Gas Analyses of First complete JET Cryopump Regeneration with ITER-Like Wall

TL;DR

This study analyzes the gas composition and residual impurities in a JET cryopump after its first regeneration with an ITER-like wall, providing insights into impurity retention and gas behavior during plasma operations.

Contribution

It presents the first comprehensive analysis of residual gases and impurities in a JET cryopump post-ITER-like wall campaign, including in-situ residual gas analysis and impurity retention.

Findings

Residual deuterium levels are very low.

Impurities like nitrogen and neon are retained on the cryopump.

Ammonia production is detected in the residual gases.

Abstract

Analytical results of a complete JET cryopump regeneration, including the nitrogen panel, following the first ITER-Like Wall campaign are presented along with the in-situ analyses of residual gas. H/D mixtures and impurities such as nitrogen and neon were injected during plasma operation in the vessel to study radiation cooling in the scrape-off-layer and divertor region. The global gas inventory over the campaign is incomplete, suggesting residual volatile impurities are remaining on the cryogenic panel. This paper presents results on a) residual deuterium on the panel which is related to the campaign very low, b) impurities like nitrogen which sticks on the panel and c) the ammonia production which can be observed in the RGA spectrum.