US2798164A

US2798164A - Portable X-ray or gamma source

Info

Publication number: US2798164A
Application number: US424536A
Authority: US
Inventors: Untermyer Samuel
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-04-20
Filing date: 1954-04-20
Publication date: 1957-07-02
Anticipated expiration: 1974-07-02
Also published as: GB766856A

Description

July 2, Y 1957 s. UNTERMYER 2,798,164

PORTABLE x-RAY 0R GAMMA SOURCE Filed April 2o, 1954 ATTORNEY United States Patent PoRrALE x-RAY on GAMMA sonnen Samuel Uiltermyer,4 Downers Grove, Ill., assigner to .the United States of Americaas'represented by the United States'Atomic Energy Commission Application April 20, 1954, SerialNo. 424,536A

3 Claims. (Cl. Z50-10,6)

This invention relates,` to, a source lof radioactivity, and more particularly, to a. radioactive source that is compact and portable;l

y The need isgreat, for aradioactive source` that can be carried by handv from place to place; Aportable source of radioactivity could have considerablel usey by Army surgeons for emergency X-ray photography-V aud. fluoroscopy at advanced: bases Orrin the feld where: use of a permanent' X-ray;` apparatus is impossible. When the portable source emits; gamma rays, there, willl be con- Sider-able; use, iu. industrial; plants for testing purposes.

'Obit-1ct." of: the: present` inventionV is: toy provide a sourceV off radioativity that is' compact and can readily becarriedr by; hand; I have been; able to: accomplish this by designingl the radioactive source. so that the,- projection: off i'tsactivi-ty can b 'e controlled without the. use; of a; shutter; whichA I haver foundt must: be; very large4` in orderr not; to. limit; the. useful solid angle of. emission of radiation. AA large;l shutter interferes with portability.

Other objects. will become apparent from the.V drawing anddescriptio-rr thatfollows.

In. the; drawing z;

. Fig.,` lis a sectional: view4 taken throughf the n'ovel radioactive, source` oi: the. present invention;-

Fig?. 2:is'.a sectionalfview taken through' theradioactive capsule. employed inithe; above source; and.

FigaA 3. is` a sectional View taken through atportion` of the releasing mechanism for the capsule;

The device;V thatfconstitutes: a radioactive; source` comprises. essentially a'. radioactive. capsule 10:, a shielding body 11 having; a= crooked't or. curved passa-ge, andia wire rod 12 for moving the capsule` 10 between:` an: operative position shown in dotted lines in Fig. l and au inoperative or inactiveA position shownin full-lines; in Fig. l.

The capsule libicomprises an active corea 13 and a casingformed. of a cup 14 and pluglS. which completely enclose, thecore 1'3. The core is formed-of a radioactive material, which emits radiation, of. the. desired.` energy. Thulium--170, which emits 52 k. e. v.,X'-rays, and americium-2l42g1whicli emits 40 k. e. v. gamma raysn are-.suitable sources for radiographic purposes, while cobalt-60 is a suitable source of 1.6 m. e. v. gamma rays for radio- 'graphic purposes and also for therapeutic purposes. The thulium can be a mixture of thulium-169 and thulium- 170, which may be formed by the irradiation of thulium- 169 in a neutronic reactor. The material of the core may be in the form of a metal disk, a compound of the metal, or an enclosure containing powder of the metal or a compound of the metal. lf the core 13 is a disk of metallic thulium, it may be .16 in. in diameter and .070 in thickness. The dimensions listed for the parts about to be described are suitable when the core 13 is thulium or americium. Much larger dimensions are required if the core is cobalt. The cap 14 and plug 15 should be of a corrosion-resistant that does not emit undesirable radiation, such as aluminum. The cup 14 should be .375 in. in length, .050 in. in base thickness, .22 in. in outer diameter, and .16 in. in inner diameter.

The base of the aluminum cap 14 serves to lter out undesirable beta radiation from the thulium. The aluminum plug 15 should be .255 in. in length and .16 in. in outside diameter. There should be an annular bond 16 formed between the ends of the cup 14 and the plug 15 to seal the core 13 within the cup aud the plug.

A fastening member 17, which is secured in a threaded connection to the plug 1S, attaches one end of the wire rod 12 to the capsule I0. The fastening member 17 and the wirev rod 12 may be formed ofk stainless steel and are attached to one another as by bonding.

