CA1114148A - Radioactive gas encapsulated in amorphous material - Google Patents
Radioactive gas encapsulated in amorphous materialInfo
- Publication number
- CA1114148A CA1114148A CA292,575A CA292575A CA1114148A CA 1114148 A CA1114148 A CA 1114148A CA 292575 A CA292575 A CA 292575A CA 1114148 A CA1114148 A CA 1114148A
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- CA
- Canada
- Prior art keywords
- particles
- gas
- radioactive gas
- radioactive
- voids
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21H—OBTAINING ENERGY FROM RADIOACTIVE SOURCES; APPLICATIONS OF RADIATION FROM RADIOACTIVE SOURCES, NOT OTHERWISE PROVIDED FOR; UTILISING COSMIC RADIATION
- G21H1/00—Arrangements for obtaining electrical energy from radioactive sources, e.g. from radioactive isotopes, nuclear or atomic batteries
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
- G21F9/02—Treating gases
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21H—OBTAINING ENERGY FROM RADIOACTIVE SOURCES; APPLICATIONS OF RADIATION FROM RADIOACTIVE SOURCES, NOT OTHERWISE PROVIDED FOR; UTILISING COSMIC RADIATION
- G21H5/00—Applications of radiation from radioactive sources or arrangements therefor, not otherwise provided for
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Physical Vapour Deposition (AREA)
- Conductive Materials (AREA)
Abstract
RADIOACTIVE GAS ENCAPSULATED IN AMORPHOUS MATERIAL
ABSTRACT OF THE DISCLOSURE
Amorphous materials containing radioactive gas in the voids thereof are useful in such applications as in the control of radioactive gases and in fabricating controlled radioactive sources. The radioactive gas encapsulating material is formed under electrical stress that entraps approximately 30 atomic percent of the radioactive gas in the voids in the material.
ABSTRACT OF THE DISCLOSURE
Amorphous materials containing radioactive gas in the voids thereof are useful in such applications as in the control of radioactive gases and in fabricating controlled radioactive sources. The radioactive gas encapsulating material is formed under electrical stress that entraps approximately 30 atomic percent of the radioactive gas in the voids in the material.
Description
~. 9 BACKG~OUND AND SUMMARY OF THE INVENTIO~ -., .
Radioactive gases have a detrimental prop!erty in that they ll require substantial care in storage and they have the beneficial 12 properties of providing a wider range of radiation type and energy source 13 than is readily available wlth solid materials. The radioactive gases 14 that are a potentially hazardous by-product of the nuclear fission power production industry are produced during reactor operation and , during nuclear fuel reprocessing. The gases are principally Krypton j 17 (half life 10.76 years), Xenon 33 (half life 5.3 days) and Xenonl35 18 (half life 9.2 hours). Studles reported by E. Csonger in Acta Physica 19 Vol. 28, pp. 109-114 (1970) set forth the fact that the Xr85 activity in the atmosphere increased by a factor of 10 between 1954 and 1964 21 and a slightly slower but comparable rate thereafter. The increasing 22 accumulation of Kr85 can be correlated with the amount of fissioned 23 material consu~ed ln nuclear dev:Lces and reactors. The principal 24 source appears to be nuclear fuel reprocessing plants. It is esti~ated that at the present rate, in the next quarter century, the total `I 26 activity level could reach 109 curies.
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1 Present methods of radioactive gas recovery and storage involve cryogenic absorption on charcoal cooled to liquid nitrogen temperature for eventual sealing into containers. The present methods carry with them the concern that as with any container type of storage there will always be a danger of container failure with a resultant release of the radioactive gas.
The invention, in its broad sense, resides in a new material con-taining radioactive gas in the voids of an amorphous material composed of intermixed, discrete particles; a second aspect of the invention is the manner in which such material is made. The material is useful for containing radioactive gas for storage purposes in solid form and it is further useful as a radioactive source in solid form that has all the flexibility of radiation type and energy of the gaseous form with the ease of handling of the solid form. Further, it has uses as both a source of heat ancl of electrical energy.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view of the material of the invention illustrating the amorphous material containing the radioactive gas.
FIG. lA is an expanded view of the materia1 of FIG. 1 showing the relative sizes of the particles and the ;nterspaces in the amorphous material.
FIG. 2 is a schematic diagram showing the manner in which the radio-active material is encapsulated in the amorphous material.
FIG. 2A is a graph showing the relationship of radioactive gas encap-sulated to the voltage applied during encapsulation.
FIG. 3 is a schematic diagram of one apparatus capable of producing the material of the invention.
FIG. 4 is a schematic diagram of another type of apparatus capable of producing the material of the invention.
. -4~3 1 FIC. 5 is a more detalled diagram of an apparatus capable
Radioactive gases have a detrimental prop!erty in that they ll require substantial care in storage and they have the beneficial 12 properties of providing a wider range of radiation type and energy source 13 than is readily available wlth solid materials. The radioactive gases 14 that are a potentially hazardous by-product of the nuclear fission power production industry are produced during reactor operation and , during nuclear fuel reprocessing. The gases are principally Krypton j 17 (half life 10.76 years), Xenon 33 (half life 5.3 days) and Xenonl35 18 (half life 9.2 hours). Studles reported by E. Csonger in Acta Physica 19 Vol. 28, pp. 109-114 (1970) set forth the fact that the Xr85 activity in the atmosphere increased by a factor of 10 between 1954 and 1964 21 and a slightly slower but comparable rate thereafter. The increasing 22 accumulation of Kr85 can be correlated with the amount of fissioned 23 material consu~ed ln nuclear dev:Lces and reactors. The principal 24 source appears to be nuclear fuel reprocessing plants. It is esti~ated that at the present rate, in the next quarter century, the total `I 26 activity level could reach 109 curies.
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1 Present methods of radioactive gas recovery and storage involve cryogenic absorption on charcoal cooled to liquid nitrogen temperature for eventual sealing into containers. The present methods carry with them the concern that as with any container type of storage there will always be a danger of container failure with a resultant release of the radioactive gas.
The invention, in its broad sense, resides in a new material con-taining radioactive gas in the voids of an amorphous material composed of intermixed, discrete particles; a second aspect of the invention is the manner in which such material is made. The material is useful for containing radioactive gas for storage purposes in solid form and it is further useful as a radioactive source in solid form that has all the flexibility of radiation type and energy of the gaseous form with the ease of handling of the solid form. Further, it has uses as both a source of heat ancl of electrical energy.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view of the material of the invention illustrating the amorphous material containing the radioactive gas.
