Relativistic Klystron Output Cavity Design And Optimization

The basic principle,main properties,typical parameters,technical characteristics and general situation of Klystron are introduced.the electron beam prebunching in the modulated cavity and shift tube of relativistic klystron amplifer (RKA) is studied analytically,a self-consistent equation of radiation generated by the prebunched electron beam in the radiation cavity is derived using the field method of particle—wave interaction instead of the electrical circuit method,and in terms of it,the gain in the linear regime calculated,a field analysis method is proposed.The theory analysis shows that the characteristic parameters,such as resonance frequency,real part of gap-impedance,external quality fadtor in all kinds of klystron output circuits including single-beam,multi-beam,single-gap,multi-gap,single-beammulti-gap,multi-beam multi-gap klystron output circuit,can be calculated by the field analysis method.Design considerations of the high power S-band RKA are described,By using electron beams of voltage-600kv,current-5000A,and the numerical simulations for three kinds of the RKA output structures are given.The three kinds of the output strctures are single-gap standing-wave(SW) cavity,traveling-wave (TW)output structure,and two output structures(single-gap+traveling-wave structure).under conditions of using two output structures,the results show that the instantaneous peak power obtained from SW output cavity and TW output structure is respectively 2.4GW and 2.1GW,the both power average of 0.96GW and 0.93GW,i.e.the S-band RKA of two output structures generates peak output power of 1.89GW at a frequency of 2.85GHz.The space charge theory of relativistic electron beam is studied and the general theory has been formulated in this paper,The space charge wave equations for relativistic electron beam have been derived ,the relativistic kinematic voltage is defined and the physical explanation is described.The theorem of relativistic kinematic energy has been derived,and the normalized model of relativistic space charge wave is derived as well.In this paper,the simulation of using electronmagnetic software and specific code is described,and corresponding simulation methods are commented.