HIGH-RESOLUTION PENUMBRAL IMAGING OF 14-MEV NEUTRONS

We have developed a neutron imaging system based on the penumbral imag ing technique. The system consists of a penumbral aperture and a sensi tive neutron detector. The aperture was made from a thick (6 cm) tungs ten block with a toroidal taper. It can effectively block 14-MeV neutr ons and provide a satisfactory sharp, isoplanatic (space-invariant) po int spread function (PSF). A two-dimensional scintillator array, which is coupled with a gated two-stage image intensifier system and a CCD camera, was used as a sensitive neutron detector. It can record the ne utron image with high sensitivity and high signal-to-noise ratio. The reconstruction was performed with a Wiener filter. The spatial resolut ion of the reconstructed neutron image was estimated to be similar to 31 mu m by computer simulation. Experimental demonstration has been ac hieved by imaging 14-MeV deuterium-tritium neutrons emitted from a las er-imploded target.