Gamma ray source devices and related systems and methods

Abstract

A method, system, apparatus, and computer-readable program product for determining the count rate linearity of one or more gamma detectors using a single gamma radiation source by varying the solid angle between the single gamma radiation source and one or more detectors (and therefore the emissivity observed by the detectors).

Description

[Technical Field]

[0001] The present technology relates to gamma counters, and more particularly to systems, apparatus, methods, and computer program products for verifying, evaluating, and / or determining whether a gamma counter detector is operating correctly. [Background technology]

[0002] Gamma counters include detectors used to detect and count gamma rays emitted from solid and liquid samples. Count rate linearity, commonly understood as the relationship between count rate and emission rate, is a commonly known performance characteristic for a given gamma detector. If the gamma detector is not working properly and / or is defective (e.g., old optical grease, degraded sodium iodide crystals, problems with the counting electronics, etc.), count rate linearity is typically affected, making the gamma counter's performance (e.g., counting) unreliable. To improve the likelihood of accurate and robust gamma counter / detector performance, it may be desirable to evaluate, determine, and / or verify the count rate linearity of a gamma counter / detector. This process of evaluating, determining, or verifying the count rate linearity of a given detector may involve sequentially using multiple sources of gamma rays of different known radioactivity levels / emission rates and observing the resulting count rates at the detector. This process requires the availability of multiple sources of gamma radiation of known activity levels / emissivities, which can be difficult at remote and other gamma counter / detector locations. Summary of the Invention

[0003] Some embodiments of the present technology are directed to a method for determining count rate linearity of one or more detectors of a gamma counter, the method including the steps of: providing a gamma ray source device including a cylinder, a gamma ray source holder within the cylinder, and a gamma ray source connected to the gamma ray source holder, wherein the gamma ray source holder and the gamma ray source are configured to be moved to a plurality of different positions within the cylinder; inserting the gamma ray source device into the detector of the gamma counter with the gamma ray source at a first position within the cylinder; determining a first count rate of the gamma ray source at the first position within the cylinder using the gamma counter; moving the gamma ray source to a second position within the cylinder; and determining a second count rate of the gamma ray source at the second position within the cylinder using the gamma counter.

[0004] In some embodiments, the method includes comparing the first count rate to a first expected count rate and comparing the second count rate to a second expected count rate.

[0005] In some embodiments, the method includes, after determining the second count rate, moving the gamma ray source to a third position within the cylinder, and determining, using a gamma counter, a third count rate of the gamma ray source with the gamma ray source at the third position within the cylinder.

[0006] In some embodiments, the method includes comparing the third count rate to a third expected count rate.

[0007] In some embodiments, the method includes, after determining the third count rate, moving the gamma ray source to a fourth position within the cylinder, and determining, using a gamma counter, a fourth count rate of the gamma ray source with the gamma ray source at the fourth position within the cylinder.

[0008] In some embodiments, the method includes comparing the fourth count rate to a fourth expected count rate.

[0009] In some embodiments, the gamma ray source holder includes a screw that threadably mates with an inner diameter of the cylinder, and moving the gamma ray source to the second position includes rotating the screw.

[0010] In some embodiments, turning the screw comprises turning the screw using a hand tool.

[0011] In some embodiments, the method includes removing the gamma ray source device from the detector after determining the first count rate, and reinserting the gamma ray source device into the detector of the gamma counter with the gamma ray source in a second position within the cylinder after rotating the screw.

[0012] In some embodiments, rotating the screw comprises rotating the screw using a motor operatively connected to the screw.

[0013] In some embodiments, the cylinder is transparent or translucent and includes a scale including a plurality of graduations, and moving the gamma ray source to the second position includes moving the gamma ray source to one of the plurality of graduations.

[0014] In some embodiments, the gamma counter includes a plurality of detectors, and the method includes inserting a gamma ray source device into at least some of the plurality of detectors under test, and determining, for each detector under test, a respective count rate with the gamma ray source at a plurality of different positions within the cylinder.

