1
Improved Magnetron Injection
Guns for Gyrotrons—Calabazas Creek
Research, Inc.,
Dr. R. Lawrence Ives, Principal Investigator,
rlives@calcreek.com
Dr. Purobi Phillips, Business
Official, purobi@calcreek.com
DOE Grant No. DE-FG02-04ER83918
Amount: $652,500
Gyrotrons and gyroklystrons,
used for high power RF applications in the DOE Fusion Program, are being adversely
impacted by poorly performing cathodes for which the current emission is not
uniform over the entire surface. Poorly
performing cathodes adversely impact all RF vacuum electron devices, including
those used for accelerators, radar, communications, medical applications, and
industrial heating. This project will
determe the specific causes of poor cathode performance and developing cost
effective solutions. In particular, controlled
porosity cathodes will be developed to address problems with uniform work
function of the emitter surface. Improved
mechanical and thermal designs will provide uniform emitter temperatures and
lower the cost of cathode assemblies. Phase
I identified specific causes of temperature variation in magnetron injection
guns and established a preliminary thermal model to analyze the problems and
develop practical solutions. A concept
for manufacturing controlled-porosity cathodes was developed and experimentally
verified. Phase II will complete the
development of controlled-porosity cathodes by defining specific processes for
determining pore size and density. The
results will be correlated with the barium diffusion rate to allow an optimal
design, based on current density and lifetime requirements. Techniques for improved thermal performance
will be developed and experimentally tested. The mechanical design of cathode heater
assemblies will be improved to simplify the construction process.
Commercial Applications and Other Benefits as described by the applicant: The results of this project should reduce the cost and risk in the manufacture of cathodes for all vacuum electron devices. The concepts will be applied to magnetron injection guns for gyrotrons, which represents the greatest challenge. Successful completion should reduce the risk and improve the performance of gyrotrons for fusion, accelerators, defense, and industrial applications, with subsequent reductions in cost.