高压直流连续波光阴极注入器中发射度补偿

空间电荷效应是引起发射度增长的主要因素，特别是在高压直流连续波光阴极注入器中。分析了高压直流连续波光阴极注入器中线性空间电荷力的特点及其对电子束横向发射度的影响，并从理论上解析地研究了螺线管发射度补偿的原理及特点。最后利用Parmela程序对中国工程物理研究院高压直流连续波光阴极注入器的发射度补偿作了模拟计算。结果表明，束团电荷量为80 pC的电子束在350 keV高压直流电子枪出口处的横向归一化发射度为5.14 mmmrad，经过螺线管补偿后，其最小横向发射度变为1.27 mmmrad。电子束的发射度得到了很好的补偿。

Emittance compensation of CW DC-gun photoinjector

Emittance growth induced by space charge effect is very important, especially for CW DC-gun photoinjector. In this work, the linear space charge force and its effect on electron beam transverse emittance are studied, and the principle and properties of emittance compensation by solenoid are analyzed. The CAEP DC-gun photoinjector with a solenoid is also simulated by code Parmela. Simulated results indicate that the normalized transverse emittance of an 80 pC bunch at the 350 keV DC-gun exit is 5.14 mm·mrad. And after compensated by a solenoid, it becomes 1.27 mm·mrad. The emittance of beam is well compensated.