FIG. lA is an expanded view of the materia1 of FIG. 1 showing the relative sizes of the particles and the ;nterspaces in the amorphous material.
FIG. 2 is a schematic diagram showing the manner in which the radio-active material is encapsulated in the amorphous material.
FIG. 2A is a graph showing the relationship of radioactive gas encap-sulated to the voltage applied during encapsulation.
FIG. 3 is a schematic diagram of one apparatus capable of producing the material of the invention.
FIG. 4 is a schematic diagram of another type of apparatus capable of producing the material of the invention.
. -4~3 1 FIC. 5 is a more detalled diagram of an apparatus capable
2 of encapsulating radioactive gas and forming the material of the
3 invention.
4 FIG. 6 is a schematic diagram of an apparatus capable of encapsulating an entrapping radioactive gas in a solid material.
6 FIG. 7 is a schematic diagram of still another apparatus 7 capable of encapsulating a radioactive gas in a solid material.
8 DETAIL~D DESCRIPTION OF THE I~ENTION
9 Referring to FIG. 1 there is set forth an amorphous body of material 1 made up of a series of discrete particles of different ~ -11 sizes 2 and 3 having between them interspaces 4 into which a radioactive 12 gas may be encapsulated. The amorphous material is a solid. It is ~ ~ -13 generally made of metal, and its only requirements being that it be in 14 a form with the appropriate interspaces for the encapsulation of the ~ -~
radioactive gas. Some amorphous materials exhibit the characteristic 16 that as the temperature is raised, a recrystallizati~n temperature is 17 reached and the entrapped gas is suddenly released in toto.
18 The ratio of encapsulated radioactive gas to amorphous material 19 is substantial and has generally been found to be approximately 30 atomic percent. --21 While the following description, for ease of communication of 22 the principles of the invention, wlll be principally focused on monoatomic 23 gases and on binary alloys as the amorphous materlal and the term particles 24 will be used for both atoms and molecules, it will be apparent to one skilled in the art that the application of the principles of the invention 26 may readily be applied to a wide range of gases and many types of materials 27 serving as the amorphous body 1.
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1 Re~errillg to 11~. IA all cxpancled view is providcd oE the relation-2 sllip betwee~ le particle size of the amorl)hous maLcrial an~ the inter-3 spaces illtO WlliCll the radioactive gas ls to be encapsulated. It will be 4 apparent that there will be a relatlonship between the atom size of the radioactive gas and the si~e of the particles that governs the quantity 6 of the radioactive gas that is encapsulated under a given set of 7 conditions. In FIG. 1~ the amorphous material particles of at least two 8 sizes 2 and 3 are sllown for illustration purposes as tangentially touclling F
9 and bonded to each other. In fact, while at least two sizes of particles are generally required for amorphous material, the particle positions are L
11 random and are somewhat dependent on the details of formation. The spaces 12 4 between indivldual particles 2 and 3 appear to be about one-fourth to 13 one-third of the total volume of the material.
14 The amorphous material serves as a solid encapsulant for the radioactive gas that encompasses the incremcntal portions of the gas 16 as the body of the amorphous material forms. The major condition for 17 a body that will accommodate a large volume of gas is for atoms of 18 different sizes, one of wllich also serves as a stabilizer of the Y
19 resulting body. Systems involving a Lanthanide or an Actinide element and a transition metal are operable. Proposed embodiments are Gadolinium 21 with Co or Fe or Ni or Cu. Similarly, ternary systems of a large atom, -22 which may be any of the Lanthanide or ~ctinide elements, with a smaller ~- F
23 atom, which may be Co, Fe, Ni, or Cu, and a stabilizer element, which may 24 be one of the refractory metals such as Mo, W, Cr, Ti or V. In the case ~_ of rare earths there is a mixture of several rare earth elements that is 26 known as ~IISCI~I~T~L*tllat has advantages of economy. Large atom systems 27 may be employed such as PbFe. A number of criteria for the formation 28 of amorphous materials are set forth in an article by A. S. Nowick and 29 Sigfried ~lader, IB~'Journal, September-November 1965, p. 358.
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1 The factors that contribute to high gas concentration in the 2 amorphous material are the size of the radioactive gas atom, which should ;~
3 be smaller than the lost atoms for ease of accommodation in the spaces 4, 4 and the force with which the gas is introduced into the amorphous material as it is produced. The force is produced by an impressed voltage main~
6 tained during growth. Table I illustrates the relationship of the radio~
7 active gas radius to the volume encapsulated in the amorphous material 8 for a particular set of amorphous material growth conditions. ~ ;
VOLU~IE
ATO~I~CINCORPORATION
GAS RADIUS A IN A CONSTANTS
11 He 0.93 3.37 % (Volts) 2 12 Ne 1.12 5.89 15.85xlO 4 13 Ar 1.54 15.30 3.79x10 4 14 Kr 1.69 20.22 2.49x10 4 Xe 1.90 28.73 1.48x10 4 16 The radioactive gas is encapsulated by the particles of the ;
17 amorphous material as the latter material is sputter deposited in a ~ -18 process whereby a potential stress in the form of an impressed voltage V
19 can be maintained that direc~s-the gas atoms or molecules into the amorphous material. The growth follows the relationship 21 Eq~ 1 % Gas = Incorporation Constant X VA .
22 The technique of bias sputtering and ion plating kno~ in the 23 art may be adapted for use in fabricating the material of the invention. ~-24 Referring now to FIG. 2 a schematic is shown of a manufacturing principle usable in producing the amorphous material as set forth in the 26 invention. In FIG. 2 the amorphous material 1 is being formed between ;
27 the cathode 5 and the target anode 6. It is illustrated as being produced 28 in the presence of a potential stress labeled VA operable to drive the YO976-058 - 5 ~
1 rndioactive gas atoms 7 into the ~rowing amorphous material 1. The 2 elements labeled 8 represent atom~ or molecules of the amorphous 3 material, the source of which is the cathode 5. ~nder this physical 4 process it will be apparent that as the amorphous material 1 forms, the presence of the electrical stress operates to entrap the radioactive 6 gas atoms or molecules in the voids in the molecules or atoms of the 7 amorphous material as it progresses in physical si~e.
8 The radioactive gas concentration in the amorphous material is g related generally as the square of the stress potential with deviations at high potentials. The relationship is illustrated in connection with 11 FIG. 2A where the concentration is seen to increase generally as a power 12 of the voltage which for the diode configuration in FIG. 2 is VA . The 13 relationship of gas concentration to potential stress is set forth in the 14 article "Incorporation of Rare Gases in Sputtered Amorphous Metal Films"
by J. J. Cuomo and R. J. Gambino, Journal of Vacuum Science & Technology, 16 Vol. 14, No. 1, January 1977, p. 152.
