A detection method of a detection system and a detection system
By combining a neutron monochromator and a detection component, and using the relationship between transmittance and thickness, the problem of low detection accuracy of boron 10-area density in boron-containing alloys was solved, enabling precise monitoring of nuclear criticality safety in spent fuel pools.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA INSTITUTE OF ATOMIC ENERGY
- Filing Date
- 2024-06-28
- Publication Date
- 2026-06-09
Smart Images
Figure CN122171387A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of nuclear technology, and in particular to a detection method and a detection system for a detection system. Background Technology
[0002] Spent fuel, also known as irradiated nuclear fuel, refers to nuclear fuel that has been irradiated and used, typically produced by nuclear reactors in nuclear power plants. Spent fuel is stored in pools using racks. These racks are constructed from boron-containing alloys such as boron-aluminum alloys or boron-steel alloys. The boron 10 areal density of the boron-containing alloy is crucial to criticality safety during dense storage of spent fuel. Before being placed in the pool, the boron 10 areal density of the boron-containing alloy needs to be non-destructively tested to verify that it meets the design value. However, over time, the boron 10 in the boron-containing alloy is gradually consumed; therefore, the boron 10 areal density needs to be periodically tested to monitor the nuclear criticality safety of the spent fuel pool.
[0003] In related technologies, the detection of boron 10-area density in boron-containing alloys is based on 252 A Cf isotope neutron source was used to obtain the boron-10 areal density of the material under test by measuring its transmittance. However, on the one hand, 252 The average energy of the Cf isotope neutron source is 2.179 MeV. Considering that the neutron intensity cannot decay too much and the moderator thickness is limited, most moderated neutron energies do not reach meV (thermal neutron energy range). Therefore, the average neutron absorption cross section of boron-10 is not high, and the neutron transmittance is not sensitive to changes in the boron-10 areal density. Furthermore, the related technologies do not consider the influence of the second phase in boron-containing alloys, resulting in low accuracy in boron-10 areal density detection. Summary of the Invention
[0004] In view of this, the main objective of the embodiments of this application is to provide a detection method and detection system that improves the detection accuracy of boron 10 areal density.
[0005] To achieve the above objectives, the technical solution of this application embodiment is implemented as follows:
[0006] The first aspect of this application provides a detection method for a detection system, used to detect the areal density of boron 10 in a boron-containing alloy. The detection system includes a neutron monochromator, a detection component, and a processor. The neutron monochromator is used to monochromate a white light neutron beam into a monochromatic neutron beam. The detection method includes:
[0007] The detection component receives the monochromatic neutron beam to obtain a direct beam count;
[0008] The detection component receives sub-beams from the environment to obtain background counts.
[0009] The detection assembly receives a first transmitted neutron beam passing through the boron carbide sample to obtain a first count.
[0010] The detection assembly receives a second transmitted neutron beam passing through the second phase sample to obtain a second count; wherein the material of the second phase sample is the second phase material in a boron-containing alloy sample;
[0011] The detection assembly receives a third transmitted neutron beam passing through the boron-containing alloy sample to obtain a third count;
[0012] The processor determines a first relationship between the first transmittance and the first thickness of the boron carbide sample based on the direct beam count, the background count, and the first count, and determines a second relationship between the first transmittance and the boron 10 areal density.
[0013] The processor determines a third relationship between the second transmittance and the second thickness of the second phase sample based on the direct beam count, the background count, and the second count.
[0014] The processor determines the areal density of boron 10 in the boron-containing alloy based on the direct beam count, the background count, the third count, the third thickness of the boron-containing alloy, the first relation, the second relation, and the third relation.
[0015] In one embodiment, the processor determines the areal density of boron 10 in the boron-containing alloy based on the direct beam count, the background count, the third count, the third thickness of the boron-containing alloy, the first relation, the second relation, and the third relation, including:
[0016] The processor determines the third transmittance of the boron-containing alloy sample based on the direct beam count, the background count, and the third count;
[0017] The processor determines a first calculated transmittance based on the third transmittance, the third thickness, the first relationship, and the third relationship; wherein the first calculated transmittance corresponds to the second phase material in the boron-containing alloy sample.
[0018] The processor substitutes the value of the fourth transmittance as the first transmittance into the second relation, and calculates the first surface density of boron 10 in the boron-containing alloy based on the surface density calculation result of the second relation; wherein, the fourth transmittance is the difference between the third transmittance and the first calculated transmittance.
[0019] In one embodiment, the processor determines a first calculated transmittance based on the third transmittance, the third thickness, the first relationship, and the third relationship, including:
[0020] The processor uses the value of the third transmittance as the first transmittance and substitutes it into the first relational expression, and obtains the equivalent boron carbide thickness based on the thickness calculation result of the first relational expression.
[0021] The processor substitutes the value of the equivalent second phase thickness as the second thickness into the third relation, and obtains the first calculated transmittance based on the transmittance calculation result of the third relation; wherein, the equivalent second phase thickness is the difference between the third thickness and the equivalent boron carbide thickness.
[0022] In one embodiment, the detection method further includes:
[0023] The processor substitutes the value of the third thickness as the second thickness into the third relation, and obtains the second calculated transmittance based on the transmittance calculation result of the third relation.
[0024] The processor substitutes the value of the fifth transmittance as the first transmittance into the second relational expression, and obtains the second surface density based on the surface density calculation result of the second relational expression; wherein, the fifth transmittance is the difference between the third transmittance and the second calculated transmittance;
[0025] The processor averages the first areal density with the second areal density to obtain a third areal density.
[0026] In one embodiment, the formulas for calculating the first transmittance, the second transmittance, and the third transmittance are as follows:
[0027]
[0028] Wherein, T is the first transmittance, the second transmittance, or the third transmittance; N1 is the first count, the second count, or the third count; N2 is the background count; and N3 is the direct beam count.
