Photoneutron yield for an electron beam on tantalum and erbium deuteride

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. In this article, we present simulation results for optimizing photoneutron yield for a 10-MeV electron beam on tantalum foil and erbium deuteride (ErD3). 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 ErD3 was included, the photoneutron yield increased with the thickness of the secondary layer. When the electron beam was directly incident upon a layer of ErD3, 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 ErD3 layer was around 12 cm. About 1 neutron was generated per 104 source electrons. When using a 2-mA beam current, it is possible to generate up to 1012 neutrons per second, making this combination a relatively-inexpensive neutron generator.

Keywords

• Neutron generator
• Erbium deuteride
• Metal hydride
• Photoneutron
• Electron beam