17 The radioactive gas encapsulated amorphous material of the 18 invention may be fo~med in any process wherein particles are agglomerated 19 and caused to coalesce in the presence of a potential stress that drives the radioactive gas atoms into the amorphous material. The techniques 21 of bias sputtering, ion plating, and of ion pumping known in the art 22 operate under principles that are adaptable to the requirements set forth.
23 In FIGS. 3, 4 and 5 there is shown sputtering, ion plating and ion pumping 24 apparatus usable ln accordance with the invention.
Referring next to FIG. 3 a schematic view of a sputtering 26 apparatus is shown. The view illustrates the amorphous material 1 27 deposited on anode 6. The ion beam source 9A contains the radioactive 28 gas 7 and direction capability. The ion beam source 9A is made up of an YO976-058 - ~ -1 AC heater 10 which provides electrons which are accelerated to ionize 2 the radioactive gas 7. The ion beam source 9A has the sides 11 at a 3 + potential and an aligning screen 12A made up of a screen grid usually 4 at a positive potential and an accelerating grid 12B usually at a negative potential. This operates to accelerate radioactive gas ions 6 7 toward the amorphous material 1. The ion beam source 9A is surrounded 7 by a cathode member 9B which serves as a source of amorphous material 8 which also causes the amorphous material 1 forming at the target to have ~ ;
g the periphery thereof of consisting entirely of amorphous material. Hence, the radioactive gas encapsulated portion will thereby be confined to the -11 center. In accordance with this principle various desired shapes may be 12 fabricated.
13 Referring next to FIG. 4, an apparatus useful in`connection 14 with the invention, patterned on the technique of ion plating, is set forth in which an evaporator portion 15 is shown having a container 16 16 in which is usually heated a source of amorphous material 17. The 17 radioactive gas 7 is in the ambient. Again, the electrical stress is 18 illustrated by VA between the forming amorphous material body 1 and the 19 radioactive gas atoms 7. Thus, simultaneously along with evaporation an electrical stress is placed on the molecules of the radioactive gas 21 atoms 7 causing them to be incorporated within the interstices of the 22 amorphous material 1 as it forms.
23 Referring nèxt to FIG. 5, an apparatus useful in colmection 24 with the invention patterned after the technique of ion pumping known in the art is shown. In FIG. 5, two cathodes 20A and 20B are shown 26 within a magnetic field labeled ~. The material of cathodes 20A
27 and 20B is the source of the amorphous material 8. The target anodes 28 21A and 21B are positioned between the cathodes 20A and 20B in the 29 magnetic field. An electrical field accelerates ions of the radioactive !
YO976~058 - 7 -1 gas 8 ]abcled ~ to the cathodes 20A alld 201~. Cooling, illustrated by 2 tube6 22, is provided to e~ ance entrapment of the radioactive gas. The 3 amorpllous materlal 8 ill~-strated by ~ is sputtcred off the cathodes 20A
4 and 20B, mixed with the radioactive gas 7 illustrated by 0 and is formed into the ~adioactive gas entrapping amorphous material on the anodes 21A ~ -6 and 21~. It should be noted that in this apparatus the radioactive gas 7 atoms are propelled to the amorphous material source as ions and are 8 reflected therefrom into the amorpllous material body as neutral atoms.
9 Where the application of the invention is directed to the control and storage of radioactlve gas produced for example, as a by-product L
11 of another operation such as that of a nuclear reaction, it is necessary 12 that provision be made that the resulting amorphous material have its 13 radioactlvity confined within handling limits and that all the radioactive 14 gas be encapsulated in the amorphous material. These goals can be accom- i plished by serial apparatus that monitors the radioactivity of the gas 16 and recycles for further processing as needed.
17 Referring next to FIG. 6 there is shown a serial sputtering 18 apparatus equipped ~ith tlle capability to introduce non-radioactlve gases19 which are used to dilute the concentration of radioactive gas in the amorphous material if needed to control the radioactivity of the amorphous 21 material and to monitor the output so that, if desired, it is possible 22 to recycle the gas so that all of the radioactive gas is entrapped in the 23 amorphous solid in the desired concentration. The apparatus of FIG. 6 24 consists of serial sputtering apparatus 30 and 31 connected by tubing 32, each of which have an anode electrode position for the amorphous material 1 26 and cathode target 33 and 34 which is the source of the amorphous material.
27 ~n electrical stress not labeled, applied as in the earlier FIG. 2 is present 28 in this apparatus. The flow of radioactive gas into the system is cor.
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l trolled by valve 35. Valves 36 and 37 are operated to lntroduce a non~
2 radioactive gas dlluent.
3 Where it is desired to increase the final radioactivity of 4 the amorphous materlal, a second source of a radioactive gas may be introduced through valve 37 instead of a diluent gas. ~ radiation 6 detector 38 is supplied to indicate whether or not all of the radio~
7 active gas has been encapsulated. Provision is made through valve 39 8 to recycle into device 30 through tublng not shown, or to exhaust, as g desired. Obviously further units such as 30 and 31 may be added as desired. In employing the principles of the apparatus of FIG. 6 it is 11 possible to entrap all of the radioactive gas in any desired concentra-12 tion in the amorphous material.
13 It will be apparent to one skilled in the art that what is 14 set forth in connection with FIG. 6 is a serial sputtering type of lS apparatus wherein, as set forth in connection with FIG. 2, the radio- ~ `
16 active gas is entrapped in the amorphous material target under electrical 17 stress, wherein flexible provision is provided to dilute or increase the ].8 concentration of the radioactive gas in the amorphoùs material and wherein 19 the radioactive gas may be recycled until all is entrapped.
Where specifications indicate it to be useful, a radioactivity 21 inhibiting coating may be placed over all or part of the amorphous 22 material.
23 Referring next to FIG. 7, the principles of an apparatus are 24 shown which extend the formation principles set forth in connection with the encapsulation of the radioactive gas in the amorphous material 26 to multiple targets. The apparatus of FIG. 7 includes a chamber 50 ; 27 into which a radioactive gas 51 such as Xenonl33 is introduced through a 28 valve 52. Provision is also made for a diluent gas if desired through Y0976-058 ~ 9 ~
1 tube 53. Tlle chamber 50 may be sealed off from the rest of the apparatus 2 by a baffle valve 54 and is equipped with refrigerating means 55 capable 3 of condensing or solid~fying the gas 51. The means 55 may, for example, 4 be a container of liquid nitrogen and results in the gas 51 forming a solid illustrated as 5iA. The function of the means 55 is to permit a ~-6 greater quantity of gas to be placed in the apparatus for entrapment.
