Increasing SLEDed Linac Gradient.

摘要

This note will show how to increase the SLED gradient by varying Qe, the external Q of the SLED cavity, by increasing its Q0 andective, then the copper losses should be small so that Q0 >> Qe. Methods of varying Qe will be indicated but no experimental data will be presented. If we increase the klystron pulse width from 3.5 to 5 S and increase Q0 from the present 100000 to 300000, then the gradient increases by 19% and the beam energy increases from 50 to 60 GeV. This note will also discuss SLED operation at 11424 MHz, the NLC frequency. Without Qe switching, using SLED at 11424 MHz increases the SLAC gradient from 21 MV/m to 34 MV/m, and at the same repetition rate, uses about 1/5 of rf average power. If we also double the compression ratio, we reach 47 MV/m and over 100 GeV beam energy.