Fragment characteristics for the photofission of 238U with 6.1–13.1 MeV bremsstrahhmg

Mass distribution in the bremsstrahlung-induced fission of 232Th, 238U and 240Pu

“…Most of the yield data on fission products available in the 9 MeV to several GeV bremsstrahlung-induced fission of 232 Th [55][56][57][58][59] and 235,238 U [61][62][63][64][65][66][67] are based on radiochemical separation and beta counting or γ -ray spectrometric techniques. In the recent past, some data on the mass distribution of 232 Th [60], 235 U [74] and 238 U [73] have become available for bremsstrahlung energies at near barrier using off-line γ -ray spectrometric techniques. Some data on the bremsstrahlung-induced fission of 235,238 U in the energy range of 12-70 MeV were obtained using off-line γ -ray spectrometric techniques [68][69][70] and physical measurements [71,72].…”

“…However, the yield of fission products around mass numbers 133-135 is more pronounced compared to mass numbers 143-145, in both neutron- [28][29][30][31][32][33] and bremsstrahlung-induced [61][62][63][64][65][66][67][68][69][70][71][72][73][74] fission of uranium isotopes and heavier actinides. In the electromagnetic fission of lighter actinides [52][53][54], higher yields of fission products around mass numbers 133-135 corresponding to a most probable charge of 52 have been observed.…”

“…Similarly yields of fission fragments in the excitation energy range of the GDR region due to electromagnetic fission in inverse kinematics [52][53][54] are available for neutron-deficient lighter actinides such as 214-223 Ac, 220-229 Th, 224-232 Pa and 231-234 U. On the other hand, yields of fission products in the bremsstrahlung-induced fission of actinides are available in a broad energy range for a limited number of actinides including 232 Th [55][56][57][58][59][60], 235,238 U [61][62][63][64][65][66][67][68][69][70][71][72][73][74] and 240,242,244 Pu [75][76][77][78]. Most of the yield data on fission products available in the 9 MeV to several GeV bremsstrahlung-induced fission of 232 Th [55][56][57][58][59] and 235,238 U [61][62][63][64][65][66][67] are based on radiochemical separation and beta counting or γ -ray spectrometric techniques.…”

Microscopic and nonadiabatic Schrödinger equation derived from the generator coordinate method based on zero- and two-quasiparticle states

“…However, there are some experimental indications that pairs are broken during the fission process. For instance, manifestations of proton pair breaking are observed in 238 U and 239 U nuclei for an excitation energy of 2.3 MeV above the barrier: first the proton odd-even effect observed in the fragment mass distributions decreases exponentially for an excitation energy slightly higher than 2.3 MeV [16] and then the total kinetic energy drops suddenly [17,18]. Some theoretical calculations have studied the dissipation during the fission process, most of them are based on a semi-classical formalism such as Focker-Plank equations [19][20][21], or Hamiltonian equations with one body dissipation and two-body viscosity [22,23], or Langevin equations [24,25].…”

Product yields for the photo-fission of 209Bi with 2.5 GeV bremsstrahlung

“…Sufficient data for neutron and bremsstrahlung-induced fission of actinides in the low energy region are available in the literature [1][2][3][4][5][6][7][8][9][10]. From all these data, it is clear that the mass-yield distribution in the low energy neutron and bremsstrahlung-induced fission of actinides are asymmetric with fine structure due to shell closure proximity and odd-even effects.…”