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The latest developments and experimental results 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 gyro-TWA was predicted to output 5 kW with a 3 dB frequency bandwidth of 90–100 GHz.
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...
A W-band corrugated horn has been designed, manufactured, and experimentally measured at the University of Strathclyde, for integration into a gyro-device as a quasi-optical launcher. This horn converts a cylindrical TE11 mode into a free space TEM00 mode in a frequency band of 84–104 GHz with a reflection better than −30 dB and a Gaussian coupling efficiency of ∼98% and directivity of 26.6 dB at...
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 amplifier is simulated to output 5–10 kW (CW) with a 3 dB frequency bandwidth of 90–100 GHz and saturated gain of 40 dB. Linear analysis, numerical simulation and experimental results...
An energy recovery system using a four-stage depressed collector was simulated and designed to improve the overall efficiency of the W-band gyrotron backward wave oscillator (gyro-BWO) in the University of Strathclyde. The spent beam information was exported from the simulation of the gyro-BWO using the 3D PIC code MAGIC. The geometry of the depressed collector was optimized using a genetic algorithm...
Theoretical calculation, numerical simulation and experimental development of W-band gyro-devices with helically corrugated waveguides 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 10 kW with a 3dB frequency bandwidth of 90–100 GHz and a saturated gain of 40 dB. The gyro-BWO output...
The latest experimental results of a W-band (75–110 GHz) gyrotron traveling wave amplifier [1] with a helically corrugated waveguide and cusp electron gun is presented. A waveguide with a helical corrugation on its inner surface has ideal dispersive properties which improve the bandwidth of the amplifier whilst maintaining the already good efficiency of operation [2,3]. The large orbit annular electron...
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...
The experimental demonstration of a W-band gyrotron backward-wave oscillator (gyro-BWO) using both thermionic cusp electron gun and helically corrugated waveguide will be presented. The cusp gun is designed to generate an axis-encircling electron beam of 1.5 A at 40 kV with an adjustable velocity ratio of up to 3.0. The beam had a simulated axial velocity spread (Δvz/vz) of ∼8% and alpha spread (Δ...
A W-band gyrotron traveling wave amplifier (gyro-TWA) with helically corrugated waveguide and cusp electron gun is presented. The beam-wave interaction, based on the cyclotron resonance maser instability, is driven by a 40 keV, 1.5 A axis-encircling electron beam generated by the cusp electron gun. Numerical simulations predict a maximum output of 5–10 kW (CW) with a 3 dB frequency bandwidth of 90–100...
A quasi-optical mode converter in the form of a corrugated horn has been designed and optimized through numerical simulations for a W-band gyrotron traveling wave amplifier (gyro-TWA). This horn converts a cylindrical TE11 mode into a free-space TEM00 mode in a frequency band of 90 GHz to 100 GHz with a return loss better than −35 dB and a Gaussian coupling efficiency of 97.8%.
The experimental demonstration of a W-band gyro-BWO using both thermionic cusp electron gun and helically corrugated waveguide will be presented. A cusp gun uses a non-adiabatic magnetic field reversal to obtain azimuthal motion on an electron beam resulting in an annular shaped, axis-encircling beam. The cusp gun was designed to generate a beam of 1.5A at 40kV with an adjustable velocity ratio of...
Recently, DGAT1 was identified as the gene that underlies the QTL for bovine milk production on chromosome 14. This study investigated the effect of the reported polymorphism in three dairy breeds in New Zealand. Statistically significant results were identified for milk fat, milk protein, and volume for Jersey and Holstein-Friesian breeds, and only milk volume for Ayrshires. The average allele substitution...
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