New Feedthrough Insulator of the Compact Tandem-Accelerator with Vacuum Insulation

The source of epithermal neutrons based on the tandem accelerator with vacuum insulation and a lithium target was created at the Budker Institute of Nuclear Physics for the development of the technique of boron-neutron capture therapy of malignant tumors (BNCT). A stationary proton beam with energy of 2 MeV was obtained, neutrons were generated, and studies of the effect of neutron radiation on cell cultures and laboratory animals were carried out. An increase in the proton energy to 2.3 MeV and equipping the beam shaping assembly will make it possible to obtain a neutron flux that satisfies the BNCT requirements the most. The report describes and discusses a new feedthrough insulator of the accelerator at the voltage of 1.15 MV, characterized by a doubled height of single insulator rings, the absence of a resistive divider inside the insulator. The proposed changes will improve the reliability of the accelerator, provide greater stability of the accelerating electric field from the influence of dark currents in accelerating gaps and reduce the height of the facility. The new feedthrough insulator is manufactured and installed in the accelerator. The voltage of 1.26 MV was received. The report presents the results of these experiments using the new feedthrough insulator.