Excitation and fission decay of 232Th by inelastic scattering of 17O at 84 MeV/u

Inelastic scattering of 84 MeV/u 17 O projectiles has been used to excite the giant resonances (GR) in 232 Th. The deduced parameters (width, energy, EWSR) of the isoscalar giant quadrupole resonance are in agreement with the known systematics. The observed giant monopole resonance strength, 100% of the EWSR, is consistent with other recent experimental results using heavy-ion projectiles. Strength is also observed at high excitation energy. The fission probability of GR in 232 Th has been measured by detecting the fission fragments in coincidence with the inelastically scattered particles. A structure is observed in the fission coincidence spectrum around 10 MeV, which can be attributed to the fission decay of giant resonances. The measured fission probability is consistent with statistical decay of the GQR.