Abstract
The investigations of fluctuations and anomalous transport lie at hart of the tokamak research program, especially in the shear zone close to and beyond the last closed flux surface. Until now fluctuation measurements using plasma radiation were only made on the edge of the plasma, since they rely on the H{sub {alpha}} emission. In order to measure electron density fluctuations with good spatial and temporal resolution in the shear zone, the OVI doublet (2s-2p) can be observed. These are very strong impurity emission lines in the VUV region (103.2 nm and 103.8 nm) emitted from a narrow layer close to the separatrix. To get an image of this layer and to achieve enough intensity for a good temporal resolution, it is necessary to develop a filter with high transmission. A possible candidate is lithium fluoride (LiF), which transmits light at shorter wavelength than other materials. By cooling LiF crystals from 300 K to 220 K the cutoff wavelength decreases from 105 nm to about 103 nm. This master thesis presents a detailed investigation of the transmission of LiF near the cutoff wavelength. Crystal sheets produced by different manufactures were tested and the temperature dependence of the cutoff edge was investigated.
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Citation Formats
Schittenhelm, M.
Development of a LiF-filter for measuring plasma fluctuations in the far ultraviolet radiation spectral range; Entwicklung eines LiF-Filters fuer Plasma-Fluktuationsmessungen im VUV-Spektralbereich.
Germany: N. p.,
1991.
Web.
Schittenhelm, M.
Development of a LiF-filter for measuring plasma fluctuations in the far ultraviolet radiation spectral range; Entwicklung eines LiF-Filters fuer Plasma-Fluktuationsmessungen im VUV-Spektralbereich.
Germany.
Schittenhelm, M.
1991.
"Development of a LiF-filter for measuring plasma fluctuations in the far ultraviolet radiation spectral range; Entwicklung eines LiF-Filters fuer Plasma-Fluktuationsmessungen im VUV-Spektralbereich."
Germany.
@misc{etde_10121311,
title = {Development of a LiF-filter for measuring plasma fluctuations in the far ultraviolet radiation spectral range; Entwicklung eines LiF-Filters fuer Plasma-Fluktuationsmessungen im VUV-Spektralbereich}
author = {Schittenhelm, M}
abstractNote = {The investigations of fluctuations and anomalous transport lie at hart of the tokamak research program, especially in the shear zone close to and beyond the last closed flux surface. Until now fluctuation measurements using plasma radiation were only made on the edge of the plasma, since they rely on the H{sub {alpha}} emission. In order to measure electron density fluctuations with good spatial and temporal resolution in the shear zone, the OVI doublet (2s-2p) can be observed. These are very strong impurity emission lines in the VUV region (103.2 nm and 103.8 nm) emitted from a narrow layer close to the separatrix. To get an image of this layer and to achieve enough intensity for a good temporal resolution, it is necessary to develop a filter with high transmission. A possible candidate is lithium fluoride (LiF), which transmits light at shorter wavelength than other materials. By cooling LiF crystals from 300 K to 220 K the cutoff wavelength decreases from 105 nm to about 103 nm. This master thesis presents a detailed investigation of the transmission of LiF near the cutoff wavelength. Crystal sheets produced by different manufactures were tested and the temperature dependence of the cutoff edge was investigated. (orig./AH).}
place = {Germany}
year = {1991}
month = {Jun}
}
title = {Development of a LiF-filter for measuring plasma fluctuations in the far ultraviolet radiation spectral range; Entwicklung eines LiF-Filters fuer Plasma-Fluktuationsmessungen im VUV-Spektralbereich}
author = {Schittenhelm, M}
abstractNote = {The investigations of fluctuations and anomalous transport lie at hart of the tokamak research program, especially in the shear zone close to and beyond the last closed flux surface. Until now fluctuation measurements using plasma radiation were only made on the edge of the plasma, since they rely on the H{sub {alpha}} emission. In order to measure electron density fluctuations with good spatial and temporal resolution in the shear zone, the OVI doublet (2s-2p) can be observed. These are very strong impurity emission lines in the VUV region (103.2 nm and 103.8 nm) emitted from a narrow layer close to the separatrix. To get an image of this layer and to achieve enough intensity for a good temporal resolution, it is necessary to develop a filter with high transmission. A possible candidate is lithium fluoride (LiF), which transmits light at shorter wavelength than other materials. By cooling LiF crystals from 300 K to 220 K the cutoff wavelength decreases from 105 nm to about 103 nm. This master thesis presents a detailed investigation of the transmission of LiF near the cutoff wavelength. Crystal sheets produced by different manufactures were tested and the temperature dependence of the cutoff edge was investigated. (orig./AH).}
place = {Germany}
year = {1991}
month = {Jun}
}