Radio-frequency defocusing of electron beams

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Radio-frequency defocusing of electron beams

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At medium relativistic velocities and high r.f. power levels, the defocusing of an electron beam is mainly due to r.f. radial forces, the space charge usually being negligible. Under these conditions, there is no opposing force preventing an electron from crossing the beam axis or coming close to it. In either case, severe scalloping or defocusing is produced. It is shown that the absence of space charge may be compensated for by allowing some axial magnetic flux to cross the cathode. Also, a partially shielded cathode is essential to avoid defocusing due to the phase oscillations or variation in the beam radius at the injection plane.

Inspec keywords: focusing; electron beams

Other keywords: RF defocusing of electron beams; injection plane; partially shielded cathode; axial magnetic flux; medium relativistic velocities; compensating for absence of space charge; phase oscillations

Subjects: Moving charges in electric and magnetic fields; Electron beams and electron optics

References

    1. 1)
      • J.R. Pierce . A gun for starting electrons straight in a magnetic field. Bell Syst. Tech. J. , 825 - 829
    2. 2)
      • A.L. Samuel . On the theory of axially symmetric electron beams in an axial magnetic field. Proc. Inst. Radio Eng. , 1252 - 1258
    3. 3)
      • Neal, R.B.: `A high energy linear accelerator', 185, Stanford University ML report, February 1953, p. 163.
    4. 4)
      • K. Johnson . (1954) , On the theory of linear accelerators.
    5. 5)
      • J.R. Aderson . Electron beam flow in superimposed periodic and uniform magnetic fields. IRE Trans. , 101 - 105
    6. 6)
      • J.F. Gittins . (1965) , Power travelling wave tubes.
    7. 7)
      • Harris, L.A.: `Axially symmetric electron beam and magnetic field systems', report 170, Massachusetts Institute of Technology technical report 170, August 1950.
    8. 8)
      • G.R. Brewer . Some characteristics of a cylindrical electron stream in immersed flow. IRE Trans. , 134 - 139
    9. 9)
      • M.L. Livingston , J.P. Blewett . (1962) , Particle accelerators.
    10. 10)
      • J.L. Palmer . Laminar flow in magnetically focused cylindrical electron beams. IRE Trans. , 262 - 269
    11. 11)
      • A. Ashkin . Dynamics of electron beams from magnetically shielded guns. J. Appl. Phys. , 1594 - 1604
    12. 12)
      • H. Goldstein . (1950) , Classical mechanics.
    13. 13)
      • K.K.N. Chang . Confined electron flow in periodic electrostatic field of very short period. Proc. Inst. Radio Eng. , 66 - 73
    14. 14)
      • K.J. Harker . Periodic focusing of beams from partially shielded cathodes. IRE Trans. , 13 - 19
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