Lanthanum Hexaboride Low Pressure Gas Discharge Characteristics

The switches are crucial components in pulsed technology and pulsed power technology, whose parameters and characteristics have the most sensitive and direct impact on the breakdown delay time and amplitude of pulse. Nowadays, the switches which are being studied or applied, such as gas spark gap, thyratron and ignitron, etc, are of different structures, operating principles, advantages and disadvantages, and are applied in various situations and fields. As the developments are made in pulsed power technology, there is more rigorous desire for better capability switches. The study in various switches with high voltage, high current, fast turn-on time, low jitter, low resistance, low inductance, low erode rate and being capable of steadily work with pulse repetition-rate, is currently a subject of growing interest.Vacuum switchgear tubes, gas spark gaps and pseudospark tubes are all switches of gas discharge theory, and have the good qualities of high withstanding voltage, high amplitude of current and high power. Most of the switch tubes used presently work in the gas spark region (the right branch of Paschen curve), and are made of graphite and mental such as tungsten, molybdenum, stainless steel and mercury.The presented thesis studies the gas discharge of LaB6 electrodes, The paper analyses the impacts of gas press and electrodes separation on the ignition voltage and voltage drop, and makes low gas pressure, lower than 10Pa, discharge switch tubes, with gas of helium and nitrogen, electrodes gaps of 5mm. The paper studies the tubes'discharge performances, and the impacts of discharge process on the electrodes. The results show that as the voltage rises, the tubes'discharge mechanism changes from glow discharge to arc discharge, the current rises suddenly and the voltage drops a lot. The tube with helium can work long time and steadily under pulses, with the voltage of 2200V, the peak value of current can exceed 100A. In the discharge process, the ions can clean and activate the surfaces of cathodes, which can reduce the work function of the electrodes, and improve the discharge tubes'emission capability and stability.The results of the presented thesis show that, as electrode, LaB6 has the...