Apparatus and method for rapidly measuring the radioactivity of nuclear isotopes in a cylindrical enclosure using current output from a lead self-powered detector element

Abstract

A radioactivity measurement device for measuring a radioactivity level of a radioisotope source is provided. The radioactivity measurement device includes a housing and a self-powered detector. The housing includes an outer shell and an inner shell, the inner shell adapted to receive an insertable radioisotope source, the outer shell and the inner shell configured to form a hollow annular region. The self-powered detector disposed within the hollow annular region of the housing includes at least one tubular emitter configured to provide a source of electronic radiation proportional to a radioactivity level of a radioisotope of the insertable radioisotope source, and at least one tubular collector configured to sink the electronic radiation. Also provided are a radioactivity level measurement system including the at least one radioactivity measurement device, a transport cask incorporating the radioactivity level measurement system, and a method of transporting the transport cask.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority under 35 U.S.C. 120 to U.S. patent application Ser. No. 17 / 660,083, entitled "A DEVICE AND METHOD FOR RAPIDLY MEASURING THE ACTIVITY OF NUCLEAR ISOTOPES CONTAINED WITHIN A CYLINDRICAL ENCLOSURE USING THE CURRENT OUTPUT FROM A LEAD SELF-POWERED DETECTOR ELEMENT," filed April 21, 2022, the contents of which are incorporated herein by reference in their entirety. [Background technology]

[0002] Radioisotopes, such as Cobalt-60 (Co60), are packaged in production capsules and transported to their final destination for commercial use. There is a need to accurately measure the levels of radioactivity contained within these production capsules prior to transport of the capsules. The equipment and methods currently used to obtain these measurements, for example, the neutron source range instruments used in CANDU reactors, can contribute to measurement uncertainty and operational labor costs. There is a need to simplify the equipment and methods for measuring the radioactivity of radioisotopes to minimize the time required to complete a measurement and / or maximize the accuracy of the measurement. Summary of the Invention [Means for solving the problem]

[0003] The following summary is provided to facilitate an understanding of some of the innovative features unique to the embodiments disclosed herein, but is not intended to be a complete description. A complete understanding of the various embodiments disclosed herein can be obtained by taking the entire specification, claims, and abstract into account.

[0004] In various embodiments, a radioactivity measuring device for measuring radioactivity levels is disclosed. In some embodiments, the radioactivity measuring device includes a housing having an outer shell and an inner shell, the inner shell adapted to accommodate an insertable radioisotope source, the outer shell and the inner shell configured to form a hollow annular region, and a self-powered detector (hereinafter "SPD") disposed within the hollow annular region. In some embodiments, the SPD comprises a tubular emitter configured to provide a source of electron emission E proportional to a radioactivity level of a radioisotope of the insertable radioisotope source, a first electrical interface electrically connected to the tubular emitter, tubular collectors, at least one tubular collector configured to sink the electron emission E, a second electrical interface electrically connected to the at least one tubular collector, and at least one electrical insulation layer comprising an electrically insulating material and configured to insulate the at least one tubular emitter from the at least one tubular collector, wherein the first electrical interface and the second electrical interface are adapted to output a current I corresponding to the electron emission E.

[0005] In various embodiments, a radiation level measurement system is disclosed that includes at least one radiation measurement device. In some embodiments, the at least one radiation measurement device includes a housing with an outer shell and an inner shell, the inner shell adapted to house an insertable radioisotope source, the outer shell and the inner shell configured to form a hollow annular region, and an SPD disposed within the hollow annular region. In some embodiments, the SPD of at least one radioactivity measuring device comprises a tubular emitter configured to provide a source of electron emission E proportional to a radioactivity level of a radioisotope of the insertable radioisotope source, a first electrical interface electrically connected to the tubular emitter, a tubular collector, the at least one tubular collector configured to sink the electron emission E, a second electrical interface electrically connected to the at least one tubular collector, and at least one electrical insulation layer comprising an electrically insulating material and configured to insulate the at least one tubular emitter from the at least one tubular collector, wherein the first electrical interface and the second electrical interface are adapted to output a current I corresponding to the electron emission E.

[0006] These and other objects, features, and characteristics of the present disclosure, as well as the method of operation and function of the associated elements of construction, and combination of parts and economies of manufacture, will become more apparent from a consideration of the following description and the appended claims, all of which form a part hereof, when taken in conjunction with the accompanying drawings. Like reference numerals refer to corresponding parts in the various drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the embodiments disclosed herein. [Brief description of the drawings]

[0007] The various aspects described herein, together with their objects and advantages, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in which:

[0008] [Figure 1] FIG. 2 is a radial cross-sectional view of a radiation measuring device according to at least one non-limiting embodiment of the present disclosure.

[0009] [Diagram 2] FIG. 1 is a plan view of a radiation measuring device according to at least one non-limiting embodiment of the present disclosure.

[0010] [Diagram 3] 2 is an axial cross-sectional view of the radiation measuring device of FIG. 1 according to at least one non-limiting embodiment of the present disclosure.

[0011] [Figure 4] FIG. 1 is a perspective view of an SPD according to at least one non-limiting embodiment of the present disclosure.

