Measurement of the $^{236}$U fission cross section and angular distributions of fragments from fission of $^{235}$U and $^{236}$U in the neutron energy range of 0.3-500 MeV

TL;DR

This study measured the fission cross section and fragment angular distributions of $^{236}$U and $^{235}$U over a broad neutron energy range, providing new data above 20 MeV and comparing with theoretical models.

Contribution

It presents the first measurements of $^{236}$U fission fragment angular distributions above 20 MeV and offers new experimental data for the fission cross section of $^{236}$U.

Findings

First measurements of $^{236}$U fragment angular distributions above 20 MeV

Fission cross section of $^{236}$U relative to $^{235}$U standard

Comparison of experimental data with theoretical calculations

Abstract

The $^{236}$U fission cross section and the angular distributions of fragments from fission of $^{235}$U and $^{236}$U were measured for incident neutron energies from 0.3 MeV to 500 MeV on the time-of-flight spectrometer of the neutron complex GNEIS at the NRC "Kurchatov Institute" -- PNPI. Fission fragments were registered using position-sensitive low-pressure multiwire counters. In the neutron energy range above 20 MeV, the angular distributions of $^{236}$U fission fragments were measured for the first time. The fission cross section of $^{236}$U$(n,f)$ was measured relative to the fission cross section of $^{235}$U$(n,f)$, which is an accepted international standard. The obtained data are compared with the results of other experimental works. Theoretical calculations of the fission cross section and the anisotropy of angular distribution of fission fragments for the $^{236}$U$(n,f)$ reaction performed within the framework of our approach are presented and discussed.