为了降低500 mA直流高压加速管高梯度区的电位梯度,对加速管轴向绝缘结构进行优化设计.首先分析了沿面闪络的机理和该加速管轴向绝缘体结构.根据SEEA理论并通过数值模拟,发现阴极、真空和绝缘体三结合点处电场畸变是产生高场强的原因,并分别对4种绝缘体结构进行模拟分析,最终确定出比较理想的结构:绝缘体沿面与阴极电极夹角为+45°,绝缘体两端开槽并均匀嵌入金属电极环,绝缘体均匀嵌入阳极电极片内.

Axial insulation structure was optimized to reduce potential gradient in DC high-voltage accelerating tubes of 500 mA.At first,both principle of surface flashover and axial insulation structure of accelerating tubes were analyzed.Then,it was found that electric field aberration at the junction of triple junction causes high electric field intensity through numerical simulation in terms of theory of SEEA.Optimal structure is ascertained by analyzing four types of insulation structure respectively and it has such features as angle of +45° between the insulator surface and the cathode,a metal electrode ring embedded evenly in flutes at both ends of insulator and the insulator embedded evenly in the anode.