高功率强流密度低发射度高亮度赝火花电子束产生

HIGH-POWER, INTENSE-CURRENT-DENSITY, LOW-EMITTANCE, HIGH-BRIGHTNESS PSEUDOSPARK ELECTRON BEAM DRIVEN BY IMPROVED PULSE LINE ACCELERATOR

由修改了的脉冲线加速器驱动的、高功率(200kV)、高电流密度、低发射度、高亮度赝火花放电电子束在15pa氮气中产生。束流强度2.2kA,脉宽400ns,束径1mm的电子束从阳极口射出,可在中性氮电离通道中传输20cm。在阳极下游5cm处,电子束相继打穿紧密粘贴在一起的酸敏纸和0.05mm厚的铜箔,分别留下0.6mm和0.3mm的穿孔。依据箍缩平衡条件算出该处的高能电子束的归一化发射度和亮度分别是23πmm mrad和8×10^(10)A/(m^2rad^2)。对同一酸敏纸连续轰击10次给出1.6mm穿孔表明它具有好的重复性。观察工作60枪后的放电室发现,各种电极和绝缘子表面几乎未见任何破坏性烧蚀痕迹。实验证明,赝火花电子束的束质量比冷阴极电子束的束质量要好得多。

High-power ( 200 kV), intense-current-density, low-emittance, high-brightness electron beam was generated in a 10 gap pseudospark chamber filled with 15 Pa N2 and driven by an improved pulse line accelerator. The ejected electron beam was characterized by 1mm diameter, 2. 2 kA beam current, and 400ns pulse length, and propagated 20cm in neutral N2 ionizing channel in the drift tube. At 5 cm downstream of the anode, it penetrated consecutively an acid-sensitive discoloring film and a 0.05 mm-thick copper foil, and left 0.6 mm and 0.3 mm holes on them, separately. According to the pinching equilibrium condition, the beam's normalized emittance and brightness are respectively calculated to be 23 πmm-mrad and 8 × 1010A/(m rad)2. That the 10 shots on the same acid-sensitive film produced a hole of 1. 6mm in diameter at 7cm showed a good repeatability of the electron beam. After 60 shots the pseudospark chamber was observed that there was almost no destructive damage traces left on the surfaces of the electrodes and insulators. It was found that the quality of electron beam produced in the pseudospark discharge chamber driven by the modified pulse line accelerator is much better than that generated by cold cathode discharges.