Search

• Two shields that each contain a collimator and simultaneously shield neutrons and gamma-rays are designed for neutron and gamma-ray diagnostics. • Monte Carlo simulations are used to determine the optimal materials and thicknesses of the shielding layers. • Replaceable collimation aperture adjustment modules are adopted, and the effects of the structure used are specifically analyzed. • For incident particles of different energies, the efficiency of the collimator is estimated. • The particle fluxes in the sensitive energy ranges of the detectors are used as the basis for evaluation. New compact radiation shields have been designed to reduce the scattered neutrons and background gamma-rays for neutron and gamma-ray diagnostics in the EAST hall. The design focused on optimizing radiation shielding performance versus volume and weight to fit the small amount of available space outside the tokamak device. Based on the Monte Carlo method and using the Geant4 tool kit, three-dimensional models of the shield were created for material selection and structural design optimization. The 10-cm and 15-cm polyethylene doped with 12 wt.% B 4 C, and 10-cm cast lead were finally selected for the main body of the shield. In addition, the shape and structure of the collimator in the front half of the shield are optimized, and a replaceable aperture adjuster module design has been adopted for the collimator. For incident particles with different energies, the collimation efficiency of the collimator has also been calculated. [ABSTRACT FROM AUTHOR]

• The neutron energy response of Cs 2 7LiYCl 6 :Ce (CLYC-7) scintillation detector was investigated, and the figures-of-merit (FOM), response function, and neutron energy resolution at different neutron energies were obtained. • The Monte Carlo method was used to simulate the particle transport within the CLYC-7 scintillator and investigate the energy response curves of different particles. • The response function was applied to the CLYC-7 scintillation detector, and it was used to measure the D-D fusion neutron spectrum on EAST. During plasma experiments on EAST (Experimental Advanced Superconducting Tokamak), the discharges heated with neutral beam injection (NBI) for plasma results in the production of 2.45 MeV deuterium-deuterium (D-D) fusion neutrons. In order to measure the energy spectrum of D-D fusion neutrons, a new Cs 2 7LiYCl6:Ce (CLYC-7) crystal with 7Li-enrichment has been developed and fabricated into a CLYC-7 scintillation detector. Before utilizing this detector for studying neutron energy spectra, it is crucial to explore the response function of the detector within a relevant neutron energy range. Therefore, the detector has been experimented using the 4.5 MeV electrostatic accelerator at Peking University to investigate its response to fast neutrons, energy resolution, and pulse discrimination capability in the neutron energy range 2.07 MeV–5.51 MeV. The neutron reactions occurring within the CLYC-7 scintillator were simulated using MCNPX, focusing on the reactions 35Cl(n,p) and 35Cl(n,α), as well as the energy response curve and the contributions of different particles (protons, alphas) to the neutron spectrum. The experimental results were successfully validated on EAST, where the 2.45 MeV fusion neutron energy spectrum was measured. That demonstrates the ability of the CLYC-7 scintillation detector to diagnose the fusion neutron energy spectrum for deuterium plasma discharge. [ABSTRACT FROM AUTHOR]