Abstract
An advanced Thomson scattering system has been built for a linear plasma generator for plasma surface interaction studies. The Thomson scattering system is based on a Nd:YAG laser operating at the second harmonic and a detection branch featuring a high etendue (f/3) transmission grating spectrometer equipped with an intensified charged coupled device camera. The system is able to measure electron density (ne) and temperature (Te) profiles close to the output of the plasma source and, at a distance of 1.25 m, just in front of a target. The detection system enables to measure 50 spatial channels of about 2 mm each, along a laser chord of 95 mm. By summing a total of 30 laser pulses (0.6 J, 10 Hz), an observational error of 3% in ne and 6% in Te (at ne = 9.4 × 1018 m -3) can be obtained. Single pulse Thomson scattering measurements can be performed with the same accuracy for ne > 2.8 × 10 20 m-3. The minimum measurable density and temperature are ne < 1 × 1017 m-3 and Te < 0.07 eV, respectively. In addition, using the Rayleigh peak, superimposed on the Thomson scattered spectrum, the neutral density (n0) of the plasma can be measured with an accuracy of 25% (at n0 = 1 × 1020 m-3). In this report, the performance of the Thomson scattering system will be shown along with unprecedented accurate Thomson-Rayleigh scattering measurements on a low-temperature argon plasma expansion into a low-pressure background.
Original language | English |
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Article number | 123505 |
Journal | Review of Scientific Instruments |
Volume | 83 |
Issue number | 12 |
DOIs | |
State | Published - Dec 2012 |
Externally published | Yes |
Funding
The authors wish to thank especially the people from the workshop, design office and Electronics and ICT departments of the FOM Institute for Plasma Physics Rijnhuizen for their wonderful support. In addition, we like to thank Christiaan de Snoo and Rob Satink from BFi OPTiLAS Benelux. This work, supported by the European Communities under the contract of the Association EURATOM/FOM, was carried out within the framework of the European Fusion Programme with financial support from NWO and the Centre-of-Excellence on Fusion Physics and Technology (NWO-RFBR Grant No. 047.018.002). The views and opinions expressed herein do not necessarily reflect those of the European Commission.