[0029] In one embodiment, the processor determines a first relationship between the first transmittance and the first thickness of the boron carbide sample based on the direct beam count, the background count, and the first count, and determines a second relationship between the first transmittance and the boron 10 areal density, including:
[0030] The processor determines a plurality of first transmittances based on the direct beam count, the background count, and a plurality of first counts; wherein the plurality of first counts are detection results received by the detection component from the first transmitted neutron beams passing through a plurality of boron carbide samples respectively;
[0031] The processor fits multiple first transmittance values with the logarithm of the first thickness of the corresponding boron carbide sample to form the first relationship;
[0032] The processor determines multiple boron 10 areal densities corresponding to the first thickness of the multiple boron carbide samples, and logarithmically fits the multiple first transmittances with the corresponding boron 10 areal densities to form the second relationship.
[0033] In one embodiment, the processor determines a third relationship between the second transmittance and the second thickness of the second phase sample based on the direct beam count, the background count, and the second count, including:
[0034] The processor determines a plurality of second transmittances based on the direct beam count, the background count, and a plurality of second counts; wherein the plurality of second counts are detection results received by the detection component from the second transmitted neutron beams passing through a plurality of second phase samples respectively;
[0035] The processor fits multiple second transmittance values with the second thickness of the corresponding second phase sample to form the third relationship.
[0036] A second aspect of this application provides a detection system comprising a neutron monochromator, a detection component, a memory, and a processor. The neutron monochromator is used to monochromate a white neutron beam into a monochromatic neutron beam. The detection component is positioned on one side of the neutron monochromator along the direction of motion of the monochromatic neutron beam. At least a portion of the structure of the detection component is spaced apart from the neutron monochromator to form a sample mounting space. The sample mounting space can be used to place a boron carbide sample, a second-phase sample, a boron-containing alloy sample, or a neutron-absorbing sample. The memory stores computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the steps of the detection method of any of the above-described detection systems.
[0037] In one embodiment, the detection assembly includes a detector and a monitor, the monitor being disposed between the neutron monochromator and the detector, the detector and the monitor being spaced apart to form the sample mounting space, and the monitor being used to allow the monochromatic neutron beam to pass through in order to obtain the neutron count of the monochromatic neutron beam.
[0038] In one embodiment, the detection system further includes a shielding assembly comprising a first shielding plug, a second shielding plug, and a shielding cover. The first shielding plug is disposed between the neutron monochromator and the monitor. The first shielding plug can calibrate the neutron count of the monochromatic neutron beam passing through the monitor by adjusting the beam spot size of the monochromatic neutron beam. The shielding cover includes a receiving cavity with an entrance port. The detector is disposed within the receiving cavity. The second shielding plug is disposed at the entrance port to limit the beam spot size of the monochromatic neutron beam incident on the detector.
[0039] This application provides a detection method and a detection system for a detection system. The detection method includes: receiving a monochromatic neutron beam through a detection component to obtain a direct beam count; receiving an ambient neutron beam through a detection component to obtain a background count; receiving a first transmitted neutron beam passing through a boron carbide sample through a detection component to obtain a first count; receiving a second transmitted neutron beam passing through a second phase sample through a detection component to obtain a second count; receiving a third transmitted neutron beam passing through a boron-containing alloy sample through a detection component to obtain a third count; a processor determining a first relationship between the first transmittance and a first thickness of the boron carbide sample based on the direct beam count, background count, and first count, and determining a second relationship between the first transmittance and the boron 10 areal density; the processor determining a third relationship between the second transmittance and a second thickness of the second phase sample based on the direct beam count, background count, and second count; and the processor determining the boron 10 areal density in the boron-containing alloy based on the direct beam count, background count, third count, third thickness of the boron-containing alloy, the first relationship, the second relationship, and the third relationship. Therefore, on the one hand, monochromating the white light neutron beam into a monochromatic neutron beam using a neutron monochromator can improve the detection accuracy of boron 10 areal density. On the other hand, the detection component can receive neutron beams from the environment and a second transmitted neutron beam passing through the second-phase sample. The processor, based on the direct beam count, background count, first count, second count, and third count, can obtain the first transmittance, second transmittance, and third transmittance corresponding to each sample, which have reduced the influence of neutron beams from the environment. At the same time, by combining the first, second, and third relationships, the influence of the second phase in boron-containing alloys on the detection accuracy of boron 10 areal density can be reduced, thereby further improving the detection accuracy of boron 10 areal density. Attached Figure Description
[0040] Figure 1 This is a flowchart of a detection method of a detection system according to an embodiment of this application;
[0041] Figure 2 This is a schematic diagram of a detection system structure according to an embodiment of this application;
[0042] Figure 3This is a schematic diagram of the measurement point location for a boron-containing alloy sample according to an embodiment of this application. Points K, G, H, L, and M in the diagram are all transmission detection points for the boron-containing alloy sample.
[0043] Figure 4 This is a schematic diagram of the first station of the sample fixture according to an embodiment of this application. The circles in the diagram represent the beam spots of the monochromatic neutron beam incident on the sample fixture.
[0044] Figure 5 This is a schematic diagram of the second station of the sample fixture according to another embodiment of this application. The circles in the figure represent the beam spots of the monochromatic neutron beam incident on the sample fixture.
[0045] Figure 6 This is a fitting curve of first transmittance and boron 10 areal density in one embodiment of this application;
[0046] Figure 7 This is a fitting curve of the first transmittance and the first thickness in one embodiment of this application;
[0047] Figure 8 This is a fitting curve of the second transmittance and the thickness of 304 stainless steel in one embodiment of this application.
