Development of a multipoint Thomson scattering system for a large reversed field pinch experiment

Journal Article · Mon Oct 01 00:00:00 EDT 1990 · Review of Scientific Instruments; (USA)

DOI:https://doi.org/10.1063/1.1141802· OSTI ID:6206675

Bassan, M; Pasqualotto, R; Sardella, A ^[1]; Giudicotti, L ^[2]

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1. Istituto Gas Ionizzati, Associazione Euratom-ENEA-CNR, Corso Stati Uniti, 4-35020 Padova (Italy)
2. Dipartimento d'Ingegneria Elettrica, Universita di Padova, Via Gradenigo 6/A-35131 Padova (Italy)

A multipoint Thomson scattering system is under development for the measurement of {ital T}{sub {ital e}} and {ital n}{sub {ital e}} spatial profiles in RFX, a large ({ital a}=0.48 m, {ital R}=2 m, {ital I}{le}2 MA) reversed field pinch experiment. In this system, the beam from a low divergence ruby laser ({ital E}=15 J, {Delta}{ital t}=30 ns) is focused to cross the plasma in the equatorial plane. The scattering signal from 30 locations along a plasma diameter is collected by means of high transmission fiber optic bundles. An effective viewing dump was obtained by engraving sharp poloidal grooves in the first wall graphite tiles. The scattering light spectra are analyzed by means of three spectrometers, each including an {ital F}/3.4, aberration corrected, holographic grating and a 40-mm-diam MCP photomultiplier with a 10{times}10 anode array. These detectors use a high strip current, V-plate, electron multiplier with 10{sup 5} electron gain and have a recovery time of less than 30 {mu}s. In the 300-channel data acquisition electronics, the plasma light background may be sampled 100 ns before the scattering pulse. The system is designed in order to achieve a spatial resolution of 2.5 cm, useful to study small-scale correlation phenomena, and will also measure fast, submillisecond fluctuations of {ital T}{sub {ital e}} and {ital n}{sub {ital e}} by exploiting the two-pulse capability of the laser.

• OSTI ID: 6206675
• Journal Information: Review of Scientific Instruments; (USA), Vol. 61:10; ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
FIELD-REVERSED THETA PINCH DEVICES
PLASMA DIAGNOSTICS
THOMSON SCATTERING
ELECTRON TEMPERATURE
FLUCTUATIONS
GAIN
LASER RADIATION
OPTICAL EQUIPMENT
OPTICAL SPECTROMETERS
PHOTOMULTIPLIERS
AMPLIFICATION
CLOSED PLASMA DEVICES
COMPACT TORUS
ELECTROMAGNETIC RADIATION
EQUIPMENT
INELASTIC SCATTERING
MEASURING INSTRUMENTS
PHOTOTUBES
PINCH DEVICES
RADIATIONS
SCATTERING
SPECTROMETERS
THERMONUCLEAR DEVICES
TORI
VARIATIONS
700102* - Fusion Energy- Plasma Research- Diagnostics