MCNP simulation study of neutron stimulated emission computed tomography system based on D-T neutron source

In this paper, Neutron Stimulated Emission Computed Tomography (NSECT) system was simulated using MCNP software, including the selection of Neutron source, the design of collimating shielding system, the setting of shielding wall and target body, and the arrangement of detector. The 14 MeV D-T Neutron source created by the Neutron generator located at Lanzhou University, was delivered, collimated and hit a cylindrical water phantom. We recorded and won the flux distribution and typical spectrum of characteristic gamma-ray and outgoing Neutron. This study has a guiding role for the detector layout during NSECT imaging experiment. From the flux distribution and typical spectrum of characteristic gamma-ray and outgoing Neutron, it is clearly shown that the position of NSECT imaging detector should be placed from 43.6° to 50.9° along the Neutron beam propagation direction. The optimized direction would be in 48.5°. From the characteristic gamma-ray spectrum, we found the characteristic peaks of 16 O. This result suggests that NSECT has the ability to identify elements and to determine the element concentrations. This work also proved that NSECT could be applied for the early diagnosis of cancer and the checking of hiding explosives and drugs.