[0015] Some other embodiments of the present technology are directed to a gamma ray source device including: a hollow tube having an inner diameter and an outer diameter, the hollow tube including a first end and an opposite second end; and a gamma ray source holder within the inner diameter of the tube. The gamma ray source holder is configured to receive and hold a gamma ray source. The gamma ray source holder and the gamma ray source are configured to be positioned at a plurality of different positions within the tube between the first end and the second end. The outer diameter of the tube is sized such that the gamma ray source device is configured to be received within a detector of a gamma counter.

[0016] In some embodiments, the gamma source holder includes a threaded member that threadably engages with the inner diameter of the tube.

[0017] In some embodiments, the threaded member includes a first end and an opposite second end, the first end of the threaded member configured to accommodate the gamma ray source.

[0018] In some embodiments, the first end of the screw member includes a threaded opening, the opening configured to threadably mate with the gamma ray source.

[0019] In some embodiments, the second end of the threaded member includes a recess configured to accommodate a tool for selectively moving the threaded member between a plurality of different positions within the tube by rotating the threaded member.

[0020] In some embodiments, a motor is operatively connected to the gamma radiation source holder and configured to move the gamma radiation source holder between a plurality of different positions within the tube.

[0021] In some embodiments, the gamma ray source device includes a scale on the tube including graduations corresponding to at least some of a plurality of different positions within the tube and representing expected count rates by a detector of the gamma counter.

[0022] In some embodiments, the scale includes first and second scales, the first scale including graduations representing an expected count rate by a first type of detector of the gamma counter, and the second scale including graduations representing an expected count rate by a second type of detector of the gamma counter.

[0023] In some embodiments, the tube is transparent or translucent so that a user can see the location of the gamma ray source through the tube.

[0024] In some embodiments, the outer diameter of the tube is between 10 mm and 30 mm.

[0025] In some embodiments, the tube has a height or length between 60 mm and 100 mm.

[0026] In some embodiments, the gamma ray source device comprises a gamma ray source.

[0027] In some embodiments, the gamma ray source comprises barium pellets.

[0028] In some embodiments, the tube is made of a polymer.

[0029] In some embodiments, the gamma ray source device includes or is supplied with an electronic or paper chart that provides the expected count rate of the gamma ray source at each of a number of different positions within the tube.

[0030] Further features, advantages, and details of the present technology will be recognized by those skilled in the art from reading the figures and detailed description of the embodiments that follow, such description being merely illustrative of the present technology.

[0031] The accompanying drawings, which form a part of this specification, illustrate embodiments of the present technology. [Brief explanation of the drawings]

[0032] [Figure 1A]FIG. 1 is a schematic diagram of a gamma counter system according to some embodiments. [Figure 1B] FIG. 1 is a perspective view of a tray holding a plurality of test tube holders. [Figure 2] 1 is a perspective view of a gamma ray source device according to some embodiments. [Figure 3] 3 is a cross-sectional view of the gamma ray source device of FIG. 2 with the gamma ray source in an upper position. [Figure 4] 3 is a cross-sectional view of the gamma ray source device of FIG. 2 with the gamma ray source in a downward position. [Figure 5] FIG. 3 is a perspective view of a gamma ray source holder of the gamma ray source device of FIG. 2. [Figure 6] 3 is another perspective view of the gamma ray source holder of the gamma ray source device of FIG. 2. [Figure 7] FIG. 3 is a perspective view of a gamma ray source of the gamma ray source device of FIG. 2. [Figure 8] 10A and 10B are cross-sectional views of gamma ray source devices according to some other embodiments. [Figure 9] 1 is a flowchart illustrating a method according to some embodiments. [Figure 10] 3 is a chart showing test results of gamma counter count rates using the gamma ray source device of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present disclosure reduces the need for multiple gamma-ray sources of varying activity levels to determine the count-rate linearity of a gamma detector. Thus, the present disclosure is based on the understanding that a given gamma detector has a given count-rate linearity, which is a detector performance characteristic characterized by a substantially linear increase or decrease in detector counts as the activity of the gamma-ray source / emitter decays / degrades. The present disclosure also contemplates that the decay or decay of the activity of the gamma-ray source / emitter can be achieved using a single gamma-ray source by varying the solid angle between the gamma-ray source (emitter) and the gamma counter / detector. By varying the solid angle between the gamma-ray source and the gamma counter, as disclosed herein, a single source can be used to achieve gamma-ray sources of varying emissivity at the detector (i.e., as seen by the detector), thereby eliminating the need for multiple gamma-ray sources of varying emissivity to enable the count-rate linearity of the detector to be determined and / or verified. Thus, disclosed are methods, systems, apparatus, and computer-readable program products for evaluating, determining, and / or verifying the performance of gamma detectors by determining the count-rate linearity of one or more gamma detectors using a single gamma radiation source by varying the solid angle between the single gamma radiation source and one or more detectors (and thus the emissivity observed by the detectors). If the expected count-rate linearity of a given detector is not as determined by the methods, systems, apparatus, and computer program products disclosed herein, the detector may be considered defective and may be repaired or replaced.

