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Title: Mass changes in NSTX Surface Layers with Li Conditioning as Measured by Quartz Microbalances

Abstract

Dynamic retention, lithium deposition, and the stability of thick deposited layers were measured by three quartz crystal microbalances (QMB) deployed in plasma shadowed areas at the upper and lower divertor and outboard midplane in the National Spherical Torus Experiment (NSTX). Deposition of 185 {micro}/g/cm{sup 2} over 3 months in 2007 was measured by a QMB at the lower divertor while a QMB on the upper divertor, that was shadowed from the evaporator, received an order of magnitude less deposition. During helium glow discharge conditioning both neutral gas collisions and the ionization and subsequent drift of Li{sup +} interrupted the lithium deposition on the lower divertor. We present calculations of the relevant mean free paths. Occasionally strong variations in the QMB frequency were observed of thick lithium films suggesting relaxation of mechanical stress and/or flaking or peeling of the deposited layers.

Authors:
Publication Date:
Research Org.:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
959344
Report Number(s):
PPPL-4319
TRN: US0904752
DOE Contract Number:  
DE-ACO2-76CHO3073
Resource Type:
Conference
Resource Relation:
Conference: 18th Int. Conference on Plasma Surface Interactions in Controlled Fusion Devices, May 26-30, 2008 Toledo Spain
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DEPOSITION; DIVERTORS; GLOW DISCHARGES; HELIUM; IONIZATION; LITHIUM; MEAN FREE PATH; MICROBALANCES; PLASMA; QUARTZ; RELAXATION; RETENTION; STABILITY; Amorphous Filmss, Desorption, Lithium S1300 Surface Effects, RO900 Redeposition, Lithium, NSTX

Citation Formats

C.H. Skinner, H.W. Kugel, A. L. Roquemore, PS. Krstic and A. Beste. Mass changes in NSTX Surface Layers with Li Conditioning as Measured by Quartz Microbalances. United States: N. p., 2008. Web.
C.H. Skinner, H.W. Kugel, A. L. Roquemore, PS. Krstic and A. Beste. Mass changes in NSTX Surface Layers with Li Conditioning as Measured by Quartz Microbalances. United States.
C.H. Skinner, H.W. Kugel, A. L. Roquemore, PS. Krstic and A. Beste. Mon . "Mass changes in NSTX Surface Layers with Li Conditioning as Measured by Quartz Microbalances". United States. doi:. https://www.osti.gov/servlets/purl/959344.
@article{osti_959344,
title = {Mass changes in NSTX Surface Layers with Li Conditioning as Measured by Quartz Microbalances},
author = {C.H. Skinner, H.W. Kugel, A. L. Roquemore, PS. Krstic and A. Beste},
abstractNote = {Dynamic retention, lithium deposition, and the stability of thick deposited layers were measured by three quartz crystal microbalances (QMB) deployed in plasma shadowed areas at the upper and lower divertor and outboard midplane in the National Spherical Torus Experiment (NSTX). Deposition of 185 {micro}/g/cm{sup 2} over 3 months in 2007 was measured by a QMB at the lower divertor while a QMB on the upper divertor, that was shadowed from the evaporator, received an order of magnitude less deposition. During helium glow discharge conditioning both neutral gas collisions and the ionization and subsequent drift of Li{sup +} interrupted the lithium deposition on the lower divertor. We present calculations of the relevant mean free paths. Occasionally strong variations in the QMB frequency were observed of thick lithium films suggesting relaxation of mechanical stress and/or flaking or peeling of the deposited layers.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jun 09 00:00:00 EDT 2008},
month = {Mon Jun 09 00:00:00 EDT 2008}
}

Conference:
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