Photoneutron Yield for an Electron Beam on Tantalum and Erbium Deuteride

TL;DR

This study uses simulations to optimize photoneutron production from a 10-MeV electron beam on tantalum and erbium deuteride, identifying optimal layer thicknesses for efficient neutron generation.

Contribution

It provides new insights into layer thickness optimization for maximizing photoneutron yield in electron beam irradiation of tantalum and erbium deuteride.

Findings

Optimal tantalum foil thickness is 1.5 mm for photon transmission.

Photoneutron yield increases with ErD₃ layer thickness, peaking at around 12 cm.

A 2-mA electron beam can produce up to 10¹² neutrons per second.

Abstract

An electron beam may be used to generate bremsstrahlung photons that go on to create photoneutrons within metals. This serves as a low-energy neutron source for irradiation experiments [1-3]. In this article, we present simulation results for optimizing photoneutron yield for a 10-MeV electron beam on tantalum foil and erbium deuteride (ErD$_3$). The thickness of the metal layers was varied. A tantalum foil thickness of 1.5 mm resulted in the most photons reaching the second metal layer. When a second metal layer of ErD$_3$ was included, the photoneutron yield increased with the thickness of the secondary layer. When the electron beam was directly incident upon a layer of ErD$_3$, the photoneutron yield did not differ significantly from the yield when a layer of tantalum was included. The directional photoneutron yield reached a maximum level when the thickness of the ErD$_3$ layer was around 12 cm. About 1 neutron was generated per $10^4$ source electrons. When using a 2-mA beam current, it is possible to generate up to $10^{ 12}$ neutrons per second, making this combination a relatively-inexpensive neutron generator.