Design of an epi-thermal neutron flux intensity monitor with GaN wafer for boron neutron capture therapy

Abstract

Boron neutron capture therapy (BNCT) is a promising cancer therapy. Epi-thermal neutron (0.5 eV < E_n < 10 keV) flux intensity is one of the basic characteristics for modern BNCT. In this work, based on the ⁷¹Ga(n,γ)⁷²Ga reaction, a new simple monitor with gallium nitride (GaN) wafer as activation material was designed by Monte Carlo simulations to precisely measure the absolute integral flux intensity of epi-thermal neutrons especially for practical BNCT. In the monitor, a GaN wafer was positioned in the center of a polyethylene sphere as neutron moderator covered with cadmium (Cd) layer as thermal neutron absorber outside. The simulation results and related analysis indicated that the epi-thermal neutron flux intensity could be precisely measured by the presently designed monitor.

Keywords:

• BNCT
• epi-thermal neutron
• flux intensity monitor
• GaN wafer
• activation method
• Monte Carlo simulation

Acknowledgements

This work is partly supported by Mitsubishi Heavy Industries Mechatronics Systems, Ltd. One of the authors, Xingcai Guan, is very grateful to the China Scholarship Council (CSC) for the financial support.