[0034] In one embodiment, a method for determining count rate linearity of one or more gamma detectors using a single gamma radiation source is disclosed, the method including, for each detector, (i) positioning the single gamma radiation source to create a first solid angle between the single gamma radiation source and each of the one or more gamma detectors, where the first solid angle may be different for each of the one or more gamma detectors, and where each first solid angle corresponding to each of the one or more detectors is associated with a first emissivity; (ii) recording a first count rate of the one or more detectors at each first solid angle; (iii) measuring the count rate linearity of the single gamma radiation source; and (iv) recording second count rates of the one or more detectors at each second solid angle and determining count rate linearity of each of the one or more detectors based on the respective relationships of the first and second recorded count rates to the respective first and second emissivities. In some embodiments, the first and second solid angles may be achieved using a positioning mechanism that can be manually manipulated to create the first and second solid angles, and in embodiments, the first and second solid angles may be created or achieved using a processor with instructions to position a single gamma radiation device to create the first and second solid angles. The processor may be in communication via a wired or wireless connection with a positioning mechanism (e.g., a controller) capable of varying the solid angle relationship between the single gamma ray source and one or more detectors, and thus includes processor instructions for performing the methods disclosed herein.

[0035] In embodiments, the disclosed methods and systems may include: (i) positioning a single gamma radiation source to create a third solid angle between the single gamma radiation source and each of one or more gamma detectors, wherein the third solid angle may be different for each of the one or more gamma detectors, and wherein each third solid angle corresponding to each of the one or more detectors is associated with a third emissivity; and (ii) recording third count rates of the one or more detectors at each third solid angle, wherein determining the count rate linearity of each of the one or more detectors is further based on the relationship between the third recorded count rate and the respective third emissivity.

[0036] It can be understood that more than three emissivities may be achieved using the methods, systems, apparatus, and computer program products of the present disclosure without departing from the scope of the present disclosure, and that the above-described determination of count rate linearity may be based on the relationship between the four or more achieved emissivities and the corresponding recorded count rates.

[0037] Thus, rather than using multiple gamma-ray sources with different disintegrations per minute (DPM), the technique allows a user to use a single gamma-ray source to vary the solid angle of the gamma particles incident on the detector, thereby changing the count rate observed by the detector and its counting electronics, thereby effectively achieving a change in the emissivity of the gamma-ray source. Using the technique, external pulse generators, special cables, and multiple gamma radiation sources are not required to determine the count rate linearity of a gamma detector.

[0038] 1A is a simplified schematic diagram of a gamma counter or gamma counter system 10. Gamma counter 10 includes multiple detectors 12, each detector 12 including a well 14. Gamma counter 10 includes a controller 16 (e.g., a processor) operatively associated with the detectors 12 and a display 18. The illustrated gamma counter 10 includes five detectors 12. However, a gamma counter may include more or fewer detectors (including a single detector in some embodiments).

[0039] Figure 1B is a perspective view of a rack 20 containing a plurality of test tube holders 22. Referring to Figures 1A and 1B, in use, test tubes containing solid and liquid samples are placed in the test tube holders 22 and the rack is loaded into the gamma counter 10. The test tube holders 22 are received in the detector 12 and gamma rays emitted from the samples are detected and counted (e.g., by the controller 16). The count rate results may be displayed on the display 18.

