Experiments with high velocity positive ions V—Further experiments on the disintegration of boron

1—In a previous paper experiments on the disintegration of lithium, boron, and carbon by heavy hydrogen ions were described. The experiments on boron showed the presence of three proton groups of ranges 31, 58, and 92 cm for deuteron energies of 500 kv. They showed also a continuous distribution of α-particles between the ranges 5 cm and 15 cm, the distribution having a maximum at about 9 cm. There were also indications of a homogeneous group of α-particles at the end of the distribution, but the numbers of particles obtained were not sufficient to allow of its existence being definitely established. Since these experiments, we have been able to obtain heavy hydrogen of much higher purity, and have improved our source of ions, so that we have been able to determine the distribution in energy of the α-particles with much greater precision. A further improvement has been made by applying magnetic analysis to our ion beam, for in our original experiments with a mixed beam of protons and deuterons, the α-particles of range less than 4 cm resulting from deuteron transmutations were masked by the large number of α-particles due to proton disintegrations.