Collector pole piece for a microwave linear beam tube

Claim 1

In a microwave linear beam tube: electron gun means for forming and projecting a beam of electrons over an elongated linear beam path; beam collector means at the terminal end of said beam path for collecting and dissipating the energy of the electron beam; microwave interaction circuit means disposed along said beam path intermediate said electron gun means and said beam collector means for electromagnetic wave interaction with the beam to produce output microwave energy; electrical solenoid means disposed surrounding said microwave interaction circuit means for generating an axial magnetic field in the beam path for focusing the electron beam through said microwave interaction circuit means; a collector pole piece structure disposed at the beam collector end of said solenoid for shaping the beam focus magnetic field in the region of said beam collector means, said collector pole piece structure being made of a ferromagnetic material and including a chamber therin; at least four passageways from said chamber through said pole piece structure: an output waveguide structure for coupling the output microwave energy from said microwave circuit to a utilization device; a portion of said chamber containing a length of said waveguide structure, and said waveguide structure passing into and out of said chamber through two of said passageways; another portion of said chamber formed to contain a fluid coolant, and at least two of said passageways disposed for conduction of said fluid coolant into and out of said chamber.