S波段1＋腔热阴极微波电子枪研究

1+CELL MICROWAVE GUN WITH A LaB_6 THERMIONIC CATHODE

叙述了１＋腔热阴极微波电子枪设计、制造与调试的情况。该枪已于１９９２年１２月调试出束，经过一年多的调试运行，测量了电子束的发射度和能谱，得到了满意的结果。当输入功率约１．１ＭＷ时，输出电子束最大能量１ＭｅＶ，平均电子能量０．６ＭｅＶ，宏脉冲电流１Ａ，宏脉冲宽度约２μａ，重复频率５０Ｈｚ，微波工作频率２９９７．７５ＭＨｚ，束流归一化发射度ε_ｎ≈５πｍｍ·ｍｒａｄ。

Free Electron Lasers(FELs)require very good quality electron beam source.A lowemittance is necessary to obtain short wavelength A high peak current provides a high gain。Ahigh-gradient,S-band 1 + cell microwave gun(i.e.RF gun)with a LaB_6 thermionic is being developed in CAEP. The design principle,fabrication and testing of the RF gun are described.TheRF gun had been first tested and produced electron beam in Dec,1992.After one year of thetesting and operating,beam emittance and electron energy spread are also measured.These resultsare very satisfactory.When input microwave power in to the RF gun is about 1.1 MW,the mainparameters of the RF gun are following:maximum electron energy is 1MeV,average electronenergy is about 0.6MeV, routine macropulse current is 1A,maximum macropulse current is 1.67A,macropulse-width is 2μs microwave frequency is 2997.75MHz, repetition rate is 50Hz,electron beamnormalized emittance is 5 π mm.mrad。