Development of a bright polychromator for Thomson scattering measurements

Akira Ejiri, Takashi Yamaguchi, Junichi Hiratsuka, Yuichi Takase, Makoto Hasegawa, And Kazumichi Narihara

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

A bright polychromator for compact, efficient YAG Thomson scattering measurement was designed on the basis of ray-tracing calculations. The optical input of the polychromator is a 2-mm-diameter optical fiber with a numerical aperture of 0.37. High refractive index glass lenses with monolayer anti-reflection coatings were used to reduce aberration effects and achieve good efficiency. A fast, low-noise detection system consisting of an avalanche photodiode and operational amplifiers was designed and tested using YAG laser pulses; the measured full width at half maximum (FWHM) of the laser pulse was 10 ns. The measured noise was dominated by the thermal noise of the input resistance R (= 470Ω) when the signal was low, and the shot noise became dominant when the number of detected photons was greater than about 500.

Original languageEnglish
Article numberS2082
JournalPlasma and Fusion Research
Volume5
DOIs
Publication statusPublished - 2010

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

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