The Production of Heavy High Speed Ions without the Use of High Voltages

A method has been developed for the multiple acceleration of ions to high speeds without the use of high voltages. The ions travel through a series of metal tubes in synchronism with an oscillating electric potential applied alternately to the tubes such that the electric field between tubes is always in a direction to accelerate the ions as they pass from the interior of one tube to the interior of the next. The ions are thereby successively accelerated to speeds corresponding to voltages as many times greater than the high frequency voltage applied to the tubes as there are tubes. In the present experiments a high frequency voltage of 42,000 volts at a wave-length of 30 meters applied to 30 such accelerator tubes in line resulted in the production of a current of ${10}^{-7\mathrm{}}$ amp. of 1,260,000 volt singly charged Hg ions. The surprising effectiveness of this experimental method for the generation of intense beams of high speed ions is due to the development of simple, convenient and effective methods for focusing and synchronizing the ions as they pass through the accelerating system. The present experiments show that ions having kinetic energies in excess of 1,000,000 volt-electrons can be produced in this way with quite modest laboratory equipment and with a convenience surpassing the direct utilization of high voltages, that the limit to the attainable ion speeds is determined mainly by the length of accelerating system and the size of the high frequency oscillator system, and consequently that the production of 10,000,000 volt ions is an entirely practicable matter.