title: Spectral survey of helium lines in a linear plasma device for use in HELIOS imaging.
abstract: Fast visible cameras and a filterscope are used to examine the visible light emission from Oak Ridge National Laboratory's Proto-MPEX. The filterscope has been configured to perform helium line ratio measurements using emission lines at 667.9, 728.1, and 706.5 nm. The measured lines should be mathematically inverted and the ratios compared to a collisional radiative model (CRM) to determine Teand ne. Increasing the number of measurement chords through the plasma improves the inversion calculation and subsequent Teand nelocalization. For the filterscope, one spatial chord measurement requires three photomultiplier tubes (PMTs) connected to pellicle beam splitters. Multiple, fast visible cameras with narrowband filters are an alternate technique for performing these measurements with superior spatial resolution. Each camera contains millions of pixels; each pixel is analogous to one filterscope PMT. The data can then be inverted and the ratios compared to the CRM to determine 2-dimensional "images" of Teand nein the plasma. An assessment is made in this paper of the candidate He I emission lines for an imaging technique.
authors.affiliation: University of Tennessee, Knoxville, Tennessee 37996, USA.
authors.forename: H B
authors.initials: HB
authors.lastname: Ray
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Biewer
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: D T
authors.initials: DT
authors.lastname: Fehling
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: R C
authors.initials: RC
authors.lastname: Isler
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.forename: E A
authors.initials: EA
authors.lastname: Unterberg