Recoil studies of photonuclear reactions on natCu, natAg, natTa, and 197Au at intermediate energies

Abstract

The recoil properties of nuclides produced in the photonuclear reactions on natcu, natAg, natTa, and 197Au induced by bremsstrahlung of end-point energies (Eo) of 250 to 1000 MeV have been investigated using the thick-target thick-catcher method. The obtained mean ranges of produced nuclides smoothly increase with an increase of the mass difference (AA) between products and target, and show E0-independence at E0 > 600 MeV, reflecting the limiting behavior above (3, 3) resonance region. The mean kinetic energies, T, deduced from the mean ranges show the following two components; (1) (7, xn) products by giant-resonance and/or quasi-deuteron resonance absorptions, (2) (7, xnyp) products by mainly (3, 3) resonance absorption. Slightly rapid increase of T was found around AA=15, 18, 24, and 25 for natcu, natAg, natwa and 197 Au, respectively, reflecting a change in mechanism. Kinematic properties of the product nuclei were calculated by using the PICA (Photon-Induced Intranuclear Cascade Analysis) code. The T calculated by the PICA code at Eo=400 MeV well reproduced the experimental results of natcu, but the same calculation for natAg, natwa, and 197Au gave lower mean kinetic energies than the experimental results.

Systematic recoil study of photospallation reactions on complex nuclei at intermediate energies

“…In our group, nuclear recoil experiments using the thick-target thick-catcher method have been applied to photospallation reactions in order to examine the effect due to a difference in the initial interactions between photon-induced reaction and hadron-induced one dynamically [1][2][3][4]. The recoil properties of 137 radionuclides formed in the photospallations on 27A1, natv, natCu, 93Nb, natAg, natza and 197Au, induced by bremsstrahlung of endpoint energies (E0) from 600 to 1100 MeV, have been successfully investigated based on the two-step vector velocity model [5].…”