Dual laser holography for in situ measurement of plasma facing component erosion (invited)
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.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); USDOE Laboratory Directed Research and Development (LDRD) Program
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1484095
- Alternate ID(s):
- OSTI ID: 1476841
- Journal Information:
- Review of Scientific Instruments, Vol. 89, Issue 10; ISSN 0034-6748
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Measurements of dynamic surface changes by digital holography for in situ plasma erosion applications
Considerations for in situ, real time measurement of plasma-material interactions using Digital Holographic imaging