7 The apparatus of FIG. 7 has a second chamber 56 in which the 8 encapsulated radioactive gas amorphous material is formed. The chamber 9 56 is equipped with a vacuum pump 57 controlled by a valve 58 with provision for recycling the evacuated gas by tubing 59j the remainder, 11 not shown, connected. In addition, the gas in the chamber may be sensed 12 by a radiation detector 60. The chamber can be back filled through ;~
13 valve 61 and tubing 62 shown, or connected to recycle or exhaust as desired.
14 The amorphous material formation chamber 56 is equipped with a series of ~ `
source tube electrodes 63A-E of amorphous material, a series of amorphous 16 material accumulation rods 64A-E each positioned with a tube 63A-E. The 17 accumulation rods may be cooled to enhance amorphous material formation 18 thereon and to extract heat produced by the radioaccive decay process. The 19 tubes 63A-E and rods 64A-E are mounted in an insulator member 65 so that an electrical stress VA may be applied as set forth in connection with 21 FIG. 2. A ground shield 66 is positioned to prevent shorting where the 22 tubes 63A-E and rods 64A-E are mounted. `
23 In operation, using Xel33 as a radioactive gas example, both 24 chambers 50 and 56 are evacuated using the vacuum pump 57 with valves 52 `
and 61 closed and 54 and 58 open. Valve 54 is then closed to separate 26 the chambers and the radioactive gas 51 in this illustration Xel33 is 27 introduced into the chamber 50 by opening valve 52. The refrigerator 55 28 solidifies the radioactive gas to the solid 51A. At this point valve 52 `~-''` ~
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1 is closed and the temperature is increased until the solid 51A begins 2 to convert to a gas with a vapor pressure of 100 milli Torr. The 3 baffle valve 54 is then opened permitting the radioactive gas 51 to 4 enter the chamber 56. A VA is then applied so that the tube electrodes 63A-E are at -2000 volts and the rod electrodes 64A-E at -150 volts.
6 The material of the tube electrodes 63A-E is sputtered onto the rod 7 electrodes 64~-E encapsulating the radioactive gas 51. When the plasma 8 current, flowing between the electrodes 63A-E and 64A-E drops, the radio-9 active gas, Xel33 in this illustration, will have been consumed. The refrigeration means 55 may then be employed to solidify any remaining 11 traces of gas. The chamber 56 may be evacuated of any remaining radio- ~;~
12 active gas by closing valve 54 and employing the vacuum pump to recycle.
13 The rods 64A-E with the radioactive gas 51 encapsulated in 14 amorphous material may be overcoated with any desired material and removed, after back filling the chamber 56 through valve 61 and tube 62.
16 It will be apparent that physical handling is minimal and that the 17 apparatus in principle will accommodate assemblage of tubes and rods 18 as an interchangeable unit.
19 The power consumption in the encapsulation is principally the plasma current times the electrical stress voltage VA. The figure is 21 generally 0.1% of the energy of the fission process producing the radio-22 active gas. For the gas Krypton35 it has been found to be 100 killowatt ~`
23 hours per mole.
24 The radioactive gas encapsulated material of the invention has a variety of uses. The material may be chosen and tailored to the radio-26 active decay process, for exàmple, with the principles of the invention 27 it is possible to produce a material which is suitable for Neutron absorp-28 tion.
29 It will also be apparent that the interatomic spacing between ~. : ~ . ,: : ,, :
1 thc host atoms of the amorphous material is essentially unaffected by 2 the incorporation of the radioactive gas atoms and by their subsequent 3 decay. This dimensional stability is an advantage over previously 4 known crystalline materials.
The following tables II and III set forth some illustrative 6 properties of the material of the invention when used as a source of 7 heat and as a source of electricity: -HEAT
g INITIAL POt~ER % ISOTOPE IN INITIAL POWER
FOR PURE SOLID ELE~IENT FISSION FOR SOLID FISSION
IS~rOPEISOTOPE PRODUCT PRODUCT _ HALF-LIFE
11 KryptOn85 _ 4.4 watts/cc - 7.5 Atomic % - 0.33 watts/cc - 10.8 years 12 Xenon -2100 watts/cc - 19 Atomic % - 390 watts/cc - 5.3 days 13 Xenonl35 - 77000 watts/cc - 18 Atomic % 14000 watts/cc - 9.2 hours 14It will be apparent from the above examples that a liter of the 15radioactive Krypton35 encapsulated in amorphous material of the invention ~;
16 would provide the 330 watts useful for hot water heating for the average 17 home for over a decade and that the heat energy available is greater than 18 the energy it takes to form the material.
ELECTRICITY
21 ~T~RIALIN WATTS/cc INITIAL CURRENT HALF-LIFE ~ ;
22 KryptOn85 0.33 7xlO 6 Ampsjcc 10.8 years 23 Xenonl33 5xlO Amps/cc 5.3 days 24 Xenonl3514000 7xlO Amps/cc 9.2 hours 25For application as a source of electricity, it will be necessary 26 to form thin films of the amor~hous material in order that the electrons 27 emitted in the radioactive decay may be captured before they lose much of 28their energy. ;' Y0976-058 - 12 - ~ ;;
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ere a class of materials suitable for a number of device 2 applications are desired WiliCIl require a radioactive source with carefully 3 tailored characteristics the principles of the invention will provide this.
4 Eor a given application the following characteristics may be required:
6 1. Radiation type ~, ~ or y.
7 2. Characteristic energy.
8 3. Level of activity.
9 4. Containment of the radioactive substance and any radioactive products of the decay process.
11 In accordance with the invention, the amorphous material 1 12 containing the radioactive gas can be prepared to meet a given set of 13 specifications by (a) selecting one of the radioactive gas isotopes with '~`-14 the desired radiation type characteristic energy and (b) incorporating that isotope into the amorphous material 1 by sputtering from a non- -16 radioactive target in a plasma containing the radioact,ive isotope.
17 The level of activity will be determined by the concentration of 18 the radioactive gas ln the amorphous matet,ial. The concentration is easily 19 controlled because it has a simple functional dependence on the bias voltage applied to the growlng amorphous material as it is formed. Containment of 21 the decay products even if they are gaseous occurs within the amorphous 22 materi.al structure. The following Table IV sets forth a number of devices 23 using radioactive sources:
24 TABLE IV '~
Radiation Activity ~ ;
Type Energy Level 26 ~-Back Scattering-Coating ~ 0.02 Mev. Low 27 Thickness Monitors to 1.0 Mev.
