ITER DNB ion source movement mechanism

Abstract

The 100 kV negative hydrogen ion source based Diagnostic Neutral Beam (DNB) injector, a part of Indian (IN) Procurement Package for ITER. DNB is expected to deliver 18–20 A of hydrogen neutral beam to the ITER plasma through a narrow blanket aperture of size 0.40( H) × 0.45( V) m 2, at a distance ∼20.67 m from the ion source position. Due to long transport length, a small misalignment of the ion source will cause significant transmission loss of the beam and produce asymmetric heat load on the beamline components and on the duct assembly. Mechanical misalignment and deflection due to tokamak stray magnetic field are also envisaged and therefore ion source positional adjustment is needed during DNB operation. This can be addressed by making provisions for the desired vertical and horizontal movements in the ion source support structure. Two independent translations for horizontal angular and linear misalignment adjustment are achieved by means of “master–slave” configuration arrangement in the support structure. The force analysis of the movement mechanism of the ion source support structure is carried out analytically by statics and generates inputs for an engineering design of such movement mechanism and discussed in the manuscript.