US3751701A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Convergent flow hollow beam x-ray gun with high average power
Assignee: KEVEX Corp FOSTER CITY CA A CORP OF
•
Filing: 1971-03-08
•
Granted: 1973-08-07
•
Expires: 1991-03-08
Abstract
Abstract An X-ray generating tube characterized by grid means formed with narrow annular slits which serve to isolate the cathode from being influenced by the high voltage of the anode. According to one embodiment, a target formed as a hollow conical surface of revolution closed at one end forms an X-ray window at one end of the tube. According to another embodiment, the axis of the tube remains substantially unobstructed whereby X-rays generated from a conical surface of the type noted above are emitted at the end of the tube disposed opposite the target end. Another embodiment combines the advantages of the first named and last named embodiment by utilizing concentricly oriented coaxially disposed electron beam control elements formed with a narrow annular slit for passing electrons radially into the axial region of the tube.
Inventors
- 👤 N Gralenski
- 👤 G Wada
- 👤 D Bates
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 18:24
CPC Classifications
H; H01; H01J; H01J35/00; H01J35/02; H01J35/14; H01J35/147
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
254 words
In an X-ray generating device of a type employing a target of material disposed to be struck by an annular beam of high energy electrons to develop X-rays, and having means for focusing the beam upon the target, said means including a grid disposed transversely to the axis of the beam and means for applying a charge to the grid for focusing the beam to form an annular hollow beam, the improvement comprising an indirectly heated cathode having an electron emitting portion adapted to be charged negatively with respect to said target to create a flow of electrons from said portion to said target, means for inhibiting the potential of said target from influencing electron emission from said cathode portion, the last named means comprising control grid means disposed between the first named said grid and said target and across said flow of electrons and formed to include an annular slit therein coaxially disposed relative to the axis of said flow for passing said flow of electrons therethrough to said target, said slit being sufficiently narrow and said cathode portion being spaced sufficiently therebehind so as to inhibit the potential of said target from influencing said electron emission from said cathode portion, an annular control element encircling said flow of electrons, and means coupled to said control element for varying the potential thereof to cause said flow of electrons to provide an annular beam impinging upon the target with a varying diameter in response to variations in said potential of the last named means.
Claim 2
Dependent Claim
254 words
In an X-ray generating device of a type employing a target of material disposed to be struck by an annular beam of high energy electrons to develop X-rays, and having means for focusing the beam upon the target, said means including a grid disposed transversely to the axis of the beam and means for applying a charge to the grid for focusing the beam to form an annular hollow beam, the improvement comprising an indirectly heated cathode having an electron emitting portion adapted to be charged negatively with respect to said target to create a flow of electrons from said portion to said target, means for inhibiting the potential of said target from influencing electron emission from said cathode portion, the last named means comprising control grid means disposed between the first named said grid and said target and across said flow of electrons and formed to include an annular slit therein coaxially disposed relative to the axis of said flow for passing said flow of electrons therethrough to said target, said slit being sufficiently narrow and said cathode portion being spaced sufficiently therebehind so as to inhibit the potential of said target from influencing said electron emission from said cathode portion, an annular control element encircling said flow of electrons, and means coupled to said control element for varying the potential thereof to cause said flow of electrons to provide an annular beam impinging upon the target with a varying diameter in response to variations in said potential of the last named means.
Claim 3
Dependent Claim
16 words
In an X-ray generating device according to claim 1 wherein said cathode comprises an oxide-coated cathode.
Claim 4
Dependent Claim
61 words
In an X-ray generating device according to claim 1 comprising a pair of axially spaced control grids formed with narrow annular slits for passing said beam therethrough and serving to inhibit the potential of said targer from influencing the electron emission from said cathode, and a pulse generator coupled to said pair of grids for gating said beam to said target.
References Cited (Backward Citations)
US3691417A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-06 | 1977-02-05 | 1977-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-06 | 1981-02-05 | 1981-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-06 | 1985-02-05 | 1985-08-07 | $7700.00 | Window Closed / Lapsed |