28 Ioniza~ion Type Smoke Detectors ~ ~5 Mev. Low 29 Trigger Source for Gas Discharge ~ 0.72 Mev. Low Lamps and Related Devices ~ 0.54 ~fev.
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lIt will be apparent to one skilled in the art that in accordance 2 Witll the principles of the invention the ability to prepare a radioactive 3 source by the technique set forth in the invention provides a source that 4 is readily adapted to fabricating in special structures. For example, a small area source approaching a point source can be made by depositing the 6 amorphous material through a mask. A planar source for such applications 7 as contact microradiography can be prepared by making a blanket coating of 8 the amorphous material containing the radioactive gas. One particular .
g advantage of these methods of fabrication are that they avoid many of the 10hazards of fabricating, machining or otherwise handling a bulk radioactive ~ -11 sample.
12~hat has been set forth is new material made up of an amorphous 13 structure having incorporated therein a radioactive gas which is useful 14 both for possibly containing radloactive gases and for a variety of special applications as an easily handleable and fabricateable radioactive source.
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6 FIG. 7 is a schematic diagram of still another apparatus 7 capable of encapsulating a radioactive gas in a solid material.
8 DETAIL~D DESCRIPTION OF THE I~ENTION
9 Referring to FIG. 1 there is set forth an amorphous body of material 1 made up of a series of discrete particles of different ~ -11 sizes 2 and 3 having between them interspaces 4 into which a radioactive 12 gas may be encapsulated. The amorphous material is a solid. It is ~ ~ -13 generally made of metal, and its only requirements being that it be in 14 a form with the appropriate interspaces for the encapsulation of the ~ -~
radioactive gas. Some amorphous materials exhibit the characteristic 16 that as the temperature is raised, a recrystallizati~n temperature is 17 reached and the entrapped gas is suddenly released in toto.
18 The ratio of encapsulated radioactive gas to amorphous material 19 is substantial and has generally been found to be approximately 30 atomic percent. --21 While the following description, for ease of communication of 22 the principles of the invention, wlll be principally focused on monoatomic 23 gases and on binary alloys as the amorphous materlal and the term particles 24 will be used for both atoms and molecules, it will be apparent to one skilled in the art that the application of the principles of the invention 26 may readily be applied to a wide range of gases and many types of materials 27 serving as the amorphous body 1.
Y0976-058 - 3 - ~ ~
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1 Re~errillg to 11~. IA all cxpancled view is providcd oE the relation-2 sllip betwee~ le particle size of the amorl)hous maLcrial an~ the inter-3 spaces illtO WlliCll the radioactive gas ls to be encapsulated. It will be 4 apparent that there will be a relatlonship between the atom size of the radioactive gas and the si~e of the particles that governs the quantity 6 of the radioactive gas that is encapsulated under a given set of 7 conditions. In FIG. 1~ the amorphous material particles of at least two 8 sizes 2 and 3 are sllown for illustration purposes as tangentially touclling F
9 and bonded to each other. In fact, while at least two sizes of particles are generally required for amorphous material, the particle positions are L
11 random and are somewhat dependent on the details of formation. The spaces 12 4 between indivldual particles 2 and 3 appear to be about one-fourth to 13 one-third of the total volume of the material.
14 The amorphous material serves as a solid encapsulant for the radioactive gas that encompasses the incremcntal portions of the gas 16 as the body of the amorphous material forms. The major condition for 17 a body that will accommodate a large volume of gas is for atoms of 18 different sizes, one of wllich also serves as a stabilizer of the Y
19 resulting body. Systems involving a Lanthanide or an Actinide element and a transition metal are operable. Proposed embodiments are Gadolinium 21 with Co or Fe or Ni or Cu. Similarly, ternary systems of a large atom, -22 which may be any of the Lanthanide or ~ctinide elements, with a smaller ~- F
23 atom, which may be Co, Fe, Ni, or Cu, and a stabilizer element, which may 24 be one of the refractory metals such as Mo, W, Cr, Ti or V. In the case ~_ of rare earths there is a mixture of several rare earth elements that is 26 known as ~IISCI~I~T~L*tllat has advantages of economy. Large atom systems 27 may be employed such as PbFe. A number of criteria for the formation 28 of amorphous materials are set forth in an article by A. S. Nowick and 29 Sigfried ~lader, IB~'Journal, September-November 1965, p. 358.
*Trade Marks Y0976-058 ~ 4 ~
t~ :
1 The factors that contribute to high gas concentration in the 2 amorphous material are the size of the radioactive gas atom, which should ;~
3 be smaller than the lost atoms for ease of accommodation in the spaces 4, 4 and the force with which the gas is introduced into the amorphous material as it is produced. The force is produced by an impressed voltage main~
6 tained during growth. Table I illustrates the relationship of the radio~
7 active gas radius to the volume encapsulated in the amorphous material 8 for a particular set of amorphous material growth conditions. ~ ;
VOLU~IE
ATO~I~CINCORPORATION
GAS RADIUS A IN A CONSTANTS
11 He 0.93 3.37 % (Volts) 2 12 Ne 1.12 5.89 15.85xlO 4 13 Ar 1.54 15.30 3.79x10 4 14 Kr 1.69 20.22 2.49x10 4 Xe 1.90 28.73 1.48x10 4 16 The radioactive gas is encapsulated by the particles of the ;
17 amorphous material as the latter material is sputter deposited in a ~ -18 process whereby a potential stress in the form of an impressed voltage V
19 can be maintained that direc~s-the gas atoms or molecules into the amorphous material. The growth follows the relationship 21 Eq~ 1 % Gas = Incorporation Constant X VA .
22 The technique of bias sputtering and ion plating kno~ in the 23 art may be adapted for use in fabricating the material of the invention. ~-24 Referring now to FIG. 2 a schematic is shown of a manufacturing principle usable in producing the amorphous material as set forth in the 26 invention. In FIG. 2 the amorphous material 1 is being formed between ;
27 the cathode 5 and the target anode 6. It is illustrated as being produced 28 in the presence of a potential stress labeled VA operable to drive the YO976-058 - 5 ~
1 rndioactive gas atoms 7 into the ~rowing amorphous material 1. The 2 elements labeled 8 represent atom~ or molecules of the amorphous 3 material, the source of which is the cathode 5. ~nder this physical 4 process it will be apparent that as the amorphous material 1 forms, the presence of the electrical stress operates to entrap the radioactive 6 gas atoms or molecules in the voids in the molecules or atoms of the 7 amorphous material as it progresses in physical si~e.