The body 11 is preferably formed of lead and has a lengthv of 4.19 in. and'a diameter of 1.87 in. The' crooked curved passagev therein mounting'the radioactive capsule 10 is formed by' a stainless-steel tube 1Sl which is embedded in the body 1'11 and extends from the neighborhood of one end face 19 ofA the body through the body almost to an opposite end face 20. The internal diameter of the. tube 18. is` .25 in., so that the capsule 1i), which has an external diameter ofA .22 in., Ihas a loose sliding t therein. The tube 1S is curved in a single plane or is spiral so that when the capsule 10l lies against the. end of a stainless-steel bushing 20a located in one end of the tube 18, that is, lies in the inactive position shown in full lines in Fig. 1, there is no line of sight to the. capsule 10 through the body from end face 19, and so emanations from the capsule 1d cannot get out at this end face. The relatively close fit of' the wire rod 12' in the bushing Ztla prevents escape lof emanations from the capsule at end face 20. The opening in the bushing 20a may be .0625 in. in diameter, and the wire rod 12, .0458 in. in diameter. The bushing 20a is about 'one inch long so that'in the inactive position of the capsule. 10 about oneinch of shieldingA body 1-1 liesbetween the endVV face 20v of thel body andthe capsule. Yet thelateral displacement 'of the intermediate portion of the tube 18 should not" be so much as to reduce the minimum thickness of the body 1'1" at the intermediate portion of the tube 18 to the extent that emanations from the capsule y can escape radially through the body 11.

The endv of the stainless-steel'tube 18 adjacent the end face 19 of the body 11i is at the small end of a conical recess that has a solidY angle Iof about and is formed of? a conical" recess 21 in the body 121 having a diameter of' .26 in. at it-s small end and a conical hole 22 formed in a stainless-steel plate. 23. The outer diameter of the tube 18 is also .26 in., and this is the same size as the smally end' of the recess 21. The depth of thel conical reces 21 is .19 in. The plate 23', which is .125 in; thick, ser-ves tohold againstend face 19 of body 1'1, a plastic plate 2dof .03 in. thickness formedV of methyl methacrylate. Theplate 24 shields the `body 11 againstl the entrance `of foreignl material such as dust at the recess 21. Thepla-te 23n is secured to thebody 11' by three screws 25` spaced about 120 from one another about the conical recess 22. The end face 20 `of the body 11 is covered by a plate 26 which is .125 in. thick and is secured thereto by three screws 27 spaced about 120 from one another about the tube 18. The bushing 20a has an end flange 27a by which the bushing is clamped in a recess in the end face 20 of the body 11 by the plate 26. The body 11 is encased in a cylindrical sheath 28 fof stainless steel, which may be suitably bonded to the

plates

23 and 26.

The wire rod 12 projects considerably beyond the protruding end of the tube 18 and has at its end remote from the capsule 10 a button 29, which may be of stainless steel. A flexible hose or tube 30, which may be of woven metal wire or cloth or both or of spirally wound wire, contains the wire rod 12 and has one end secured within a tubular ange 30a formed on the end plate 26 and a perforated metal disk 31 secured to its other end. The

rod 12 passes through the which surrounds a portion of the rod 12 and lies within the hose 30 has one end secured to the disk 31 and the other end secured to the rod 12 and serves yieldingly to hold the capsule in its inactive position and the button 29 spaced from the disk 31, both as shown in full lines in Fig. 1.

The spacing of the button 29 in its full-line position from the perforated disk 31 is about equal to the distance between the inactive full-line position of the capsule 10 and the active dotted-line position thereof, so that depression of the button 29 to the perforated disk 31 causes the capsule 10 to move from inactive position to active disk 31. A coil `spring 32 position. Engagement of the button 29A with the disk thereby. Release of the button 29 permits the capsule 5 10 to be returned to its inactive full-line position through the action of spring 32. Depression yof the button 29 to the disk 31 may be accomplished by engagement of the button 29 by the thumb and of the disk 31by the index and middle fingers of the same hand, the disk 31 protruding radially outwardly beyond the tube 30 to make the latter engagement possible.

The significant thing about the device of the present invention is that the active capsule 10 moves from an exposed active position at one end of the shielding body 11 to an inactive position deep within the shielding body and that shifting of the active capsule between these positions is carried out manually by means of the wire rod 12 and the spring 32. This arrangement dispenses with the need for shutters or other movable closure elements at the end `where the capsule lies exposed in its active position. Thus there are no moving parts where the active capsule is exposed, the construction is simple and compact, and the over-al1 dimensions are held to a minimum. It is t0 be noted that capsule 10 in its active position gives 01T radiation through a wide angle, about 120, as shown. A rotary shutter at the outside of the plate 23 would have to be quite large in order to handle the wide angle of radiation. The large shutter would make associated parts large and the large over-all size would interfere with portability. Itis also significant that the tube 18 in which the capsule 10 is moved between active and inactive positions is curved in such a way that, when the capsule is in its inactive position, there is no line of sight to the capsule through the end of the tube 18 adjacent the cover 24, and emanations cannot escape through this end of the tube. Emanations cannot escape from the other end of tube 18, because of the relatively close fit of the wire rod 12 in the tubular section 20a.

