US3582656A - Time base combining radioactive source and solid-state detector - Google Patents
Time base combining radioactive source and solid-state detector Download PDFInfo
- Publication number
- US3582656A US3582656A US714954A US3582656DA US3582656A US 3582656 A US3582656 A US 3582656A US 714954 A US714954 A US 714954A US 3582656D A US3582656D A US 3582656DA US 3582656 A US3582656 A US 3582656A
- Authority
- US
- United States
- Prior art keywords
- detector
- standard
- set forth
- array
- mask
- 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.)
- Expired - Lifetime
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Classifications
-
- G—PHYSICS
- G04—HOROLOGY
- G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
- G04C10/00—Arrangements of electric power supplies in time pieces
- G04C10/02—Arrangements of electric power supplies in time pieces the power supply being a radioactive or photovoltaic source
-
- G—PHYSICS
- G04—HOROLOGY
- G04F—TIME-INTERVAL MEASURING
- G04F5/00—Apparatus for producing preselected time intervals for use as timing standards
- G04F5/16—Apparatus for producing preselected time intervals for use as timing standards using pulses produced by radio-isotopes
Definitions
- radioactive standardconstit uted AND SOLIDSTATE DETECTOR by a radioact ve source of alpha particles combined with a H Claims, 6 Drawing Figs solid-state radiation detector, the source being in the form of a backing having a planar array of discrete islands of a radioac- [52] U.S.Cl 250/83.3, five isotope the alpha particles emitted therefrom passing 58/23, 250/83 250/105i 250/106 through an apertured mask and impinging on the sensitive sur- [51] Int. Cl 0. G01!
- This invention relates generally to radioactive time bases, and in particular to a timekeeping standard constituted by a radioactive source of alpha particles combined with a solidstate radiation detector.
- the'p'referred form of radioactive source for the timekeeping-standard is an isotope which emits alpha particles and has a prolonged halflife. Whilegamma' rays are radiated with-discrete energies,
- Beta particles on the other'hand, are not emitted with discrete energies, but have a continuous distribution 'of energies.
- This radiation is a high-speed "electron that is emitted at the transformation of-a neutron to aproton within the nucleus of an atom. While it is possible to effect shielding of beta parti cles with a few millimeters of aluminum, timing control is very difficult since the particles are not monoenergetic.
- Alpha particles consist of two protons and'two neutrons
- alpha radiation is highly ionizing accounts 'for its relatively short range whentraversingmatter. This range'is only'a few'centimeters in standard-air, and several sheets of'ordi'narypaper will absorb even the most energetic of alpha particles. Yet
- alpha particles are suitable for radioactive timekeeping standards, for not only are they nearly monoenergetic, but they can be handled in a practical sense within the confines ofa small timepiece.
- alpha particle energies are absorbed within the thickness of'the radioisotope deposit itself.
- a continuous distribution of energies will result from alpha particles being radiated from various depthsin the thick'layer. The spread of this'distribution can be minimized by obtaining the required activity from the thinnest source possible.
- an object of the invention is to provide an efficient and reliable assembly of radioactive source and solid-state radiation detector.
- a radioactive time base assembly comprising a backing-having an array of discrete islands thereon of a radioactive isotope emitting alpha particles and having a relatively protracted'half-life, a
- the mask being interposed between the islands and the surface of a solid-state radiation detector, the mask having a matching array of apertures therein whose geometry is such as to conline the particulate energyimpinging on the detector surface to substantially normal angles of incidence and to prevent particles emanating from any one island from impinging on a neighboringportion of the detector surface associated with another island.
- FIG. 1 schematically illustrates an assembly composed of a single layer of radioactive material and a detector, anapertured mask being interposed therebetween, this illustration being'for purposes of background analysis;
- FIG. 2 schematically illustratesthe behavior of the device shown in FIGpl
- FIG. 3 schematically shows a radioactive timekeeping standard in accordance with the invention
- FIG. 4 illustrates the behavior of the standard shown in FIG.
- FIG. 5 is an exploded perspective view of an assembly of the typeshown inFIG. 3;
- FIG. 6 is a modified form of standard in accordance with the I invention.
- a layer 10 of the selected radioisotope is formed on a backing 11, which may be of platinum or alu minum, or any other material providing adequate support and preferably having shielding properties. To minimize the spread of energy distribution, the layer is made as thin and as uniform as possible. To this end, a deposition technique may be employed, the radioactive material being laid down in a very dilute solution on the backing and then allowed to dry, the resultant film adhering to the backing.
