Design And Study Of The Ultracold Electron Gun

With the development of accelerator technology,the requirements for beam quality are getting higher and higher,especially for high current intensity,high brightness and low emission.The beam quality of the electron source is an important part to improve the quality of the electron beam generated by the accelerator.The ultra-cold electron source refers to an electron gun in which electron beams are extracted from ultra-cold plasma and accelerated in an electrostatic field.The ultra-cold plasma is generated by near-field photoionization of laser-cooled cold atoms.The electrostatic field is generally obtained by the plate electrode.Compared to conventional electron guns(photocathode electron guns,hot cathode electron guns,field emission electron guns,etc.),the ultra-cold electron source has an atomic energy dispersion of only 10 neV,and the temperature of the extracted electron source is relatively low,about 10K,and the thermal emittance can basically be ignored.These qualities make it can be widely used in the new generation of particle accelerators,such as free electron laser(FEL),laser plasma accelerators and so on.In this passsge the process of electron beam from ultra-cold electron sources from generation to extraction and acceleration was studied.In the laser cooling part it mainly introduces the laser cooling of the Rubidium atom in the magneto-optical trap,and finds the laser beam frequency,the laser intensity,and the magnetic field generated by the anti-Helmholtz coil when the depth of the potential well is the largest.In the laser ionization part it mainly studies the generation process of ultra-cold plasma,especially its ionization process under the action of ionizing laser in the magneto-optic trap.In the extraction and ionization sections it mainly discuss the extraction of electrons in the magneto-optical trap in the electrostatic field and the acceleration process in the microwave field.The corresponding beam current intensity,beam energy,beam emission and beam spot size is introduced in this part.In the accelerating part it mainly studies the acceleration process of the electron,aiming to obtain electron bunches satisfying the corresponding beam energy requirements.The above parameters(including the structure of the MOT,laser intensity and frequency,beam extraction,and acceleration of structural parameters,etc.)can provide a certain reference for the actual development of ultra-cold electron sources.