Optimization of SPIDER Grounded Grid Segment Design

Source for the production of ions of deuterium extracted from a radio frequency plasma (SPIDER) is a full-size negative ion source and a multibeamlet 100-kV accelerator, operational since 2018. It serves as the test bed for the full development of the heating neutral beam system for megavolt ITER injector and concept advancement (ITER). In 2020, the third grounded grid segment broke at the electrodeposited copper layer near one of the four feeders causing leakage. This article reports the redesign development of the SPIDER GG segment. In the first part of the article, several design configurations are proposed and compared to each other. The comparison serves to identify a suitable redesign configuration. A set of coupled analyses, including computational fluid dynamic (CFD) and finite-element method (FEM) analyses, is then performed to finally evaluate the redesigned component in accordance with the ITER structural design criteria for in-vessel components (ITER SDC-IC) criteria.