George Bekefi from 137 Gardner Rd, Brookline, MA 02445, Phone: 617 731-6042

Rippled-Field Magnetron Apparatus
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US Patent:

44659539, Aug 14, 1984
Filed:

Sep 16, 1982
Appl. No.:

6/418867
Inventors:

George Bekefi - Brookline MA
Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC
International Classification:

H01J 2550
US Classification:

315 3971
Abstract:

The rippled-field magnetron is a novel cross-field millimeter wave source in which electrons move under the combined action of a radial electric field, an axial magnetic field and an azimuthally periodic wiggler magnetic field,. vertline. B. sub. w. vertline. cos (N. theta. ) oriented transversely to the flow. Estimates are given of the frequency and growth rate of the free electron laser (FEL) type of instability excited in this smooth-bore magnetron configuration.

Double Beam Cyclotron Maser
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US Patent:

53630548, Nov 8, 1994
Filed:

Feb 27, 1992
Appl. No.:

7/842246
Inventors:

George Bekefi - Brookline MA
Assignee:

Massachusetts Institute of Technology - Cambridge MA
International Classification:

H01S 330
H01J 2308
US Classification:

330 4
Abstract:

A double beam cyclotron maser comprising two electron guns for introducing two electron beams traveling parallel to each other at different speeds into an electron drift tube/waveguide. The beams have respectively different electron cyclotron space-charge harmonics. A solenoid maintains a magnetic field parallel to the direction of propagation of the electron beams while a magnetic wiggler field initially imparts a transverse force to the electrons such that they propagate down the drift tube with a helical gyration. The magnetic fields, electron beam velocities, and beam space charge harmonics are adjustable to set the interaction frequency at which amplification of electromagnetic radiation can occur. The waveguide is a slow wave structure so configured as to slow the signal from the magnetron to match the phase velocity of the double stream cyclotron space-charge wave.

Lowbitron - A Source Of Coherent Electromagnetic Radiation
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US Patent:

45300968, Jul 16, 1985
Filed:

Nov 15, 1982
Appl. No.:

6/441700
Inventors:

George Bekefi - Brookline MA
Wayne A. McMullin - Belmont MA
Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC
International Classification:

H01S 330
US Classification:

372 4
Abstract:

A source of coherent electromagnetic radiation capable of generating or amplifying waves in the centimeter, millimeter, and submillimeter wavelength range. An annular beam of gyrating electrons is produced which is then compressed to its paraxial position by means of a solenoid magnetic field around the wave-guide. This electron beam is also subjected to a transverse motion in an interaction region by a longitudinal rippled (wiggler) magnetic field. Such a field is generated by a periodic assembly of rings magnetized in the axial direction. The electron beam during its accelerated motion generates or amplifies coherent electromagnetic radiation in the centimeter, millimeter, or submillimeter range.

Relativistic Electron Beam Crossed-Field Device
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US Patent:

42008212, Apr 29, 1980
Filed:

Mar 17, 1977
Appl. No.:

5/778392
Inventors:

George Bekefi - Brookline MA
Thaddeus J. Orzechowski - Livermore CA
Assignee:

Massachusetts Institute of Technology - Cambridge MA
International Classification:

H01J 2550
US Classification:

315 3951
Abstract:

An intense relativistic crossed field device in a nested configuration wherein a field emission cathode is nested within a segmented annular anode with an annular gap separating the two.

Reverse Guide Field Free Electron Laser
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US Patent:

52804909, Jan 18, 1994
Filed:

Nov 22, 1991
Appl. No.:

7/797451
Inventors:

Manoel Conde - Cambridge MA
George Bekefi - Brookline MA
Assignee:

Massachusetts Institute of Technology - Cambridge MA
International Classification:

H01S 300
US Classification:

372 2
Abstract:

An electromagnetic radiation amplification device comprising an electron gun for introducing a stream of electrons into an electron drift tube/wavequide in which an axial magnetic field and a wiggler magnetic field have been induced to impart a helical gyration to the electrons as they travel parallel to the tube. The axial, or guide, magnetic field is directed in the direction opposite to the direction of propagation of the electrons if the electrons have a right handed helical gyration and is directed in the direction of propagation of the electrons if the electrons have a left handed helical gyration.

Cerenkov Electrooptic Shutter
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US Patent:

48353914, May 30, 1989
Filed:

Jul 1, 1987
Appl. No.:

7/068977
Inventors:

Frederick Hartemann - Paris, FR
George Bekefi - Brookline MA
Assignee:

The United States of America as represented by the Secretary of the Air
Force - Washington DC
International Classification:

G21K 400
G02F 103
US Classification:

250361R
Abstract:

A system which couples Cerenkov emission with a gated electrooptic effect to allow viewing of Cerenkov radiation in sub nanosecond time-scales is disclosed. Cerenkov radiation is generated by transmitting an electron beam through a transparent medium with a high index of refraction. The Cerenkov radiation is then gated into a sample pulse of subanosecond duration by an electrooptic crystal which has an index of refraction controlled by an electric field. the electrooptic crystal is opaque to the Cerenkov radiation until receiving a 6. 0 kV voltage for about 750 picoseconds, upon which a pulsed sample of Cerenkov radiation is transmitted to a display system.

George Bekefi