The Distribution in Angle of the Long Range Alpha-Particles from Fluorine Bombarded with Protons

The distribution in angle of the long alpha-particles from the reaction ${\mathrm{F}}^{19}+{\mathrm{H}}^1\to {\mathrm{O}}^{16}+{\mathrm{He}}^4$ has been determined at bombarding energies of 330, 375 and 435 kev. This distribution shows a very strong fore and aft asymmetry which varies only slightly with the bombarding voltage. The distribution is well represented by the expression $1+0.66cos\theta +0.25\mathrm{}{cos}^2\theta +0.41\mathrm{}{cos}^3\theta$.