title: Implementation of a multichannel soft x-ray diagnostic for electron temperature measurements in TJ-II high-density plasmas.
abstract: Based on the multi-foil technique, a multichannel soft x-ray diagnostic for electron temperature measurements has been recently implemented in the TJ-II stellarator. The diagnostic system is composed by four photodiodes arrays with beryllium filters of different thickness. An in-vacuum amplifier board is coupled to each array, aiming at preventing induced noise currents. The Thomson scattering and the vacuum ultraviolet survey diagnostics are used for assessing plasma profiles and composition, being the analysis carried out with the radiation code IONEQ. The electron temperature is determined through the different signal-pair ratios with temporal and spatial resolution. The design and preliminary results from the diagnostic are presented.
authors.affiliation: Associação EURATOM∕IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade Técnica de Lisboa, 1049-001 Lisboa, Portugal. dbaiao@ipfn.ist.utl.pt
authors.forename: D
authors.initials: D
authors.lastname: Baião
authors.forename: F
authors.initials: F
authors.lastname: Medina
authors.forename: M
authors.initials: M
authors.lastname: Ochando
authors.forename: I
authors.initials: I
authors.lastname: Pastor
authors.forename: C
authors.initials: C
authors.lastname: Varandas
authors.forename: A
authors.initials: A
authors.lastname: Molinero
authors.forename: J
authors.initials: J
authors.lastname: Chércoles