Magnetic means for focusing and densifying the electron beam in traveling wave tubes

Claim 1

AN ELECTRON BEAM-PRODUCING SYSTEM FOR DISCHARGE TUBES WITH A MAGNETIC SYSTEM FOR THE GUIDANCE OF A FOCUSED AND DENSIFIED ELECTRON BEAM, SAID MAGNETIC SYSTEM PRODUCING A PREDETERMINED MAGNETIC FIELD EXTENDING IN THE DISCHARGE DIRECTION OVER A MAJOR PART OF THE DISCHARGE RANGE, THE CATHODE OF SAID SYSTEM BEING DISPOSED IN THE NONHOMOGENEOUS RANGE OF THE MAGNETIC FIELD WHICH PRECEDES THE PREDETERMINED RANGE THEREOF AS SEEN IN THE ELECTRON BEAM DIRECTION AND EMITTING AN ELECTRON BEAM WITH NONCONVERGING BORDERS, A RING-SHAPED WEHNELT CYLINDER AND AT LEAST ONE ANODE OPERATIVELY SPACED FROM SAID CATHODE, THE MAGNETIC FIELD EXTENDING BETWEEN THE CATHODE AND THE PREDETERMINED RANGE OF SAID FIELD PASSING THROUGH A MAXIMUM AND A MINIMUM AND A MAGNETICALLY SOFT CYLINDRICALLY SHAPED RING DISPOSED APPROXIMATELY COAXIALLY WITH THE ELECTRON BEAM WITHIN THE REGION BETWEEN THE EMITTING CATHODE SURFACE AND THE POINT OF HIGHEST VALUE OF THE MAGNETIC FIELD STRENGTH UPON THE SYSTEM AXIS TO INCREASE THE ACTION OF THE MAGNETIC FIELD DIRECTLY AHEAD OF THE END OF THE CATHODE.