[0012] [Diagram 5] 5 is an axial cross-sectional view of the SPD of FIG. 4 in accordance with at least one non-limiting embodiment of the present disclosure.

[0013] [Figure 6] FIG. 6 is a radial cross-sectional view of the SPD of FIG. 5, in accordance with at least one non-limiting embodiment of the present disclosure.

[0014] [Figure 7] FIG. 2 is a radial cross-sectional view of a tubular emitter according to at least one non-limiting embodiment of the present disclosure.

[0015] [Figure 8] FIG. 1 is a schematic diagram of a radiation level measurement system according to at least one non-limiting embodiment of the present disclosure.

[0016] Corresponding reference characters indicate corresponding parts in the various views. The examples described herein illustrate one form of various aspects of the present disclosure, and such examples are not to be construed as limiting the scope of the aspects disclosed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Next, certain exemplary embodiments of the present disclosure will be described to provide a general understanding of the principles of the compositions, functions, manufacture, use of the compositions, and methods disclosed herein. Examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the compositions, articles, and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary embodiments, and the scope of the various examples of the present invention is defined only by the claims. Features illustrated or described with respect to one exemplary embodiment can be combined with features of other embodiments. Such modifications and variations are intended to be included within the scope of the present invention.

[0018] References herein to "various examples," "several examples," "one example," "an example," and the like mean that the particular feature, structure, or characteristic described with respect to that example is included as an example. Thus, the appearances of "various examples," "in several examples," "in one example," "in an example," and the like in various places throughout this specification do not necessarily all refer to the same example. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more examples. Thus, a particular feature, structure, or characteristic illustrated or described with respect to one example may be combined, in whole or in part, without limitation, with a feature, structure, or characteristic of another example. Such modifications and variations are intended to be included within the scope of the present examples.

[0019] In the following description, like reference characters indicate like or corresponding parts in the several views of the drawings. Also, it will be understood that in the following description, terms such as "front," "rear," "left," "right," "upper," "lower," "upper," "lower," and the like are used for convenience only and are not to be construed as limiting.

[0020] A radioisotope is an unstable isotope of an element that has excess nuclear energy. In general, radioisotopes can occur naturally or artificially. In the case of nuclear fission, various radioisotopes inevitably occur as products of the fission. Alternatively, synthetic radioisotopes can be intentionally produced in the form of radioisotope production capsules for use in various commercial applications. For example, cobalt-60 (hereinafter "Co60"), a radioisotope of cobalt-59 (hereinafter "Co59"), can be intentionally produced by bombarding a target of Co59 with thermal neutrons produced by a neutron source. The synthetic radioisotope can be packaged in a production capsule and then used as a radioisotope source.

[0021] Due to their excess nuclear energy, radioisotopes undergo radioactive decay and emit ionizing radiation, which can include elementary particles and electromagnetic waves. This ionizing radiation is used in a variety of applications, including nuclear medicine, food sterilization, and industrial production. For example, radioisotope-producing capsules containing Co60 are used in radiation therapy as a gamma ray source to kill cancer cells in the patient's body.

[0022] The amount of ionizing radiation produced by a radioisotope production capsule is typically quantified as a radioactivity level in Curies (Ci). Due to the inherent dangers involved in transporting and handling radioactive materials, current regulations mandate that cargoes containing radioisotope sources do not exceed required radioactivity level limits. Additionally, the radioactivity levels of these radioisotope sources must be verified to ensure that the cargo meets or exceeds contracted activity levels between the supplier and the customer. In light of this, various aspects of the present disclosure provide various methods and apparatus for quickly and accurately identifying the radioactivity levels of radioisotope sources without the need to deploy equipment, sample materials, and / or perform laboratory analysis.

[0023] Various methods and apparatus provided by the present disclosure optimize the technical and economic aspects of performing radioisotope activity level measurements in commercial applications, such as, for example, verifying total radioactivity levels during transportation of a production capsule of an object containing a radioisotope. In some implementations, optimization may allow the radioactivity level of a production capsule to be measured more quickly and / or more accurately, thereby reducing costs associated with transporting radioactive material while complying with transportation regulations.

[0024] Referring to FIG. 1, a cross-sectional view of a radiation measurement device 100 according to at least one non-limiting embodiment of the present disclosure is provided. The radiation measurement device 100 includes a housing and an SPD. In various examples, the housing includes an inner shell 110 and an outer shell 112, and the SPD includes a tubular emitter 222, a first electrical interface 229, a tubular collector 232, a second electrical interface 239, and an electrical insulator 241. Each of the elements 110, 112, 222, 232, 241 of the radiation measurement device 100 may be configured as layers disposed on top of one another, as shown in FIG. 1. In some examples, the SPD may optionally include a second tubular emitter layer 223, a second tubular collector layer 234, a second electrical insulation layer 241, and a third electrical insulation layer 243. In some examples, the measurement device 100 may be configured in a cylindrical or other tubular shape. In a cylindrical layered configuration of the measurement device 100, each of the layers 110, 112, 222, 232, 241 may be concentrically arranged in the order shown in Figure 1. Other shapes are contemplated by the present disclosure. For example, in some implementations, the measurement device 100 may be configured in a cube shape, a sphere shape, or a rectangular prism shape.

