Design and implementation of a portable diagnostic system for Thomson scattering and optical emission spectroscopy measurements

N. Kafle, D. Elliott, E. W. Garren, Z. He, T. E. Gebhart, Z. Zhang, T. M. Biewer

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

A diagnostic system, which has a design goal of high-portability, has been designed at Oak Ridge National Laboratory (ORNL). This project aims at providing measurements of key plasma parameters (ne, Te, ni, Ti) for fusion-relevant devices, utilizing Thomson scattering (TS) and optical emission spectroscopy (OES). The innovative design employs mostly commercial off-the-shelf instrumentation and a traveling team of researchers to conduct measurements at various magnetic-confinement plasma devices. The TS diagnostic uses a Quantel Q-smart 1500 Nd:YAG laser with a 2ω harmonic generator to produce up to 850 mJ of 532 nm laser pulses at 10 Hz. Collection optics placed at the detection port consists of an 11 × 3 optical fiber bundle, where the TS diagnostic uses an 11 × 1 subset array of the fibers, the OES diagnostic uses another 11 fibers, and the remaining fibers are available to the host institution. The detection system is comprised of two separate IsoPlane-320 spectrometers with triple-grating turrets of various line spacing and two PI-MAX 4 intensified CCD detectors, used simultaneously to measure a broad range of ion, impurity, and electron parameters. The self-contained diagnostic package also includes a data processing and storage system. The design and initial implementation of the TS-OES diagnostic system are described. The experiments from the proof-of-principle operation of the portable package on a high density (∼2.5 × 1022 m-3) and low-temperature (∼5 eV) electrothermal arc source at ORNL are also discussed.

Original languageEnglish
Article number063002
JournalReview of Scientific Instruments
Volume92
Issue number6
DOIs
StatePublished - Jun 1 2021

Funding

This project was supported by the U.S. Department of Energy, Contract No. D.E.-AC05-00OR22725. The authors greatly appreciate the funding support provided by the Advanced Research Projects Agency-Energy (ARPA-E) to make this work possible. This paper was authored, in part, by UT-Battelle, LLC, under contract with the U.S. DOE. The U.S. government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this article, or allow others to do so, for U.S. government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). With the advancements in laser and detector technologies, the concept of a modular TS and OES diagnostic system has been funded by the Advanced Research Projects Agency-Energy (ARPA-E). Once completed, the portable diagnostic package (PDP) will travel to several potentially transformational fusion-relevant concept devices to measure fundamental plasma parameters.

FundersFunder number
U.S. Department of EnergyD.E.-AC05-00OR22725
Advanced Research Projects Agency - Energy
UT-Battelle

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