DESIGN AND HIGH POWER TEST OF A 30 GHZ PLANAR ACCELERATING STRUCTURE

The paper presents1 the design of a planar R-Band accelerating structure and results of a first high power test. The structure is a traveling wave, constant impedance structure, with 37 cells operating in the 2π/3-mode. It consists of two halves which were fabricated by high speed, high precision CNC milling. The two halves and all flanges were brazed at high temperature in a two step procedure. The high power test was done in the CLIC Test Facility II at CERN [1]. The structure was powered with 30 GHz power extracted from the CTF drive beam. Power ratings were between 80 and 40 MW in pulses from 4 to 16 ns long. No evidence of breakdown could be observed. The cavity which is slightly out of frequency accelerated a probe beam with an effective gradient of 23 MV/m after manipulating the CLIC drive beam and thus shifting the frequency upwards by 150 MHz.