中子发生器中二次电子抑制的数值模拟

讨论了密封中子发生器中二次电子流的产生机制，介绍了几种不同的二次电子流的抑制方法。针对不同的抑制方法进行了粒子模拟实验，结果表明，在直接利用法拉第圆筒形状的加速电极抑制的情况下，只能抑制住部分二次电子，一部分电子还可以通过加速孔进入加速空间形成二次电子流，二次电子流约占靶面二次电子发射电流的1/5。在法拉第圆筒状加速电极的基础上加上电场抑制，能很好地抑制二次电子流的产生，当偏压为300V时，二次电子电流近似为零。

Simulation for Suppressing of Secondary Electrons in Neutron Generator

The producing mechanism of secondary electrons in sealed neutron generator is discussed and several methods to suppress secondary electrons are introduced. The PIC simulation is carried out for the different methods. The result indicates that only a part of secondary electrons can be suppressed by Faraday cylinder and a part of them can enter into the accelerating gap to form electron current. The secondary electron current is about 1/5 of emitting current of secondary electrons on target. But almost all secondary electrons can be suppressed by electrostatic field combined with Faraday cylinder and the secondary electron current is about zero when the deflection voltage is 300 V.