8 The radioactive gas concentration in the amorphous material is g related generally as the square of the stress potential with deviations at high potentials. The relationship is illustrated in connection with 11 FIG. 2A where the concentration is seen to increase generally as a power 12 of the voltage which for the diode configuration in FIG. 2 is VA . The 13 relationship of gas concentration to potential stress is set forth in the 14 article "Incorporation of Rare Gases in Sputtered Amorphous Metal Films"
by J. J. Cuomo and R. J. Gambino, Journal of Vacuum Science & Technology, 16 Vol. 14, No. 1, January 1977, p. 152.
17 The radioactive gas encapsulated amorphous material of the 18 invention may be fo~med in any process wherein particles are agglomerated 19 and caused to coalesce in the presence of a potential stress that drives the radioactive gas atoms into the amorphous material. The techniques 21 of bias sputtering, ion plating, and of ion pumping known in the art 22 operate under principles that are adaptable to the requirements set forth.
23 In FIGS. 3, 4 and 5 there is shown sputtering, ion plating and ion pumping 24 apparatus usable ln accordance with the invention.
Referring next to FIG. 3 a schematic view of a sputtering 26 apparatus is shown. The view illustrates the amorphous material 1 27 deposited on anode 6. The ion beam source 9A contains the radioactive 28 gas 7 and direction capability. The ion beam source 9A is made up of an YO976-058 - ~ -1 AC heater 10 which provides electrons which are accelerated to ionize 2 the radioactive gas 7. The ion beam source 9A has the sides 11 at a 3 + potential and an aligning screen 12A made up of a screen grid usually 4 at a positive potential and an accelerating grid 12B usually at a negative potential. This operates to accelerate radioactive gas ions 6 7 toward the amorphous material 1. The ion beam source 9A is surrounded 7 by a cathode member 9B which serves as a source of amorphous material 8 which also causes the amorphous material 1 forming at the target to have ~ ;
g the periphery thereof of consisting entirely of amorphous material. Hence, the radioactive gas encapsulated portion will thereby be confined to the -11 center. In accordance with this principle various desired shapes may be 12 fabricated.
13 Referring next to FIG. 4, an apparatus useful in`connection 14 with the invention, patterned on the technique of ion plating, is set forth in which an evaporator portion 15 is shown having a container 16 16 in which is usually heated a source of amorphous material 17. The 17 radioactive gas 7 is in the ambient. Again, the electrical stress is 18 illustrated by VA between the forming amorphous material body 1 and the 19 radioactive gas atoms 7. Thus, simultaneously along with evaporation an electrical stress is placed on the molecules of the radioactive gas 21 atoms 7 causing them to be incorporated within the interstices of the 22 amorphous material 1 as it forms.
23 Referring nèxt to FIG. 5, an apparatus useful in colmection 24 with the invention patterned after the technique of ion pumping known in the art is shown. In FIG. 5, two cathodes 20A and 20B are shown 26 within a magnetic field labeled ~. The material of cathodes 20A
27 and 20B is the source of the amorphous material 8. The target anodes 28 21A and 21B are positioned between the cathodes 20A and 20B in the 29 magnetic field. An electrical field accelerates ions of the radioactive !
YO976~058 - 7 -1 gas 8 ]abcled ~ to the cathodes 20A alld 201~. Cooling, illustrated by 2 tube6 22, is provided to e~ ance entrapment of the radioactive gas. The 3 amorpllous materlal 8 ill~-strated by ~ is sputtcred off the cathodes 20A
4 and 20B, mixed with the radioactive gas 7 illustrated by 0 and is formed into the ~adioactive gas entrapping amorphous material on the anodes 21A ~ -6 and 21~. It should be noted that in this apparatus the radioactive gas 7 atoms are propelled to the amorphous material source as ions and are 8 reflected therefrom into the amorpllous material body as neutral atoms.
9 Where the application of the invention is directed to the control and storage of radioactlve gas produced for example, as a by-product L
11 of another operation such as that of a nuclear reaction, it is necessary 12 that provision be made that the resulting amorphous material have its 13 radioactlvity confined within handling limits and that all the radioactive 14 gas be encapsulated in the amorphous material. These goals can be accom- i plished by serial apparatus that monitors the radioactivity of the gas 16 and recycles for further processing as needed.
17 Referring next to FIG. 6 there is shown a serial sputtering 18 apparatus equipped ~ith tlle capability to introduce non-radioactlve gases19 which are used to dilute the concentration of radioactive gas in the amorphous material if needed to control the radioactivity of the amorphous 21 material and to monitor the output so that, if desired, it is possible 22 to recycle the gas so that all of the radioactive gas is entrapped in the 23 amorphous solid in the desired concentration. The apparatus of FIG. 6 24 consists of serial sputtering apparatus 30 and 31 connected by tubing 32, each of which have an anode electrode position for the amorphous material 1 26 and cathode target 33 and 34 which is the source of the amorphous material.
27 ~n electrical stress not labeled, applied as in the earlier FIG. 2 is present 28 in this apparatus. The flow of radioactive gas into the system is cor.
'~
_~ _. . .... _ .. .. . _ .
l trolled by valve 35. Valves 36 and 37 are operated to lntroduce a non~
2 radioactive gas dlluent.
3 Where it is desired to increase the final radioactivity of 4 the amorphous materlal, a second source of a radioactive gas may be introduced through valve 37 instead of a diluent gas. ~ radiation 6 detector 38 is supplied to indicate whether or not all of the radio~
7 active gas has been encapsulated. Provision is made through valve 39 8 to recycle into device 30 through tublng not shown, or to exhaust, as g desired. Obviously further units such as 30 and 31 may be added as desired. In employing the principles of the apparatus of FIG. 6 it is 11 possible to entrap all of the radioactive gas in any desired concentra-12 tion in the amorphous material.
13 It will be apparent to one skilled in the art that what is 14 set forth in connection with FIG. 6 is a serial sputtering type of lS apparatus wherein, as set forth in connection with FIG. 2, the radio- ~ `
16 active gas is entrapped in the amorphous material target under electrical 17 stress, wherein flexible provision is provided to dilute or increase the ].8 concentration of the radioactive gas in the amorphoùs material and wherein 19 the radioactive gas may be recycled until all is entrapped.
