Secondary Neutron Production from Thick Target Deuteron Breakup

TL;DR

This study measures neutron yields from thick beryllium targets during deuteron breakup at 33 and 40 MeV, introduces a hybrid model with empirical parameters for predicting neutron production, and optimizes model parameters for better data fit.

Contribution

The paper presents new experimental neutron yield data and a simple hybrid model with fitted parameters that accurately predict neutron production across energies and light target materials.

Findings

Neutron yields measured at 33 and 40 MeV deuteron energies.

A hybrid model with four empirical parameters fits experimental data.

Model parameters extrapolate well to higher energies and other light targets.

Abstract

Thick target deuteron breakup is a variable-energy accelerator-based source of high-energy neutrons, with applications in fundamental and applied nuclear science and engineering. However, the breakup mechanism remains poorly understood, and data on neutron yields from thick target breakup remains relatively scarce. In this work, the double-differential neutron yields from deuteron breakup have been measured on a thick beryllium target at $\epsilon_d=33$ and 40 MeV, using both time-of-flight and activation techniques. We have also introduced a simple hybrid model for the double-differential deuteron breakup cross section, applicable in the $\epsilon_d=10$--$100$ MeV energy range on light ($Z\leq 6$) targets. This model features four empirical parameters that have been fit to reproduce experimental breakup measurements on beryllium targets, using the method of least-squares. It was shown that these parameters extrapolate well to higher energies, and to other low-Z target materials. We also include optimization of the parameters that modify the Kalbach systematics for compound and pre-equilibrium reactions, in order to better reproduce the experimental data for beryllium targets at large angles.