Research On Characteristics Of Coherent Electron Source Based On Cold Atom Trap

The light-emitting principle of traditional lasers is realized by the way of energy level transition of bound electrons in atoms.Obviously,it is very difficult to reach hard X-rays by this method.Compton scattering principle emits light to produce free electron laser.After continuously improving the quality of free electron beams,high-energy and high-brightness electron beams are injected into a twister built with alternating magnets to produce Compton scatteringThe alternating static magnetic field of this torsion pendulum is an electromagnetic field in the electronic satellite coordinate system,so it is the same as Compton's principle of luminescence.However,when the brightness of the electron beam is high enough,the X-rays generated based on this Compton scattering will react to the electron beam,which can cause electron micro-agglomeration,which triggers exponential gain to produce a hard X-ray free electron laser.While the vast majority of scientific research teams are continuously increasing the intensity of the laser used for Compton scattering,we propose to improve the coherence of the electron beam used for Compton scattering.That is to study the possibility of using a coherent electron source to produce coherent Compton scattering and quantum free electron lasers in a strong laser field.Moreover,this kind of high-brightness,high-coherent electrons can not only realize the necessary conditions for compact free electron lasers to produce high-intensity X-sources,but can also be directly used in scientific research,such as ultrafast electron diffraction and ultrafast electron microscopy.For the radio frequency photocathode gun commonly used in X-ray free electron laser projects,the coherence of the electron beam produced by it is far less than its theoretical limit value = 1.Therefore,we have developed a set of coherent electron source design scheme based on cold atom trap,the purpose is to obtain a high-coherent,highquality electron source.The cold atom trapping technology allows us to obtain sufficiently low temperature cold atoms.Based on this,we use 780 nm and 480 nm lasers to excite the trapped cold atoms to the Grydberg state by sequential excitation or two-color multiphoton excitation,using Grydberg Due to the easy ionization properties of electrons in state atoms,a set of electron beam acceleration focusing system was designed.Through understanding the principle of electron motion and magnetic field focusing characteristics,we designed the electric field and magnetic field,and finally decided to use four-electrode plates with two intercept spirals.The structure of the wire tube is used as an electron beam acceleration and focusing system,through the internal refractive index of the electrode,the distance between each electrode,the voltage of each electrode,the length and wire diameter of each solenoid,the number of turns of each solenoid,and the current of each solenoid by analyzing and optimizing the influence of parameters and device errors on the quality of the electron beam,determining the design parameters of the electrodes and solenoids,we can obtain a high-quality,high-coherence electron source whose transverse coherence temperature can be lower than 5.High coherence is a necessary prerequisite for realizing the spatial resolution required by electron diffraction.Using the Fourier slice theorem,research on electron diffraction imaging algorithms is carried out in this article.