[0040] It may be desirable to determine the count rate linearity of a gamma counter to verify proper operation of the detectors 12. Figure 1A shows a single gamma source device 100 according to the present technology in one of the detectors 12. The gamma source device 100 allows a user to determine the count rate linearity using a single gamma source, as will now be described.

[0041] A single gamma ray source device 100 according to some embodiments is shown in Figures 2-4. The illustrated gamma ray source device 100 includes a hollow tube or cylinder 102. The tube 102 includes an inner diameter D1 and an outer diameter D2. The tube 102 includes a first end 104 and an opposite second end 106. The inner diameter D1 defines a channel 108.

[0042] The apparatus 100 includes a gamma radiation source holder 110 within an interior diameter D1 of the tube 102. The gamma radiation source holder 110 is configured to receive and hold a gamma radiation source 112.

[0043] As described in more detail herein, the gamma ray source holder 110 and the gamma ray source 112 are configured to be positioned at a plurality of different positions within the channel 108 of the tube 102 between the first end 104 and the second end 106 of the tube, thereby varying the solid angle between the gamma ray source and the detector. For example, the gamma ray source holder 110 and the gamma ray source 112 may be moved to a plurality of different positions within the channel 108 between an upper position at the first end 104 of the tube 102 ( FIG. 3 ) and a lower position at the second end 106 of the tube 102 ( FIG. 4 ).

[0044] An adjustment mechanism is operable to move the gamma source holder 110 and the gamma source 112 within the channel 108 of the tube 102 .

[0045] In some embodiments, the gamma source holder 110 is a screw or threaded member. As shown in Figures 3 and 4, the threaded member 110 may include threads 114 that mate with threads 116 of the inner diameter D1 of the tube 102 or the channel 108.

[0046] 5 and 6, the illustrated gamma ray source holder 110 includes a first end 118 and an opposite second end 120. The first end 118 may be configured to receive a gamma ray source 112 (FIG. 7).

[0047] The first end 118 of the gamma source holder 110 may include an opening or channel 122. The opening 122 may include a thread 124.

[0048] A gamma ray source 112 according to some embodiments is shown in Figure 7. The gamma ray source includes a stem 126 and a top 128. The stem 126 may include threads 130. In some embodiments, the gamma ray source 112 is or includes barium pellets.

[0049] 5 and 7, the shank 126 of the gamma ray source 112 may be received in the opening 122 of the gamma ray source holder 110. In some embodiments, such as the illustrated embodiment, the shank 126 is threadedly engaged with the opening 122.

[0050] Referring to FIG. 6 , the second end 120 of the gamma ray source holder 110 may include a recess or receptacle 130. The recess 130 is configured to accommodate a tool or other adjustment for rotating the gamma ray source holder 110 to selectively move the gamma ray source holder 110, and therefore the gamma ray source 112, within the channel 120 ( FIGS. 3 and 4 ) of the tube 102, thereby changing the solid angle relationship between the single gamma ray source 112 and the detector 12. In the illustrated embodiment, the recess 130 has a hexagonal shape and is configured to accommodate a socket wrench or Allen wrench. In some embodiments, the recess 130 includes one or more elongated slots and is configured to accommodate a screwdriver. Those skilled in the art will understand that such examples are illustrative only and that other known mechanisms for rotating the gamma ray source holder 110 may be used in accordance with the present disclosure.

[0051] In some other embodiments, referring to FIG. 8 , rather than manually moving the gamma ray source holder 110, a motor M may be operatively connected to the gamma ray source holder 110 and configured to move the gamma ray source holder 110 up and down between a plurality of different positions within the tube 102.

[0052] 2, at least one scale 132 including graduations 134 may be present on the tube 102. The graduations 134 (also referred to herein as % CPM positions or % markings) represent the expected count rate by the detector 12 (FIG. 1A) of the gamma counter 10 when the device 100 is within the detector 12.

[0053] In some embodiments, the scale 132 includes first and second scales 132A, 132B. The first scale 132A may include a first graduation 134A representing an expected, known, or characteristic count rate by a first type of detector at various specified solid angle relationships between the gamma-ray source 112 and the detector 12. The second scale 132B may include a second graduation 134B representing an expected, known, or characteristic count rate by a different second type of detector at the same solid angle.