[0048] Explanation of reference numerals in the attached figures
[0049] 1. Reactor; 2. Neutron transport channel; 3. Neutron monochromator; 4. Detection assembly; 41. Monitor;
[0050] 42. Detector; 5. Shielding assembly; 51. First shielding plug; 52. Second shielding plug; 53. Shielding cover;
[0051] 6. Deflector monochromator; 7. Rotary stage; 8. Sample fixture; 81. Sample mounting bracket; 82. Fixed slide bar;
[0052] 83. Boron-containing alloy sample; 9. Neutron beam gate. Detailed Implementation
[0053] One embodiment of this application provides a detection method for a detection system. Please refer to [link / reference]. Figure 1 , Figure 2 , Figure 6 , Figure 7 and Figure 8 The detection method of this detection system is used to detect the areal density of boron 10 in boron-containing alloys. The detection system includes a neutron monochromator 3, a detection component 4, and a processor. The neutron monochromator 3 is used to monochromate a white light neutron beam into a monochromatic neutron beam.
[0054] The detection method of the detection system includes the following steps:
[0055] Step S1: Receive the monochromatic neutron beam through the detection component 4 to obtain the direct beam count.
[0056] Step S2: Receive the sub-beams in the environment through the detection component 4 to obtain the background count.
[0057] Step S3: Receive the first transmitted neutron beam passing through the boron carbide sample via the detection component 4 to obtain the first count.
[0058] Step S4: Receive the second transmitted neutron beam passing through the second phase sample via the detection component 4 to obtain the second count.
[0059] Step S5: Receive the third transmitted neutron beam passing through the boron-containing alloy sample 83 via the detection component 4 to obtain the third count.
[0060] Step S6: The processor determines the first relationship between the first transmittance and the first thickness of the boron carbide sample based on the direct beam count, background count, and first count, and determines the second relationship between the first transmittance and the boron 10 areal density.
[0061] Step S7: The processor determines the third relationship between the second transmittance and the second thickness of the second phase sample based on the direct beam count, background count, and second count;
[0062] Step S8: The processor determines the areal density of boron 10 in the boron-containing alloy based on the direct beam count, background count, third count, third thickness of the boron-containing alloy, first relation, second relation, and third relation.
[0063] Specifically, direct beam counting refers to the sum of the number of direct neutrons from the monochromatic neutron beam (after the white light neutron beam is monochromated into a monochromatic neutron beam by the neutron monochromator 3) and the number of neutrons from the ambient light beam (which does not pass through the sample and directly strikes the detector assembly 4). In other words, the direct beam counting originates from two sources: one is the count of the monochromatic neutron beam incident on the detector assembly 4, and the other is the count of the ambient light beam incident on the detector assembly 4.
[0064] The neutron beam in the environment refers to the neutron beam received by the detector component 4 from the environment that does not pass through the sample.
[0065] Furthermore, during the detection process, the intensity of the monochromatic neutron beam can be ensured by maintaining the direct beam count at a certain level. For example, the direct beam count can be above 100,000.
[0066] The background count refers to the number of neutrons in the environment received by the detection component 4. This is achieved by inserting neutron-absorbing material between at least a portion of the structure of the neutron monochromator 3 and the detection component 4. The neutron-absorbing material is used to absorb neutrons in the monochromatic neutron beam, thereby eliminating the influence of the monochromatic neutron beam on the background count and making the number of neutrons obtained by the detection component 4 closer to the number of neutrons in the environment.
[0067] The neutron-absorbing material has a high neutron absorption cross-section, enabling it to effectively absorb neutrons. The entire region of the detector assembly 4 can be located on the side opposite to the neutron-absorbing material and the neutron monochromator 3. However, depending on the specific structure of the detector assembly 4, a portion of the detector assembly 4 can be located on the side opposite to the neutron monochromator 3, while another portion can be located on the same side as the neutron monochromator 3.
[0068] The first count refers to the sum of the number of neutrons transmitted through the boron carbide sample inserted between at least a portion of the structure of the neutron monochromator 3 and the detector assembly 4, after the white neutron beam is monochromated into a monochromatic neutron beam by the neutron monochromator 3, passes through the boron carbide sample, and is received by the detector assembly 4. That is, the first count originates from two parts: one part is the count of the monochromatic neutron beam transmitted through the boron carbide sample and onto the detector assembly 4, received by the detector assembly 4; the other part is the count of the ambient neutron beam incident on the detector assembly 4, received by the detector assembly 4.
[0069] The second count refers to the number of neutrons transmitted through the monochromatic neutron beam after the white light neutron beam is monochromated by the neutron monochromator 3 into a monochromatic neutron beam, and the sum of the number of neutrons transmitted through the monochromatic neutron beam through the second-phase sample and the number of neutrons in the environment after the monochromatic neutron beam is transmitted through the second-phase sample by the neutron monochromator 3. In other words, the second count originates from two parts: one part is the count of the monochromatic neutron beam transmitted through the second-phase sample and onto the detector 4, received by the detector 4; the other part is the count of the neutrons in the environment incident on the detector 4.
[0070] It should be noted that the term "second phase" refers to all other phases in a material that are different from the matrix phase. In boron-containing alloy sample 83, boron carbide is the matrix phase, and the other non-boron carbide components are the second phases in boron-containing alloy sample 83. The type of material for the second phase is not limited and can be one or more, such as pure aluminum, different types of aluminum alloys, or different types of steel.
[0071] The third count refers to the sum of the number of neutrons transmitted through the boron-containing alloy sample 83 and the number of neutrons in the environment after the white neutron beam is monochromated by the neutron monochromator 3 into a monochromatic neutron beam, as received by the detector assembly 4. In other words, the third count originates from two parts: one part is the count of the monochromatic neutron beam transmitted through the boron-containing alloy sample 83 and onto the detector assembly 4, and the other part is the count of the ambient neutron beam incident on the detector assembly 4.
[0072] It should be noted that the number of third counts is unlimited; there can be one or more. By performing multi-point detection on the sample, the detection accuracy can be improved, enabling non-destructive testing of the uniformity of boron 10 surface density.
[0073] For example, five points are used to measure the transmittance of the boron-containing alloy sample 83, thereby obtaining five third counts corresponding to the transmittance measurement points of the boron-containing alloy sample 83. One detection point is located at the center of the boron-containing alloy sample 83, and the remaining detection points are located at the four corners at a distance of 1 / 4L from the edge line of the long side of the boron-containing alloy sample 83 and a distance of 2.54cm from the edge line of the short side of the boron-containing alloy sample 83, where L represents the length of the long side of the boron-containing alloy sample 83.
