Injector of Electron Linac for NESTOR Storage Ring
National Science Center "Kharkov Institute of Physic and Technology", Kharkov, Ukraine
Design of the compact S-band injector and results of simulation of particle dynamics are presented in the report. The injector consists of the low-voltage diode electron gun and a bunching system based on the resonant system with the evanescent oscillations. RF field increases in amplitude along the axis in such bunching system. RF power is supplied to the injector through a coaxial coupler. The injector can be supplied with two types of the guns: 25 kV, 250 mA and 25 kV, 1.5 A. The first gun will provide the linac with the electron beam in a long pulse regime (1500 ns) while the second one will be used in a short pulse regime (40 ns). The resonance system of the injector has been optimized to obtain the electron bunches with energy about 1 MeV, phase length less than 20° and energy spread less than 5% (for 70 % particles) at the linac entrance. The coaxial coupler allows applying the solenoid magnetic field along the bunching system. Influence of magnetic field configuration on beam parameters is described.
RF Electron Guns With Plasma-Assisted Emission Cathodes
The National Science Center "Kharkov Institute of Physic and Technology" (KIPT), Kharkov, Ukraine
Electron beams with charge up to 100 nC in a nanosecond current pulse can be generated by photoemission RF guns. Thermal heating of a cathode caused by high power flow density of laser pulse limits the increasing of the pulse charge. The alternative way the high charge can be achieved in RF guns is the application of cathodes with plasma-assisted electron emission. The feature of the cathodes is high emission current density (>102 À/cm2). It was proposed earlier to apply in RF guns plasma cathodes based on ferroelectrics. Results of beam dynamics simulation and results of the experimental research of one-cell S-band RF gun operation with driven plasma cathode are considered in the paper. Results of operation of experimental samples of the cathode are provided and analysed.