Summary: A novel diagnostic for time-resolved spectroscopic
argon and lithium density measurements
L. Schmitz *, P. Calderoni, A. Ying 1
, M.A. Abdou
MAE Department, 43-133 Eng. IV, University of California, Los Angeles, CA 90095-1597, USA
A new diagnostic technique for determining neutral gas and metal vapor densities over a wide pressure range with
high time resolution is described. A compact, current-stabilized hollow cathode/anode discharge is use to ionize the gas
and/or trace impurity to be analyzed. We report proof-of-principle operation of the diagnostic in a well characterized
argon discharge in the pressure range 6.7265Pa. The intensity ratio of neutral and singly ionized argon lines (IAr I/IAr II)
is shown to increase monotonically with the neutral argon density. In a second experiment, absolute neutral lithium
vapor densities have been measured using this diagnostic.
Ó 2004 Elsevier B.V. All rights reserved.
PACS: 52.50.D; 07.60.R; 52.70; 52.25.Y
Keywords: Argon; First wall; Lithium; Neutrals; Spectroscopy
The vacuum quality and neutral contaminants in fu-
sion devices and inertial fusion energy (IFE) liquid
chambers are usually determined by mass spectrometry.
The required differential pumping limits the time resolu-