New Accelerating Tube for 4 MV Van de Graaff Accelerator

Abstract

The accelerating tube with diametrically magnetized ring magnets for the bending of backstreaming electrons was constructed for the 4 MV Van de Graaff accelerator of Kyoto University. The X-ray yield due to the electron loading was reduced to a factor of about 100 ; and the ion beam current was increased by a factor of about five compared with that of the old tube which had plane electrodes with small accelerating apertures. Characteristics of evacuation, beam convergence and accelerator operation are described ; and typical results of ion analysis are given for hydrogen, helium, nitrogen, neon and argon.