US1590971A - Method of and apparatus for producing sharp rontgen imagen - Google Patents

Description

June 29 1926.

o. GOETZE METHOD OF AND APPARATUS FOR PRODUCING .SHARP RQ NTGEN IMAGES Filed August so, 1921 OTTU GOETZE J I June as, me

UNITED STATES 1,590,911 PATENT omen.

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llyinvention relate steim rovements gliirpRon 1112;1 5:393? t ore beenpropoeedtous'eRiin tgentubes with un- .sharpsourcesof ras fordiagnosticpurposes which require images. For this meethe Biintgen proJectionhasnotbeen by means of the rays which emanate from the anticathode at an angle of about 45 but by means ofrays which the anticathode in asuhstantially par- Therebyatleastinone direction the source of rays appears to be shortenedtoav smallarea, andthetube u'hasmu sled ,to thatof-a'tuhehavob ect of the resent improvements is to provide a moth which makes use of a tube having anincandescent so cathode andan unsharp focal spot and yet produces which are sharp in anydi- Wi this object in view my invention consists in using a Riintgen tube having an t cathode producing .on I the anticathodea focal spot in the form'ot '2 is a vertical section ofihe art of cent cathode and the anticathode, and

Fig. 8 is a similar section taken at right fernng nowto Fig. lit will bees-1 thatthe target or. hand providing of the rags and on the to be'produced.

des position of the object and the elongated source of rays 4 acts wi a length tion-II or in a positionnear the use of a tube an unsharplsource very small. For taking a hotega h of a n ob'ect{for example of a Band on 2 senll, 81 plate 5 I useonly such rays as are emitted substantially in the direction of the l ne 4 which therefore form ve small angles with the plane of the antics ode 3; For this purpose the object to be projected on and the plate 5 are set inthe position I. When viewed from this point the line m pears to have been reducedto a very length as compared to its actual length. If the actual length of the lineis L and the rays neelt-infithewbject are at a median a (this Milli the angle between; the median ray and a 'ne perpendicular to the anticathode), the 1 as seen from the point I appears'te be cos a. If 10 a 1s large,this value is small, and the elongated source of light acts as a'focus in the form of a point. 4

In Fig. 15 the e a is about 70. It will be evident that this is alsothe anglewhich II the anticathode portion or source of rays 4' forms with the longitudinal of the antica'thode (anode), which axis in this embodb' ment coincides with thelongitudinal of I j thetube,seeFigs.2and3. Th the le '0 which the anticathode surface 4 orms' with the axis of the tube, and therefore with the.

axis ofthe pencil of cathode rays, is an'acute 'angle'greater than the angle of 45 customarily employed hitherto,'and as a result of 86 thisrnew arrangement, I obtain, in the equatorial zone of the tube, an approximately point-like projection of theelongated spot upon the plane-in which;the image is roved The difierence between my um method and the one now in use will derstood when setting the object and the sensitized late 5 inthe 'tion II. Inthis P P M L cos B. The 1e B is about 15. Them"- fore with the ob ect and plate in the thereto reproductions can not be had, and when seen frompoint II the source of rays 4 will appear as a lineof substantial length and fromwhich only anunsharp can be had. Therefore, my improved methedpei'mits of rays in the form of a band loo.

purposes for roducing sharp Rontgen images, the resu t being the same as that of a tube having a shar source of rays.

In Figs. 2 and 3 have shown a preferred exam le of the essential parts of a Riintgen. tu e having an incandescent cathode and collecting means (Coolidgetube), which in a simple way ermits\the production of'a source of rays in the form of a band. For this purpose the incandescent wire 1 is not disposed in the usual way and in the formof a coil, but I prefer to arrange the same along a straight'lineand in one direction, and it is surrounded by a collector 2, havin the form of an elon gated box: By means of this collector the cathode rays are distributed over a space the cross-section ofwhich is likewise in the form of a narrow rectangle, so that-the rays produce on the anticathode 3a focal spot 4 in the form of a rectangle.

i It will be noted thatin the specific embodiment illustrated, the heated filament or.

cathode extends in a substantially straight line located in a planeperpendicular to the plane of the anticathode, and. that the cathode and the anticathode converge in such perpendicular plane. It will be further noted the collector co-operating with the said cathode is in the form of an elongated box open toward the anticathode,'the lonfitudinal axis of said box being parallel tot at of the cathode.

In a Rontgen tube with incandescent cathodeprovided with an intermediate electrode the focal spot in the form of a band is produced in a simple way by forming the intermediate electrode with an opening] in the form of a rectangle for the passage.

of the rays therethrough.

To permit the use of the Rentgen tube with incandescent cathode the direction of the linear focus should be such that it can be put to use without materially changing the usual tripods. For this reason all the j parts projecting from the tube are arranged in the usual way, and in some cases the anti-..

cathode must be inclined relatively to the axis of the tube at a greater angle than is usual in other tubes, as will be understood from an inspection of-the drawing.-

I claim:

' 1. The herein desci'ibedmethod of pro ducmg Rentgen'images which consists incausing emission of.R6ntgen rays from. an elongated focal spot,and using, for the production of the images, the rays emanating from said spotsubstantially in the direction of the length of the spot- 2. .The method herein described of proof said target.

ducing Rontgen images, which consists in causing the emission of Rentgen rays from a focal spot havin a length great as compared with its width, and producing an image from such of the rays emanating from said spot as are projected therefrom in a direction nearly coincidin with the general direction of the spot. a

3. An X-ray tube having a plane'anticathode, an incandescent cathode constructed to produce, in conjunction with said anti- *to less than half the actual length of said length 0 said focal target, said means comprising a plane target shaped as a narrow band, a cathode consisting of a straight incandescent filament, said target and filament lying in a common plane at an angle of less than 45 degrees to each other, and a collector partially surrounding the cathode.

. 5. Inan X-ray tube, means for obtaining, in the equatorial zone of the tube, a pro jection of the target which is foreshortened to less than half the actual length of sa d target, said means comprising a target 1n the form of a narrow band, a cathode con sistingof an incandescent filament extending in a substantially straight line, said target and cathode bein positioned in a common plane at an ang e of less than45 degrees'to each other, and a collector partially surrounding the cathode.

" 6. An X-raytube having a plane target in the form of a narrow band, an elongated incandescent cathode, said target and cathode being disposedin a common plane, a

collector associated with said cathede the active surface of said target being inclined at an angle of more than 45' degrees to the longitudinal axis of the tube, so as to obtain, in the equatorial zone of the tube, a projection of "the target which is foreshortened to less than half the actual length In testimony signature.

whereof I hereunto afiix my.

m. o'i'ro GoE'rzn.

Images