Performance Evaluation of Boron Doped NMCP Used in Neutron Radiography

Abstract

Neutron radiography plays an important role in the development of safer and more efficient nuclear power plants by providing valuable information for the irradiated nuclear fuel, nuclear waste containers and other critical components. Neutron sensitive microchannel plate (nMCP) doped with boron and gadolinium is a popular neutron imaging detector. It has been successfully employed in neutron resonances imaging of irradiated nuclear fuel, providing the possibility in mapping the elemental composition of reactor components. However, the exiting of gadolinium in nMCP degrades the spatial resolution and neutron-gamma discrimination capability, because of the long range and low energy deposition of the electrons generated by gadolinium. nMCP doped with boron has advantages on spatial resolution and neutron-gamma discrimination capability. In this paper, performances of boron doped nMCP were studied. According to the simulation, the theoretical detection efficiency of nMCP doped with 20mol% 10B2O3 could reach 34%, and the spatial resolution can be close to the pore size at the same time. Moreover, it is expected to achieve good neutron-gamma discrimination ability. The detection efficiency for nMCP which doped with 10mol% natB2O3 was experimented detailly at CSNS. Results show that the detection efficiency is 4.55% for 2.9 Å neutron and 7.26% for 4.8 Å neutron, which agrees well with simulation results. These results indicate that the excellent performance of boron doped nMCP is possible to be achieved. In the future, nMCP doped with 20mol% 10B2O3 will be fabricated and it will be a promising scheme for the application of neutron radiography in nuclear reactors.