Where specifications indicate it to be useful, a radioactivity 21 inhibiting coating may be placed over all or part of the amorphous 22 material.
23 Referring next to FIG. 7, the principles of an apparatus are 24 shown which extend the formation principles set forth in connection with the encapsulation of the radioactive gas in the amorphous material 26 to multiple targets. The apparatus of FIG. 7 includes a chamber 50 ; 27 into which a radioactive gas 51 such as Xenonl33 is introduced through a 28 valve 52. Provision is also made for a diluent gas if desired through Y0976-058 ~ 9 ~
1 tube 53. Tlle chamber 50 may be sealed off from the rest of the apparatus 2 by a baffle valve 54 and is equipped with refrigerating means 55 capable 3 of condensing or solid~fying the gas 51. The means 55 may, for example, 4 be a container of liquid nitrogen and results in the gas 51 forming a solid illustrated as 5iA. The function of the means 55 is to permit a ~-6 greater quantity of gas to be placed in the apparatus for entrapment.
7 The apparatus of FIG. 7 has a second chamber 56 in which the 8 encapsulated radioactive gas amorphous material is formed. The chamber 9 56 is equipped with a vacuum pump 57 controlled by a valve 58 with provision for recycling the evacuated gas by tubing 59j the remainder, 11 not shown, connected. In addition, the gas in the chamber may be sensed 12 by a radiation detector 60. The chamber can be back filled through ;~
13 valve 61 and tubing 62 shown, or connected to recycle or exhaust as desired.
14 The amorphous material formation chamber 56 is equipped with a series of ~ `
source tube electrodes 63A-E of amorphous material, a series of amorphous 16 material accumulation rods 64A-E each positioned with a tube 63A-E. The 17 accumulation rods may be cooled to enhance amorphous material formation 18 thereon and to extract heat produced by the radioaccive decay process. The 19 tubes 63A-E and rods 64A-E are mounted in an insulator member 65 so that an electrical stress VA may be applied as set forth in connection with 21 FIG. 2. A ground shield 66 is positioned to prevent shorting where the 22 tubes 63A-E and rods 64A-E are mounted. `
23 In operation, using Xel33 as a radioactive gas example, both 24 chambers 50 and 56 are evacuated using the vacuum pump 57 with valves 52 `
and 61 closed and 54 and 58 open. Valve 54 is then closed to separate 26 the chambers and the radioactive gas 51 in this illustration Xel33 is 27 introduced into the chamber 50 by opening valve 52. The refrigerator 55 28 solidifies the radioactive gas to the solid 51A. At this point valve 52 `~-''` ~
Y0976-058 - 10 - ~
.
. .' , ' "
`:
1 is closed and the temperature is increased until the solid 51A begins 2 to convert to a gas with a vapor pressure of 100 milli Torr. The 3 baffle valve 54 is then opened permitting the radioactive gas 51 to 4 enter the chamber 56. A VA is then applied so that the tube electrodes 63A-E are at -2000 volts and the rod electrodes 64A-E at -150 volts.
6 The material of the tube electrodes 63A-E is sputtered onto the rod 7 electrodes 64~-E encapsulating the radioactive gas 51. When the plasma 8 current, flowing between the electrodes 63A-E and 64A-E drops, the radio-9 active gas, Xel33 in this illustration, will have been consumed. The refrigeration means 55 may then be employed to solidify any remaining 11 traces of gas. The chamber 56 may be evacuated of any remaining radio- ~;~
12 active gas by closing valve 54 and employing the vacuum pump to recycle.
13 The rods 64A-E with the radioactive gas 51 encapsulated in 14 amorphous material may be overcoated with any desired material and removed, after back filling the chamber 56 through valve 61 and tube 62.
16 It will be apparent that physical handling is minimal and that the 17 apparatus in principle will accommodate assemblage of tubes and rods 18 as an interchangeable unit.
19 The power consumption in the encapsulation is principally the plasma current times the electrical stress voltage VA. The figure is 21 generally 0.1% of the energy of the fission process producing the radio-22 active gas. For the gas Krypton35 it has been found to be 100 killowatt ~`
23 hours per mole.
24 The radioactive gas encapsulated material of the invention has a variety of uses. The material may be chosen and tailored to the radio-26 active decay process, for exàmple, with the principles of the invention 27 it is possible to produce a material which is suitable for Neutron absorp-28 tion.
29 It will also be apparent that the interatomic spacing between ~. : ~ . ,: : ,, :
1 thc host atoms of the amorphous material is essentially unaffected by 2 the incorporation of the radioactive gas atoms and by their subsequent 3 decay. This dimensional stability is an advantage over previously 4 known crystalline materials.
The following tables II and III set forth some illustrative 6 properties of the material of the invention when used as a source of 7 heat and as a source of electricity: -HEAT
g INITIAL POt~ER % ISOTOPE IN INITIAL POWER
FOR PURE SOLID ELE~IENT FISSION FOR SOLID FISSION
IS~rOPEISOTOPE PRODUCT PRODUCT _ HALF-LIFE
11 KryptOn85 _ 4.4 watts/cc - 7.5 Atomic % - 0.33 watts/cc - 10.8 years 12 Xenon -2100 watts/cc - 19 Atomic % - 390 watts/cc - 5.3 days 13 Xenonl35 - 77000 watts/cc - 18 Atomic % 14000 watts/cc - 9.2 hours 14It will be apparent from the above examples that a liter of the 15radioactive Krypton35 encapsulated in amorphous material of the invention ~;
16 would provide the 330 watts useful for hot water heating for the average 17 home for over a decade and that the heat energy available is greater than 18 the energy it takes to form the material.
ELECTRICITY
21 ~T~RIALIN WATTS/cc INITIAL CURRENT HALF-LIFE ~ ;
22 KryptOn85 0.33 7xlO 6 Ampsjcc 10.8 years 23 Xenonl33 5xlO Amps/cc 5.3 days 24 Xenonl3514000 7xlO Amps/cc 9.2 hours 25For application as a source of electricity, it will be necessary 26 to form thin films of the amor~hous material in order that the electrons 27 emitted in the radioactive decay may be captured before they lose much of 28their energy. ;' Y0976-058 - 12 - ~ ;;
s~
ere a class of materials suitable for a number of device 2 applications are desired WiliCIl require a radioactive source with carefully 3 tailored characteristics the principles of the invention will provide this.
4 Eor a given application the following characteristics may be required:
6 1. Radiation type ~, ~ or y.
7 2. Characteristic energy.
8 3. Level of activity.
9 4. Containment of the radioactive substance and any radioactive products of the decay process.
