ISOTOPE SEPARATION BY DC ARC DISCHARGE

当电极间的直流放电通过压力约为10Torr的细毛细管时，电极区域富含重同位素，而阳极区富含轻同位素。我们制作了一台装置，使DC在足够长的时间内产生等离子体，以进行Ne同位素分离实验。放电管(毛细管)由石英制成，并包含在直径13厘米的焦化玻璃管中。在它的两端，两个法兰相连，它们固定电极和毛细管。两个电极的尖端均由钽箔管制成，并安装在水冷铜导线上。毛细管的两端连接到法兰中的金属腔，每个金属腔连接到不同的采样气室。我们研究了闭合体系条件下的Ne同位素的分离。我们检查了松弛到平衡浓度的时间常数，发现是60-80分钟。考察了毛细管长度、放电电流和放电压力对平衡浓度的影响。压力越低，毛细管越长，放电电流越大，分离系数越大。我们通过修正所提出的一个理论公式，从实验参数中得到了给出浓缩因子的公式。用该方程很好地解释了观测到的浓缩因子。

When a DC are discharge between electrodes took place across a thin capillary with its pressure about 10 Torr, the eathode region became enriched in the heavy isotope, while the anode region became enriched in the light isotope. We made an apparatus to make the DC are plasma for a sufficient long time to make the experiments of the neon isotope separation. The discharge tube (capillary) is made of quartz, and contained in a pyrex-glass pipe of 13-cm i.d. On its both ends, two flanges are connected, and they hold the electrodes and the capillary. The tips of the both electrodes are made of tantalum foil tube and mounted on water-cooled copper conductor. The ends of the capillary are connected to metal chambers in the flanges, and each of them is connected to a different sampling gas chambr. We studied the separation of neon isotopes under closed-system conditions. We examined the time constant for the relaxation to an equilibrium concentration, which was found to be 60-80 minutes. We investigated the effects of the length of capillary, discharging current, and the discharging pressure, on the equilibrium concentration. Consequyently, the separation factor became larger when the pressure was lower, when the capillary was longer, and when the discharging current was larger. We derive the equation which gives the enrichment factor from the experimental parameters by modifying one of the theoretical equations proposed. The observed enrichment factor is well explained by the equation.