Patent ID: 8547006

Claim:
A multiple beam electron gun having: a magnetic field generator providing a substantially uniform magnetic field over an RF circuit extent of a Z axis, said magnetic field diverging from said Z axis through an electron gun extent outside said RF circuit extent; a plurality of N electron guns arranged about said central Z axis, each said electron gun having: a cathode having an electron emission surface, said cathode having a local cathode axis and a center cathode point located at the intersection of said local cathode axis and said electron emission surface; a separate focus electrode associated with each said cathode; a separate single anode associated with each said cathode which is circularly symmetric about said local cathode axis; said cathode oriented with a cathode divergence angle formed by the angle of perpendicular projection of said local cathode axis onto a cathode reference plane formed by said Z axis and said center cathode point, whereby said cathode divergence angle is substantially equal to a magnetic flux angle in a plane containing said center cathode point and said Z axis; said cathode oriented with a cathode azimuthal angle formed by the angle between said local cathode axis and said cathode reference plane; where said cathode azimuthal angle is selected such that said each said electron gun generates an electron beam which is substantially parallel to said Z axis over said RF circuit extent and where the distance from said Z axis to said cathode center point is greater than the distance from said Z axis to the center of an associated electron beam over said RF circuit axial extent; whereby each said electron beam travels in a separate beam tunnel.