Abstract: Numerical information necessary to an experimental study of the polarization of bremsstrahlung is presented. One may conclude that it is possible to produce significantly polarized γ-ray beams with existing electron accelerators. These beams will provide a new tool for the study of photonuclear reactions over a wide range of energy.

Abstract: "Theoretical and experimental results of the effect of gamma moderation are described. A 6.7-fold enhancement factor was obtained with a 1/8-in. - thick sodium-iodide crystal when using gamma moderation and a Co-60 gamma source. A counter was designed and built to make the most use of gamma source. A counter was designed and built to make the most use of gamma moderation. The results indicate that this counter can be made energy independent over a wide region. Though the cost of the counter is about 1/3 that of a 1-in, -diam, 1-in. -thick sodium-iodide crystal plus photomultiplier, the counting efficiency for gammas such as Na-24 is over two times greater."