[0025] The area enclosed by the inner shell layer 110 is configured as a hollow cavity. The size and / or shape of the inner shell layer 110 may be configured to facilitate insertion and / or placement of a radioisotope source within the hollow cavity enclosed by the inner shell layer 110. In various examples, the length of the inner shell layer 110 is configured to be substantially the same as or slightly longer than the length of the radioisotope production capsule. In some examples, the inner shell layer 110 may be configured to have a cross-sectional shape that is substantially the same as or slightly larger than the cross-section of the insertable radioisotope production capsule.

[0026] The housing may be configured to form a hollow annular region. In various examples, the hollow annular region of the housing is formed between the inner shell layer 110 and the outer shell layer 112. In some examples, the housing includes an electrically insulating layer 140 disposed about the inner shell layer 110 and an electrically insulating layer 142 covering an inner wall of the outer shell layer 112. In some examples, the hollow annular region is defined as the region between layers 140 and 142. The electrically insulating layers 140 and 142 may include aluminum oxide, magnesium oxide, or a combination thereof.

[0027] 2 illustrates a plan view of a radiation measuring device 100 according to at least one non-limiting embodiment of the present disclosure. In some examples, the radiation measuring device 100 may include an upper ceramic insulating ring 114. The upper ceramic insulating ring 114 may be configured to cover the axial ends of the SPD without obstructing access to the electrical interfaces 229 and 239. For example, the upper ceramic insulating ring 114 may be configured to have openings for the electrical interfaces 229 and 239.

[0028] 3, an axial cross-sectional view of the radiation measurement device 100 of FIG 1 is provided. In some examples, the radiation measurement device 100 includes a bottom shell ring 116. The bottom shell ring 116 may be configured to cover substantially the entire bottom cross-sectional area surrounded by the outer shell layer 112.

[0029] With reference to FIG. 4, a perspective view of a self-powered detector in accordance with at least one non-limiting embodiment of the present disclosure is provided. The SPD is configured to fit within a hollow annular region defined by a housing. In some examples, the SPD is configured to be press-fit or slip-fit ​​into the hollow annular region of the housing. In a particular example, the SPD may be configured to have an outer diameter of about 0.385 inches and an axial length of about 1.5 inches.

[0030] 5 and 6 show axial and radial cross-sectional views, respectively, of the SPD 230 of FIG. 4. In various examples, the SPD may include an emitter 220, a collector 230, an electrical insulation layer 241, a first electrical interface 229, and a second electrical interface 239. The electrical insulation layer 241 is configured to electrically insulate the emitter 220 from the collector 230. In various examples, the electrical insulation layer 241 may include aluminum oxide, magnesium oxide, or a combination thereof. The thickness of the electrical insulation layer 241 may be configured to provide a desired electrical resistance.

[0031] Referring to FIG. 7, a radial cross-sectional view of an emitter 220 according to at least one non-limiting embodiment of the present disclosure is provided. In various examples, the emitter 220 may be configured as a cylinder including at least one tubular emitter layer 222. In a particular example, the tubular emitter layer 222 may have a thickness of about 1.0 mm. The emitter 220 includes a tubular emitter layer 222 including a material that is responsive to radioactive materials. For example, the tubular emitter layer 222 may include a high density material that is primarily responsive to gamma or neutron radiation. In various examples, the tubular emitter layer 222 may include a high density, high impedance material. In some examples, the tubular emitter layer 222 includes a lead, tungsten, or Co59 based material. In one example, the tubular emitter layer 222 is lead based.

[0032] The emitter 220 substantially surrounds the inner shell layer 110 and is configured to provide a source of electron emission E proportional to the radioactivity level of the radioisotope source. In some instances, when the radioisotope source is inserted into the inner shell layer 110, ionizing radiation produced by the radioisotope source may interact with bound electrons in the emitter layer material. For example, gamma rays of about 0.6 MeV to 4 MeV emitted by the radioisotope source inserted into the inner shell layer 110 may interact with lead electrons in the lead-based emitter layer 222, scattering the electrons and immediately producing electron emission E. This configuration of the emitter 220 may provide the advantage of a linear electron emission response over a wide range of incident ionizing radiation fluxes without the need for external bias sources or other compensation requiring external power sources over the life of the radiation measurement device 100. For example, the working characteristics of the lead-based emitter material do not change significantly with use or working time, providing the advantage of consistency of working and long life.

[0033] The emitter 220 may include optional emitter layers in addition to the tubular emitter layer 222. In some examples, the emitter 220 includes the tubular emitter layer 222 and the second tubular emitter layer 223. In particular examples, the emitter 220 includes the tubular emitter layer 222, the second tubular emitter layer 223, and the third tubular emitter layer 224. The optional tubular emitter layers 223 and 224 are configured to have an outer diameter that is smaller than the inner diameter of the emitter layer 222. In some examples, the third tubular emitter layer 224 is disposed between the tubular emitter layer 222 and the second tubular emitter layer 223, as shown in FIG. 7. In some examples, the optional tubular emitter layers 223 and / or 224 are configured to be electrically connected to the emitter layer 222. The second tubular emitter layer 223 and / or the third tubular emitter layer 224 may each include a material that is primarily responsive to ionizing radiation. In some examples, the second tubular emitter layer 223 includes the same material as the tubular emitter layer 222. In some examples, the third tubular emitter layer 224 includes a different material than the tubular emitter layer 222.

