Abstract

A high-transmission (~45%) twenty-channel polychromator equipped with near-infrared sensitive photo-multipliers has been constructed to record Thomson scattering spectra at the TORTUR tokamak. The high transmission was achieved by the use of mirrors instead of fiber optics to guide the spectrally resolved light to a set of photomultipliers. Spectral analysis is performed with a holographically ruled concave grating. Acceptable dimensions of the wavelength selection mirrors were obtained by magnifying the spectral image by a factor of 5 with a Mangin mirror. Electron temperatures up to 1000 eV at a density of 5 × 10¹⁹ m⁻³ can be measured with an accuracy of ≈1%. Both high sensitivity and high resolution enable the detection of irregularities in the velocity distribution. For example, satellites corresponding to partial densities of (5 ± 1) × 10¹⁷ m⁻³ were found at 23 nm from the laser wavelength.

© 1988 Optical Society of America

Triple grating polychromator for Thomson scattering

M. Greenwald and W. I. B. Smith
Appl. Opt. 16(3) 587-590 (1977)

Mirror system for collecting Thomson-scattered light in a tangential direction

C. J. Barth, B. J. J. Grobben, and G. C. H. M. Verhaag
Appl. Opt. 33(25) 6062-6067 (1994)

Thomson-scattering diagnostic on the Frascati tokamak upgrade

F. Orsitto, A. Brusadin, E. Giovannozzi, D. Santi, R. Bartiromo, and P. Pizzolati
Appl. Opt. 34(15) 2712-2720 (1995)

Rotational Raman scattering of hydrogen for calibrating a Thomson scattering device

Toshihiko Yamauchi and Ichiro Yanagisawa
Appl. Opt. 24(5) 700-709 (1985)

Multichannel Thomson scattering apparatus

N. Bretz, D. Dimock, V. Foote, D. Johnson, D. Long, and E. Tolnas
Appl. Opt. 17(2) 192-202 (1978)