Optimal design of coded aperture used for Z-Pinch driven fusion neutron imaging

Abstract

Currently, the neutron yield of Z-Pinch is lower than that of laser driven fusion. In the neutron imaging for this facility, the signal to noise ratio (SNR) has a significant influence on the expected spatial resolution of the reconstructed fusion core, especially in the condition of low neutron yield. In this paper, mathematical model is purposed to describe the dependence of aperture parameters on the imaging SNR. The investigation shows that the imaging SNR is closely related to the size of contrast boundary on the point spread function. According to this, a novel non-uniform redundancy penumbra apertures array is designed. In addition, the imaging performances of this novel coded aperture, penumbra aperture and ring aperture are evaluated and compared by Monte Carlo method. The comparison shows that this novel aperture has significant advantage compared to the penumbra aperture which is commonly used for neutron imaging with low yield. The encouraging results can provide reference for the optimal design of the coded aperture used in the neutron imaging for Z-pinch driven fusion with low neutron yield.