[0034] 4-6, the collector 230 is configured to provide a sink for electron emissions generated by the emitter 220. For example, the collector 230 may include at least one collector layer configured to substantially surround the emitter 220. In various examples, the collector 230 includes a tubular collector layer 232 having an inner diameter larger than an outer diameter of the emitter 220. In some examples, the tubular collector layer 232 may include a metal or metal alloy. In one example, the tubular collector layer 232 may include 316L stainless steel or Inconel 690.

[0035] 5-6, the collector 230 may optionally include a second collector layer 234 and a second electrical insulation layer 243. In various examples, the second tubular collector layer 234 may be disposed radially inward from the tubular collector layer 232. In some examples, the second electrical insulation layer 243 may be disposed around the second tubular collector layer 234. For example, the second electrical insulation layer 243 may be in direct contact with and surround the second tubular collector layer 234. In some examples, the collector 230 and the emitter 220 are disposed in a sandwich configuration. In one example, the emitter 220 may be disposed between the tubular collector layer 232 and the second tubular collector layer 234, as shown in FIGS. 5-6. The second electrical insulation layer 243 may include aluminum oxide, magnesium oxide, or a combination thereof.

[0036] The SPD includes a first electrical interface 229 and a second electrical interface 239. In various examples, the first electrical interface 229 may be electrically connected to the emitter 220, and the second electrical interface 239 may be electrically connected to the collector 230. In some examples, the first electrical interface 229 may be electrically connected to the tubular emitter layer 222, and the second electrical interface 239 may be electrically connected to the tubular collector layer 232. Each electrical interface may be configured to provide an electrical communication path between the tubular element and an external auxiliary component. In various examples, the first electrical interface 229 and / or the second electrical interface 239 may include a metallic conductive material and / or a non-metallic conductive material. The first electrical interface 229 and / or the second electrical interface 239 may optionally include a shielding material, an insulating material, or a combination thereof.

[0037] The first electrical interface 229 and / or the second electrical interface 239 may be configured as an electrical connector, an electrical lead, or a combination thereof. In an example, the first electrical interface 229 and / or the second electrical interface 239 may be configured as a pin, a socket, a plug, a header, a terminal, an electrode, an integrated cable assembly, or a wire. In one example, the first electrical interface 229 and / or the second electrical interface 239 are configured as pins that protrude axially through the upper ceramic insulating ring 114, as shown in FIG. 3.

[0038] 3 and 5, the first electrical interface 229 and the second electrical interface 239 may be located at one axial end of the radiation measurement device 100. In various examples, the first electrical interface 229 and the second electrical interface 239 may be configured to be coplanar. In certain examples, the first electrical interface 229 and the second electrical interface 239 may be positioned to be coplanar in the same radial quadrant or in opposing radial quadrants.

[0039] The first electrical interface 229 and the second electrical interface 239 are adapted to output a current I(t) at any time t. For example, when the collector 230 captures electron radiation E(t) from the emitter 220, the captured electrons accumulate to generate a voltage between the emitter 220 and the collector 230. When an electrical load is connected to the first electrical interface 229 and the second electrical interface 239, a current I(t) may flow between the first electrical interface 229, the connected load, and the second electrical interface 239 based in part on the voltage between the emitter 220 and the collector 230 and the electrical characteristics of the load. In various examples, the current I(t) is at least about 1 nanoampere. In some examples, the current I(t) is at least about 10 microamperes. If the connected load has an electrical meter, such as a voltmeter or ammeter, an electrical measurement is obtained. The electrical measurement may be used to determine the radioactivity level A corresponding to I(t). gen For example, a known level of radiation A ref When a reference radioisotope source having a reference current I is inserted into the radioactivity measuring device 100, a reference current I flows through a load electrically connected to the first electrical interface 229 and the second electrical interface 239. ref After that, A ref and I refmay be used to identify a proportionality constant α specific to the configuration of the measurement device 100 and the radioisotope source. The proportionality constant α may then be used to identify the unknown activity level of the inserted radioisotope source in terms of I(t) if the inserted radioisotope source is of a configuration similar to that of the reference radioisotope source and measurement device 100.

[0040] If the radioactivity measurement device is used with multiple radioisotope sources, the process of determining the proportionality constant described in the previous paragraph may be repeated with another radioisotope source. For example, inserting a Co60 reference radioisotope source into a measurement device 100 configured with a lead-based emitter will result in an α Pb-Co-60 is then identified. By replacing the Co60 reference radioisotope source with a Cs137 reference radioisotope source, a new constant α Pb-Cs-137 may be specified.

