부산대학교 도서관

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.
Comment: 15 pages, 9 figures, 4 tables