Parameters research of coated MCP thermal neutron collimator

In this paper, we present the parameter research of coated MCP as thermal neutron collimator. B₂O₃ and Gd₂O₃ are selected as coating materials to absorb thermal neutrons for their large cross-sections. Before coating, the effect of doping and coating is compared by simulation. Results show that coating can provide better collimation effect than doping. As the rocking curve of coated MCP looks like sawtooth, we define the first maximum point in rocking curve as the parameter responding to the collimation effect of MCP. The parameters of coating materials, coating thickness, pore diameter, pitch, thickness of MCP are varied to achieve better collimation effect. Contour plot of transmission probability is used to evaluate the performance of MCP collimation. With a market available MCP of 13.5¿m pore diameter, 16.25¿m pitch and 510¿m pore length, 1¿m of Gd₂O₃ coating may implement the collimation result of 0.02 (transmission probability of 25.3 neutron that should be shielded). Two coated MCP collimators and one BF₃ neutron counter are used to setup an experiment to measure the rocking curve.