands in Th-228, U-232 and U-234 are compare d and discussed.