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The design and experiment of an upgraded W-band gyrotron travelling wave amplifier (gyro-TWA) based on a helically corrugated interaction region is presented. The upgrade of the input coupler, output window, corrugated output mode converter enabled a measured output power of a few kWs from the gyro-TWA with an unsaturated gain of up to 40 dB and a 3 dB frequency bandwidth of at least 5.5 GHz.
Latest developments of a gyrotron travelling wave amplifier (gyro-TWA) with a helically corrugated waveguide and a cusp electron gun for operation over a bandwidth of 90–100 GHz at a high pulse repetition rate (5 kHz) are presented. Performance upgrades of the input coupler, pulsed power system and beam collector with water-cooling capability were realized for the high power wide band gyro-TWA.
Experimental results will be presented of a frequency tunable gyrotron backward wave oscillator (gyro-BWO). A helically corrugated interaction region (HCIR) was used to allow efficient interaction over a wide frequency band at the second harmonic of the electron cyclotron frequency without parasitic output [1-5]. The gyro-BWO generated a maximum output power of 12 kW when driven by a 40 kV, 1.5 A,...
A gyrotron traveling wave amplifier (gyro-TWA) with a cusp electron gun and a helically corrugated waveguide operating in the W-band is presented. When driven by an electron beam of energy 40 keV and current 1.5 A, the simulated microwave output power is 5 kW (CW) with a 3 dB frequency bandwidth of 90–100 GHz and a saturated gain of 37 dB. Linear analyses, numerical simulation and the latest experimental...
Latest experimental developments of W-band gyro-devices with helically corrugated waveguides and a cusp electron gun are presented. The cusp generated a 40 keV, 1.5 A axis-encircling electron beam. Helical corrugated waveguides have ideal dispersive properties which improve the frequency tuning range of a gyrotron backward wave oscillator (gyro-BWO) whilst maintaining the already good efficiency of...
Theoretical calculation, numerical simulation and experimental development of a W-band gyro-TWA with a helically corrugated waveguide and a cusp electron gun are presented. The cusp gun generated a 40 keV, 1.5 A axis-encircling electron beam. The maximum output of the gyro-TWA was predicted to be 5 kW with a 3 dB frequency bandwidth of 90–100 GHz and a saturated gain of 37 dB. The latest experimental...
Microwave pulse compression results from a five-fold helically corrugated waveguide are presented. In these experiments an X-band microwave pulse of duration 80 ns and a 6% frequency sweep was compressed from 5.8 kW to 128kW into a 1.6 ns pulse with a compression factor of 22 in the peak power.
Microwave pulse compression has applications in radar technology and plasma diagnostics. The pulse compressor requires a dispersion curve with a monotonic group velocity and low losses in a reasonable wide frequency band. It can be achieved by the helically corrugated waveguide (HCW) [1–3] with both axial and azimuthal periodicity that couples modes in the circular waveguide to generate new operating...
A quasi-optical corrugated horn has been constructed for a W band gyro-TWA1,2 based on a cusp electron beam source3–5 with a helically corrugated interaction region6–8. The design is intended to provide an effective method to decouple the radiation and the beam so that a depressed collector energy recovery system may be used9–11. The horn converts a cylindrical TE11 mode into a free-space TEM00 mode...
A W-band gyrotron travelling wave amplifier (gyro-TWA) with a cusp electron gun and a helically corrugated waveguide is presented. The large orbit electron beam from the cusp gun interacts resonantly with an ideal eigenwave existing in the interaction region based on the cyclotron resonance maser instability. When driven by the 40 keV, 1.5 A electron beam the amplifier was simulated to output a maximum...
A 390 GHz harmonic gyrotron based on a cusp electron gun was designed to operate on a TE71 mode and the 7th cyclotron harmonic of a large orbit electron beam. This beam is produced by a cusp electron gun with a voltage of 40 keV, a current of 1.5 A and an adjustable velocity ratio from 1 to 3. Smooth cylindrical waveguide was studied and built as the interaction cavity. The relationship between the...
The experimental demonstration of a gyrotron backward wave oscillator (gyro-BWO) using a cusp electron gun and helically corrugated waveguide will be presented. Operating in the W-band frequency range the gyro-BWO is predicted to output ~10 kW with a frequency tuning range of 85-104 GHz at 18% electronic efficiency before the energy recovery. The annular axis-encircling electron beam has been experimentally...
To realize the full potential of a Gyrotron backward wave oscillator (Gyro-BWO), an energy recovery system was designed using Particle-In-Cell (PIC) simulations and optimized using both a Genetic Algorithm and PIC simulations. Simulations were carried out to optimize a periodic structure for separation of the spent electron beam and the output radiation produced by a gyro-BWO in the 8.0 – 9.5GHz frequency...
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