US3801854A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Modulator circuit for high power linear beam tube
Assignee: Varian Medical Systems Inc
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Filing: 1972-08-24
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Granted: 1974-04-02
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Expires: 1992-08-24
Abstract
Abstract A high power linear beam tube; to be modulated, such as a highpower klystron, has its cathode directly connected with the depressed collector electrode of a modulator tetrode tube and its anode connected to the accelerating electrode of the tetrode modulator tube. The modulator tetrode tube includes a gridded convergent flow linear beam electron gun and a mirror image, substantially 100 percent depressed collector. The control grid is non-intercepting grid with and provides a voltage gain of 20 to 50 and a relatively high-power gain, as of 20 to 40 db. The electron gun includes a massive non-intercepting accelerating anode disposed between the control grid and the depressed collector. When the beam traverses the accelerating anode to the depressed collector, the collector is lowered toward cathode potential, causing an equivalent current to flow in the thermionic diode load. The beam perveance of the load tube is preferably substantially equal to the perveance of the electron gun of the tetrode modulator tube.
Inventors
- 👤 R Giebeler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:33
CPC Classifications
H; H01; H01J; H01J25/00; H01J25/02; H01J25/10
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
236 words
A high power modulator circuit, comprising: high power beam tube means having a thermionic cathode and an anode spaced therefrom to define an operable electron gun for generating an electric beam which is to be modulated; modulator tube means having a thermionic cathode, a centrally apertured, substantially non-intercepting accelerating anode spaced from said cathode for drawing electrons through said accelerating aperture for forming a high power electron beam, collector means for collecting said electron beam, said collector means operating at a depressed potential with respect to said anode, and a substantially non-intercepting control grid interposed between said anode and said cathode for controlling said electron beam; power supply means for supplying direct current power to said beam tube means and said modulator tube means; said modulator tube means being series-connected with the beam circuits of said beam tube means and said power supply means, the positive terminal of said power supply means being connected to said anode of said modulator tube means, and said thermionic cathode of said beam tube means being directly connected electrically to said depressed-potential collector means of said modulator tube means, whereby said beam tube means forms the load of said modulator tube means; and means for pulsing said control grid of said modulator tube means positive with respect to said cathode thereof for modulating the beam current of said modulator tube and hence the beam current of said beam tube means.
Claim 2
Dependent Claim
236 words
A high power modulator circuit, comprising: high power beam tube means having a thermionic cathode and an anode spaced therefrom to define an operable electron gun for generating an electric beam which is to be modulated; modulator tube means having a thermionic cathode, a centrally apertured, substantially non-intercepting accelerating anode spaced from said cathode for drawing electrons through said accelerating aperture for forming a high power electron beam, collector means for collecting said electron beam, said collector means operating at a depressed potential with respect to said anode, and a substantially non-intercepting control grid interposed between said anode and said cathode for controlling said electron beam; power supply means for supplying direct current power to said beam tube means and said modulator tube means; said modulator tube means being series-connected with the beam circuits of said beam tube means and said power supply means, the positive terminal of said power supply means being connected to said anode of said modulator tube means, and said thermionic cathode of said beam tube means being directly connected electrically to said depressed-potential collector means of said modulator tube means, whereby said beam tube means forms the load of said modulator tube means; and means for pulsing said control grid of said modulator tube means positive with respect to said cathode thereof for modulating the beam current of said modulator tube and hence the beam current of said beam tube means.
Claim 3
Dependent Claim
99 words
The apparatus of claim 1 including control grid bias means connected for supplying a direct current bias potential to said control grid of said modulator tube, said bias potential being sufficiently negative relative to the potential of said thermionic cathode of said modulator tube such that in the presence of a turn-on pulse of predetermined positive potential applied to said control grid relative to said thermionic cathode of said modulator tube means, the perveance of the electron gun of said modulator tube means will be substantially equal to the perveance of the electron gun of said beam tube means.
Claim 4
Dependent Claim
188 words
The apparatus of claim 1 wherein said thermionic cathode of said modulator tube means has a concave emitting surface facing said central aperture in said accelerating anode of said modulator tube means, said central aperture of said accelerating anode being unobstructed and of substantially less cross-sectional area than said concave emitting surface of said cathode emitter, and wherein said collector means includes a cavity having a constricted beam entrance mouth portion facing said central aperture of said accelerating anode for passage of the beam into said collector means while restricting the backstreaming of secondary electrons from said collector cavity back toward said accelerating anode, and wherein the portions of said collector means facing said accelerating anode are shaped relative to the shape of the opposed surfaces of said accelerating aNode to provide a series of generally concave equipotentials in the space between said accelerating anode and said collector means, which series of equipotentials are generally a mirror image of a similar series of equipotentials in the space between said cathode and said accelerating anode when said tube is conducting maximum rated beam current into said beam tube means.
Claim 5
Dependent Claim
86 words
The apparatus of claim 2 wherein said beam tube means comprises a high frequency linear beam tube including said thermionic cathode, a non-intercepting centrally apertured anode spaced from said thermionic cathode for forming and projecting a beam of electrons over an elongated beam path, a beam collector structure at the terminal end of said beam path for collecting said beam, and a high frequency electrical circuit disposed along the beam path intermediate said anode and said collector in electromagnetic wave energy exchanging relation with said beam.
Claim 6
Dependent Claim
25 words
The apparatus of claim 2 wherein the electron gun of said beam tube means has a microperveance falling within the range of 0.75 to 3.5
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-01 | 1977-10-01 | 1978-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-01 | 1981-10-01 | 1982-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-01 | 1985-10-01 | 1986-04-02 | $7700.00 | Window Closed / Lapsed |