Recent Advances in the Production of Heavy High Speed Ions Without the Use of High Voltages

A description is given of improvements in the Sloan-Lawrence method of accelerating heavy ions. The new apparatus yields mercury ions with energies of 2,850,000 electron volts, while the previous apparatus yielded ions with energies of 1,260,000 electron volts. The intensity of the beam of ions is of the order of ${10}^{-8\mathrm{}}$ amperes—only slightly less than in the previous tube which was considerably shorter. The new tube withstands the application of 79,000 volts while the previous tube was limited to 42,000 volts. This improvement is due principally to decreased heating of the electrodes as a result of lowering their resistance and capacity. The spacing of the electrodes has been increased to 20 percent of their length, and their diameter decreased from 13 mm to 6 mm. The number has been increased from 30 to 36 and the length of each is now 25 percent greater. The possibility of extending this method to the acceleration of lighter ions is discussed.