Hollow-beam microwave linear accelerator

A linear accelerator for charged particles, comprising:

• a plurality of accelerating cavities disposed in a linear arrangement along a central axis between input and output cavities, all said cavities being directly coupled to each other, each accelerating cavity having a first passageway radially spaced from the central axis for transmitting a lower energy accelerating beam of charged particles through said first passageway of said accelerating cavities, each accelerating cavity further including a second passageway for transmitting a higher energy accelerating beam of charged particles, said cavities for said first passageway and for said second passageway, each being spaced so that said lower and said higher energy beams passing therethrough are in phase between cavities when transmitting r.f. power;
• coupling circuits for coupling electromagnetic wave energy between adjacent ones of said accelerating cavities, said coupling between said adjacent ones of said accelerating cavities capable of being either predominantly electric or magnetic field coupling;
• and
• means for coupling said accelerating beam of charged particles through said first passageway of said accelerating cavities for producing an accelerating electric field and simultaneously producing an accelerating electric field in said second passageway of each of said accelerating cavities for accelerating said higher energy beam of charged particles therethrough.

A linear accelerator for charged particles, comprising;

• a plurality of accelerating cavities disposed in a linear arrangement along a central axis between input and output cavities, all said cavities being directly electromagnetically coupled to each other, each accelerating cavity having two or more discrete apertures at a predetermined radius from said central axis for transmitting two or more beams of charged particles through said accelerating cavity in energy exchanging relation with an electromagnetic wave in said accelerating cavity;
• means for coupling electromagnetic wave energy to said accelerating cavities to produce an accelerating electric field in a region of each of said discrete apertures of each said accelerating cavity;
• and
• coupling circuits for coupling said electromagnetic wave energy between adjacent ones of said accelerating cavities along said central axis.

A linear accelerator for charged particles comprising;

• a plurality of accelerating cavities disposed in a linear arrangement along a central axis, each accelerating cavity having a continuous annular aperture at a radius R from said central axis for transmitting a hollow beam of charged particles through said accelerating cavity in energy exchanging relation with an electromagnetic wave in said accelerating cavity;
• an opening at the central axis of said cavities for coupling an electromagnetic wave through the accelerator,
• means for coupling electromagnetic wave energy to said accelerating cavities to produce an accelerating electric field in a region of the continuous annular aperture of each of said accelerating cavities;
• and
• RF coupling circuits for coupling said electromagnetic wave energy between adjacent ones of said accelerating cavities.

A linear accelerator for charged particles, comprising:

• a plurality of accelerating cavities disposed in a linear arrangement along a central axis, each accelerating cavity having at least one passageway radially spaced from the central axis for transmitting a beam of charged particles through said accelerating cavity in energy exchanging relation with an electromagnetic wave in said accelerating cavity;
• means for coupling electromagnetic wave energy to said accelerating cavities to produce an accelerating electric field in a region of the passageway of each of said accelerating cavities;
• coupling circuits for coupling said electromagnetic wave energy between adjacent ones of said accelerating cavities;
• and
• a beam bending device positioned at one end of said passageway for reversing the beam exiting said passageway and directing it through another and second passageway through said accelerating cavities increasing its energy as it passes therethrough, said cavities for said first and for said second passageways being spaced so that the beams passing through said first passageway and through said second passageway are in phase between cavities when transmitting r.f. power and whereby said beam makes at least two passes through said accelerating cavities.