Travelling wave resonant-ring for RF window high power test

A travelling wave resonant-ring was constructed for RF window high power test of NSRL 200 MeV Linac. The principle of the resonant-ring was described. A power gain of 4.5 and a peak power of 60 MW were achieved in the ring. The power test method and procedure were given out, and the electron multiple effect was discussed. The RF window passed test under the conditions of a peak power of 30 MW, an average power of 3.7 kW and a pulse length of 2.5μs．