title: Validations of calibration-free measurements of electron temperature using double-pass Thomson scattering diagnostics from theoretical and experimental aspects.
abstract: This paper evaluates the accuracy of electron temperature measurements and relative transmissivities of double-pass Thomson scattering diagnostics. The electron temperature (Te) is obtained from the ratio of signals from a double-pass scattering system, then relative transmissivities are calculated from the measured Teand intensity of the signals. How accurate the values are depends on the electron temperature (Te) and scattering angle (θ), and therefore the accuracy of the values was evaluated experimentally using the Large Helical Device (LHD) and the Tokyo spherical tokamak-2 (TST-2). Analyzing the data from the TST-2 indicates that a high Teand a large scattering angle (θ) yield accurate values. Indeed, the errors for scattering angle θ = 135° are approximately half of those for θ = 115°. The method of determining the Tein a wide Terange spanning over two orders of magnitude (0.01-1.5 keV) was validated using the experimental results of the LHD and TST-2. A simple method to provide relative transmissivities, which include inputs from collection optics, vacuum window, optical fibers, and polychromators, is also presented. The relative errors were less than approximately 10%. Numerical simulations also indicate that the Temeasurements are valid under harsh radiation conditions. This method to obtain Tecan be considered for the design of Thomson scattering systems where there is high-performance plasma that generates harsh radiation environments.
authors: National Institutes for Quantum and Radiological Science and Technology, 801-1 Mukoyama, Naka 311-0193, Japan.
authors: H
authors: H
authors: Tojo
authors: National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
authors: I
authors: I
authors: Yamada
authors: National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
authors: R
authors: R
authors: Yasuhara
authors: Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan.
authors: A
authors: A
authors: Ejiri
authors: National Institutes for Quantum and Radiological Science and Technology, 801-1 Mukoyama, Naka 311-0193, Japan.
authors: J
authors: J
authors: Hiratsuka
authors: Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan.
authors: H
authors: H
authors: Togashi
authors: National Institutes for Quantum and Radiological Science and Technology, 801-1 Mukoyama, Naka 311-0193, Japan.
authors: E
authors: E
authors: Yatsuka
authors: National Institutes for Quantum and Radiological Science and Technology, 801-1 Mukoyama, Naka 311-0193, Japan.
authors: T
authors: T
authors: Hatae
authors: National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
authors: H
authors: H
authors: Funaba
authors: National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan.
authors: H
authors: H
authors: Hayashi
authors: Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8561, Japan.
authors: Y
authors: Y
authors: Takase
authors: National Institutes for Quantum and Radiological Science and Technology, 801-1 Mukoyama, Naka 311-0193, Japan.
authors: K
authors: K
authors: Itami