- Detector 12 which is used to intercept alpha particles emanating from layer 10, may be of the surface barrier or diffused-junction type commercially available. While the present invention resides in the use of an apertured mask in combination with a radioactive source in the form of an array of separate islands of radioisotope material, the mask 13 in FIG. I is shown in combination with a single, continuous radioactive layer 10, and is provided with an array of apertures 13A, 13B, 13C, etc., defining parallel passages of uniform cross section for the emanations. This combination is not in accordance with the invention, but is shown only for purposes of background analysis.
- FIG. 2 indicates the trajectories of particles emanating at various angles from different points on source 10, and traveling towardthe surface of detector 12.
- Path P is normal. to the surface of detector 12. This is the shortest and most direct path and provides maximum energy.
- the angle of incidence of path P is such that it passes through the upper edge of the mask, some energy being absorbed therein, whereby the remaining energy of the particles arriving at the detector is reduced.
- Path P which cuts through the lower edge of the mask, is even further reduced in energy.
- paths P P and P are intercepted by varying thickness of the solid body of the mask, and are more or less reduced in energy by absorption.
- the particles in path P will produce a relatively large output pulse in the detector, whereas those in the other paths will produce pulses having lesser and varying degrees of amplitude.
- the detector responds as if the source had a spread of energy distribution, which is undesirable for timekeeping purposes.
- Each island 14A, 143, etc. is centered with respect to the upper zone of the corresponding aperture defined by the upper section I, which upper zone has a relatively large and uniform cross section, the diameter of the island being equivalent to or less than that of the upper zone.
- the lower zone of the aperture defined by the lower section II has at its top side a smaller diameter preferably equal to or greater than the diameter of the associated island, the underside of the aperture being chamfered to provide a flared mouth of increasing cross section.
- the preferred geometry of the mask structure eliminates those events which would cause an energy loss in the aperture edge adjacent the radioactive island.
- emission paths Pa, Pb and'Pc normal to the detector surface are unobstructed by the'mask.
- Paths Pd and Fe, which represent very low angles of incidence are intercepted by the upper section I of the mask and completely absorbed thereby.
- paths Pf, Pg and Ph which are not normal but which have relatively high angles of incidence, go directly to the detector surface without striking an aperture edge and hence without being degraded.
- Virtual elimination of the detector-side aperture edge by flaring causes a minimization of the solid angle subtended by absorptive mask material at the source, thus minimizing the number of particles that can actually be energy degraded in the mask material.
- the apertured mask in accordance with the invention prevents particles from any one island from impinging on a neighboring portion of the detector surface at a low angle of incidence, and provides an entrance aperture subtending an optimum angle at the detector.
- the geometry of the aperture in the mask is such as to minimize edge effects as well as to reduce airgap losses.
- Backing 11 for the radioactive source is in the form of a thin disc of suitable shielding material on which is deposited a uniform array of thin circular islands 14A, 143, etc., of radioactive material possessing alpha-particle-emitting properties.
- the islands are constituted by the deposits of radioactive material substantially equispaced from each other.
- Mask 13 includes a circular upper plate I having relatively large apertures in a configuration matching the array of the islands, the diamet er of the plate being equal to that of the backing 11.
- Mask 13 is provided also with a lower plate I] having a corresponding array of smaller apertures whose underside (not shown) is flared, as indicated in connection with FIG. 3.
- plate II is a disc-shaped solid-state radiation detector 12.
- the resultant wafer constitutes a highly compact and efficient timekeeping standard which may readily be incorporated in a small timepiece or watch.
- the geometry of the mask is such as to restrict emanations impinging on the detector surface to nearly normal angles of incidence and furthermore preventing particles emanating from any one island from impinging on a neighboring portion of the detector surface associated with another island.
- the diameter of each island or the diameter of the circle circumscribing the island is no greater than twice the distance between the sur face of the island and the plane of the detector, the diameter of each mask aperture being not less than the diameter of the island or the circle.
- the low sensitivity dictates the use of high-gain amplifiers.
- high-gain amplication is necessary.
- the output signal from a conventional solid-state radiation detector lies in the millivolt range and is not much more pronounced in amplitude than the noise level in the associated electronic amplifying circuits for elevating the signal to a level suitable for measurement and analysis. This noise may give rise to spurious signals which cannot readily be distinguished from the radiation signals, thus adversely affecting the sensitivity and energy resolution of the detection system.
