We describe an experimental measurement technique which allows us to determine the interface temperature and the emissivity of shocked sample through window material (the lithium fluoride). We determine the temperature upon the partial release pressure of the sample. The infrared radiation emitted by the sample through the window material is collected and carried out to detectors by a four core fluoride glass optical fiber. The spectral bandwidth of this fiber is 1.5 micrometer to 4 micrometer. In order to deduce the temperature from the electrical signals amplified and recorded on a numerical oscilloscope, four narrow filters are used with different spectral bandwidth. A static calibration of the detectors with a black body is performed. Different ratios between static and dynamic measurements give access to the temperature as well as to the variation law of the emissivity versus wavelength. The shock generator for the dynamic experiment is an explosive plane wave generator. The shock pressure obtained is about 50 GPa. The purpose of this experimental measurement technique is the study of materials in solid phase as well as in liquid phase. Two samples have been studied, bismuth with solid- liquid transition at about 20 GPa and copper which remains solid in our pressure range.
展开▼
