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US3916239A Expired / Lapsed US ⏱️ 0.0 years remaining

High energy beam launching apparatus and method

Assignee: Varian Medical Systems Inc
•
Filing: 1973-07-05
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Granted: 1975-10-28
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Expires: 1993-07-05
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Abstract

Abstract Apparatus and method are disclosed for launching a high energy beam of charged particles along an axis into a substantially long path region from an exit aperture, in a manner such that the beam remains confined without application of external focusing fields in the region. The apparatus comprises a cathode, which is a source of electrons to compose the beam, and electrode means for producing an axial accelerating electric field to accelerate electrons in the beam to a relativistic velocity in an accelerating space. At relativistic velocity, the beam itself produces a solenoid-shaped magnetic field which undesirably tends to converge the beam when ionized gas molecules neutralize the space charge in the beam. An external magnet means for producing an axial magnetic field in the accelerating space and a radial magnetic field at the exit aperture, imparts a cyclotron angular momentum to the electrons. The cyclotron angular momentum provides a force to the electrons to substantially cancel the force of the self-magnetic field. Once the beam leaves the accelerating and cyclotron motion inducing space, it remains confined to a desired range of cross section. Such beams may be used for heating plasmas, or in high power microwave oscillators and amplifiers.

Inventors

  • 👤 Fred Irwin Friedlander

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-30 05:10
CPC Classifications
G; G21; G21K; G21K1/00; G21K1/08; H; H01; H01J; H01J27/00; H01J27/02; H01J3/00; H01J3/02

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 108 words
An apparatus for launching a linear beam, having an axis, into a region substantially free from fields other than those produced by said beam and maintaining said beam focused in said region comprising: A source of charged particles; means for accelerating said charged particles to a relativistic velocity, whereby a self-magnetic beam-converging force exists; means for providing a circumferential component of motion to said particles whereby centrifugal force on said particles opposes said self-magnetic force; and an aperture means downstream from said accelerating means whereby said beam remains limited in outward and inward excursions over a substantial path length after exiting said aperture without external forces applied thereto.
Claim 2
Independent Claim 108 words
An apparatus for launching a linear beam, having an axis, into a region substantially free from fields other than those produced by said beam and maintaining said beam focused in said region comprising: A source of charged particles; means for accelerating said charged particles to a relativistic velocity, whereby a self-magnetic beam-converging force exists; means for providing a circumferential component of motion to said particles whereby centrifugal force on said particles opposes said self-magnetic force; and an aperture means downstream from said accelerating means whereby said beam remains limited in outward and inward excursions over a substantial path length after exiting said aperture without external forces applied thereto.
Claim 3
Dependent Claim 33 words
The apparatus of claim 1 where said circumferential motion causing means is means for producing a magnetic field penetrating said source and having a radial component threading said beam downstream of said source.
Claim 4
Dependent Claim 47 words
The apparatus of claim 2 where said particles are electrons and where said source is a cathode, where said accelerating means is an electrode and where there are additional means for biasing the electrode in excess of one hundred thousand volts positive with respect to said cathode.
Claim 5
Dependent Claim 33 words
The apparatus of claim 3 wherein the said electrode has an aperture for passing the electrons of the beam and where said electrode and said aperture means are coaxial with the beam axis.
Claim 6
Dependent Claim 37 words
The apparatus of claim 4 where said magnetic means comprises an annular pole piece coaxial with the beam axis and located substantially at said aperture means and a pole piece behind said cathode and coaxial with it.
Claim 7
Dependent Claim 48 words
The apparatus of claim 1 where said magnetic means comprises an annular pole piece coaxial with the beam axis and located at said aperture means and a pole piece behind said source and coaxial with it for producing an axial magnetic field which ends at said aperture means.
Claim 8
Independent Claim 84 words
The method of launching a confined beam of charged particles down an axis into a substantially field-free region comprising: accelerating charged particles from a source in an axial direction to a relativistic velocity whereby axially moving particles having a self-magnetic beam converging force are produced; inducing a circumferential component of motion to the axially moving particles whereby a centrifugal force on said particles opposes said self-magnetic force dependent on their axial velocity; shielding the particles of the beam from all further downstream external fields.
Claim 9
Independent Claim 84 words
The method of launching a confined beam of charged particles down an axis into a substantially field-free region comprising: accelerating charged particles from a source in an axial direction to a relativistic velocity whereby axially moving particles having a self-magnetic beam converging force are produced; inducing a circumferential component of motion to the axially moving particles whereby a centrifugal force on said particles opposes said self-magnetic force dependent on their axial velocity; shielding the particles of the beam from all further downstream external fields.

References Cited (Backward Citations)

US3489944A Cited
US3489943A Cited
US3700952A Cited
US3700945A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-10-27 1979-04-28 1979-10-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-10-27 1983-04-28 1983-10-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-10-27 1987-04-28 1987-10-28 $7700.00 Window Closed / Lapsed

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