Study of photofission fragment mass distribution of 232Th, 238U, 237Np and 240Pu isotopes in various γ-ray energies

Abstract

Photofission of [Formula: see text]Th, [Formula: see text]U, [Formula: see text]Np and [Formula: see text]Pu isotopes are investigated. Modified version of Gorodisskiy approach that is developed to study the neutron-induced fission are employed to simulate fission fragment mass distribution for these isotopes in different energies. The effect of emitted neutron prior to scission point is studied. Peak to valley ratio is also extracted. Obtained results using this approach are compared with original Gorodisskiy model as well as available experimental data. Satisfactory agreement is achieved between theoretical and experimental data especially in medium and low [Formula: see text]-ray energies than original formalism of Gorodisskiy.

Mass yield of spontaneous fission of 238 U within the systematic statistical scission-point model

“…At last, for each mass number A, only one charge number Z was taken as the integer value of the most probable charge obtained from the common relation as [35]…”

The calculation of total fragment excitation energy for photofission of Uranium isotopes

“…To calculate the fission fragments mass distribution, this energy is used in formalisms. Otherwise, the values of peak-to-valley and average mass number are calculated by the average electron energy from zero to end-point energy ( < E > ) [21]. Thus, the excitation energy is the average excitation energy (i.e.…”

The investigation on fragments mass distributions for photofission of ${}^{232}{Th}$, ${}^{238}U$, ${}^{237}{Np}$ and ${}^{240}{Pu}$ isotopes by systematics methods

“…The new model [16], which has developed the Gorodisskiy model in photofission phenomena, is fixed the structure of original model and reclaimed its parameters for photofission phenomena. Here's a brief overview of the relations of this model to plot the photofission fragment mass distribution:…”

“…The first systematic model in neutron/proton fission is the Gorodisskiy model [15] in which the variances and average mass are calculated by mass and charge number of compound nuclei. Although the original model has not proper results in photofission process, but [16] modified this model for photofission phenomena to reach the experimental results on a normal scale. The second model is the Robert Mills model [17], which is the easiest model to calculate fission fragment mass distribution yields (section 3).…”

“…The calculated results of three neutron-fission models accompany with photofission experimental data show that the calculated results are not in agreement to experimental data exactly. In[16], the photofission fragments mass distributions in normal scale were studied only for one model (the Modified Gorodisskiy model). So here, we look more accurately using the logarithmic scale.…”