Untersuchungen der Temperaturbedingungen in der Graphitlaserdampfwolke

With the goal to obtain information on the evaporation and atomization conditions in the vapour cloud produced by laser impact on graphite (‘graphite laser torch’) the authors determined the spatial distribution of the gas temperature of the atomic vapour and the vibrational temperature of the CN molecules. The gas temperature was determined as the colour temperature of the ‘torch’. The applied method permits measurements not only in the vicinity of the target but also at a large distance from both the target and the axis of the torch. The distribution of the ‘effective’ temperature along the axis of symmetry of the torch and the local temperature distribution along the radius were used to derive the mean temperature of the atomic vapour. It was found that about 70% of the material ejected from the crater has a mean temperature of about 3400 K in the region between the target and the analytical zone. In order to determine the local vibrational temperature of the CN molecules in the analytical zone, the authors modulated the radiation from the torch electromechanically so that the radiation from the torch was recorded during the same period of time as analytical signals. The vibrational temperature of the CN molecules in the analytical region was found to be in a range between 3100 and 3600 K.