94 GHz, 25 kW CW, low-voltage harmonic gyrotron

Summary form only given. A low-voltage second-harmonic gyrotron intended as a compact, lightweight source is under construction at UCD. The fieldable gyrotron's cryogen-free 17 kG solenoid magnet with a closed-loop cryocooler utilizes the tremendous advances made in high-T/sub c/ superconducting technology. The design is for CW operation. However, the 94 GHz prototype will be tested at low duty in pulse mode with an existing conventional low-T/sub c/ superconducting magnet. The second-harmonic gyrotron has been designed and evaluated with a particle-tracing code and the particle-in-cell code MAGIC. The 25 kW CW, 94 GHz gyrotron with a predicted conversion efficiency of 32% and device efficiency of 22.5% is driven by a 25 kV, 4.5 A, v/sub /spl perp///v/sub z/=1.5, electron beam from a magnetron injection gun (MIG) with 7% axial velocity spread. A MIG from a CPI/Varian 60 GHz gyrotron will be employed. The electron beam center radius of the new 94 GHz second-harmonic gyrotron is nearly the same as in the 60 GHz gyrotron. The long-term goal of this activity is to extend the power level to 100 kW CW.