[0074] The first transmittance is determined by the direct beam count, background count, and first count, thus eliminating the influence of the ambient neutron beam on the transmittance of the boron carbide sample. In practice, the first transmittance is the ratio of the number of neutrons passing through the boron carbide sample by the monochromatic neutron beam to the total number of monochromatic neutrons; its specific calculation formula can be set according to actual conditions.
[0075] For example:
[0076] Where T is the first transmittance; N1 is the first count; N2 is the background count; and N3 is the direct beam count.
[0077] The second transmittance is determined by the direct beam count, background count, and second count, thereby eliminating the influence of the ambient neutron beam on the transmittance of the second-phase sample. In practice, the second transmittance is the ratio of the number of neutrons passing through the second-phase sample from the monochromatic neutron beam to the total number of monochromatic neutrons; its specific calculation formula can be set according to actual conditions.
[0078] For example:
[0079] Where T is the second transmittance; N1 is the second count; N2 is the background count; and N3 is the direct beam count. It should be noted that the background count is introduced to eliminate the influence of environmental sub-beams on the results. However, this elimination does not mean the complete removal of environmental sub-beams, but rather a reduction in their impact on the detection results.
[0080] The first thickness refers to the thickness of the boron carbide sample, the second thickness refers to the thickness of the second phase sample, and the third thickness refers to the thickness of the boron-containing alloy sample 83. The terms "first," "second," and "third" are used only to distinguish the three thicknesses for ease of description.
[0081] The first relationship refers to the functional relationship between the first transmittance and the first thickness, which is obtained by fitting the first transmittance and the first thickness together. For example, by fitting the first transmittance and the first thickness logarithmically, the first relationship is obtained as: y = ab * ln(x + c). Where y is the first thickness, x is the first transmittance, and a, b, and c are all constants.
[0082] The second relationship refers to the functional relationship between the first transmittance and the boron 10 areal density, which is obtained by fitting the first transmittance and the boron 10 areal density together. For example, by fitting the first transmittance and the boron 10 areal density logarithmically, the first relationship is obtained as: y = ab * ln(x + c). Where y is the boron 10 areal density, x is the first transmittance, and a, b, and c are all constants.
[0083] The third relationship refers to the functional relationship between the second transmittance and the second thickness, which is obtained by fitting the second transmittance and the second thickness together. For example, the third relationship is: y = A1*exp(-x / t1) + y0. Where y is the second transmittance, x is the second thickness, and A1, t1, and y0 are all constants.
[0084] It should be noted that the order of steps S1, S2, S3, S4, and S5 is not limited. That is, the detection component 4 does not strictly follow the order of steps S1, S2, S3, S4, and S5 when counting; the steps can be randomly arranged.
[0085] Similarly, the order of steps S6 and S7 is not limited. The processor can perform step S6 first and then step S7, or it can perform step S7 first and then step S6.
[0086] However, it should be noted that step S6 must follow S1, S2, and S3, and step S7 must follow S1, S2, and S4. Furthermore, step S8 must follow all steps from S1 to S7.
[0087] The detection method of the detection system in this application specifically involves: receiving a monochromatic neutron beam through the detection component 4 to obtain a direct beam count; receiving an ambient neutron beam through the detection component 4 to obtain a background count; receiving a first transmitted neutron beam passing through a boron carbide sample through the detection component 4 to obtain a first count; receiving a second transmitted neutron beam passing through a second phase sample through the detection component 4 to obtain a second count; wherein the material of the second phase sample is the second phase material in the boron-containing alloy sample 83; receiving a third transmitted neutron beam passing through the boron-containing alloy sample 83 through the detection component 4 to obtain a third count; the processor determines a first relationship between the first transmittance and the first thickness of the boron carbide sample based on the direct beam count, the background count, and the first count, and determines a second relationship between the first transmittance and the boron 10 areal density; the processor determines a third relationship between the second transmittance and the second thickness of the second phase sample based on the direct beam count, the background count, the third count, the third thickness of the boron-containing alloy, the first relationship, the second relationship, and the third relationship; and the processor determines the areal density of boron 10 in the boron-containing alloy based on the direct beam count, the background count, the third count, the third thickness of the boron-containing alloy, the first relationship, the second relationship, and the third relationship. Therefore, on the one hand, by monochromating the white light neutron beam into a monochromatic neutron beam through the neutron monochromator 3, the detection accuracy of boron 10 surface density can be improved. On the other hand, the detection component 4 can receive neutron beams from the environment and second transmitted neutron beams passing through the second phase sample. The processor can obtain the first transmittance, second transmittance, and third transmittance corresponding to each sample, which have reduced the influence of neutron beams from the environment, based on the direct beam count, background count, first count, second count, and third count. At the same time, by combining the first, second, and third relationships, the influence of the second phase in the boron-containing alloy on the detection accuracy of boron 10 surface density can be reduced, thereby further improving the detection accuracy of boron 10 surface density.
[0088] Furthermore, in related technologies, the isotopic neutron source diverges in the 4π direction, and its intensity is inversely proportional to the square of the distance. Considering that the neutron intensity cannot attenuate too much, the spatial arrangement of the moderator, the test material, and the detector 42 must be very compact, thus limiting the size and thickness of the sample. Therefore, due to spatial limitations and intensity considerations, related technologies cannot detect the boron 10 areal density at a specific point on the test material, cannot detect the uniformity of the boron 10 areal density, and are not conducive to monitoring changes in the boron 10 areal density. In addition, related technologies measure the boron 10 areal density based on the white light neutron beam from reactor 1. This method has the following problems: First, the background is relatively high, and the transmittance can only be measured down to about 5%, making it impossible to measure engineering plates with a thickness of 3.05 mm; only thin slices of samples can be taken from the engineering plates. Therefore, non-destructive testing of the boron 10 areal density cannot be achieved. Second, the influence of the second phase is not considered. Third, the white light neutron energy spectrum changes before and after transmission to the sample. Since the transmitted neutron energy spectrum of each sample cannot be obtained, the experimentally obtained transmittance cannot be corrected according to the changes in the neutron energy spectrum.
