Experiments with high velocity positive ions.―(I) Further developments in the method of obtaining high velocity positive ions

Abstract

In a previous communication we described the development of a method of obtaining positive ions of hydrogen with energies up to 300 kilovolts. A system of rectifiers was built which allowed steady potentials of this order to be obtained, and the methods necessary for the acceleration of positive ions from a hydrogen discharge tube were worked out. With this apparatus, investigations were made to determine whether any X-radiations or γ-radiations of appreciable intensity were produced by the impact of protons and molecular ions of hydrogen on matter. It was found, when all secondary effects were excluded, that if any such radiation is produced its intensity was comparable with the limits of error of the experiment, and was certainly not greater in intensity than one-millionth of the intensity of the continuous X-radiation which would have been produced by an equal electron source of the same energy. Since the intensity of any radiation would be expected to increase rapidly with the energy of the ions it became apparent that to obtain results of interest it would be necessary to extend the field of the work to higher voltages. The method used in the present experiments is an extension of that described in the previous paper. A source of high voltage has been developed, using thermionic rectifiers and condensers, which is capable of producing 800,000 volts steady potential. This potential is applied to an experimental tube down the axis of which protons from a hydrogen canal ray tube are accelerated. The protons can be transmitted through a mica window into an experimental chamber. Up to the present we have been able to produce and carry out experiments with protons having energies up to 710 kilovolts, and there seems no reason to doubt that the method will allow of this range being extended considerably.