US3555334A - Cathode with graphite end shields - Google Patents
Cathode with graphite end shields Download PDFInfo
- Publication number
- US3555334A US3555334A US770668A US3555334DA US3555334A US 3555334 A US3555334 A US 3555334A US 770668 A US770668 A US 770668A US 3555334D A US3555334D A US 3555334DA US 3555334 A US3555334 A US 3555334A
- Authority
- US
- United States
- Prior art keywords
- rings
- cathode
- magnetron
- graphite
- end shields
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 15
- 229910002804 graphite Inorganic materials 0.000 title claims description 8
- 239000010439 graphite Substances 0.000 title claims description 8
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 11
- 239000010937 tungsten Substances 0.000 claims abstract description 11
- 239000007787 solid Substances 0.000 claims abstract description 4
- 150000001341 alkaline earth metal compounds Chemical class 0.000 claims description 3
- 230000002401 inhibitory effect Effects 0.000 claims description 2
- 230000001629 suppression Effects 0.000 abstract description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 7
- 229910052750 molybdenum Inorganic materials 0.000 description 5
- 239000011733 molybdenum Substances 0.000 description 5
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Inorganic materials [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 description 3
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- QIJNJJZPYXGIQM-UHFFFAOYSA-N 1lambda4,2lambda4-dimolybdacyclopropa-1,2,3-triene Chemical compound [Mo]=C=[Mo] QIJNJJZPYXGIQM-UHFFFAOYSA-N 0.000 description 1
- 229910039444 MoC Inorganic materials 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- FQNGWRSKYZLJDK-UHFFFAOYSA-N [Ca].[Ba] Chemical compound [Ca].[Ba] FQNGWRSKYZLJDK-UHFFFAOYSA-N 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 description 1
- 229910052762 osmium Inorganic materials 0.000 description 1
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 229910052702 rhenium Inorganic materials 0.000 description 1
- WUAPFZMCVAUBPE-UHFFFAOYSA-N rhenium atom Chemical compound [Re] WUAPFZMCVAUBPE-UHFFFAOYSA-N 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
- H01J23/02—Electrodes; Magnetic control means; Screens
- H01J23/04—Cathodes
- H01J23/05—Cathodes having a cylindrical emissive surface, e.g. cathodes for magnetrons
Definitions
- Trifari ABSTRACT A tungsten dispenser cathode for a magnetron is described.
- the cathode is provided with end shields in the form of solid graphite rings to improve suppression of undesirable electron emission.
- the invention relates to a magnetron in which the activated part of the cathode which consists of porous tungsten with alkaline earth metal compounds incorporated therein. is mounted or enclosed between rings the surface of which counteracts thermal emission.
- the rings consist of carbonized or zirconium-coated molybdenum.
- Barium and/or barium oxide which migrates to said rings from the activated cathode part does not give rise to primary or secondary emissions thereon.
- the life of the known constructions is not quite satisfactory because under the influence of the high operating temperature the molybdenum carbide decarbonizes and the zirconium difiuses into the molybdenum. The emission-inhibiting properties of the surface of the rings have then disappeared.
- ring s rings consist of graphite
- Graphite has not only the property that also when coating the cathode with activating material the thennal emission is extremely low, but also due to the nonsmooth surface the secondary emission is very low. The graphite itself does not experience any change even after prolonged operation at the high cathode temperature.
- the activated part of the cathode may be coated in known manner with osmium, iridium, ruthenium, rhenium or a similar material to increase the emission or to decrease the temperature. See US. Pat. Nos. 3,373,307 and 3,402,314 re for a more detailed description of the known tungsten dispenser cathodes with and without the emission-increasing coating.
- FIG. I shows a cathode for a magnetron according to the invention of large continuous power
- F IG. 2 shows a cathode for a magnetron according to the invention for producing pulses in the millimeter wavelength range.
- reference numeral 1 denotes a molybdenum tube within which a heater element 2 is arranged.
- the cylinder 3 is rigidly enclosed or mounted between the rings 4 and 5 of graphite, which likewise readily fit the tube 1.
- graphite rings 4 and 5 are fixed by the welded narrow molybdenum rings 6 and 7.
- the diameter of the cylinder 3 is l4mm.
- the filament power of the element 2 is 200 Watt.
- a continuous power of 2 KW can be produced with a magnetron provided with the cathode as described above, at a frequency of 2450 mcls.
- reference numeral 8 denotes a profiled molybdenum body in which the heater element .9 is arranged in the thicker part.