[0089] The detection method of the detection system in this application can reduce the influence of neutron beams and second phases in the environment, and the use of monochromatic neutron beams for detection can greatly improve the detection accuracy of boron 10 surface density.
[0090] In one embodiment, the processor determines the areal density of boron 10 in the boron-containing alloy based on the direct beam count, background count, third count, third thickness of the boron-containing alloy, first relation, second relation, and third relation, including the following steps:
[0091] The processor determines the third transmittance of the boron-containing alloy sample 83 based on the direct beam count, background count, and third count.
[0092] The processor determines the first calculated transmittance based on the third transmittance, the third thickness, the first relation, and the third relation; wherein the first calculated transmittance corresponds to the second phase material in the boron-containing alloy sample 83.
[0093] The processor substitutes the value of the fourth transmittance as the first transmittance into the second relation, and calculates the first surface density of boron 10 in the boron-containing alloy based on the surface density calculation result of the second relation; wherein, the fourth transmittance is the difference between the third transmittance and the first calculated transmittance.
[0094] Specifically, the third transmittance is determined by the direct beam count, background count, and third count, thereby eliminating the influence of ambient neutron beams on the transmittance of the boron-containing alloy sample 83. In practice, the third transmittance is the ratio of the number of neutrons transmitted through the boron-containing alloy sample 83 by a monochromatic neutron beam to the total number of monochromatic neutron beams; its specific calculation formula can be set according to actual conditions.
[0095] For example:
[0096] Where T is the third transmittance; N1 is the third count; N2 is the background count; and N3 is the direct beam count.
[0097] It should be noted that by introducing background counting to eliminate the influence of sub-bundles in the environment on the results, the elimination does not mean the complete removal of sub-bundles in the environment, but rather the reduction of the influence of sub-bundles in the environment on the detection results.
[0098] The first calculated transmittance is the calculated transmittance of the second phase material in the boron-containing alloy. By introducing the first calculated transmittance, and substituting the difference between the third transmittance and the first calculated transmittance as the first transmittance into the second relationship, the influence of the second phase in the boron-containing alloy sample 83 on the detection results can be eliminated, thus obtaining the calculated transmittance of boron carbide in the boron-containing alloy sample 83. This elimination does not mean complete removal of the second phase, but rather reducing its influence on the detection results.
[0099] It should be noted that the processor can determine the first transmittance based on the third transmittance, the third thickness, the first relation, and the third relation in any way.
[0100] For example, the above steps specifically include:
[0101] The processor substitutes the value of the third transmittance as the first transmittance into the first relation, and obtains the equivalent boron carbide thickness based on the thickness calculation result of the first relation.
[0102] The processor substitutes the value of the equivalent second phase thickness as the second thickness into the third relation, and obtains the first calculated transmittance based on the transmittance calculation result of the third relation; wherein, the equivalent second phase thickness is the difference between the third thickness and the equivalent boron carbide thickness.
[0103] Specifically, by substituting the value of the third transmittance as the first transmittance into the first relational formula, the equivalent boron carbide thickness is calculated. The influence of the second phase material in the boron-containing alloy on the calculation results is ignored, and the equivalent boron carbide thickness is considered to be equivalent to the thickness of boron carbide in the boron-containing alloy.
[0104] The equivalent second phase thickness is the difference between the third thickness and the equivalent boron carbide thickness, that is, the equivalent second phase thickness is equivalent to the thickness of the second phase material in the boron-containing alloy sample 83.
[0105] Substituting the equivalent second phase thickness into the third equation yields the first calculated transmittance. From this, the extent to which the second phase material affects the neutron transmittance of the boron-containing alloy sample 83 can be determined, allowing it to be subtracted.
[0106] The detection method of the detection system of this application introduces a first calculated transmittance. By subtracting the third transmittance from the first calculated transmittance, the influence of the second phase in the boron-containing alloy sample 83 can be eliminated, thereby obtaining the first areal density after eliminating the influence of the second phase. This improves the detection accuracy of the areal density of boron 10.
[0107] In one embodiment, the detection method of the detection system further includes:
[0108] The processor uses the value of the third thickness as the second thickness and substitutes it into the third relation, and obtains the second calculated transmittance based on the transmittance calculation result of the third relation.
[0109] The processor substitutes the value of the fifth transmittance as the first transmittance into the second relation, and calculates the second surface density based on the surface density result of the second relation; wherein, the fifth transmittance is the difference between the third transmittance and the second calculated transmittance.
[0110] The processor averages the first and second areal densities to obtain the third areal density. Thus, the second areal density, obtained through the fifth transmittance and the second relationship, eliminates the influence of neutrons in the environment and the second relative detection results in the boron-containing alloy sample 83. Simultaneously, by detecting the effectiveness of the first and second areal densities, the average of the first and second areal densities is taken as the areal density of boron 10 in the boron-containing alloy, further improving the detection accuracy of the boron 10 areal density.
[0111] Specifically, the second calculated transmittance corresponds to the transmittance of the boron-containing alloy second phase material. That is, the value of the second calculated transmittance is used as the value of the second transmittance to be eliminated from the third transmittance.
[0112] The fifth transmittance is the difference between the third transmittance and the second calculated transmittance. In other words, the fifth transmittance represents the transmittance of boron carbide in the boron-containing alloy sample 83 after removing the influence of the second phase.
[0113] The second areal density is the areal density of boron 10 in a boron-containing alloy after removing the influence of neutrals and the second phase in the environment.
[0114] It should be noted that, depending on the actual situation, in some embodiments, the effectiveness of the first and second surface densities can also be detected by the ratio of the first surface density to the second density.
