Review on Design of main Post Insulator of DNB Beam Source for INTF vacuum vessel

Abstract

The Diagnostic neutral beam (DNB) is used as a beam for active charge exchange recombination
spectroscopy to measure the helium ash density in the core plasma region. The DNB injects H0
beam to the plasma. The
Indian Test Facility (INTF) is a facility being constructed at Institute for Plasma Research (IPR), to characterize ITER
(International Thermonuclear Experimental Reactor) -DNB beam with full specification. INTF is a vacuum vessel of 180
m3 volume and capable of providing Ultra High Vacuum Environment for the beam operation. The DNB beam source
produces and accelerates negative ions. It is supported on the vessel mechanically and, for its functionality, is feed with
high electrical potential of -100kV. For electrical isolation between Beam Source and Vacuum vessel, Post Insulators
have to be provided to meet the electrical and mechanical requirements. The Post Insulators are mainly composed of
ceramic attached with the metallic flanges and then coupled to beam source support structure to provide them
mechanical support and electrical isolation.