- the aluminate-impregnated tungsten body 10 which exactly fits around the thinner part of the body 8, is enclosed or arranged between the graphite rings 11 and 12.
- a molybdenum ring 13 locks the ring 12.
- a plate 14 of molybdenum terminates the body 8 and supports one end of the heater element 9.
- the diameter of the body 10 is 2mm.
- the magnetron is suitable for a frequency of approximately 33Gc/s at which pulses of 2 5 KW peak value can be produced.
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- Microwave Tubes (AREA)
Abstract
A tungsten dispenser cathode for a magnetron is described. The cathode is provided with end shields in the form of solid graphite rings to improve suppression of undesirable electron emission.
Description
United States Patent {72] Inventor Johannes Antonius Van de Goor Emmasingel, Eindhoven, Netherlands [211 Appl. No. 770,668 [22] Filed Oct. 25, 1968 [45] Patented Jan. 12, 1971 {73] Assignee U. S. Philips Corporation New York, N.Y. a corporation of Delaware by mesne assignments [32] Priority Nov. 3, 1967 3 3 Netherlands [31 1 No. 6714947 [54] MAGNETRON CATHODE WlTl-l GRAPHITE END SHIELDS 3 Claims, 2 Drawing Figs.
[52] U.S.CI 313/107, 313/346, 313/356 51 no.0 ..1-10lj 19/06, 1101 j 19/42 501 Field ofSearch 313/107, 106,31l,345,346,355,356
Primary Examiner-R0y Lake Assistant ExaminerDavid OReilly Attorney-Frank R. Trifari ABSTRACT: A tungsten dispenser cathode for a magnetron is described. The cathode is provided with end shields in the form of solid graphite rings to improve suppression of undesirable electron emission.
PATENTEUJAWIQH 3555334 INVENTOR. JOHANNES A.VAN DE 600R 32% K AGENT MAGNETRON CATHODE WITH GRAPHITE END SHIELDS The invention relates to a magnetron in which the activated part of the cathode which consists of porous tungsten with alkaline earth metal compounds incorporated therein. is mounted or enclosed between rings the surface of which counteracts thermal emission.
ln known magnetrons the rings consist of carbonized or zirconium-coated molybdenum. Barium and/or barium oxide which migrates to said rings from the activated cathode part does not give rise to primary or secondary emissions thereon. The life of the known constructions, however, is not quite satisfactory because under the influence of the high operating temperature the molybdenum carbide decarbonizes and the zirconium difiuses into the molybdenum. The emission-inhibiting properties of the surface of the rings have then disappeared.
' It is an object of the invention to provide an improved construction.
According to the invention, in a magnetron in which the activated part of the electrode which consists of porous tungsten with alkaline earth metal compounds incorporated therein is enclosed or arranged between rings the surface of which counteracts thermal emission, said ring s rings consist of graphite.
Graphite has not only the property that also when coating the cathode with activating material the thennal emission is extremely low, but also due to the nonsmooth surface the secondary emission is very low. The graphite itself does not experience any change even after prolonged operation at the high cathode temperature.
The activated part of the cathode may be coated in known manner with osmium, iridium, ruthenium, rhenium or a similar material to increase the emission or to decrease the temperature. See US. Pat. Nos. 3,373,307 and 3,402,314 re for a more detailed description of the known tungsten dispenser cathodes with and without the emission-increasing coating.
in order that the invention may be readily carried into effect, two embodiments thereof will now be described in greater detail, by way of example, with reference to the accompanying drawing, in which:
FIG. I shows a cathode for a magnetron according to the invention of large continuous power; and
F IG. 2 shows a cathode for a magnetron according to the invention for producing pulses in the millimeter wavelength range.
Referring now to FIG. 1, reference numeral 1 denotes a molybdenum tube within which a heater element 2 is arranged. A porous tungsten cylinder 3 impregnated with barium calcium aluminate, the commercially available, so called Philips B" cathode, exactly fits around the tube 1. The cylinder 3 is rigidly enclosed or mounted between the rings 4 and 5 of graphite, which likewise readily fit the tube 1. The
referring now to FIG. 2, reference numeral 8 denotes a profiled molybdenum body in which the heater element .9 is arranged in the thicker part. The aluminate-impregnated tungsten body 10 which exactly fits around the thinner part of the body 8, is enclosed or arranged between the graphite rings 11 and 12. A molybdenum ring 13 locks the ring 12. A plate 14 of molybdenum terminates the body 8 and supports one end of the heater element 9. The diameter of the body 10 is 2mm. The magnetron is suitable for a frequency of approximately 33Gc/s at which pulses of 2 5 KW peak value can be produced.
