Experimental study on a high power microwave amplifier driven by low rf power

In order to suppress high order mode self-oscillation in a high gain amplifier, some special procedures, such as decreasing the coupling between beam and rf field in the forepart of the amplifier, are taken such that the tube works in a fully amplified state in an operation range. In simulation, the rf output power is 1. 7 GW with a beam of 7. 5 kA at 750 kV when input power is 6. 8 kW and the corresponding gain is 53. 9dB. Based on the results from 2D PIC simulation, the experiment is performed on the Sinus accelerator. In experiment, the amplifier is driven by a beam of 8 kA at 800 kV, and the maximum output power is 2. 04 GW when input power is 62 kW; the maximum gain reaches 46. 7dB when the input reduces to 39 kW, the corresponding output power is about 1. 84 GW. Both the simulation and the experiment prove that a kW-level rf power can drive the tube to generate a GW-level output power.