Tokamak plasma diagnostics based on measured neutron signals [Review]

摘要

Neutron diagnostics are of increasing importance for future: fusion devices. Consequently, efforts are being made to improve the accuracy of underlying experimental and computational methods. The present article reviews the modelling and the analysis of measured neutron signals relevant for plasma diagnostics on tokamaks. The underlying numerical simulation of neutron signals involves various aspects. Firstly, a realistic characterization of the plasma as a neutron source is needed. Secondly. detailed knowledge about changes in energy spectra and total number of the initially emitted neutrons due to scattering and absorption in the volume between the neutron source and the detector system is required. Finally, the detection properties of the measuring systems have to be taken into account. Presently, a sophisticated numerical procedure which directly relates detector signals to physics properties of the emitted neutrons from the plasma is not available and progress is found to be incremental rather than revolutionary. This is mainly attributable to problems with modelling the plasma neutron source based on measured plasma data and modelling difficulties for the neutron transport. However, more recent results of plasma parameters derived from neutron measurements provide evidence for the improvements in the measurement, simulation and analysis procedures over the past two decades. (C) 1999 Elsevier Science B.V. All rights reserved. [References: 463]