[0041] The emitter 220 may be configured to provide an essentially linear electron emission response such that the current resulting therefrom is not dependent on any bias voltage or excitation field. Thus, the radioactivity measurement device 100 does not rely on an external power source to provide a radioactivity level measurement of the insertable radioisotope source. Furthermore, because the current I(t) is inherent to the direct and linear E(t) response to the inserted radioisotope source, the radioactivity measurement device 100 provides the advantages of rapid, reliable, and accurate measurements.

[0042] FIG. 8 shows a schematic diagram of a radiation level measurement system 400 including at least one radiation measurement device 300 according to at least one non-limiting embodiment of the present disclosure. Each of the at least one radiation measurement device 300 includes a housing and an SPD and is similar in many respects to other radiation measurement devices disclosed elsewhere in the present disclosure, but for brevity, the description of the other radiation measurement devices will not be repeated here at the same level of detail. In various examples, each of the radiation measurement devices 300 may include a housing including an inner shell layer and an outer shell layer, and an SPD including at least one tubular emitter layer, a first electrical interface, at least one tubular collector layer, a second electrical interface, and at least one electrical insulation layer. In some examples, the at least one radiation measurement device 300 of the radiation level measurement system 400 includes at least one lead-based tubular emitter layer. Each of the at least one measurement device 300 may be configured similarly to the measurement device 100 described above. That is, each of the at least one measurement device 300 may be adapted to accommodate an insertable radioisotope source and output a current based on the response of each measurement device 300 to the inserted radioisotope source. In various examples, at least one measurement device 300 of the radiation level measurement system 400 is adapted to accommodate an insertable Co60 source and output a current based on the response of the at least one measurement device 300 to the inserted Co60 source.

[0043] A radioactivity level measurement system 400 configured to include multiple radioactivity measurement devices 300 may accommodate one radioisotope source or various radioisotope sources. For example, the radioactivity level measurement system 400 may include a first radioactivity measurement device having a first configuration and a second radioactivity measurement device having a second configuration, the first configuration and the second configuration corresponding to different radioisotope sources. In various examples, the radioisotope measurement system 400 includes two or more radioactivity measurement devices 300. In some examples, the radioisotope measurement system 400 includes two or more radioactivity measurement devices 300 configured to accommodate a Co60 source or a Cs-137 source. In one example, the radioisotope measurement system 400 includes a first radioactivity measurement device configured to accommodate an insertable Co60 source and a second radioactivity measurement device configured to accommodate an insertable Cs-137 source.

[0044] Continuing with reference to FIG. 8 , the radioactivity level measurement system 400 may include an auxiliary interface 420. The auxiliary interface 420 may be configured to input a current I. For example, the auxiliary interface 420 may be electrically connected to the first electrical interface 310 and the second electrical interface 320 of the at least one measurement device 300 to receive a current I generated by the at least one measurement device 300 when a radioisotope source is inserted into the at least one measurement device 300. The auxiliary interface 420 may be configured with multiple sets of inputs. For example, the auxiliary interface 420 may be electrically connected to the multiple measurement devices 300. In various examples, the auxiliary interface 420 may be configured to be electrically connected to the first electrical interface and the second electrical interface of each of the multiple measurement devices 300. In a particular example, the auxiliary interface 420 and the first electrical interface and the second electrical interface of each of the multiple measurement devices 300 may be electrically connected to an auxiliary control hub.

[0045] The auxiliary interface 420 may be configured to calculate in real time the radioactivity level of an insertable radioisotope source housed in the measurement device 300. For example, the auxiliary interface 420, electrically connected to the measurement device 300 housing a reference radioisotope source, may determine a proportionality constant α and then use α to read the current I(t) generated at time t by the measurement device 300 housing a radioisotope source of unknown radioactivity and calculate the corresponding radioactivity level A(t). gen (t). In some examples, the auxiliary interface 420 may be programmed with multiple proportionality constants corresponding to different radioisotope sources and / or different configurations of the measurement device 300. In a multiple input configuration of the auxiliary interface 420, the auxiliary interface 420 may be programmed to read multiple inputs simultaneously. For example, an auxiliary interface 420 electrically connected to multiple measurement devices, each containing a unique radioisotope source composition and outputting a unique current, may be programmed with an appropriate set of proportionality constants corresponding to unique measurement device-radioisotope source pairs, simultaneously generating a corresponding set of radioactivity levels in real time. In certain examples, the auxiliary device 420 may be programmed to output data corresponding to the radioactivity levels of at least one radioisotope source. The auxiliary device 420 may be programmed to output data continuously, periodically, or in response to a trigger event.

[0046] The radioactivity level measurement system 400 may be incorporated into a container adapted for transport or storage of multiple radioactivity measurement devices. For example, the radioactivity measurement system 400 may be incorporated into a transport cask adapted to house multiple radioisotope sources. In various examples, the transport cask is adapted to house multiple radioisotope production capsules. In some examples, the transport cask is adapted to house multiple Co60 production capsules. A transport cask incorporating a radioactivity level measurement system may provide the advantage of being able to continuously or on-demand measure the contents contained within the cask without the undesirable risk of exposure to ionizing radiation that is inevitable with conventional sampling methods.