- a multicellular, solid-state radiation detector assembly adapted to produce exceptionally large signals in response to incident radiation, the detector being constituted by an array of individual surface-barrier or diffusedjunction, radiation-sensitive, semiconductive cells, each of which has a small area and a low internal capacitance.
- the cells in the array are unidirectionally connected in parallel relation with respect to current flow, but are otherwise electrically isolated from each other, whereby the overall capacitance of the array is low while the detection efficiency thereof is substantially equal to a unitary radiation detector whose surface area is equivalent to the aggregate area of the cells, the signal output from the multicellular detector being far greater than that yielded by the unitary detector.
- the multicellular solidstate radiation detector is combined with an array of radioactive islands 14A, 143, etc., and an apertured mask 13 of the type shown in FIG, 3.
- the multicellular detector is constituted by an array of tiny radiation detector cells 16A, 16B, 16C, 16D, etc., whose diameters are substantially the same as that of the radioactive islands and which are positioned in registration therewith.
- Cells 16A, 168, etc. are unidirectionally connected in parallel relation with respect to current flow by diodes 17A, 17B, 17C, etc., but are otherwise electrically isolated from each other, whereby the overall capacitance of the array of cells is low, whereby the detection efficiency thereof is substantially equal to a unitary radiation detector, such as detector 12, whose surface area is equivalent to the aggregate area of the cells.
- a unitary radiation detector such as detector 12
- the signal output from the multicellular detector is far greater than that yielded by the unitary detector.
- the parallel-connected detector cells are connected to an output circuit which imposes a reverse bias thereon.
- a radioactive timekeeping standard adapted to produce substantially monoenergetic timing pulses and comprising:
- a solid-state radiation detector having a sensitive surface in parallel relationship to said planar array, the area of said surface being substantially coextensive with the area of said array, and
- an alpha particle-absorbing mask interposed between said array and said surface and having a matching array of alpha particle-admitting apertures whose geometry is such as to restrict the emanations impinging on the detector surface through the spaces in the apertures to nearly normal angles of incidence and preventing particles emanating from any one island from impinging on a neighboring portion of the detector surface associated with another island to obviate a spread in energy distribution.
- each aperture in said mask is composed of a first zone adjacent its associated island having a relatively large cross section and a second zone adjacent the detector surface having a constricted cross section.
- radioisotope is selected from a class consisting of uranium 238, uranium 235, neptunium 237 and plutonium 239.
- said mask is composed of two circular plates, one having apertures defining the first zone and the second having apertures defining the second zone.
- said detector is formed by an array of individual cells, each disposed to intercept radiation from a respective island, the cells being connected unidirectionally in parallel.
- a radioactive timekeeping standard comprising:
- a mask interposed between said array and said surface having a matching array of circular apertures whose geometry is such as to restrict the emanations impinging on the detector surface to nearly normal angles of incidence and furthermore preventing particles emanating from any one island from impinging on a neighboring portion of the detector surface associated with another island, wherein the diameter of the circle circumscribing such islands is not greater than twice the distance between the surface of the islands and the plane of the detector and furthermore that the diameter of each of said apertures is not less than the diameter of said circle.
