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SummaryThe energy and angular distributions of protons produced in the 1°F (y, p) reaction have been obtained for the photon energy range 10-16·5 MeV. An integrated cross section of 18 MeV-mbarn was obtained for this region. The angular distribution was found to be of the form (a+b sin" 8) with the ratio b/a strongly energy dependent. The higher energy protons show evidence of an independent particle-type interaction which is in plausible agreement with the shell model structure of fluorine.The range-energy relation for the target gas, CF., is presented in Appendix 1.

SummaryThe power absorption coefficient a of microwaves of wave number v = O· 333 cm-1 by methyl chloride at 33· 7°C has been studied at pressures up to 2 atm, and the results are compared with theoretical predictions. Discrepancies which have previously been attributed to the effect of transitions between low.lying rotational states are shown to be due to three· body collisions. The collision diameter for pressure broadening of the inversion transition in methyl chloride is found to be 8·6 A; this is significantly larger than the figure of 7 . 2 A reported by earlier workers who neglected the effect of three-body collisions.

The Wilson cloud chamber has been employed with the method of projected angles in a study of the scattering of positrons and electrons in thin gold foil, for the energy range 0.39-1.1 Mev. The small angle scattering is in reasonable agreement with current multiple scattering theory. Further, the investigation of the large angle scattering gives indications in favour of a spin orbital interaction, and the absolute intensity of the scattering for positrons and electrons under these conditions is believed to be approximately correct.

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