[0054] In some embodiments, the tube 102 is transparent or translucent so that a user can see the position of the gamma ray source 112 through the tube 102. This allows the user to align the gamma ray source 112 with one of the graduations 134 on the scale 132, thus achieving one or more specified solid angle relationships between the gamma ray source 112 and the detector 12. The tube 102 may be made of a polymer.

[0055] 1, scale 132 is shown next to tube 102, it will be understood that scale 132 may be on a label affixed to tube 102. Alternatively, scale 132 may be (permanently) printed on tube 102.

[0056] 4, the outer diameter D2 of the tube 102 may be between 10 mm and 30 mm. The outer diameter D2 of the tube 102 is sized so that the gamma ray source device 100 is configured to be received in the detector 12 of the gamma counter 10 (FIG. 1A) or one of the test tube holders 22 (FIG. 1B).

[0057] For example, according to some of the illustrated embodiments, the length L of the tube 102 is between 60 mm and 100 mm, between 70 mm and 90 mm, between 70 mm and 80 mm, and approximately 75 mm. Those skilled in the art will understand that the present disclosure is not limited to the configurations of the tube 102 disclosed, and thus is similarly not limited to any physical characteristics of such tube 102.

[0058] In some embodiments, the apparatus 100 includes an electronic or paper chart for recording the expected count rate of the gamma-ray source 112 at various specified solid angles represented by position within the tube 102 (e.g., by each division 134 of the scale 132). Such a calibration sheet may include the expected count rate at a particular emissivity corresponding to a given solid angle, as well as the expected count rate when the gamma-ray source is moved to various other divisions representing other specified solid angle relationships between the gamma-ray source 112 and the detector 12. In some embodiments, a spreadsheet may be configured to calculate the expected count rate, automatically correct for decay of the activity of the gamma-ray source, and display the expected count rate.

[0059] 9 is a flowchart illustrating a method for determining count rate linearity of one or more detectors of a gamma counter, according to some embodiments. Referring to FIGS. 1-4 and 9, method 200 includes providing a gamma ray source apparatus as described herein (block 202). For example, gamma ray source apparatus 100 may include a cylinder 102, a gamma ray source holder 110 within cylinder 102, and a gamma ray source 112 connected to gamma ray source holder 110. Gamma ray source holder 110 and gamma ray source 112 are configured to be moved to a plurality of different positions within cylinder 102.

[0060] In the illustrated embodiment, the method includes inserting the gamma ray source device 100 into the detector 12 of the gamma counter 10 with the gamma ray source 112 at a first position within the cylinder 102 (block 204). The method includes determining, using the gamma counter 10, a first count rate of the gamma ray source 112 with the gamma ray source 112 at the first position within the cylinder 102 (block 206).

[0061] The method includes moving the gamma ray source 112 to a second position within the cylinder 102 (block 208). The method includes determining a second count rate of the gamma ray source 112 with the gamma ray source 112 at the second position within the cylinder 102 using the gamma counter 10 (block 210).

[0062] In some embodiments, the method includes comparing the first count rate to a first expected count rate and comparing the second count rate to a second expected count rate.

[0063] In some embodiments, the method includes moving the gamma ray source 112 to at least one additional position within the cylinder and determining the count rate of the gamma ray source 112 at each of the at least one additional position (block 212).

[0064] For example, the method may include, after determining the second count rate, moving the gamma ray source 112 to a third position within the cylinder 102 and determining, using the gamma counter 10, a third count rate of the gamma ray source 112 with the gamma ray source 112 at the third position within the cylinder 102. The method may include, after determining the third count rate, moving the gamma ray source 112 to a fourth position within the cylinder 102 and determining, using the gamma counter 10, a fourth count rate of the gamma ray source 112 with the gamma ray source 112 at the fourth position within the cylinder 102.

[0065] The method may include comparing the third count rate to a third expected count rate and / or comparing the fourth count rate to a fourth expected count rate.

[0066] The gamma ray source 112 may be moved to five or more positions in some embodiments.