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Measurement Of Radiation (AREA)
- Light Receiving Elements (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US71495468A | 1968-03-21 | 1968-03-21 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3582656A true US3582656A (en) | 1971-06-01 |
Family
ID=24872156
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US714954A Expired - Lifetime US3582656A (en) | 1968-03-21 | 1968-03-21 | Time base combining radioactive source and solid-state detector |
Country Status (5)
Country | Link |
---|---|
US (1) | US3582656A (fr) |
JP (1) | JPS4830910B1 (fr) |
CH (2) | CH427269A4 (fr) |
DE (2) | DE1966493A1 (fr) |
FR (1) | FR2004447B1 (fr) |
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3699407A (en) * | 1971-09-29 | 1972-10-17 | Motorola Inc | Electro-optical coupled-pair using a schottky barrier diode detector |
US3724201A (en) * | 1971-01-27 | 1973-04-03 | Hmw Industries | Nuclear-paced solid state wristwatch |
US3860821A (en) * | 1970-10-02 | 1975-01-14 | Raytheon Co | Imaging system |
US3881309A (en) * | 1973-03-13 | 1975-05-06 | Biviator Sa | Electronic timepiece |
US4158286A (en) * | 1976-07-06 | 1979-06-19 | Texas Instruments Incorporated | Horologic instruments with random timing source |
US4275405A (en) * | 1973-01-22 | 1981-06-23 | Mullard Limited | Semiconductor timing device with radioactive material at the floating gate electrode of an insulated-gate field-effect transistor |
US4541003A (en) * | 1978-12-27 | 1985-09-10 | Hitachi, Ltd. | Semiconductor device including an alpha-particle shield |
US6103295A (en) * | 1997-12-22 | 2000-08-15 | Mds Nordion Inc. | Method of affixing radioisotopes onto the surface of a device |
US6596998B1 (en) * | 2000-07-31 | 2003-07-22 | Westinghouse Electric Company Llc | Method and system for identifying the source of a signal |
US6676988B2 (en) | 1997-12-22 | 2004-01-13 | Mds (Canada) Inc. | Radioactively coated devices |
GB2405225A (en) * | 2003-08-20 | 2005-02-23 | Alan Charles Sturt | Using radioactive decay to produce standard timing signals |
US20070058493A1 (en) * | 2005-09-13 | 2007-03-15 | International Business Machines Corporation | Methods and apparatus capable of indicating elapsed time intervals |
US20100289121A1 (en) * | 2009-05-14 | 2010-11-18 | Eric Hansen | Chip-Level Access Control via Radioisotope Doping |
US20110014572A1 (en) * | 2007-12-21 | 2011-01-20 | Cornell Research Foundation, Inc. | Self-powered lithography method and apparatus using radioactive thin films |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3716147A (en) * | 1971-02-22 | 1973-02-13 | Eaton Yale & Towne | Stacker crane order picker |
DE2201955C3 (de) * | 1972-01-17 | 1982-05-13 | Continental Gummi-Werke Ag, 3000 Hannover | Einrichtung zum Ablegen und/oder Lagern insbesondere von unvulkanisierten Rohlaufstreifen für Fahrzeugluftreifen |
DE2723012C3 (de) * | 1977-05-21 | 1981-06-19 | G. Siempelkamp Gmbh & Co, 4150 Krefeld | Tischweiche bei Anlagen zur Herstellung von Spanplatten, Faserplatten u.dgl. |
CH631940A5 (en) * | 1978-08-04 | 1982-09-15 | Erwin Jenkner | Workpiece-related size adjustment device for a panel alignment table. |
US4823369A (en) * | 1987-02-16 | 1989-04-18 | Siemens Aktiengesellschaft | Dental x-ray diagnostics installation for producing panorama slice exposures of the jaw of a patient |
DE3717867A1 (de) * | 1987-05-26 | 1988-12-15 | Schiepe Stapelautomaten Gmbh | Stapelvorrichtung |
DE4114215A1 (de) * | 1991-05-01 | 1992-11-05 | Focke & Co | Einrichtung zum beladen von paletten mit kartons |
DE29812106U1 (de) | 1998-07-09 | 1998-10-15 | Grässlin KG, 78112 St Georgen | Vorrichtung zur maschinellen Handhabung von Paletten |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2683813A (en) * | 1950-06-30 | 1954-07-13 | Friedman Herbert | Alpha ray tachometer |
US3223842A (en) * | 1962-03-15 | 1965-12-14 | James L Hyde | Digital measuring apparatus utilizing a radioactive source and detector |
US3370414A (en) * | 1965-06-22 | 1968-02-27 | Benrus Watch Company Inc | Electronic timepiece |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB636338A (en) * | 1946-03-14 | 1950-04-26 | United States Radium Corp | Improvements in radioactive metal products and method of manufacturing them |