11 In accordance with the invention, the amorphous material 1 12 containing the radioactive gas can be prepared to meet a given set of 13 specifications by (a) selecting one of the radioactive gas isotopes with '~`-14 the desired radiation type characteristic energy and (b) incorporating that isotope into the amorphous material 1 by sputtering from a non- -16 radioactive target in a plasma containing the radioact,ive isotope.
17 The level of activity will be determined by the concentration of 18 the radioactive gas ln the amorphous matet,ial. The concentration is easily 19 controlled because it has a simple functional dependence on the bias voltage applied to the growlng amorphous material as it is formed. Containment of 21 the decay products even if they are gaseous occurs within the amorphous 22 materi.al structure. The following Table IV sets forth a number of devices 23 using radioactive sources:
24 TABLE IV '~
Radiation Activity ~ ;
Type Energy Level 26 ~-Back Scattering-Coating ~ 0.02 Mev. Low 27 Thickness Monitors to 1.0 Mev.
28 Ioniza~ion Type Smoke Detectors ~ ~5 Mev. Low 29 Trigger Source for Gas Discharge ~ 0.72 Mev. Low Lamps and Related Devices ~ 0.54 ~fev.
:: . . .. .:,, j, .. : .. ... ... . .
- ' ''' : : -:
L4~ ;
lIt will be apparent to one skilled in the art that in accordance 2 Witll the principles of the invention the ability to prepare a radioactive 3 source by the technique set forth in the invention provides a source that 4 is readily adapted to fabricating in special structures. For example, a small area source approaching a point source can be made by depositing the 6 amorphous material through a mask. A planar source for such applications 7 as contact microradiography can be prepared by making a blanket coating of 8 the amorphous material containing the radioactive gas. One particular .
g advantage of these methods of fabrication are that they avoid many of the 10hazards of fabricating, machining or otherwise handling a bulk radioactive ~ -11 sample.
12~hat has been set forth is new material made up of an amorphous 13 structure having incorporated therein a radioactive gas which is useful 14 both for possibly containing radloactive gases and for a variety of special applications as an easily handleable and fabricateable radioactive source.
~, `.
~:
.
: .
.. . .
Claims (8)
1. A material comprising in combination:
a body composed of at least two different types of particles of at least two different sizes, one of said types of particles being operable to stabilize said body, said particles being bonded together and enclosing voids throughout said body, and a radioactive gas occupying said voids.
a body composed of at least two different types of particles of at least two different sizes, one of said types of particles being operable to stabilize said body, said particles being bonded together and enclosing voids throughout said body, and a radioactive gas occupying said voids.
2. The material of claim 1 wherein one of said types of particles is a rare earth and another of said types of particles is a transition metal.
3. The material of claim 1 wherein one of said types of particles is gadolinium and another of said types of particles is selected from the group comprising Co, Fe, Ni, and Cu.
4. The material of claim 3 and further including a stabilizer element selected from the group comprising Mo, W, Cr, Ti and V.
5. A process for manufacturing a product of a radioac-tive gas encapsulated in a solid material comprising the steps of:
growing a retaining material body composed of at least two different types of particles of at least two different sizes in the presence of a radioactive gas, one of said types of particles being operable to stabilize said body, bonding said particles together during said growing step to thereby enclose voids in said body and providing an electrical stress operable to drive the atomic or molecular scale particles of said radioactive gas into said voids during formation of said voids.
growing a retaining material body composed of at least two different types of particles of at least two different sizes in the presence of a radioactive gas, one of said types of particles being operable to stabilize said body, bonding said particles together during said growing step to thereby enclose voids in said body and providing an electrical stress operable to drive the atomic or molecular scale particles of said radioactive gas into said voids during formation of said voids.
6. A process for manufacturing a body of material con-taining a radioactive gas comprising the steps of:
forming a body composed of at least two different types of particles of at least two different sizes, one of said types of particles operable to stabilize said body, bonding said particles together and enclosing voids in said body, and propelling atoms or molecules of a radioactive gas of the order of the size of said voids into said voids dur-ing the forming of said body.
forming a body composed of at least two different types of particles of at least two different sizes, one of said types of particles operable to stabilize said body, bonding said particles together and enclosing voids in said body, and propelling atoms or molecules of a radioactive gas of the order of the size of said voids into said voids dur-ing the forming of said body.
7. The process of claim 6 wherein said forming is provided by at least one of the processes of sputtering, ion plating and ion pumping.
8. The process of claim 7 wherein said propelling is by at least one of electrical and magnetic stress.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US77657977A | 1977-03-11 | 1977-03-11 | |
| US776,579 | 1977-03-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1114148A true CA1114148A (en) | 1981-12-15 |
Family
ID=25107806
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA292,575A Expired CA1114148A (en) | 1977-03-11 | 1977-12-07 | Radioactive gas encapsulated in amorphous material |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS53112399A (en) |
| BR (1) | BR7801419A (en) |
| CA (1) | CA1114148A (en) |
| DE (1) | DE2809965A1 (en) |
| FR (1) | FR2383501A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3323060C2 (en) * | 1983-06-27 | 1986-03-20 | Deutsche Gesellschaft für Wiederaufarbeitung von Kernbrennstoffen mbH, 3000 Hannover | Method for fixing radioactive krypton and device for carrying out the method |
| US4729903A (en) * | 1986-06-10 | 1988-03-08 | Midi-Physics, Inc. | Process for depositing I-125 onto a substrate used to manufacture I-125 sources |
| JPH01143999A (en) * | 1987-11-30 | 1989-06-06 | Toshiba Corp | Storage treatment of gas |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2251889A1 (en) * | 1973-11-20 | 1975-06-13 | Atomic Energy Authority Uk | Long-life storage of radioactive and other materials - by inclusion in solids whose thickness increases |
-
1977
- 1977-12-07 CA CA292,575A patent/CA1114148A/en not_active Expired
-
1978
- 1978-02-01 FR FR7803451A patent/FR2383501A1/en active Granted
- 1978-02-15 JP JP1548778A patent/JPS53112399A/en active Pending
- 1978-03-08 DE DE19782809965 patent/DE2809965A1/en not_active Withdrawn
- 1978-03-08 BR BR7801419A patent/BR7801419A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JPS53112399A (en) | 1978-09-30 |
| BR7801419A (en) | 1978-10-03 |
| FR2383501B1 (en) | 1985-02-15 |
| FR2383501A1 (en) | 1978-10-06 |
| DE2809965A1 (en) | 1978-09-14 |
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