US2637818A - Electron accelerator - Google Patents

Description

May 5, 1953 K. GUND ET AL ELECTRON ACCELERATOR Filed July 2l, 1951 Patented May 5, 1495.3

Konrad Gund, Hans Berger, Max Martin Scheer, and Rudolf Schittenhelm, Erlangen, Germany Application July 21, 1951, Serial No. 237,925 In Germany July 24, 1950 This invention is concerned with an electron accelerator having means for deiiecting the electrons describing a circular orbit inwardly within the accelerating vessel, from this orbit onto an X-ray-producing target disposed inside the orbit and alternatively outwardly of said orbit, to produce X-ray radiation and electron radiation, respectively, and comprising separate radiation exit windows, one for electrons and the other for X- rays, and control means for selectively utilizing,

e; g., for medical p-urposes, either one or the otherradiation emerging from the respective windows.

The deflection means is in accordance with the invention alterable or switchable, e. "g., to change the polarity of suitable eld control means to cause the desired deection of the accelerated electrons.

An auxiliary field or interference coil may be used throughv which is conducted a current, im-

pulse of predetermined direction, at the end of.

the electron acceleration, and a switch maybe provided for controlling the direction of current flow of the impulse flowing through the coil.

14 claims. (c1. aso-4.9.5)

A large X-ray radiation exitwindow may be provided in conjunction with a coacting adjustable, e. g., slidable, shield for selectively freeing predetermined portions of such window to permit passage of X-rays or of electrons emerging from the corresponding electron exit window. Suitable contact means may be operated by the displacement of the adjustable shield which effect, the operative switching ofthe electron deiiection means.

The objects indicated in the foregoing and additional objects andfeatures will appear from the description of an embodiment of the invenf tion which will be rendered with reference to the accompanying drawings. In these; drawings,

Fig. l shows in diagrammatic representation an embodiment of an electron accelerator according to the invention, as seen from the front thereof; and

Fig. 2 is a transverse sectional view of the ac. celerator.

Numeral I indicates the magnet yoke of the accelerator and 2 a doughnut-shaped accelerating vessel. The dot-dash circle 3 in Fig. 2 denotes the orbital acceleration or equilibrium path of the electrons. An X-ray target "4 A(anode-l is disposed within the accelerating-vessel;inside of the orbital equilibrium path 3. The electron exit,

window 6 is provided in the necks of the "vessel 2. The accelerator is partly shielded by alead shield 'l which is provided with the X-jrayexlt window 8. The window 8 is larger thanisne'cessary for the desired X-ray radiatiomf thatl is, it is so large that the electrons emerging from the window 6 can pass therethrough.

Within the large window' is disposed a lead member 9 which is adjustable to form in one terminal position a shield to block the electron radiation vfrom the exit window t, while permitting the passage of the X-ray radiation. In its other terminal position the lead member ii frees the part of the window 8 in the shield l, which is required for the exit of the electrons.

The lead member 9 is secured to the bars iii which are guided in cross-sectionally U-shaped rails Il. Movably connected with the lead member are the arms l2. These arms are linked to the crossbar l5 which may be displaced for moving'or shifting the lead member from one to the other terminal position responsive to actuation-ofthe sprindle l5 journalled at i3 and L4, the spindle -being in threaded engagement with the Icrossbar It and being operable by the handwheel il. The drive for the lead member 9 thus is a self-locking drive which holds ,the lead member. in any` position of adjustment. One of the arms I2 carries a pin i8 for operating contact springs i9 and 2l] in the two respective terminal positions of the lead member 9.

The contact Ilgoverns the operation of a control device for lswitching in suitable means to deflect the electrons from the orbital equilibrium pathinwardly whenever terminal velocity is attained; and the contact 20 is disposed in the circuit of control means for similarly switching in suitable means to deflect the electrons from the orbital equilibrium path outwardly whenever terminal velocity is attained.

The control device and the associated electron deflection means have not been illustrated in the drawings, because these means may be of any known kind for obtaining the desired and described results. The control device may, for example,v comprise suitable electronic circuits and the propei` elements therefor, for switching in and out at thel proper times the electron deection m.e`ans;.fY andthe latter, in accordance withk'nwn practice, may comprise suitable field control means', for example, ,auxiliary windings on the magnet' of the accelerator, for causing deilectio'n of theelectrons in the corresponding directions. Thecontacts I9 and 20 thus operate the' control .means inthe manner of triggers Which inturncause momentary current impulses in the deilection coil means, to produce deflection ofthe electrons in the desired direction, either inwardly'or outwardly of the orbital equilibriumpathi..

Inside ofjthe shieldV I is provided a suitable light" source 2| for projecting Iover the mirrors 22f "and 23 two light beams indicated in Fig. 2 by arrows. The mirrors may be formed by foils of suitable material which -is penetrable by the electronsvfrom the window 6 and by the X-rays along -the path to the window 8, respectively. The-mirror 22 disposed in the path of the electron radiation, and the mirror 23 is disposed in the path of the X-ray radiation. The light beams correspond in their spatial dimensions to the dimensions of the electron and X-ray radiations, respectively.

