A simulation study of a collimating shield structure in a vertical neutron camera on HL-3.

A shield structure with five collimating tubes has been designed in a vertical neutron camera (VNC) on HL-3. Polyethylene is used to screen scattered neutrons, and the lead layer is applied to obstruct the stray X-rays and γ -rays in the environment, as well as secondary γ -rays produced by neutrons interacting with materials. The shielding effect of the structure is studied by using GEANT4. The energy spectra of the incident neutrons and the rate of direct neutrons at the end of five channels are obtained, which demonstrates that the design of shield achieve the criteria as we excepted. • Designing a vertical neutron camera for HL-3. • A compact collimating shield structure with five channels. • Examining the shield ability and optimizing the structure by GEANT4. • Calculating the neutron flux identified by detectors in the simulation. [ABSTRACT FROM AUTHOR]