Low temperature Thomson scattering on MAST-U

Clark, JG, Bowden, MD ORCID: 0000-0003-4128-4823 and Scannell, R (2021) Low temperature Thomson scattering on MAST-U. REVIEW OF SCIENTIFIC INSTRUMENTS, 92 (4). 043545-.

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Official URL: http://dx.doi.org/10.1063/5.0043813

Abstract

A new divertor Thomson scattering system has been developed for the MAST-U tokamak. The diagnostic will produce electron density and temperature profiles along the Super-X strike leg. The existing polychromator design has been adapted for low temperature measurements. A new 1061 nm channel with 2 nm bandwidth has been added to enable measurements down below the previous ∼5 eV limit on the core system. The optical filters used in the system have OD6 light rejection alongside a 1064.1 nm laser line filter to reduce stray light in the digitized channels. A new averaging technique has been applied to the scattered signal traces to improve the core Thomson data in the scrape-off layer. The technique reduces the systematic noise level in this region. This leads to a reduction in the error values for electron density and temperature measurements and, in particular, the digitizer noise. The technique has been applied to produce a radial profile for a number of L-mode MAST discharges down to very low densities of ∼1 × 10<sup>18</sup> m<sup>-3</sup>.

Item Type:	Article
Divisions:	Faculty of Science and Engineering > School of Electrical Engineering, Electronics and Computer Science
Depositing User:	Symplectic Admin
Date Deposited:	18 Aug 2022 14:55
Last Modified:	09 Aug 2023 12:19
DOI:	10.1063/5.0043813
Open Access URL:	https://aip.scitation.org/doi/10.1063/5.0043813
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3125106