[0067] In some embodiments, the gamma ray source holder includes a screw that threadably mates with an inner diameter of the cylinder, and moving the gamma ray source to the second position (or the third position and / or the fourth position) includes rotating the screw. Rotating the screw may include rotating the screw using a hand tool.

[0068] In some embodiments, after determining the first count rate, the method includes removing the gamma ray source device from the detector and, after rotating the screw, reinserting the gamma ray source device into the detector of the gamma counter with the gamma ray source in a second position (and / or a third position and / or a fourth position) within the cylinder.

[0069] The cylinder may be transparent or translucent and may include a scale including a plurality of graduations, and the step of moving the gamma ray source to the second position (and / or the third position and / or the fourth position) includes the step of moving the gamma ray source to one of the plurality of graduations.

[0070] In some embodiments, the gamma counter 10 includes multiple detectors 12. The method may include inserting at least some of the multiple detectors 12 under test into the gamma source device 100 and determining, for each detector 12 under test, a respective count rate with the gamma source 112 at multiple different positions within the cylinder. [Example]

[0071] One embodiment of the disclosed gamma ray source device 100 was used with a 2470 Wizard, both available from PerkinElmer Health Sciences, Inc. 2 Gamma Counter and 2480 Wizard 2 The count rate linearity of the gamma counter was investigated. The position of the gamma ray source 112 was set at each of the divisions 134 or % CPM positions of the scale 132. The % CPM indicator was set by the 2470 Wizard. 2 Equipment and the 2480 Wizard 2Note that the difference in detector geometry and therefore solid angle is different between instruments.

[0072] The gamma source 112 was counted at each % CPM position and the results were confirmed to be within the desired tolerances. The gamma source device 100 used a single gamma source 112 moved to different positions within the tube 102 to confirm that each device had sufficient count rate linearity. The results obtained during testing are contained in Table 1 and charted in Figure 10. 2470 Wizard 2 The gamma counter includes six detectors (D5 to D10) and is equipped with a 2480 Wizard 2 Note that the gamma counter contains one detector (2480).

[0073] [Table 1]

[0074] The present technology is described herein with reference to the accompanying drawings, in which exemplary embodiments of the technology are shown. In the drawings, the relative sizes of areas or features may be exaggerated for clarity. However, this technology may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the technology to those skilled in the art.

[0075] Although terms such as "first" and "second" are used herein to describe various elements, components, regions, layers, and / or portions, it will be understood that these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, or portion from another region, layer, or portion. Thus, a first element, component, region, layer, or portion described below could be referred to as a second element, component, region, layer, or portion without departing from the teachings of the present technology.

[0076] Spatial terms such as "below," "under," "below," "above," and the like may be used herein for ease of description to describe the relationship of one element or feature shown in a figure to another element or feature. It will be understood that spatial terms encompass other orientations of the device in use or operation in addition to the orientation shown in the figures. For example, if the device in the figures were turned over, elements described as being "below" or "below" another element or feature would then be oriented "above" the other element or feature. Thus, the term "below" can encompass both an above and below orientation. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatial descriptors used herein will be interpreted accordingly.

[0077] The present disclosure can be implemented using one or more computer programs, where a computer program can be understood to include one or more processor-executable instructions. The computer programs can be executed by one or more programmable processors and stored in one or more storage media readable by the processor (including volatile and non-volatile memory and / or storage elements), one or more input devices, and / or one or more output devices. Thus, the processor can access one or more input devices to obtain input data and one or more output devices to communicate output data. The input devices and / or output devices can include one or more storage devices accessible by the processor provided herein.

[0078] The computer programs may be implemented using one or more high-level procedural or object-oriented programming languages ​​to communicate with a computer system, although the programs may be implemented in assembly or machine language if desired, and the language may be compiled or interpreted.

[0079] Thus, as provided herein, a processor may be incorporated into one or more devices capable of operating independently or together in a networked environment, where the network may include, for example, a local area network (LAN), a wide area network (WAN), and / or an intranet and / or the Internet and / or another network. The network may be wired or wireless or a combination thereof, and may use one or more communication protocols to facilitate communication between different processors. The processor may be configured to distribute processing, and in some embodiments, may utilize a client-server model as appropriate. Thus, methods and systems may utilize multiple processors and / or processor devices, and processor instructions may be divided among such single or multiple processors / devices. References herein to (micro)processor instructions or (micro)processor-executable instructions may be understood to include programmable hardware, in accordance with the above.