Depending .on the position 1.1.1 which the ,lead

member 9 is adjustedeither for electron'radiel tion from the window 6 or for X-ray radiation from the Window 8-one or the other light beam corresponding thereto will be permitted, topass to the outside to indicate in the manner of a pointer the kind of radiation that i5 atnytime..

eflective.

We ciaim:

1. Electron accelerator having a vessel in which the electrons describe a circular orbital equilibrium path comprising means. formingv Within said vessel insideof said orbital path an X-ray target, means for deectillg the @19619191.15 from the orbital equilibrium path inwardly ont@v said target and alternativeiy .outwardlythereoh means forming separate radiation exibwndows,

one exit window for electrons .and another-remt.

window for X-rays, and control means: for selectively switching in .either one .of sadelectron deection means to produce X-ray .and electron radiation, respectively, for emergence, through the respective exit window.

2. The structure dened in claim i, comprising` X-ray radiationishielding means, a cutoutprovided in said shielding means for-ming said. Xrayy radiation exit window and a' passageforlectrons emerging from said electron exit window, movable shielding means, and means for moving. said movable shielding means for selectively blocking. either said X-ray radiation window orfsaidlelec. tron radiation passage.

3. The structure defined-in claim 2, comprising control means operated bysaid means for moving said movable shielding means to'golern the operation of said deiiection means.

4. The structure definedV in claim J2, wherein said means for moving SaidmoVa'ble shieid-ing means comprises self-locking gear mea-11s.

5. The structuredeiined in claim l, comprising means for producing a light -beamto indi.-

cate the respective operatively eective fX-.ray radiation or electron radiation emerging-"from said Windows.

6. The structure defined in claim 2, coniprisirig means disposed between said Xfray radiationA shielding means and said -vessel to'produce a light beam for individually indicating zthergespeg:T tive radiation emerging from either one of-id.

exit Windows.V

4'1'. Apparatus ior vproducing electron radiation and X-ray radiation, respectively; comprising an electron acceleration AVessel-in vv'uehthe-elec-A trons are caused to move'along a circulariyfex tending orbital path, means forming" inside .of said orbital path an X-ray target, means #forme ing in said vessel an electron exit Window, 2i-ray radiation shielding means disposed outside o f said vessel, an aperture formed-in saidsshieiding means, a radiation blocking member ,movaly disposed in said aperture, andY means for'-moyring said blocking memberto lone termin@ posh.

tion within said aperture in .which position 'the electron radiation from said electron exit 'Window is vblocked while the'X-ray :radiation his efeted;

through the remainder 0.1 the area of Said apen ture and for alternativelrmovng .Said blookms member to the other terminal position in which the X-ray radiation is blocked `while the electron radiation is effected from sadeleetron exitwindow.

8. The structure as set forth in claim 7, in which the means for moving said radiation blockins member comprises means forming guider/ars for movably Asecuring said blocking member, link means articulately connected with said blocking member, and self-locking gear means for ,movingsaid link means to move said blocking member.

9. The. .structure as set forth in ciaim 7, togetherwith'optical means for producing a beam ofV light trained. .to the outside to indicate the. passeggini X-ray radiation or electron radiation, respectively, from said vessel.

l0; Thestructure as set forth in claim 7, together with optical means for producing a beam of liebt trained to the outside to' indicate the passage. of 'Xpres' .radiation 0r eleetlfm radiation, respectively. from said vessel. said optical means compris-ing .a ,light sou-ree .and two mirrors one ofsad mirrors beine;4 disposed in the path of said Xerayradation and the other mirror beine disposed in therath ofnsad electron radiation- '11.;'Ihe .structure as set forth in claim 7, .tog-ether with Contactv means controlled bv said means'for moving said radiation blocking meinber, and. .control means governed by said Contact meansv for effecting ldeilection of the electrons in said vessel .relative to said orbital path.

y12. IThe .structure asset forth in ,claim 7, to.-y getheriwith means for deflecting the ,electrons withinsaid vessel vrelative .to said orbital path. control means for governing said deflection means; and contact'means controlledV by the means` `for moving: said radiation blocking 111cm-, ber ,for governing .the .operation of said vcontrol means,

y1B. TheA structureas set forth in claim 7, to.-

vgather with coi-lv means for defiecting the electrons .within said vesselr relative to said orbital path, control means for governing the current ow. through said coil means, and contact means controlled bythe means `for moving said radiation blocking member for governing the operation lof said control means.

1 4. The structure as set forth in claim 7, -togather with coil means. forfdeflecting the elec trons zwithn said vessel relative to said yX-ray target and said orbital path, respectively, control meansv foi-.governing thecurrent flow through said coll means, and contact means controlled ,pysthe means -fonmoving said radiation blocking member: which become operatively effective iXi-.the respectiveterminal positions thereof for governing 'the operation of said control .means to eiect. alteration of theeurrent now through said coilmeans kforthe purpose of effecting deiection of said electrons upon terminal acceleration thereof.

KONRAD GUND.

HANS. BERGER.

MAX MARTIN SCHEER.

RUDOLF SCHITTENHELM.

References Cited in the 111e 0.5 this patent UNITED STATES PATENTS

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