[0047] As described herein, a transport cask adapted to accommodate a plurality of radioisotope sources may be incorporated into a transport method. For example, a method of transporting a transport cask may include inserting a radioisotope production capsule into the inner shell of each of a plurality of radioactivity measurement devices of the transport cask and determining a total radioactivity level. In some examples, determining the total radioactivity level includes calculating a real-time radioactivity level of each inserted radioisotope production capsule and combining the calculated real-time radioactivity levels to obtain a total radioactivity level. In a particular example, the method 600 includes inserting a Co60 production capsule into the inner shell of each of a plurality of radioactivity measurement devices of the transport cask and determining a total radioactivity level of the transport cask. If the total radioactivity of the transport cask is above an acceptable limit or below a contract limit, the use of a radioactivity measurement system in the transport method disclosed above can quickly and reliably confirm the radioactive content in the transport cask, thereby avoiding economic and / or safety issues associated with transporting a cask with a problematic radioactivity level.

[0048] Various aspects of the invention according to the present disclosure include, but are not limited to, those recited in the following numbered paragraphs. 1. A radioactivity measuring device for measuring a radioactivity level, comprising: a housing comprising an outer shell and an inner shell, the inner shell adapted to house an insertable radioisotope source, the outer shell and the inner shell configured to form a hollow annular region; a self-powered detector disposed within the hollow annular region of the housing; Self-powered detectors are at least one tubular emitter configured to provide a source of electron radiation E proportional to the activity level of the radioisotope of the insertable radioisotope source; a first electrical interface electrically connected to the at least one tubular emitter; at least one tubular collector configured to sink electron radiation E; a second electrical interface electrically connected to the at least one tubular collector; at least one electrically insulating layer comprising an electrically insulating material and configured to insulate the at least one tubular emitter from the at least one tubular collector; The first electrical interface and the second electrical interface are adapted to output a current I corresponding to the electron radiation E, a radioactivity measuring device. 2. A radioactivity measuring device as described in paragraph 1, wherein the insertable radioisotope source is in the form of a radioisotope production capsule. 3. The radioactivity measuring device according to any one of items 1 to 2, wherein at least one tubular emitter contains lead. 4. The radiation measuring device according to any one of items 1 to 3, wherein at least one tubular emitter contains tungsten, cobalt 59, or a combination thereof. 5. The at least one tubular emitter comprises a first tubular emitter and a second tubular emitter; the first tubular emitter and the second tubular emitter are electrically connected; 5. The radioactivity measuring device according to any one of items 1 to 4, wherein the first tubular emitter is disposed radially inward from the second tubular emitter. 6. The at least one tubular collector comprises a first tubular collector and a second tubular collector; the first tubular collector and the second tubular collector are electrically connected; 6. The radioactivity measuring device according to any one of items 1 to 5, wherein the first tubular collector is disposed radially inward from the second tubular collector. 7. A radioactivity measuring device according to item 6, wherein at least one tubular emitter is arranged radially between the first tubular collector and the second tubular collector. 8. The radioactivity measuring device according to any one of items 1 to 7, wherein the electrically insulating material contains aluminum oxide or magnesium oxide. 9. The radioactivity measuring device according to any one of items 1 to 7, wherein the electrically insulating material contains aluminum oxide. 10. The radiation measuring device according to any one of claims 1 to 9, wherein at least one tubular collector element comprises Inconel, stainless steel, or a combination thereof. 11. A radiation level measurement system comprising at least one radiation measurement device, At least one radiation measuring device a housing comprising an outer shell and an inner shell, the inner shell adapted to house an insertable radioisotope source, the outer shell and the inner shell configured to form a hollow annular region; a self-powered detector disposed within the hollow annular region of the housing; Self-powered detectors are at least one tubular emitter configured to provide a source of electron radiation E proportional to the activity level of the radioisotope of the insertable radioisotope source; a first electrical interface electrically connected to the at least one tubular emitter; at least one tubular collector configured to sink electron radiation E; a second electrical interface electrically connected to the at least one tubular collector; at least one electrically insulating layer comprising an electrically insulating material and configured to insulate the at least one tubular emitter from the at least one tubular collector; A radiation level measurement system, wherein the first electrical interface and the second electrical interface are adapted to output a current I corresponding to an electronic emission E. 12. Further comprising an auxiliary interface configured to receive a current I; Item 12. A radiation level measurement system as described in item 11, wherein the auxiliary interface is electrically connected to the first electrical interface and the second electrical interface of at least one measurement device. 13. The auxiliary interface is configured to calculate a real-time radiation level based on the following relationship: A gen (t)=αI(t) Here, A gen Item 13. The radiation level measurement system of item 12, wherein (t) is the calculated radiation level at measurement time t, α is a proportionality constant, and I(t) is the current output by at least one measurement device at measurement time t. 14. A radioactivity level measurement system as described in paragraph 13, wherein the proportionality constant α is based in part on the known response of the self-powered detector to a reference radioisotope source. 15. A radiation level measurement system according to any one of claims 11 to 14, wherein the self-powered detector comprises a lead-based tubular emitter. 16. A radioactivity level measurement system according to any one of claims 11 to 15, wherein the reference radioisotope source includes cobalt-60. 17. A transport cask equipped with a radioactivity level measurement system according to any one of items 11 to 16, the transport cask is adapted to house a plurality of radioisotope sources; The multiple radioisotope sources include at least one radioisotope production capsule, a transportation cask. 18. A transport cask as described in paragraph 17, wherein the multiple radioisotope production capsules contain Co60. 19. A method for transporting a transport cask according to any one of items 17 to 18, comprising: inserting a radioisotope production capsule within an inner shell of each of a plurality of radioactivity measurement devices of the transport cask; determining a total radioactivity level; Identifying the total radiation level calculating the real-time radioactivity level of each inserted radioisotope production capsule; combining the calculated real-time radioactivity levels to obtain a total radioactivity level. 20. The method of claim 19, wherein the radioisotope production capsule contains Co-60.

