Effect of scattered neutrons on point spread function in neutron penumbral imaging

The point spread function (PSF) has been calculated by Monte Carlo method for neutron penumbral imaging in inertial confinement fusion experiments, and the impact of scattered neutrons in the aperture, the chamber and the pipe, and the high density target was analyzed. The neutron penumbral imaging for a planar neutron source was simulated and the image was reconstructed by Wiener method. According to the results, the scattered neutrons in the penumbral-aperture, the chamber and the pipe will only raise the background but not distort the PSF, thus their influence on diagnosis can be ignored. The scattered neutrons in the high density target can smooth the PSF, however, the effect on diagnosis is quite limited.