• M.I.Ayzatskiy, A.N.Dovbnya, V.V.Zakutin, V.N.Boriskin, N.G.Reshetnyak, V.P.Romasko, N.A.Dovbnya
  Kharkov Institute of Physics and Technology, Kharkov, Ukraine

The paper reports the results of experimental studies on formation of electron beams in three types of secondary-emission sources. Experiments were carried out with a magnetron gun having a cylindrical anode (70 mm in diameter): 1) with a smooth cathode (40 mm in diameter) and a modified cathode: 2) with 4 longitudinal seams and 3) composed of 8 copper rods (5 mm in diameter). Parameters of beams were studied and beam indentations were obtained. In the first case the beam formation occurs with a current of ~40 A (at a cathode voltage of 40 kV) and an azimuthal uniformity of ±5 %. In the second case, at a field nonuniformity of ~30%, the azimuthal nonuniformity is ~15 A. In the third case, at a field nonuniformity of ~60% there occurs formation of 8 separate beams having the form close to the half-ring and with a total current of ~10A (at a cathode voltage of 30 kV). The beam current amplitude stability in all the cases was 2 ... 5 %.

319

• M.I.Ayzatskiy, A.N.Dovbnya, V.A.Kushnir, V.V.Mytrochenko, A.N.Opanasenko, S.A.Perezhogin, V.F.Zhiglo
  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.

330

• N.G.Reshetnyak, A.N.Dovbnya, M.I.Ayzatskiy, V.N.Boriskin, V.V.Zakutin, V.P.Romasko, I.A.Chertishchev, N.A.Dovbnya
  Kharkov Institute of Physics and Technology, Kharkov, Ukraine

The electron accelerator for radiation technology purposes is being created at the NSC KIPT. The accelerator is designed to have a particle energy up to 200 keV and a beam power up to 5 MWt/cm2 at a voltage pulse duration between 8 and 40 mks and a pulse repetition rate up to 10 Hz. A magnetron gun with a cold secondary-emission cathode in cross fields is used as an electron source. Results are reported from the experiments on electron beam production in the magnetron gun (the diameters of the cathode and anode being 40 mm and 78 mm, respectively). The longitudinal magnetic field was measured to range from 1500 to 2300 Oe. In one of the modes of operation, an accelerated electron energy of ~ 100 keV was obtained (beam current 110 A, duration ~ 16 mks), the power density on the target was ~ 4 MW/cm2. Targets made from different materials (stainless steel, aluminum, etc.) were exposed to radiation.

375

• M.I.Ayzatskiy, A.N.Dovbnya, I.V.Khodak, V.A.Kushnir, V.V.Mytrochenko
  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 А/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.

392