Speaker
Description
Compact accelerator-driven neutron sources provide useful platforms for neutron science, industrial applications, and medical applications. In particular, neutron sources based on the $^{7}$Li(p,n)$^{7}$Be reaction are attractive because neutrons can be produced using low-energy proton beams. RANS-III is a transportable compact neutron system designed for outdoor use to visualize internal deterioration in bridges. For the development and optimization of such compact neutron sources, accurate neutron-production data and reliable nuclear reaction models are essential.
Although the $^{7}$Li(p,n)$^{7}$Be reaction has been studied for many years, existing data in the low-energy region still show significant discrepancies. In particular, around a proton energy of 2.5 MeV, which is relevant to compact neutron source applications, reported neutron yields and cross sections differ depending on the experiment, and their interpretation may be affected by target thickness and other experimental conditions. These uncertainties directly influence neutron-yield simulations and source design. In the case of RANS-III, the observed neutron yield is smaller than that expected from PHITS-based simulations, motivating a re-examination of the reaction data and calculation framework.
In this work, we study the $^{7}$Li(p,n)$^{7}$Be reaction around 2.5 MeV from both experimental and theoretical viewpoints. Experimentally, measurements are planned using the electrostatic Pelletron accelerator at Institute of Science Tokyo, which is suitable for precise reaction measurements with a defined proton energy. LiF targets with different thicknesses are being prepared by vacuum evaporation, and their thicknesses will be characterized using several methods. The obtained data will be compared with nuclear reaction calculations based on the Gaussian Expansion Method, which aims to describe the reaction.
This study is being carried out as part of a program to advance compact neutron sources through precise numerical calculations. While the present work is not a direct report on RANS-III hardware development, its goal is to provide nuclear reaction data and a calculation framework that can be applied to the future design and optimization of transportable compact neutron sources. In this presentation, we will discuss the motivation, current status, and future prospects of this approach.