[0080] References to "a microprocessor" and "a processor," or "the microprocessor" and "the processor," may be understood to include one or more microprocessors capable of communicating in a standalone environment and / or a distributed environment, and thus may be configured to communicate with other processors via wired or wireless communication, and such one or more processors may be configured to operate on one or more processor-controlled devices, which may be similar or different devices. Thus, such use of the term "microprocessor" or "processor" may also be understood to include a central processing unit, an arithmetic logic unit, an application-specific integrated circuit (IC), and / or a task engine, and such examples are provided for purposes of illustration and not limitation.

[0081] Furthermore, unless otherwise specified, references to memory can include one or more processor-readable and accessible memory elements and / or components that may be internal to the processor-controlled device, external to the processor-controlled device, and / or accessible via wired or wireless networks using various communication protocols, and can be arranged to include a combination of external and internal memory devices, unless otherwise specified, and such memory can be contiguous and / or partitioned depending on the application. Accordingly, references to a database can be understood to include one or more memory associations, and such references can include commercially available database products (e.g., SQL, Informix, Oracle) and proprietary databases, and may also include other structures for associating memory, such as links, queues, graphs, trees, etc., and such structures are provided for purposes of illustration and not limitation.

[0082] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless expressly stated otherwise. It will be further understood that the words "comprise," "comprise," "includes," and / or "comprising," when used herein, specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. When an element is referred to as "connected" or "coupled" to another element, it will be understood that it may be directly connected or coupled to the other elements, or that intervening elements may be present. As used herein, the word "and / or" includes any or all combinations of one or more of the associated listed items. When the word "about" or "substantially equal to" is used herein, the intended meaning is that the value is plus or minus 5% of the specified value.

[0083] It is noted that one or more aspects or features described in connection with one embodiment may be incorporated into another embodiment even if not specifically described therein. That is, all embodiments and / or features of any embodiment may be combined in any manner and / or combination. Applicant reserves the right to modify the originally filed claims or to file new claims accordingly, including the right to amend the originally filed claims to depend from and / or incorporate features of other claims even if not originally so claimed. These and other objects and / or aspects of the present technology are described in detail in the specification set forth herein.

[0084] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art to which this technology belongs. Furthermore, terms such as those defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless expressly defined to that effect in this specification.

[0085] The foregoing is illustrative of the present technology and should not be construed as limiting thereof. While several exemplary embodiments of the present technology have been described, those skilled in the art will readily recognize that many variations are possible in the exemplary embodiments without substantially departing from the teachings and advantages of the present technology. Accordingly, all such variations are intended to be included within the scope of the present technology as defined in the claims. The present technology is defined by the following claims, with equivalents of the claims to be included therein.

Claims

1. 1. A method for determining count rate linearity of one or more detectors of a gamma counter, comprising: providing a gamma ray source device comprising a cylinder, a gamma ray source holder within the cylinder, and a gamma ray source connected to the gamma ray source holder, wherein the gamma ray source holder and the gamma ray source are configured to be moved to a plurality of different positions within the cylinder; inserting the gamma ray source device into a detector of the gamma counter with the gamma ray source in a first position within the cylinder; using the gamma counter to determine a first count rate of the gamma ray source with the gamma ray source in the first position within the cylinder; moving the gamma ray source to a second position within the cylinder; using the gamma counter to determine a second count rate of the gamma ray source with the gamma ray source in the second position within the cylinder; A method comprising:

2. The method of claim 1 , further comprising the steps of comparing the first count rate to a first expected count rate and comparing the second count rate to a second expected count rate.

