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Title: Dual laser holography for in situ measurement of plasma facing component erosion (invited)

Abstract

A digital holography (DH) surface erosion/deposition diagnostic is being developed for 3D imaging of plasma facing component surfaces in situ and in real time. Digital holography is a technique that utilizes lasers reflected from a material surface to form an interferogram, which carries information about the topology of the surface when reconstructed. As described, dual CO2 lasers at 9.271 and 9.250 μm wavelengths illuminate the interrogated surface (at a distance of ~1 m) in a region of ~1 cm × 1 cm. The surface feature resolution is ~0.1 mm in the plane of the surface, and the depth resolution ranges from ~0.0001 to ~2 mm perpendicular to the surface. The depth resolution lower limit is set by single-laser and detector optical limitations, while the upper limit is determined by 2π phase ambiguity of the dual-laser synthetic wavelength. Measurements have been made “on the bench” to characterize the single-laser and dual-laser DH configurations utilizing standard resolution targets and material targets that were previously exposed to high flux plasmas in either the Prototype Material Plasma Exposure eXperiment (Proto-MPEX) or the electro-thermal (ET) arc source. Typical DH measurements were made with 0.03 ms integration with an IR camera that can be framed atmore » rates approaching 1.5 kHz. Finally, the DH diagnostic system is progressing toward in situ measurements of plasma erosion/deposition either on Proto-MPEX or the ET arc source.« less

Authors:
ORCiD logo [1];  [2];  [2]; ORCiD logo [3]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Mechanical, Aerospace and Biomedical Engineering
  3. Third Dimension Technologies, LLC, Knoxville, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC); USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1484095
Alternate Identifier(s):
OSTI ID: 1476841
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 89; Journal Issue: 10; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; plasma facing components; photographic instruments; measurement theory; lasers; interferometers; stereoscopy; cameras; holograms; digital holography

Citation Formats

Biewer, T. M., Sawyer, J. C., Smith, C. D., and Thomas, C. E.. Dual laser holography for in situ measurement of plasma facing component erosion (invited). United States: N. p., 2018. Web. doi:10.1063/1.5039628.
Biewer, T. M., Sawyer, J. C., Smith, C. D., & Thomas, C. E.. Dual laser holography for in situ measurement of plasma facing component erosion (invited). United States. https://doi.org/10.1063/1.5039628
Biewer, T. M., Sawyer, J. C., Smith, C. D., and Thomas, C. E.. 2018. "Dual laser holography for in situ measurement of plasma facing component erosion (invited)". United States. https://doi.org/10.1063/1.5039628. https://www.osti.gov/servlets/purl/1484095.
@article{osti_1484095,
title = {Dual laser holography for in situ measurement of plasma facing component erosion (invited)},
author = {Biewer, T. M. and Sawyer, J. C. and Smith, C. D. and Thomas, C. E.},
abstractNote = {A digital holography (DH) surface erosion/deposition diagnostic is being developed for 3D imaging of plasma facing component surfaces in situ and in real time. Digital holography is a technique that utilizes lasers reflected from a material surface to form an interferogram, which carries information about the topology of the surface when reconstructed. As described, dual CO2 lasers at 9.271 and 9.250 μm wavelengths illuminate the interrogated surface (at a distance of ~1 m) in a region of ~1 cm × 1 cm. The surface feature resolution is ~0.1 mm in the plane of the surface, and the depth resolution ranges from ~0.0001 to ~2 mm perpendicular to the surface. The depth resolution lower limit is set by single-laser and detector optical limitations, while the upper limit is determined by 2π phase ambiguity of the dual-laser synthetic wavelength. Measurements have been made “on the bench” to characterize the single-laser and dual-laser DH configurations utilizing standard resolution targets and material targets that were previously exposed to high flux plasmas in either the Prototype Material Plasma Exposure eXperiment (Proto-MPEX) or the electro-thermal (ET) arc source. Typical DH measurements were made with 0.03 ms integration with an IR camera that can be framed at rates approaching 1.5 kHz. Finally, the DH diagnostic system is progressing toward in situ measurements of plasma erosion/deposition either on Proto-MPEX or the ET arc source.},
doi = {10.1063/1.5039628},
url = {https://www.osti.gov/biblio/1484095}, journal = {Review of Scientific Instruments},
issn = {0034-6748},
number = 10,
volume = 89,
place = {United States},
year = {2018},
month = {10}
}

Works referenced in this record:

Developing structural, high-heat flux and plasma facing materials for a near-term DEMO fusion power plant: The EU assessment
journal, December 2014


Digital holography for in situ real-time measurement of plasma-facing-component erosion
journal, November 2014


Developing the science and technology for the Material Plasma Exposure eXperiment
journal, July 2017


The relative motion of the Earth and of the luminiferous ether
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Material impacts and heat flux characterization of an electrothermal plasma source with an applied magnetic field
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Characterization of an electrothermal plasma source for fusion transient simulations
journal, January 2018


Progress in the Development of a High Power Helicon Plasma Source for the Materials Plasma Exposure Experiment
journal, August 2017


Design of a digital holography system for PFC erosion measurements on Proto-MPEX
journal, October 2016