US982552A - X-ray tube. - Google Patents

Description

H. P. WAITB.

1 X-RAY TUBE. APPLIoATIoN FILED 1111.25, 190e. RENBWED MAY 1a, 1910.

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Patented J an. 24, 1911.

vwentoz SH01/wup UNITED n' sTATEs PATENT 'oEEIcE `HARRY F. WAITE, OF NEW YORK, N. Y.

I t y x-EAY TUBE.

Specification of Letters Patent.

`Application led January 25, 1906, Serial No. 297,834; Renewed May 13, 1910. Serial No. 561,174.

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To all/whomy 'it that I, HARRY F. WAITE, a

Be it known citizen of the United States, and resident of ings zFigure 1 is a view o the city, county, and State of New York, have invented Acertain new and useful Imrovements in X-Ray Tubes, of which the ollowing is a specification.

My invention relates to improvements 1n Roentgen or X-ray tubes, and has for its object to improve the construction, arrangement and operation of such tubes, and to' these ends my invention consists in a tube embod ing the features of construction arrange and operating substantiall in the manner hereinafter more partie arly set forth.

Referring to the accom anying drawan X-ray tube embodying my invention, and Fig. 2 is a modification.

In the operation of an X-ray tube or bulb of the ordinary character, especially ywhen it lis connected to X-ray coils as a source .of

energy, it is found that there is more or less inverse current, that is, a part of the time the poles are reversed so that what is ordinarily the anode becomes the cathode and the cathode becomes the anode. When the current is iiowin'g inthe proper direction the cathode stream from the cathode cup strikes upon the target, generating the Roentgen or X-rays in the manner well understood. lVhen, however, the current is reversed, as happens in an alternating current machine, the target becomes the negative or cathode and the cup becomes the anode, and the cathode rays stream from the target and strike upon the body of the tube, and bombarding this part of the tube, produce or generate X-rays at this point.

The target T is usually made of metal, and I have found that when X-rays are generated by the cathode stream striking the body of the tube or bulb whichisof glass, the are of a different quality from those Vwhich are generated when the cathode kstream strikes the target T, and this change in the quality of the rays interferes with the use thereof, especially when the X-rays are used in making photographic plates.

the quality or character of the rays gener ated when the cathodestream im inges upon the target or the body of the tu e 1s eliminated. l v

One form of my invention is shown in Fig. 1, wherein R re resents the main tube o bulb, and forme tube Ris what may be termed an interior or secondary tube E. This tube may be mechanically produced in various ways known Patented Jan. 24, 1911.

in. or connected with the to those skllled in glass working, and they need not to be described specifically herein. This secondary tube is arranged so that it may be subjected to the same degree of exhaustion as the interior of the main or primary tube R, and a simple way to insure this is to provide the secondary tube with an opening D. This interior or secondary tube is made of some material which is opaque to X-'rays, as for instance, it may be made of or secondary tube is arran eda secondary target G which is preferab y of metal, and also arranofed thereln is the anode A which is adapted to be connected to the positive terminal B of the g-rav coil or other source of energy. The cathode or negative terminal C is shown preferabl provided with a cup-shaped disk C', and t e target T, which is preferably of metal, is shown as having a flat surface and supported by a.bar extending into a neck A.

In operation, the terminal B is connected to the positive terminal of the source and the terminal C to the negative terminal of lead glass, and mounted within the interior Y the source. A. will thus be the anode and understood. If, however, there is a reversal of current, then C becomes the anode and A the cathode. lThe cathode stream from A will impin e upon the secondary target Gr, producing -rays. The direction of this X-rays is, however, away from the X-ray plate that would be exposed and away from the operator using afluorosco e, and 1n addition the lead glass wall of t e tube E will effectively cut oif 'any X-rays generated.V Since the cathode stream is rectilinear and entirely cut oft by the target -or screen G, target T will be in the shadow and the cathode rays will not im inge upon it. At this time, that is, when is the anode and A.

vthe cathode, the target T is entirel visolated and does not form a `cathode as is t e case in the ordinarytube. When, however, A is the anode and Cthe cathode, then -no X- Y rays will be produced at G, but only. at T. While X-rays would be generated at, the secondary target G, their direction is awa from the X-ray plate that would be expose 0r would be away from the operator using a fluoroscope. In the ordinary operation of the tube however if there is no reverse current then there will be no X-ray generated at the secondary target, all of the X-rays being generated at the target T.

It will thus be seen that artube constructed on the general principles above set forth, that is, providing the main tube or bulb with a secondary tube which is opaque to X-rays, and generating the X-rays therein, a simple means .is 'provided' for overcoming the disadvantages inherent in the ordinary X-ray tube whenever reversals of the currentv or changes of direction of the stream of cathode rays take place.

In Fig. 2 I have shown a similar embodiment of my inventionexcept that the sec--- ondary tube is external to the main bulb or tube the parts being otherwise arranged sub,-

. stantially as shown in Fig. 1, and being similarly lettered.

While I have shown several embodiments of my invention, it is evident to those skilled in the art that the principles thereof may be otherwise embodied without departing from the spirit of theinvention, and the detailsI of construction of X-ray tubes em bodying the invention are immaterial.

l. *An X-ray bulb'comprising a main tube and a secondary tube opaque to X-rays and 40 communicating with the interior oi the main tube, a main target mounted 1n said mam tube and a secondary target mounted in said l secondary tube, and electrodes.

2. An X-ray bulb comprising a main and secondary tube, a target mounted in the vided with one of the electrodes and with a target, and another electrode.

4. An X-ray bulb comprising a main tube and a secondary tube, the latter beingopaque to X-rays, one of the electrodes being located in the secondary tube and the other being located in the main tube, and two targets one of which is located Within the sccondary tube.

5. In an X-ray apparatus, a bulb provided with a target and a pair of electrodes, and a screen between one of the electrodes and the target.

6. In an X-ray apparatus, a bulbcomprising a main tube, and a communicating secondary tube formed of a material opaque to X-rays, a target and an electrode in the main tube, an electrode in the secondary tube, and a screen in the secondary tube positioned to cut off the cathode rays which proceed from the electrode in the secondary tube.

In testimony whereof I aiix my signature in presence of two witnesses.

HARRY F. WAITE. Witnesses:

HENRY E. WAITE, CHARLES KALLMEYER.

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