[0049] Various features and characteristics are described herein to provide an understanding of the composition, structure, manufacture, function, and / or operation of the invention, including the disclosed methods and systems. It is understood that the various features and characteristics of the invention described herein may be combined in any manner, whether or not such features and characteristics are explicitly described in combination herein. The inventors and applicants expressly intend that such combinations of features and characteristics are within the scope of the invention described herein. Thus, the claims may be amended to recite any combination of features and characteristics explicitly or inherently described herein or features and characteristics explicitly or inherently incorporated by this specification. Furthermore, applicants reserve the right to amend the claims to affirmatively disclaim features or characteristics that may be described in the prior art, even if those features or characteristics are not explicitly described herein. Thus, such amendments do not add new matter to the specification or claims, but are in compliance with the requirements of the specification, sufficiency of the specification, and additional matter.

[0050] With respect to the appended claims, those skilled in the art will appreciate that the operations described therein may generally be performed in any order. Also, while various operational flows are shown in a sequence, it should be understood that various operations may be performed in orders other than those shown, or may be performed simultaneously. Examples of such alternative orders include overlapping, interleaved, interrupted, reordered, incremented, preparatory, supplemental, concurrent, reversed, or other variant orders, unless otherwise noted. Moreover, words such as "according to," "related to," and other past tense adjectives are generally not intended to exclude such variants, unless otherwise noted.

[0051] The inventions described herein may comprise, consist of, or consist essentially of various features and characteristics described herein. Words such as "comprise" (and any form of "comprise" such as "comprise" or "comprising"), "have" (and any form of "have" such as "had" or "having"), "include" (and any form of "include" such as "included" or "comprising"), and "include" (and any form of "include" such as "included" or "comprising") are open-ended linking verbs. Thus, a method or system that "comprises", "has", "includes" or "includes" a feature or a plurality of features and / or characteristics is one that has that feature or those features and / or characteristics, but is not limited to having only that feature or those features and / or characteristics. Similarly, an element of a composition, coating, or process that "comprises," "has," "contains," or "includes" a feature or a number of features and / or characteristics means that the element has that feature or those characteristics and / or characteristics, but is not limited to having only that feature or those characteristics and / or characteristics, and may have additional features and / or characteristics.

[0052] The grammatical articles "a," "an," and "the" as used herein, including the claims, are intended to include "at least one" or "one or more," unless otherwise indicated. Thus, these articles are used herein to refer to one or more than one (i.e., "at least one") of the grammatical objects of the article. As an example, "part" means one or more parts, and thus, one or more parts may be contemplated and may be employed or used in the practice of the compositions, coatings, and processes described. Nevertheless, it is understood that the use of the terms "at least one" or "one or more" in some instances and not in others is not intended to construe the grammatical articles "a," "an," and "the" as limiting the object to one. Furthermore, unless the context otherwise requires, the use of a singular noun includes the plural, and the use of a plural noun includes the singular.

[0053] As used herein, unless otherwise indicated, all numerical parameters should be understood to be prefaced and modified in all instances by the word "about," in which case the numerical parameters have the inherent variability inherent in the underlying measuring technique employed to determine the numerical value of the parameter. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter set forth herein should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0054] Numerical ranges mentioned herein include all subranges subsumed within the mentioned range. For example, the range "1-10" includes all subranges between (and including) the minimum value "1" and the maximum value "10", i.e., all subranges with a minimum value of 1 or more and a maximum value of 10 or less. Also, all ranges mentioned herein include the endpoints of the mentioned range. For example, the range "1-10" includes the endpoints 1 and 10. Every maximum numerical limitation set forth herein is intended to include all lower numerical limitations subsumed therein, and every minimum numerical limitation set forth herein is intended to include all higher numerical limitations subsumed therein. Accordingly, applicants reserve the right to amend this specification, including the claims, to expressly set forth any subranges subsumed within the expressly set forth ranges. All such ranges are inherently described herein.

[0055] As used herein, particularly with respect to layers, the words "on," "up," "above," and variations thereof (e.g., "applied on," "formed on," "disposed on," "provided on," "located on," etc.) mean applied to, formed on, disposed on, provided on, or located on the surface of a substrate, but not necessarily in contact with the surface of the substrate. For example, a layer "applied on" a substrate does not exclude the presence of another layer or other layer of the same or different composition located between the applied layer and the substrate. Similarly, a second layer "applied on" a first layer does not exclude the presence of another layer or other layer of the same or different composition located between the applied second layer and the applied first layer.

