The Experiment Technique And The Resistivity Of Liquid Silane Under Multiply Shock-Compressed

The electrical conductivity study of rich-hydrogen fluid under high pressure is an important part of the high-pressure hydrogen metallization,but in previous electrical measurements, scientists simply measured the electrical resistivity of samples under the final compression while the stepwise loading process was completed. The details of the resistance decrease during multiple shock were ignored because the time periods of each re-shock compression could not read out from the measured electrical signal. Obviously the meaningful information about the resistance change along the quasi-isentropic loading path was not effectively utilized. Especially when the pressure dependence of the electrical resistivity was studied, the data points got from different experiments could not be smoothly fitted because the contribution from the temperature might cause the change of resistivity. It also made discussion on mechanisms more difficult. To overcome the mentioned limitations of the previous electrical measuring experiments, we measure the history signals of the shock-induced luminescence, and combine it with the calculated time durations of multiple shock compressions. We tried to relate the conductivity increase history of shocked sample to the reverberation of shock in sample, and to determine the resistivity change with the pressures during multiple shock compressions.In this work, the liquid silane was prepared by a cold target technology, the history of shock-induced light was recorded by a photoelectric conversion element of PMT, and a two-stage light-gas gun was used to stepwise shock the silane to high pressure states. During such a repeated shock compression, the electrical resistivities were measured. The conclusions are asfollows:1. By repeated experiments, we found that our experimental techniques and the related systems workedwith high stability and good repeatability, which hadachieved the expected goals;2. By using the photoelectric synchronous measurement system, we had got multiple resistivity data of silane under a pressue of 10-140GPa. Sapphire was used as baseplates and window during the shock wave loading, and it was also used as insulating median to support the electrodes. The resistivity was measured by means of a constant current source and a difference circuit, and the signals were recorded by a wideband oscilloscope. The stepwise characteristics of the recorded electrical current signal was related to the process of repeated shock loading, and the signal to nose ratio (SNR) was higher than that of other author’s. Analysis shows that under the pressure of 15～120 GPa, the shock-compressed silane was of good electrical conducttivity, and under the pressure of 120-140 GPa, its electrical conductivity reached the level of metal;...