FR1238886A (fr) * | 1959-07-09 | 1960-08-19 | Lignes Telegraph Telephon | Perfectionnements aux détecteurs de particules lourdes |
FR1279587A (fr) * | 1960-12-19 | 1961-12-22 | Vakutronik Veb | Procédé et dispositif pour la mesure, indépendante de l'énergie, d'une contamination radioactive superficielle produite par des substances alphagènes |
FR1367866A (fr) * | 1963-08-14 | 1964-07-24 | Bbc Brown Boveri & Cie | Collimateur pour des faisceaux d'électrons rapides |
-
1968
- 1968-03-21 US US714954A patent/US3582656A/en not_active Expired - Lifetime
-
1969
- 1969-03-21 FR FR696908348A patent/FR2004447B1/fr not_active Expired
- 1969-03-21 CH CH427269D patent/CH427269A4/xx not_active IP Right Cessation
- 1969-03-21 DE DE19691966493 patent/DE1966493A1/de active Pending
- 1969-03-21 CH CH427269A patent/CH528109A/de not_active IP Right Cessation
- 1969-03-21 DE DE1914569A patent/DE1914569C3/de not_active Expired
- 1969-03-22 JP JP44021988A patent/JPS4830910B1/ja active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2683813A (en) * | 1950-06-30 | 1954-07-13 | Friedman Herbert | Alpha ray tachometer |
US3223842A (en) * | 1962-03-15 | 1965-12-14 | James L Hyde | Digital measuring apparatus utilizing a radioactive source and detector |
US3370414A (en) * | 1965-06-22 | 1968-02-27 | Benrus Watch Company Inc | Electronic timepiece |
Cited By (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3860821A (en) * | 1970-10-02 | 1975-01-14 | Raytheon Co | Imaging system |
US3724201A (en) * | 1971-01-27 | 1973-04-03 | Hmw Industries | Nuclear-paced solid state wristwatch |
US3699407A (en) * | 1971-09-29 | 1972-10-17 | Motorola Inc | Electro-optical coupled-pair using a schottky barrier diode detector |
US4275405A (en) * | 1973-01-22 | 1981-06-23 | Mullard Limited | Semiconductor timing device with radioactive material at the floating gate electrode of an insulated-gate field-effect transistor |
US3881309A (en) * | 1973-03-13 | 1975-05-06 | Biviator Sa | Electronic timepiece |
US4158286A (en) * | 1976-07-06 | 1979-06-19 | Texas Instruments Incorporated | Horologic instruments with random timing source |
US4541003A (en) * | 1978-12-27 | 1985-09-10 | Hitachi, Ltd. | Semiconductor device including an alpha-particle shield |
US6103295A (en) * | 1997-12-22 | 2000-08-15 | Mds Nordion Inc. | Method of affixing radioisotopes onto the surface of a device |
US6676988B2 (en) | 1997-12-22 | 2004-01-13 | Mds (Canada) Inc. | Radioactively coated devices |
US6596998B1 (en) * | 2000-07-31 | 2003-07-22 | Westinghouse Electric Company Llc | Method and system for identifying the source of a signal |
GB2405225A (en) * | 2003-08-20 | 2005-02-23 | Alan Charles Sturt | Using radioactive decay to produce standard timing signals |
EP1508841A2 (fr) * | 2003-08-20 | 2005-02-23 | Alan Charles Sturt | Garde-temps radioactif |
EP1508841A3 (fr) * | 2003-08-20 | 2005-12-14 | Alan Charles Sturt | Garde-temps radioactif |
GB2405225B (en) * | 2003-08-20 | 2006-05-17 | Alan Charles Sturt | Radioactive timekeeping |
US20070058493A1 (en) * | 2005-09-13 | 2007-03-15 | International Business Machines Corporation | Methods and apparatus capable of indicating elapsed time intervals |
US7489596B2 (en) * | 2005-09-13 | 2009-02-10 | International Business Machines Corporation | Methods and apparatus capable of indicating elapsed time intervals |
CN1932697B (zh) * | 2005-09-13 | 2010-10-06 | 国际商业机器公司 | 确定时间间隔的方法及时间测量装置 |
US20110014572A1 (en) * | 2007-12-21 | 2011-01-20 | Cornell Research Foundation, Inc. | Self-powered lithography method and apparatus using radioactive thin films |
US8658993B2 (en) * | 2007-12-21 | 2014-02-25 | Cornell University | Self-powered lithography method and apparatus using radioactive thin films |
US20100289121A1 (en) * | 2009-05-14 | 2010-11-18 | Eric Hansen | Chip-Level Access Control via Radioisotope Doping |
Also Published As
Publication number | Publication date |
---|---|
DE1914569B2 (de) | 1973-05-17 |
JPS4830910B1 (fr) | 1973-09-25 |
DE1914569A1 (de) | 1969-10-09 |
FR2004447B1 (fr) | 1973-03-16 |
FR2004447A1 (fr) | 1969-11-21 |
DE1914569C3 (de) | 1973-11-29 |
CH528109A (de) | 1972-04-14 |
CH427269A4 (fr) | 1972-04-14 |
DE1966493A1 (de) | 1973-03-08 |
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