94 GHz sixth-harmonic slotted gyrotron

Summary form only given, as follows. High power harmonic gyrotrons utilizing Cusp electron guns are being developed in a new facility at UC Davis. The initial experiment will test a 50 kW, sixth-harmonic slotted /spl pi/-mode gyrotron with a predicted efficiency of 20%. The gyrotron is driven by a 70 kV, 3.5 A, v/spl perp//v/sub z/=1.5, axis-encircling electron beam from a first-of-its-kind Cusp gun delivered by Northrop Grumman. For a fixed ratio of Larmor radius to inner vane radius, slotted gyrotrons are fairly insensitive to the electron energy. Thus the operating voltage was chosen for favorable beam propagation and the desired level of output power. Using the profile of the adiabatic field reversal of the UC Davis superconducting test-magnet, EGUN simulations predict that an axis-encircling electron beam will be generated with an axial velocity spread of /spl Delta/v/sub z//v/sub z/=10% for the desired velocity ratio of /spl alpha/=v/spl perp//v/sub z/=1.5. The design will also be presented for an 8th-harmonic W-band gyrotron whose magnetic field can be supplied by a lightweight permanent magnet.