[0115] For example, before the processor averages the first surface density with the second surface density to obtain the third surface density, the detection method of the detection system further includes: confirming that the ratio of the first surface density to the second surface density is less than a set ratio.
[0116] In other words, before using the average of the first and second areal densities as the final areal density of boron 10 in the boron-containing alloy, the two values can be compared to confirm the validity of the measurement results. The ratio should not be set too high, as an excessively high ratio will lead to inaccurate measurement results. For example, the ratio should be less than or equal to 1.05.
[0117] Understandably, by setting a specific ratio, if an experimental error causes at least one data point between the first and second areal densities to be significantly erroneous, the erroneous data point will not be used as a reference. This can further improve the accuracy of the final areal density result for Boron-10.
[0118] In one embodiment, the processor determines a first relationship between the first transmittance and the first thickness of the boron carbide sample based on the direct beam count, background count, and a first count, and determines a second relationship between the first transmittance and the boron 10 areal density, including:
[0119] The processor determines multiple first transmittances based on the direct beam count, background count, and multiple first counts; wherein, the multiple first counts are the detection results of the first transmitted neutron beams received by the detection component 4, which pass through multiple boron carbide samples respectively.
[0120] The processor fits multiple first transmittance values with the logarithm of the first thickness of the corresponding boron carbide sample to form a first relationship.
[0121] The processor determines multiple boron 10 areal densities based on the first thickness of multiple boron carbide samples, and fits the multiple first transmittances to the logarithm of the corresponding boron 10 areal densities to form a second relationship. Thus, by obtaining multiple sets of first transmittances from multiple boron carbide samples, it is possible to accurately fit the curves of first transmittance versus boron carbide thickness and curves of first transmittance versus boron 10 areal densities, thereby obtaining highly accurate first and second relationships.
[0122] Specifically, among the multiple boron carbide samples, the thickness of the boron carbide samples is different, and the first transmittance will change with the different thicknesses of the boron carbide samples. There is a one-to-one correspondence between the thickness of the boron carbide and the boron 10 areal density.
[0123] For example, there are nine boron carbide samples, two of which have similar thicknesses. The detection results of the first transmitted neutron beam passing through each of the nine boron carbide samples are received by the detection component 4, yielding nine first transmittance values. A first relationship is obtained by logarithmically fitting these nine first transmittance values to their corresponding boron carbide sample thicknesses. A second relationship is obtained by establishing a one-to-one correspondence between boron carbide thickness and boron 10 areal density.
[0124] In fact, there is a corresponding relationship between the thickness of a boron carbide sample and its boron 10 areal density. For example, the thickness of a boron carbide sample is directly proportional to its boron 10 areal density. That is to say, different boron carbide samples will have different first transmittance and first thickness. Since the first thickness is proportional to the boron 10 areal density, different boron 10 areal density results can be obtained, and thus the corresponding relationship between the first transmittance and the boron 10 areal density can be obtained.
[0125] In one embodiment, the processor determines a third relationship between the second transmittance and the second thickness of the second phase sample based on the direct beam count, background count, and second count, including:
[0126] The processor determines multiple second transmittances based on the direct beam count, background count, and multiple second counts; wherein, the multiple second counts are the detection results of the second transmitted neutron beams received by the detection component 4, which pass through multiple second phase samples respectively.
[0127] The processor fits multiple second transmittance values with the corresponding second thickness of the second phase sample to form a third relationship. Thus, by obtaining multiple sets of second transmittance values from multiple second phase samples, the second transmittance and second phase sample thickness curves can be fitted with relatively high accuracy, resulting in a highly accurate third relationship.
[0128] Specifically, the thickness of the multiple second-phase samples is different, and the second transmittance will change with the thickness of the second-phase samples.
[0129] The material of the second phase sample is not limited and can be aluminum or steel. In this embodiment, 304 stainless steel plate is selected as the second phase sample.
[0130] For example, there are 7 304 stainless steel plates, and the thickness of the 7 304 stainless steel plates is different. The detection results of the second transmitted neutron beam passing through the 7 304 stainless steel plates are received by the detection component 4 to obtain 7 second transmittances. The 7 second transmittances and their corresponding 304 stainless steel plate thicknesses are fitted to obtain the third relationship.
[0131] Another embodiment of this application provides a detection system; please refer to [link / reference]. Figure 2 The detection system includes a neutron monochromator 3, a detection component 4, a memory, and a processor. The neutron monochromator 3 is used to monochromate a white light neutron beam into a monochromatic neutron beam. The detection component 4 is positioned on one side of the neutron monochromator 3 along the direction of motion of the monochromatic neutron beam. At least a portion of the structure of the detection component 4 is spaced apart from the neutron monochromator 3 to form a sample mounting space. The sample mounting space can be used to place a boron carbide sample, a second-phase sample, a boron-containing alloy sample 83, or a neutron-absorbing sample. The memory stores computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the steps of the detection method of the detection system of any embodiment of this application. This improves the detection sensitivity, eliminates the influence of the second phase, and maximizes the detection accuracy of the boron 10 areal density.
[0132] Specifically, the type of monochromator is not limited, as long as it can monochromate a white light neutron beam into a monochromatic neutron beam. For example, a copper monochromator can be used. In reactor 1, the chain reaction is moderated with heavy water to produce white light thermal neutrons. The monochromator can monochromate these white light thermal neutrons into a monochromatic neutron beam with a wavelength of 0.9 angstroms and an energy of 0.1 eV. The wavelength resolution of the monochromatic neutron beam is less than 2%, and the neutron extraction flux can reach 10. 7 / cm 2 / s or more.
[0133] There is an installation space for placing the sample between the detection component 4 and the neutron monochromator 3, which facilitates the detection component 4 to receive and measure the neutron beam passing through the sample.
[0134] The material of the neutron absorbing sample is not limited, as long as it has a good absorption effect on neutrons. For example, the neutron absorbing sample is a cadmium sheet.
