Nuclear Techniques ›› 2016, Vol. 39 ›› Issue (9): 90203-090203.doi: 10.11889/j.0253-3219.2016.hjs.39.090203

• LOW ENERGY ACCELERATOR, RAY AND APPLICATIONS • Previous Articles     Next Articles

Physical design of low-emittance L-band photocathode microwave electron gun

LI Chenglong, TANG Zhenxing, PEI Yuanji   

  1. National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230022, China
  • Received:2016-04-05 Revised:2016-05-17 Online:2016-09-10 Published:2016-09-09
  • Supported by:

    Supported by National High Technology Research and Development Program 863 (No.2013AA8122009B)

Abstract:

Background: The development of high performance electron beam source has been a challenge for Free-electron Laser(FEL)based THz source which is critical for the energy,energy spread and emittance of the electron beam.Purpose: This work aims to find out the mechanism of emittance growth and developing a compensation technique for this emittance growth in the Radio Frequency(RF)gun cavity.Methods: First of all,a RF gun cavity is designed using POISSON Superfish to calculate its electro-magnetic field distribution for analysis of the emittance growth mechanism.Then,a compensation scheme is developed by employing a pair of solenoids to reduce the space charge emittance.Finally,the effectiveness of scheme is evaluated using the commonly used reliable simulation program ASTRA.Results: The simulation results show that the normalized transverse emittance of a 5.67-MeV electron bunch with 200 pC is reduced to 0.373 mm·mrad while the energy spread is reduced to 2.3‰.For a 5.67-MeV electron bunch with 1000 pC,the emittance and energy spread are reduced to 0.934 mm·mrad and 7.6‰,respectively.Conclusion: Simulation of the final design shows that the performance of the electron beam produced by the RF gun has achieved the requirements for THz source.

Key words: High quality electron beam source, Photocathode RF gun, Emittance, Compensation solenoid, Space charge force, Energy spread

CLC Number: 

  • TL503.5