Radiography with the Fission Neutrons from Californium-252
ARMY MATERIALS AND MECHANICS RESEARCH CENTER WATERTOWN MA
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Fission neutron radiography, with images formed on thin sheets of cellulose nitrate, has been investigated using neutrons from Cf-252. A polyethylene converter provides recoil protons from neutron elastic scattering by hydrogen, which in turn create damage in the cellulose nitrate. Chemical etching then produces a frosted etch-track image which can be reproduced photographically by either scattered or transmitted light. The most readily available cellulose nitrate sheets were found to contain undesirable internal defects and thus films are recast in thicknesses of several mils. The images are of high resolution, as expected from a computer calculation which considered the direction and ranges of the recoil protons in polyethylene. All materials, including those of low atomic weight, may be radiographed with good penetration. The technique is simple and employs inexpensive materials.