Study of radiation scattering in the hard X-ray energy range by a tokamak inner wall
The analysis of hard X-ray (HXR) emission has become an important method for diagnosing electrons in both the real and the momentum spaces of a tokamak plasma during lower hybrid current drive (LHCD). The effect of wall reflectivity on line integrated measurements is investigated for various HXR emission profiles. Using a simplified model for radiation backscattering by the inner wall, the reflected contribution is evaluated in the cylindrical geometry for various positions of the line of sight. Using the same model, but with the toroidal geometry, numerical calculations are carried out for the Tore Supra HXR diagnostic. A detailed modelling of the X-rays scattered back to the detector is then introduced. The microscopic processes experienced by X-rays in solid matter are presented, while a Monte Carlo procedure is discussed for the calculation of the solid angle and energy distributions of photons emerging from the wall. A comparison between the numerical predictions and the experimental data is presented and the overall results are summarised.
Bibliographic Reference: Article: Nuclear Fusion, Vol. 33 (1993) No. 8, pp. 1133-1145
Record Number: 199311611 / Last updated on: 1994-11-28
Original language: en
Available languages: en