3. After determining the second count rate, moving the gamma ray source to a third position within the cylinder; using the gamma counter to determine a third count rate of the gamma ray source with the gamma ray source in the third position within the cylinder; The method of claim 1 further comprising:

4. The method of claim 3 further comprising the step of comparing the third count rate to a third expected count rate.

5. After determining the third count rate, moving the gamma ray source to a fourth position within the cylinder; using the gamma counter to determine a fourth count rate of the gamma ray source with the gamma ray source in the fourth position within the cylinder; The method of claim 3 further comprising:

6. The method of claim 5 further comprising the step of comparing the fourth count rate to a fourth expected count rate.

7. 2. The method of claim 1, wherein the gamma ray source holder comprises a thread that threadably engages an inner diameter of the cylinder, and moving the gamma ray source to the second position comprises rotating the thread.

8. The method of claim 7 , wherein the step of rotating the screw comprises the step of using a hand tool to rotate the screw.

9. 8. The method of claim 7, further comprising the steps of: removing the gamma ray source device from the detector after determining the first count rate; and, after rotating the screw, reinserting the gamma ray source device into the detector of the gamma counter with the gamma ray source in the second position within the cylinder.

10. The method of claim 7 , wherein rotating the screw comprises rotating the screw using a motor operatively connected to the screw.

11. 2. The method of claim 1, wherein the cylinder is transparent or translucent and includes a scale with a plurality of graduations, and moving the gamma ray source to the second position includes moving the gamma ray source to one of the plurality of graduations.

12. the gamma counter comprises a plurality of detectors, and the method comprises: inserting the gamma ray source device into at least some of the plurality of detectors under test; determining, for each detector under test, count rates with the gamma ray source at a plurality of different positions within the cylinder; The method of claim 1 , comprising:

13. 1. A gamma ray source device comprising: a hollow tube having an inner diameter and an outer diameter, the tube having a first end and an opposite second end; a gamma ray source holder within the inner diameter of the tube; Equipped with the gamma ray source holder is configured to receive and hold a gamma ray source; the gamma ray source holder and the gamma ray source are configured to be positioned at a plurality of different positions within the tube between the first end and the second end; The gamma ray source device, wherein the outer diameter of the tube is sized such that the gamma ray source device is configured to be housed within a detector of a gamma counter.

14. 14. The gamma ray source apparatus of claim 13, wherein the gamma ray source holder comprises a threaded member that threadably engages the inner diameter of the tube.

15. 15. The gamma ray source device of claim 14, wherein the screw member comprises a first end and an opposite second end, the first end of the screw member configured to receive the gamma ray source.

16. 16. The gamma ray source device of claim 15, wherein the first end of the screw member comprises a threaded opening, the opening configured to threadably mate with the gamma ray source.

17. 16. The gamma ray source device of claim 15, wherein the second end of the threaded member comprises a recess configured to mate with a tool for rotating the threaded member to selectively move the threaded member between the plurality of different positions within the tube.

18. 14. The gamma ray source device of claim 13, further comprising a motor operatively connected to the gamma ray source holder and configured to move the gamma ray source holder between the plurality of different positions within the tube.

19. 14. The gamma ray source device of claim 13, further comprising a scale with graduations on the tube, the graduations corresponding to at least some of the plurality of different positions within the tube and representing an expected count rate by the detector of the gamma counter.

20. 20. The gamma ray source device of claim 19, wherein the scale includes first and second scales, the first scale including graduations representing an expected count rate by a first type of detector of the gamma counter, and the second scale including graduations representing an expected count rate by a second type of detector of the gamma counter.

21. 20. The gamma ray source device of claim 19, wherein the tube is transparent or translucent so that a user can see the position of the gamma ray source through the tube.

22. 14. The gamma ray source device according to claim 13, wherein the outer diameter of the tube is between 10 mm and 30 mm.

23. 14. The gamma ray source device according to claim 13, wherein the tube has a height or length between 60 mm and 100 mm.

24. 14. The gamma ray source device of claim 13, further comprising the gamma ray source.

25. 25. The gamma ray source device of claim 24, wherein the gamma ray source comprises barium pellets.

26. 14. The gamma ray source device of claim 13, wherein the tube is made of a polymer.

27. 14. The gamma ray source device of claim 13, further comprising an electronic or paper chart providing an expected count rate of the gamma ray source at each of the plurality of different positions within the tube.

Images