The intention is to limit the invention only within the scope of the appended claims.

What is claimed is:

1. An assembly comprising a body of shielding material having a curved passage extending therethrough between first and second opposite ends of the body, a capsule con- 4 taining radioactive material and being slidably mounted in the passage for movement between an active position in which it is adjacent said first end of the body and can project its activity through such first end and an inactive position in which it lies between and spaced from said first and second ends while being nearer the second end and is capable of projecting its activity through neither of said ends, a rod connected to the capsule and extending therefrom through the passage and out said second end of the body, a bushing mounted in the end of the tube adjacent the second end of the body and fitting the rod relatively closely, a iiexible tube attached to said second end of the body and housing the portion ofthe rod exterior of said second end of the body While leaving the end of said exterior rod position exposed for manipulation, and resilient means acting between the rod and the end of the flexible tube beyond which the rod lies exposed whereby l. the capsule is urged to its inactive position.

2. The assembly specified in claim 1, the end of the curved passage at said' first end of the body being conical, the assembly further comprising a plastic plate covering said first end of the body and the conical end of the curved passage to retain the capsule in the body, and a retaining plate holding the plastic plate against the body and having a conical opening formed as a continuation of the conical end of the curved passage in the body.

3. An assembly comprising a lead body having a curved passage extending therethrough between first and second opposite faces, a curved stainless-steel tube conforming to the passage throughout its length, a capsule having a radioactive core and an aluminum casing completely enclosing the core, the core being formed of a material emitting gamma rays having an energy of at least 40 k. e. v., said capsule being slidably mounted in the passage for movement between an active position in which it is adjacent said first end of the body and can project its activity through said first end and an inactive position in which it lies between and spaced from said first and second ends but nearer the second end and is capable of projecting its activity through neither of said ends, a rod connected to the capsule casing and extending therefrom through the stainless-steel tube and out of the end of the tube beyond said second face of the body, a bushing mounted in the -tube adjacent the second face of the body and fitting the 45 rod relatively closely, a exible tube having one end connected to the second face of the body and containing the rod, the rod projecting beyond the other end of the exible tube, and a spring acting between the rod and said other end of the flexible tube for acting through the rod to urge the capsule to its inactive position.

References Cited in the file of this patent UNITED STATES PATENTS 2,412,174 Rhoades Dec. 3, 1946 2,551,491 Gilks May 1, 1951 2,622,209 Hjulian et al. Dec. 16, 1952 2,719,823 Zinn Oct. 4, 1955 2,750,517 Baum June 12, 1956

Claims

1.AN ASSEMBLY COMPRISING A BODY OF SHIELDING MATERIAL HAVING A CURVED PASSAGE EXTENDING THERETHROUGH BETWEEN FIRST AND SECOND OPPOSITE ENDS OF THE BODY, A CAPSULE CONTAINING RADIOACTIVE MATERIAL AND BEING SLIDABLY MOUNTED IN THE PASSAGE FOR MOVEMENT BETWEEN AN ACTIVE POSITION IN WHICH IT IS ADJACENT SAID FIRST END OF THE BODY AND CAN PROJECT ITS ACTIVITY THROUGH SUCH FIRST END AND AN INACTIVE POSITION IN WHICH IT LIES BETWEEN AND SPACED FROM SAID FIRST AND SECOND ENDS WHILE BEING NEARER THE SECOND END AND IS CAPABLE OF PROJECTING ITS ACTIVITY THROUGH NEITHER OF SAID ENDS, A ROD CONNECTED TO THE CAPSULE AND EXTENDING THEREFROM THROUGH THE PASSAGE AND OUT SAID SECOND END OF THE BODY, A BUSHING MOUNTED IN THE END OF THE TUBE ADJACENT THE SECOND END OF THE BODY A ND FITTING THE ROD RELATIVELY CLOSELY, A FLEXIBLE TUBE ATTACHED TO SAID SECOND ENDND OF THE BODY AND HOUSING THE PORTION OF THE ROD EXTERIOR OF SAID SECOND END OF THE BODY WHILE LEAVING THE END OF SAID EXTERIOR ROD POSITION EXPOSED FOR MANIPULATION, AND RESILIENT MEANS ACTING BETWEEN THE ROD AND THE END OF THEE FLEXIBLE TUBE BEYOND WHICH THE ROD LIES EXPOSED WHEREBY THE CAPSULE IS URGED TO ITS INACTIVE POSITION.