Experiment Analysis Of PACIS (Pulsed Arc Cluster Ion Source) And Improvement Of PACIS Power

Due to the fact that cluster materials have different physical and chemical properties with different size, we can get expected materials by changing the size of cluster. In the beginning of this thesis, we briefly introduce different techniques of producing metal clusters, in which we find the technology of pulsed arc cluster ion source is the best choice for our purpose, and we present the elements for creating cluster by arc and the framework of this experiment. Because of failing to get any mass spectral signals of cluster, we analyze the experimental phenomenon and the circuit of power supply. In our experiments, discharge can be only emerged at the rear of the carrier gas pulse, and the change of wave figure of discharged voltage is not correct. We doubt that the discharged current and the power of power supply are not enough to meet our request. In order to prove the assumption, we give a detailed calculation and analysis for the charge and discharge processes of PACIS power circuit. We perform a detailed calculation and analysis for the charging and discharging process of PACIS power circuit. From the results, we know that the energy for single pulsed discharge of PACIS power is only 5.4J, and the average discharge current is only 100A. The result indicates that the capability of the power which is used in our laboratory is much lower than that in foreign groups. There are two shortcomings about PACIS power supply: the capacitance used to store energy is not large, and the inductance in discharge loop is too small. In the light of the analysis, we take measures to improve the power. We combine thoughts of G. Gantefor, a German scientist, with the compound pulsed power designing technique, which is usually used in spark technique. We designed a new type of PACIS power. In this project, firstly, the medium between two electrodes is ignited by DC high voltage (0-1200V, 3A). Subsequently the energy stored in the capacitance is transferred to the two electrodes by DC low voltage (150V, 2500A), which can produce high temperature, and then melt the metal surface of the electrodes, and produce metal vapor of aluminum and plasma. At last, the metal vapor, and plasma are transmitted by the carrier gas into the vacuum to generate clusters by cooling expansion. Our new type of PACIS power consists of four parts: a DC power supply system, a DC high voltage igniting system, a DC low voltage discharge system and a trigger system. Firstly, DC power supply...