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Publication numberUS2665391 A
Publication typeGrant
Publication dateJan 5, 1954
Filing dateMar 4, 1950
Priority dateMar 4, 1950
Publication numberUS 2665391 A, US 2665391A, US-A-2665391, US2665391 A, US2665391A
InventorsJan Bleeksma
Original AssigneeAmperex Electronic Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
X-ray tube having a mica window
US 2665391 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

Jan. 5, 1954 J BLEEKSMA 2,665,391

X-RAY TUBE HAVING A MICA WINDOW Filed March 4, 1950 5 7 7 A k s I 10 1," J @MNBLEJEES'A/M INVENTOR.

AGENI.

Patented Jan. 5, 1954 2,665,391 X-RAY TUBE HAViNG A MICA WINDOW Jan Bleeksma, Mount Vernon, N. Y., assignor to Amperex Electronic Corporation, Brooklyn,

Application March 4, 1950, Serial No. 147,739

My invention relates to X-ray tubes and particularly to X-ray tubes for X-ray difiraction purposes.

In general for X-ray diffraction study, it is desirable to have a tube with a relatively large output of X-radiation. In the prior art such tubes have been provided with windows which permitted afair output of X-radiation but which had several disadvantages. Such windows either were difficult to fabricate, and assemble into the tube structure, or they resulted in considerable leakage.

It is an object of my invention to provide an X-ray tube for X-ray diffraction study which is superior to and has striking advantages over existing X-ray tubes.

It is a further object of my invention to provide a window for an X-ray tube having a relatively large output of X-radiation which is relatively easy to fabricate and assemble into the tube structure and which is secure against undesired leakage.

It is a still further object of my invention to provide a window construction for an X-ray tube in which the window is protected from undesired electronic bombardment as a result Of secondary emission from the anode target.

These and further objects of my invention will appear as the specification progresses.

According to the invention, an X-ray tube, primarily for X-ray difiraction study, is provided with a radiation permeable window which comprises a thin disc of insulating material which is permeable to X-radiation and which is sealed to the tube envelope in a vacuum-tight fashion and a thin foil of conductive material interposed between the disc of insulating material and the target of the tube to protect the latter from electron bombardment by providing a conductive path for electrons striking the window.

In the preferred embodiment of my invention, a thin mica disc is powder-glass sealed in a window support sealed to the walls of the tube envelope thereby providing a vacuum-tight window for the tube. Between the mica window and the target and supported by the walls of the tube envelope is a thin disc of beryllium which protects the mica window from electron bombardment.

The invention, however, is not restricted to this particular combination since I have found that aluminum, although somewhat less desirable, is suitable in place of beryllium, and of course the mica window could be replaced with other types 5 Claims. (Cl. 313-59) 2 of windows having a relatively low absorption for X-rays.

The invention will be described with reference to the drawing in which Fig. 1 shows a conventional X-ray tube for X-ray diffraction study provided with a window according to the invention and Fig. 2 shows the window construction in greater detail.

Fig. 1 shows an Xray tube for diffraction purposes provided with a sealed and evacuated envelope I, a cathode 2, and an anode 3. The envelope at the level of the target is provided with four windows 4 of the type about to be described, through which a beam of X-radiation emerges. Provision is made in the jacket 5 for supplying power to energize the tube.

The window construction is shown in greater detail in Fig. 2. The window comprises a ringshaped support 6 of stainless steel which is sealed to the envelope with powder-glass l. Seated on a ridge in the support is a mica disc 8 having athickness of about 0.0003 to 0.0005 inch, which is sealed to the support with powder-glass 9 thereby providing a vacuum-tight seal for the window. Seated beneath the support and supported by the envelope is a disc of beryllium l8- having a thickness of about 0.004 to 0.006 inch, which is sealed in place but is not vacuum-tight, and which serves to protect the mica disc from electron bombardment.

The absorption of X-rays by the mica and beryllium discs has been found to be about the same or less than absorption of X-rays by vacuum-tight beryllium discs which must be thicker to prevent atmospheric penetration of the beryllium, thereby destroying the vacuum in the tube.

While I have disclosed my invention with specific examples and applications thereof, other obvious variants will be apparent to those skilled in the art Without departing from the spirit and scope of the invention as defined in the appended claims.

What I claim is:

1. An X-ray tube comprising an evacuated envelope, cathode and anode electrodes, and a radiation permeable window in a wall portion of said envelope facing said anode, said window comprising a metallic window support powder-glass sealed into said envelope, a mica window seated in said support and powder-glass sealed thereto to provide a vacuum-tight seal for said mica disc, and a thin foil of radiation permeable metal secured to said envelope between said support and the anode of the tube to provide a conductive path for electrons striking the window.

