METHOD FOR ENERGY DITHER OF A PARTICLE BEAM

摘要

A method for applying an energy dither to a charged particle beam in order to vary the wavelength of the charged particle beam. Bunches of charged particle beams are accelerated by cavities that are operated at a harmonic of the bunch repetition rate. One or more secondary radiofrequency accelerator cavities are added near the wiggler after the primary beam transport to apply a fluctuation between individual bunches with a pseudo-random distribution. The secondary radiofrequency accelerator cavities provide fine variations of the beam energy about a nominal operating point. Operating a free electron laser (FEL) with a 1% change in the electron beam energy via the secondary cavity will result in a 2% wavelength variation of the FEL output.

主权项

1. A method for varying the wavelength of a charged particle beam output by changing the energy of the input particle beam, comprising:
a. providing an input charged particle beam having a primary accelerator bunch frequency; b. providing a wiggler to periodically laterally deflect the beam of charged particles inside the charged particle beam; c. adding one or more secondary radiofrequency accelerator cavities after the primary beam transport and near the wiggler; d. setting the frequency of each added secondary radiofrequency accelerating cavity to a harmonic or sub-harmonic of the primary accelerator bunch frequency; and e. operating the secondary radiofrequency accelerator cavities at the harmonic or sub-harmonic of the primary accelerator bunch frequency to provide an energy dither to the input charged particle beam thereby providing fine variations of the output beam energy about a nominal operating point.