天鹅绒阴极脉冲放气及重复频率运行真空特性

为获得天鹅绒阴极加电运行时的放气信息，在加速器Torch-02（电压约300 kV、脉宽约6 ns、电阻约100 Ω、频率1~300 Hz）上开展了单次及重复频率下的真空兼容性实验研究。对于发射面积为28 cm2、阴阳极间距50 mm、有效抽速62 L/s、容积为4.6 L的真空二极管-天鹅绒阴极系统，根据不同电流发射密度时的气压历史曲线，确定了单位面积上天鹅绒表面中性气体释放数目与脉冲能量的关系。通过实时记录不同频率下的气压演化，在本底气压约5×10-3 Pa、单脉冲能量约6 J条件下，得到了平衡压强与重复频率的变化关系：10~100 Hz时，平衡压强与重复频率近似呈线性递增；超过100 Hz时，真空恶化明显，气压随频率呈超线性增长，300 Hz时平衡压强已升至Pa量级。最后，针对重复频率运行时的放气特点，讨论了一种“分布式”抽气思想以改善系统有效抽速。

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