[0135] In addition, the sample mounting space is used to mount boron carbide samples, second-phase samples, boron-containing alloy samples 83, or neutron-absorbing samples. In fact, it is to facilitate the detection component 4 to obtain the first count, second count, third count, or background count.
[0136] Furthermore, during a single test, the sample mounting space is used only to place one of the aforementioned samples.
[0137] In one embodiment, please refer to Figure 2 The detection component 4 includes a detector 42 and a monitor 41. The monitor 41 is positioned between the neutron monochromator 3 and the detector 42. The detector 42 and the monitor 41 are spaced apart to form a sample mounting space. The monitor 41 is used to allow the monochromatic neutron beam to pass through in order to obtain the neutron count of the monochromatic neutron beam. Thus, the direct beam is read out through the monitor 41, ensuring that the direct beam count of the monochromatic neutron beam before passing through the sample is consistent, thereby avoiding the influence of different direct beam counts on the detection results and improving the detection accuracy of boron 10 areal density.
[0138] Specifically, there is an installation space for placing the sample between the monitor 41 and the detector 42, and the monochromatic neutron beam passes sequentially through the monitor 41, the sample and the detector 42 along its direction of motion.
[0139] In fact, the detection methods of the detection system include:
[0140] The monochromatic neutron beam is received by detector 42 to obtain the direct beam count.
[0141] The detector 42 receives the ambient sub-beams to obtain the background count.
[0142] The detector 42 receives the first transmitted neutron beam passing through the boron carbide sample to obtain the first count.
[0143] The second transmitted neutron beam passing through the second phase sample is received by detector 42 to obtain the second count.
[0144] The third transmitted neutron beam passing through the boron-containing alloy sample 83 is received by detector 42 to obtain the third count.
[0145] In one embodiment, please refer to Figure 2The detection system also includes a shielding assembly 5, which comprises a first shielding plug 51, a second shielding plug 52, and a shielding cover 53. The first shielding plug 51 is disposed between the neutron monochromator 3 and the monitor 41. The first shielding plug 51 can calibrate the neutron count of the monochromatic neutron beam passing through the monitor 41 by adjusting the size of the monochromatic neutron beam spot. The shielding cover 53 includes a receiving cavity with an entrance port, and the detector 42 is disposed within the receiving cavity. The second shielding plug 52 is disposed at the entrance port to limit the size of the monochromatic neutron beam spot incident on the detector 42. Thus, by adjusting the diameter of the shielding plug hole, the size of the monochromatic neutron beam spot is adjusted, thereby making the count obtained by the detection assembly 4 more accurate. At the same time, the shielding cover 53 eliminates the influence of the ambient neutron beam on the results, improving the accuracy of the boron 10 areal density detection.
[0146] Specifically, the monitor 41 is placed close to the first shielding plug 51, and the first shielding plug 51 adjusts the beam spot size of the monochromatic neutron beam transmitted through the monitor 41 by adjusting the diameter of the plug hole. For example, the diameter of the plug hole of the first shielding plug 51 is adjusted to 18 mm.
[0147] The second shielding plug 52 is disposed at the entrance of the receiving cavity. By adjusting the diameter of the plug hole, the beam spot size of the incident beam of the monochromatic neutron beam received by the detector 42 is adjusted, thereby making the number of neutrons acquired by the detector 42 more accurate. For example, the diameter of the plug hole of the second shielding plug 52 is adjusted to 14 mm.
[0148] The detector 42 is housed within the containment cavity of the shield 53. The shield 53 can reduce the background and minimize the influence of scattered neutrons in the external environment on the receiving results of the detector 42. This allows the neutron beam received by the detector 42 to be as close as possible to the transmitted neutron beam of the monochromatic neutron beam passing through the sample, thereby improving the detection accuracy of boron 10 surface density.
[0149] There is a mounting space for placing the sample between the monitor 41 and the detector 42. The monochromatic neutron beam passes sequentially through the monitor 41, the sample, and the detector 42 along its direction of motion.
[0150] It should be noted that the installation space contains a sample fixture 8, and the specific structure of the sample fixture 8 is not limited.
[0151] For example, the sample fixture 8 includes a sample placement position for placing the sample and a fixing slide bar 82. The fixing slide bar 82 adjusts the position of the sample relative to the sample fixture 8 and fixes the sample.
[0152] In one embodiment, please refer to Figure 3 , Figure 4 and Figure 5The boron-containing alloy sample 83 is a plate. There can be 5 points for transmittance detection. One point is located at the center of the plate, and the remaining points are located at the four corners at a distance of 1 / 4L from the edge of the long side of the plate and a distance of 2.54cm from the edge of the short side of the plate. Here, L represents the length of the long side of the boron-containing alloy sample 83.
[0153] The sample fixture 8 has two stations. The first station is used to measure the transmittance at the center point of the sample, and the second station is used to measure the transmittance at the other points of the sample.
[0154] In one embodiment, please refer to Figure 2 The detection assembly 4 includes a reactor 1, a neutron transmission channel 2, a neutron beam gate 9, a neutron monochromator 3, a detection assembly 4, a shielding assembly 5, a deflection monochromator 6, a rotating stage 7, and a sample fixture 8. The detection assembly 4 includes a monitor 41 and a detector 42. The shielding assembly 5 includes a first shielding plug 51, a second shielding plug 52, and a shielding cover 53. A white neutron beam generated by the reactor 1 enters the neutron monochromator 3 through the neutron transmission channel 2. The neutron monochromator 3 monochromates the white neutron beam into a monochromatic neutron beam. The monochromatic neutron beam passes through the first shielding plug 51 and the monitor 41 and enters the deflection monochromator 6. The deflection monochromator 6 deflects the beam to the direction of the detector 42. The deflected beam from the deflection monochromator 6 enters the sample, which is placed on the sample fixture 8. The neutrons transmitted from the sample pass through the second shielding plug 52 and enter the detector 42. This improves the accuracy of boron 10 areal density detection.
