LINEAR ACCELERATOR FOR ELECTRON AND BEAM ACCELERATING METHOD TO GENERATE HIGH BRIGHTNESS

摘要

PROBLEM TO BE SOLVED: To accelerate an electron beam of high quality which has a high brightness and large current by adjusting optimally the magnetic field distribution in an accelerator by the distance from the cathode surface. ;SOLUTION: A linear accelerator for electrons is equipped with a plurality of convergence coils for forming the required converging magnetic field in a path for the electron beam. If the Z-axis is taken in the running direction of electrons emitted from the cathode surface of an electron gun, the magnetic field intensity B(Z) in the accelerator can be expressed as shown in the attached illustration. The value of B(Z) is calculated through approximation from the specified formula. Accordingly the position and intensity of each convergence coil and the number of coils may be adjusted so that the describeds distribution is generated, and they can be determined experimentally. As a result, the intended converging magnetic field is generated, and the electron beam is prevented from increasing in the diameter of the bunch in the process of forming a short bunch, and it is possible to supply a high quality electron beam having a high brightness and large current.;COPYRIGHT: (C)1997,JPO