400 kV强流中子发生器的物理设计

对400 kV强流中子发生器进行了物理设计。采用Poisson/Superfish软件对中子发生器高压电极和加速管的电场分布进行了模拟，结果显示，各关键区域的空间电场最大值远低于击穿电场限值。以强流束旁轴包络方程为基本模型，发展了强流束传输系统束包络的计算机模拟程序IONB1.0，模拟了中子发生器传输系统中40 mA的D束流包络。结果显示，设计方案中所采取的两间隙高梯度加速结构有较强的聚焦性能，能有效抵消强流束空间电荷效应造成的束流发散，加速管出口处的束包络半径约3 cm，由加速管出口处的空间电荷透镜和三重四极磁透镜组成的传输系统能将束流聚焦在约140 cm处的靶上，且束斑直径小于2 cm。

Design of 400 kV Intense Neutron Generator

The design of 400 kV intense neutron generator was presented. The electric fields of high voltage electrode and accelerating column were simulated using Poisson/Superfish code. The results show that the maximum value of electric field in the key areas is far less than the value of breakdown electric field. The program for simulating high current ion beam envelope, called IONB1.0, was developed based on high current ion beam envelope equations. The envelopes of 40 mA D ion beam were simulated in the beam transport system of 400 kV intense neutron generator. The results show that the strong focus performance from the accelerating column with two gaps high gradient electric field can effectively offset ion beam divergence caused by the space charge effect. The radius of envelope is about 3 cm at accelerating column exit. The beam transport system composed of a space charge lens and a triple quadrupole magnetic lens can focused 40 mA D beam on the target at 140 cm distance, and the beam spot diameter is less than 2 cm.