US3609581A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low power reentrant stream crossed-field noise generator tube
Assignee: Varian Medical Systems Inc
•
Filing: 1969-07-25
•
Granted: 1971-09-28
•
Expires: 1989-07-25
Abstract
Abstract A crossed-field reentrant stream noise generator tube is disclosed. The tube is of the circular crossed-field geometry having a cathode electrode structure coaxially disposed of an anode electrode structure to define an unobstructed crossed-field interaction region in the space between the anode and cathode such that the electron stream can circulate completely around the cathode. The cathode electrode structure includes one or more thermionic emitter buttons forming the emitting portion and the remaining portion of the cathode forms a nonemitting sole structure. A microwave circuit is formed in the anode structure facing an arcuate portion of the cathode structure. In one embodiment, the nonemitting sole portion of the cathode structure is treated to inhibit secondary emission therefrom by reducing the secondary emission ratio of the surface to less than 1. In a second embodiment, the nonemitting sole portion of the cathode structure is biased negatively relative to the thermionic emitter to prevent bombardment of the sole and thus to inhibit secondary emission therefrom.
Inventors
- 👤 Hunter L Mcdowell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 02:12
CPC Classifications
H; H01; H01J; H01J25/00; H01J25/34; H01J25/42; H01J25/44
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
203 words
In a crossed-field reentrant stream noise generator tube, means forming a cathode electrode structure, means forming an anode electrode structure having a microwave circuit portion generally concentrically disposed of said cathode structure to define a crossed-field reentrant stream interaction region in an unobstructed annular space between said cathode and anode structures, means forming a plurality of discrete thermionic emitters circumferentially spaced apart around the periphery of said cathode structure to inject electrons into said interaction region for interaction with microwave energy on said microwave circuit portion to produce output microwave noise energy, said anode electrode structure including a circuit sever portion defining an upstream end and an output downstream end for said microwave circuit portion adjacent the ends of said circuit sever portion, means forming a resistive termination for terminating the upstream end of said microwave circuit portion, THE IMPROVEMENT WHEREIN, said cathode electrode structure includes cathode sole portions disposed facing said microwave circuit portion and separating said thermionic emitters, each of said thermionic emitters being positioned on said cathode structure opposite said microwave circuit portion, and means for inhibiting secondary emission from said cathode sole portions of said cathode structure, whereby the noise generator tube may be operated at relatively low-power levels.
Claim 2
Dependent Claim
203 words
In a crossed-field reentrant stream noise generator tube, means forming a cathode electrode structure, means forming an anode electrode structure having a microwave circuit portion generally concentrically disposed of said cathode structure to define a crossed-field reentrant stream interaction region in an unobstructed annular space between said cathode and anode structures, means forming a plurality of discrete thermionic emitters circumferentially spaced apart around the periphery of said cathode structure to inject electrons into said interaction region for interaction with microwave energy on said microwave circuit portion to produce output microwave noise energy, said anode electrode structure including a circuit sever portion defining an upstream end and an output downstream end for said microwave circuit portion adjacent the ends of said circuit sever portion, means forming a resistive termination for terminating the upstream end of said microwave circuit portion, THE IMPROVEMENT WHEREIN, said cathode electrode structure includes cathode sole portions disposed facing said microwave circuit portion and separating said thermionic emitters, each of said thermionic emitters being positioned on said cathode structure opposite said microwave circuit portion, and means for inhibiting secondary emission from said cathode sole portions of said cathode structure, whereby the noise generator tube may be operated at relatively low-power levels.
Claim 3
Dependent Claim
91 words
The apparatus of claim 1 wherein said means for inhibiting secondary electron emission from said cathode sole portions includes an electrical insulator structure disposed between each of said thermionic cathode emitters and said cathode sole portions for holding off a negative bias potential applied to said cathode sole portions relative to the potential applied to said thermionic emitters, whereby back bombardment of said cathode sole portions by electrons driven out of the electron stream is substantially reduced in use to inhibit secondary emission from said sole portions of said cathode structure.
Claim 4
Dependent Claim
43 words
The apparatus of claim 1 wherein the surfaces of said sole portions of said cathode structure which face the interaction region are formed in such a way as to reduce the effective secondary emission ratio of the surfaces to less than 1 .
Claim 5
Dependent Claim
47 words
The apparatus of claim 1 wherein the surfaces of said sole portions of said cathode structure which face the interaction region are grooved to reduce the effective secondary emission ratio of the surfaces by trapping secondary electrons in the grooves in the surfaces of said sole portions.
Claim 6
Dependent Claim
30 words
The apparatus of claim 1 wherein the surfaces of said sole portions which face the interaction region are formed of a material having a secondary emission ratio less than 1.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-27 | 1975-03-29 | 1975-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-27 | 1979-03-29 | 1979-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-27 | 1983-03-29 | 1983-09-28 | $7700.00 | Window Closed / Lapsed |