GB1283414A - High voltage accelerator and accelerating tube therefor - Google Patents

Abstract

1283414 lon beam tubes NATIONAL ELECTROSTATICS CORP 3 Sept 1969 43543/69 Heading HID The accelerating tube 14, connected between the high voltage electrode 18 and the grounded electrode 28 of a high voltage accelerator, is subdivided into a number of insulating sections 56, which are preferably separated by conductive apertured isolating diaphragms 58, and at least one evacuating device 72, preferably one for each insulating section 56, is connected to the interior of the accelerating tube 14 intermediate the electrodes 18, 28. The apertures 60 in diaphragms 58 may be axially aligned conductive tubes 62, and the arrangement tends to prevent the propagation of any local sparking or other discharge occurring along the inner wall of any of the sections 56 of the highly evacuated tube 14. The insulating sections 56 are preferably laminated comprising alternate insulating layers 64 and conductive layers 66 and are connected together by clamping flanges 68. The evacuating devices 72 may be passive gas absorbing devices but are preferably ion-getter orbitron type vacuum pumps. The pumps 72 are mounted on the intermediate electrodes 74 supported by insulators 36 between the electrodes 18, 28, and preferably two insulating sections 56 are arranged between adjacent electrodes 74, so that two pumps 72 are mounted on each electrode 74, one serving each of the sections respectively above and below the corresponding diaphragm 58. Further pumps 72 may be mounted in the high voltage electrode 18. The vacuum pumps 72 may be powdered by batteries mounted on the electrodes '74, but are preferably powered by the arrangement claimed in Specification 1,283,415 in which separate generators 102 are connected via a common insulating shaft 106 to a motor 104. The high voltage generator 12 is generally of the construction disclosed in U.S.A. Specification 3,469,118 and the whole accelerator is enclosed within a tank containing a high pressure dielectric gas, e.g. sulphur hexafluoride. The accelerator construction shown is single-ended, but a double-ended construction with a second -accelerator tube 14 extending from the opposite side of the high voltage electrode .18 may also be employed.