I claim:
1. In a magnetron-type electron tube having an electronand graphite rings are mounted ona common cylindrical support.
Tffgljff UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,555,334 Dated January 12, 1971 I fl JOHANNES ANTONIUS VAN DE GOOR It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
line 19, "referring" should read Referring Signed and sealed this 20th day of April 1971.
(SEAL) Attest:
EDWARD M. FLETCHERJR. WILLIAM E. SCHUYLER, JR Attestlng Officer Commissioner of Patents
Claims (3)
1. In a magnetron-type electron tube having an electron-emitting cathode comprising a porous tungsten cylinder with alkaline earth metal compounds incorporated therein and with emission-inhibiting rings mounted coaxially with adjacent opposite ends of the tungsten cylinder, the improvement comprising both of said rings consisting essentially of solid graphite.
2. The magnetron of claim 1 and further including means for supporting said solid graphite rings in abutting relationship with the ends of the tungsten cylinder.
3. The magnetron of claim 2 wherein the tungsten cylinder and graphite rings are mounted on a common cylindrical support.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL676714947A NL153370B (en) | 1967-11-03 | 1967-11-03 | MICROWAVE IN WHICH THE ACTIVATED PART OF THE CATHODE IS ENCLOSED BETWEEN RINGS WHOSE SURFACE CONTACTS THERMAL EMISSIONS. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3555334A true US3555334A (en) | 1971-01-12 |
Family
ID=19801629
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US770668A Expired - Lifetime US3555334A (en) | 1967-11-03 | 1968-10-25 | Cathode with graphite end shields |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US3555334A (en) |
| DE (1) | DE1803348A1 (en) |
| FR (1) | FR1591244A (en) |
| GB (1) | GB1189940A (en) |
| NL (1) | NL153370B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3760214A (en) * | 1971-12-30 | 1973-09-18 | Hitachi Ltd | Shadow masks for use in colour picture tubes |
| US3988636A (en) * | 1974-04-02 | 1976-10-26 | Hitachi, Ltd. | Magnetron with cathode end shields coated with secondary electron emission inhibiting material |
| US4349424A (en) * | 1981-05-15 | 1982-09-14 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Ion sputter textured graphite |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1897933A (en) * | 1928-08-02 | 1933-02-14 | Peoples Gas By Products Corp | Electrode for electron discharge tubes and method of forming the same |
| US2683671A (en) * | 1952-07-17 | 1954-07-13 | Westinghouse Electric Corp | Low primary and secondary electron emission surface |
| US3308329A (en) * | 1962-11-23 | 1967-03-07 | Litton Industries Inc | Thermionic emissive cathode with end structure for emissive suppression |
-
1967
- 1967-11-03 NL NL676714947A patent/NL153370B/en not_active IP Right Cessation
-
1968
- 1968-10-16 DE DE19681803348 patent/DE1803348A1/en active Pending
- 1968-10-25 US US770668A patent/US3555334A/en not_active Expired - Lifetime
- 1968-10-31 GB GB51710/68A patent/GB1189940A/en not_active Expired
- 1968-11-04 FR FR1591244D patent/FR1591244A/fr not_active Expired
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1897933A (en) * | 1928-08-02 | 1933-02-14 | Peoples Gas By Products Corp | Electrode for electron discharge tubes and method of forming the same |
| US2683671A (en) * | 1952-07-17 | 1954-07-13 | Westinghouse Electric Corp | Low primary and secondary electron emission surface |
| US3308329A (en) * | 1962-11-23 | 1967-03-07 | Litton Industries Inc | Thermionic emissive cathode with end structure for emissive suppression |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3760214A (en) * | 1971-12-30 | 1973-09-18 | Hitachi Ltd | Shadow masks for use in colour picture tubes |
| US3988636A (en) * | 1974-04-02 | 1976-10-26 | Hitachi, Ltd. | Magnetron with cathode end shields coated with secondary electron emission inhibiting material |
| US4349424A (en) * | 1981-05-15 | 1982-09-14 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Ion sputter textured graphite |
Also Published As
| Publication number | Publication date |
|---|---|
| DE1803348A1 (en) | 1969-06-19 |
| NL6714947A (en) | 1969-05-06 |
| NL153370B (en) | 1977-05-16 |
| GB1189940A (en) | 1970-04-29 |
| FR1591244A (en) | 1970-04-27 |
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