Photographic Detectors for Neutron Diffraction

Abstract

Although new boron‐ and lithium‐loaded scintillators yield very fast photographic response for thermal neutrons, it is pointed out that reciprocity‐law failure responses will complicate intensity analyses of diffraction pattern films made with these techniques. The magnitude of this effect for a B¹⁰‐loaded scintillator and type F x‐ray film is such that the response is decreased by a factor of at least 4 times at a neutron intensity of 3×10³ neutrons/cm²‐ sec when compared to the response at a neutron intensity 100 times higher. This objection, and that of image nonuniformities, can be eliminated by using slower response metal screens and film detectors. A rhodium‐gadolinium screen combination used with a fast x‐ray film such as type KK is shown to be a fast technique which will yield diffraction patterns having useful intensity information.