Enhancement of the JET edge LIDAR Thomson scattering diagnostic with ultrafast detectors

Journal Article · Wed Oct 15 04:00:00 EDT 2008 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.2969078· OSTI ID:21266551

Kempenaars, M; Flanagan, J C; Walsh, M J; Beurskens, M; Balboa, I ^[1]; Giudicotti, L ^[2]

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1. Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB (United Kingdom)
2. Consorzio RFX, Associazione Euratom, ENEA Sulla Fusione, Corso Stati Uniti 4, I-35127 Padova (Italy)

The edge light detection and ranging (LIDAR) Thomson scattering diagnostic at the Joint European Torus fusion experiment uses a 3 J ruby laser to measure the electron density and temperature profile at the plasma edge. The original system used a 1 GHz digitizer and detectors with response times of {approx_equal}650 ps and effective quantum efficiencies <7%. This system has recently been enhanced with the installation of a new 8 GHz digitizer and four new ultrafast GaAsP microchannel plate photomultiplier tube detectors with response times of <300 ps and effective quantum efficiencies in the range of {approx}13%-20% (averaged over {lambda}=500-700 nm). This upgrade has enabled the spatial resolution to be reduced to {approx}6.3 cm along the laser line of sight for a laser pulse of 300 ps full width at half maximum, which is close to the requirements for the ITER core LIDAR. Performance analysis shows that the new system will have an effective spatial resolution of up to 1 cm in the magnetic midplane via magnetic flux surface mapping.

• OSTI ID: 21266551
• Journal Information: Review of Scientific Instruments, Journal Name: Review of Scientific Instruments Journal Issue: 10 Vol. 79; ISSN 0034-6748; ISSN RSINAK
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BOUNDARY LAYERS
ELECTRON DENSITY
GHZ RANGE
ITER TOKAMAK
MICROCHANNEL ELECTRON MULTIPLIERS
OPTICAL RADAR
PHOTOMULTIPLIERS
PLASMA
QUANTUM EFFICIENCY
RUBY LASERS
SPATIAL RESOLUTION
THOMSON SCATTERING