[0056] Although specific examples of the invention have been described above for purposes of illustration, it will be apparent to those skilled in the art that many changes may be made in the details of the invention without departing from the invention as defined in the appended claims.

Claims

1. A radioactivity measuring device for measuring a radioactivity level, comprising: The radioactivity measuring device is a housing comprising an outer shell and an inner shell, the inner shell adapted to accommodate an insertable radioisotope source, the outer shell and the inner shell configured to form a hollow annular region; a self-powered detector disposed within the hollow annular region of the housing; The self-powered detector comprises: at least one tubular emitter configured to provide a source of electron radiation E proportional to the activity level of a radioisotope of the insertable radioisotope source; a first electrical interface electrically connected to the at least one tubular emitter; at least one tubular collector configured to sink the electron radiation E; a second electrical interface electrically connected to the at least one tubular collector; at least one electrically insulating layer comprising an electrically insulating material and configured to insulate the at least one tubular emitter from the at least one tubular collector; The first electrical interface and the second electrical interface are adapted to output a current I corresponding to the electron radiation E.

2. 2. The radiation measurement device of claim 1, wherein the insertable radioisotope source is in the form of a radioisotope production capsule.

3. 3. The radiation measuring device according to claim 1, wherein the tubular emitter contains lead.

4. The radiation measuring device according to any one of claims 1 to 3, wherein the tubular emitter comprises tungsten, cobalt 59, or a combination thereof.

5. the at least one tubular emitter comprises a first tubular emitter and a second tubular emitter; the first tubular emitter and the second tubular emitter are electrically connected; 5. The radiation measuring device according to claim 1, wherein the first tubular emitter is disposed radially inward from the second tubular emitter.

6. the at least one tubular collector comprises a first tubular collector and a second tubular collector; the first tubular collector and the second tubular collector are electrically connected; 6. The radiation measuring device according to claim 1, wherein the first tubular collector is disposed radially inward from the second tubular collector.

7. 7. The radiation measurement device according to claim 6, wherein the at least one tubular emitter is disposed radially between the first tubular collector and the second tubular collector.

8. 8. The radiation measuring device according to claim 1, wherein the electrically insulating material comprises aluminum oxide or magnesium oxide.

9. The radiation measuring device of claim 8 , wherein the electrically insulating material comprises aluminum oxide.

10. The radiation measurement device of any one of claims 1 to 9, wherein the at least one tubular collector comprises Inconel, stainless steel, or a combination thereof.

11. A radiation level measurement system comprising at least one radiation measurement device, The at least one radiation measuring device a housing comprising an outer shell and an inner shell, the inner shell adapted to accommodate an insertable radioisotope source, the outer shell and the inner shell configured to form a hollow annular region; a self-powered detector disposed within the hollow annular region of the housing; The self-powered detector comprises: at least one tubular emitter configured to provide a source of electron radiation E proportional to the activity level of a radioisotope of the insertable radioisotope source; a first electrical interface electrically connected to the at least one tubular emitter; at least one tubular collector configured to sink the electron radiation E; a second electrical interface electrically connected to the at least one tubular collector; at least one electrically insulating layer comprising an electrically insulating material and configured to insulate the at least one tubular emitter from the at least one tubular collector; A radiation level measurement system, wherein the first electrical interface and the second electrical interface are adapted to output a current I corresponding to the electron radiation E.

12. and an auxiliary interface configured to receive a current I; 12. The radiation level measurement system of claim 11, wherein the auxiliary interface is electrically connected to the first electrical interface and the second electrical interface of the at least one radiation measurement device.

13. The auxiliary interface is configured to calculate a real-time radiation level based on the following relationship: A ｇｅｎ (t)=αI(t) Here, A ｇｅｎ 13. The radiation level measurement system of claim 12, wherein (t) is the calculated radiation level at measurement time t, α is a proportionality constant, and I(t) is the current output by the at least one radiation measurement device at measurement time t.

14. 14. The radiation level measurement system of claim 13, wherein the proportionality constant .alpha. is based in part on a known response of the self-powered detector to a reference radioisotope source.

15. 15. The radiation level measurement system of claim 14, wherein the self-powered detector comprises a lead-based tubular emitter.

16. 16. A radiation level measuring system according to any one of claims 14 to 15, wherein the reference radioisotope source comprises Cobalt-60.

17. A transport cask comprising the radiation level measurement system according to any one of claims 14 to 16, the transport cask is adapted to house a plurality of radioisotope sources; The multiple radioisotope sources include at least one radioisotope production capsule.

18. 20. The transport cask of claim 17, wherein the multiple radioisotope sources include Co60.

19. 1. A method for transporting a radioisotope production capsule, comprising: inserting a radioisotope production capsule within an inner shell of each of a plurality of radioactivity measurement devices of the transport cask; determining a total radioactivity level; Identifying the total radiation level calculating the real-time radioactivity level of each inserted radioisotope production capsule; combining the calculated real-time radioactivity levels to obtain a total radioactivity level.

20. 20. The method of claim 19, wherein the radioisotope production capsule comprises Co60.

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