Outgassing characteristics of velvet cathode under single and repetition rate pulse operation

Outgassing characteristics of a polymer velvet cathode under single shot and repetition rate (rep-rate) operation were experimentally investigated on a pulser, Torch-02, which has an about 300 kV, adout 6 ns and 1 to 300 Hz rep-rate output. For a 10 L vacuum diode-velvet cathode system with an emission area of 28 cm2, an A-K gap of 50 mm and an effective pumping speed of 62 L/s, the pulse desorption profiles with different emitting current densities were obtained. According to the pressure histories, the dependence of equilibrium pressure on pulse rep-rate was presented in the condition of about 5×10-3 Pa base pressure and about 6 J single pulse energy. The diode pressure for burst mode test increased almost linearly with pulse rep-rate from 10 to 100 Hz, and increas