2. An X-ray tube comprising an evacuated envelope, cathode and anode electrodes facing said anode, and a radiation permeable window in a wall portion of said envelope, said window comprising a window support powder-glass sealed into said envelope, a mica window seated in said support and powder-glass sealed thereto to provide a vacuum-tight seal for the mica disc, and a thin foil of beryllium interposed between the mica window and the anode of the tube to provide a conductive path for electrons striking thewindow. H l h 3. An X-ray tube comprising an evacuated envelope, cathode and anode electrodes, and a radiation permeable window in a wall portion of said envelope facing said anode, said window comprising a mica disc vacuum sealed to said envelope, and a thin beryllium disc interposed between the mica disc and the anode of the tube to provide a conductive path for electrons striking the window.

4. An X-ray tube comprising an evacuated envelope, cathode and anode electrodes, and a radiation permeable window in a wall portion of said envelope facing said anode, said window comprising a metallic window support powderglass sealed to said envelope, a mica window seated in said support and powder-glass sealed thereto to provide a vacuum-tight seal for the mica window, and a beryllium window secured to the walls of the envelope and interposed between the mica window and the anode of the tube for providing a conductive path for elec trons striking the window.

5. An X-ray tube comprising an evacuated References Cited in the file of this patent UNITED STATES PATENTS Number Name Date. 1,626,465 Holst et al. Apr. 26, 1927 1,626,693 Rentschler May 3, 1927 1,927,475 Volkel Sept. 19, 1933 2,009,457 Sloan July 30, 1935 2,024,332 Bouwers Dec. 17, 1935 2,125,700 Volkel Aug., 2, 1938 2,356,645 .Atlee et al. Aug. 22, 1944

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1626465 *Nov 6, 1923Apr 26, 1927Philips NvChi-ray tube
US1626693 *Nov 29, 1922May 3, 1927Westinghouse Lamp CoHigh-voltage electron device
US1927475 *Sep 8, 1931Sep 19, 1933Mueller C H F AgHigh vacuum discharge vessel in particular X-ray tubes
US2009457 *Apr 11, 1932Jul 30, 1935Research CorpMethod and apparatus for producing high voltage
US2024332 *Apr 6, 1931Dec 17, 1935Philips NvDischarge tube having a metal envelope
US2125700 *Nov 16, 1933Aug 2, 1938Mueller C H F AgHigh tension discharge vessel
US2356645 *Feb 8, 1943Aug 22, 1944Gen Electric X Ray CorpX-ray tube
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2866114 *Jun 15, 1954Dec 23, 1958Philips CorpBeryllium window x-ray tube
US2899598 *May 28, 1956Aug 11, 1959 ginzton
US3018398 *Oct 27, 1958Jan 23, 1962Dunlee CorpChi-ray generator
US3135889 *May 22, 1962Jun 2, 1964Soules Jack AProtected window x-ray tube
US3419741 *Apr 19, 1966Dec 31, 1968Thomas Electronics IncVacuum seal for a thin beryllium x-ray window
US3500097 *Mar 6, 1967Mar 10, 1970Dunlee CorpX-ray generator
US4045699 *Aug 26, 1975Aug 30, 1977Siemens AktiengesellschaftUse of light-metal panes as x-ray transmissive windows
US4178509 *Jun 2, 1978Dec 11, 1979The Bendix CorporationSensitivity proportional counter window
US5013922 *Mar 13, 1990May 7, 1991General Electric CompanyReduced thickness radiation window for an ionization detector
US6052429 *Feb 19, 1998Apr 18, 2000Dkk CorporationX-ray analyzing apparatus
US6118852 *Jul 2, 1998Sep 12, 2000General Electric CompanyAluminum x-ray transmissive window for an x-ray tube vacuum vessel
US6215852Dec 10, 1998Apr 10, 2001General Electric CompanyThermal energy storage and transfer assembly
US6301332Nov 28, 2000Oct 9, 2001General Electric CompanyThermal filter for an x-ray tube window
US8681943Jan 26, 2009Mar 25, 2014Excillum AbX-ray window
CN102293061BJan 26, 2009May 7, 2014伊克斯拉姆公司X-射线窗口
DE10313863A1 *Mar 21, 2003Oct 21, 2004Siemens AgX-ray beam window for vacuum tubes, has ceramic radiation-transmissive plate held in window frame made of metal having expansion rate suited to ceramic
DE10313863B4 *Mar 21, 2003Jan 19, 2006Siemens AgRöntgenstrahlaustrittsfenster, insbesondere für Megalixröhren
EP0768699A1 *Sep 27, 1996Apr 16, 1997Kevex X-Ray Inc.X-ray tube and barrier means therefor
EP0991106A2 *Nov 21, 1991Apr 5, 2000Varian Associates, Inc.High power X-Ray tube
Classifications
U.S. Classification378/140, 378/161
International ClassificationH01J35/18, H01J35/00
Cooperative ClassificationH01J35/18, H01J2235/168
European ClassificationH01J35/18