title: JET divertor diagnostic upgrade for neutral gas analysis.
abstract: With installation of the ITER-like wall in JET a major diagnostic upgrade to             measure the neutral gas pressure and composition in the sub-divertor region has been             completed, to characterise retention and outgassing of the new metallic first wall. The             upgrade includes two new magnetically shielded systems consisting of sensitive             capacitance manometers and residual gas analysers, both capable of providing data during             plasma operation. These enable absolute pressure and gas composition measurements             (pressure range: 10(-5)-10(-1) mbar, mass range:             1-200 amu, respectively) and have been used to characterise the neutral gas             behaviour under various plasma conditions.
authors.affiliation: IEF, Plasmaphysik, FZJ Jülich GmbH, Association EURATOM-FZJ, Jülich, Germany. uron.kruezi@ccfe.ac.uk
authors.forename: Uron
authors.initials: U
authors.lastname: Kruezi
authors.forename: G
authors.initials: G
authors.lastname: Sergienko
authors.forename: P D
authors.initials: PD
authors.lastname: Morgan
authors.forename: G F
authors.initials: GF
authors.lastname: Matthews
authors.forename: S
authors.initials: S
authors.lastname: Brezinsek
authors.forename: S
authors.initials: S
authors.lastname: Vartanian