Resonance-Energy Neutron Radiography Using a Dynamitron Accelerator

In certain circumstances epithermal neutrons may be used for radiography in preference to thermal or cold neutrons so that greater object penetration can be obtained. Epithermal beams from nuclear reactors have been employed successfully, but their use is not always convenient and it was felt valuable to demonstrate the capabilities of an accelerator. Equipment built for thermal neutron radiography was used with simple modifications, including the filtering of the beam through 0.5mm of cadmium. The transfer imaging technique was employed with an indium (0.125mm) screen to take advantage of the indium resonance at 1.5eV. Successful radiographs of boron nitride and uranium-235 samples were obtained using the Be(d,n) reaction at 3MeV as the neutron source and with an L/D ratio of 40, a screen exposure of about 0.5mAh, and overnight transfer on to Industrex C film.