[0155] Specifically, there is no limit to the type of monochromator, as long as it can monochromate a white light neutron beam into a monochromatic neutron beam.
[0156] The neutron beam gate 9 is placed between the neutron transmission channel 2 and the neutron monochromator 3 to control the on / off state of the neutron beam.
[0157] The monitor 41 is placed in close proximity to the first shielding plug 51. The first shielding plug 51 adjusts the beam spot size of the monochromatic neutron beam passing through the monitor 41 by adjusting the diameter of the plug hole, in order to calibrate the neutron count of the monochromatic neutron beam passing through the monitor 41. For example, the diameter of the plug hole of the first shielding plug 51 is adjusted to 18 mm.
[0158] Monitor 41 is used to allow the monochromatic neutron beam to pass through in order to obtain the neutron count of the monochromatic neutron beam.
[0159] The deflector monochromator 6 is fixed at the center of the rotating stage 7 and positioned in the direction of the output beam of the monochromatic neutron beam. The center of the deflector monochromator 6 is located on the center line of the output beam, and the rotation center of the rotating stage 7 is located on the center line of the output beam of the neutron monochromator 3. The takeoff angle of the deflector monochromator 6 is precisely adjusted by the rotating stage 7.
[0160] The shape and type of the deflector monochromator 6 are not limited, as long as it can deflect the monochromatic neutron beam and cause it to be incident on the sample. For example, the deflector monochromator 6 is a disc-shaped germanium monochromator.
[0161] The sample fixture 8 has a sample placement position for placing boron carbide samples, second-phase samples, boron-containing alloy samples 83, or neutron-absorbing samples. The sample fixture 8 is placed between the deflecting monochromator 6 and the detector 42 and is perpendicular to the deflection beam.
[0162] The material of the neutron absorbing sample is not limited, as long as it has a good absorption effect on neutrons. For example, the neutron absorbing sample is a cadmium sheet.
[0163] The shield 53 includes a receiving cavity with an entrance port, and the detector 42 is disposed in the receiving cavity. The shield 53 can reduce the background and eliminate the influence of neutrons in the external environment on the receiving results of the detector 42, so that the neutron beam received by the detector 42 is the transmitted neutron beam of monochromatic neutron beam passing through the sample, thereby improving the detection accuracy of boron 10 areal density.
[0164] The second shielding plug 52 is disposed at the entrance of the receiving cavity. By adjusting the diameter of the plug hole, the beam spot size of the incident beam of the monochromatic neutron beam received by the detector 42 is adjusted, thereby making the number of neutrons acquired by the detector 42 more accurate. For example, the diameter of the plug hole of the second shielding plug 52 is adjusted to 14 mm.
[0165] In the description of this application, the references to terms such as "in one embodiment," "in some embodiments," "in a specific embodiment," or "exemplary," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the embodiments of this application. In this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine the different embodiments or examples described in this application, as well as the features of the different embodiments or examples.
[0166] The above are merely preferred embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the protection scope of this application.
Claims
1. A detection method of a detection system for detecting the surface density of boron 10 in a boron-containing alloy, characterized by, The detection system includes a neutron monochromator, a detection component, and a processor. The neutron monochromator is used to monochromate a white light neutron beam into a monochromatic neutron beam. The detection method of the detection system includes: The detection component receives the monochromatic neutron beam to obtain a direct beam count; The detection component receives sub-beams from the environment to obtain background counts. The detection assembly receives a first transmitted neutron beam passing through the boron carbide sample to obtain a first count. The detection assembly receives a second transmitted neutron beam passing through the second phase sample to obtain a second count; wherein the material of the second phase sample is the second phase material in a boron-containing alloy sample; The detection assembly receives a third transmitted neutron beam passing through the boron-containing alloy sample to obtain a third count; The processor determines a first relationship between the first transmittance and the first thickness of the boron carbide sample based on the direct beam count, the background count, and the first count, and determines a second relationship between the first transmittance and the boron 10 areal density. The processor determines a third relationship between the second transmittance and the second thickness of the second phase sample based on the direct beam count, the background count, and the second count. The processor determines the areal density of boron 10 in the boron-containing alloy based on the direct beam count, the background count, the third count, the third thickness of the boron-containing alloy, the first relation, the second relation, and the third relation.
2. The detection method of the detection system according to claim 1, characterized in that, The processor determines the areal density of boron 10 in the boron-containing alloy based on the direct beam count, the background count, the third count, the third thickness of the boron-containing alloy, the first relationship, the second relationship, and the third relationship, including: The processor determines the third transmittance of the boron-containing alloy sample based on the direct beam count, the background count, and the third count; The processor determines a first calculated transmittance based on the third transmittance, the third thickness, the first relationship, and the third relationship; wherein the first calculated transmittance corresponds to the second phase material in the boron-containing alloy sample. The processor substitutes the value of the fourth transmittance as the first transmittance into the second relation, and calculates the first surface density of boron 10 in the boron-containing alloy based on the surface density calculation result of the second relation; wherein, the fourth transmittance is the difference between the third transmittance and the first calculated transmittance.
3. The detection method of the detection system according to claim 2, characterized in that, The processor determines the first calculated transmittance based on the third transmittance, the third thickness, the first relationship, and the third relationship, including: The processor uses the value of the third transmittance as the first transmittance and substitutes it into the first relational expression, and obtains the equivalent boron carbide thickness based on the thickness calculation result of the first relational expression. The processor substitutes the value of the equivalent second phase thickness as the second thickness into the third relation, and obtains the first calculated transmittance based on the transmittance calculation result of the third relation; wherein, the equivalent second phase thickness is the difference between the third thickness and the equivalent boron carbide thickness.
4. The detection method of the detection system according to claim 2, wherein, The detection method of the detection system further includes: The processor substitutes the value of the third thickness as the second thickness into the third relation, and obtains the second calculated transmittance based on the transmittance calculation result of the third relation. The processor substitutes the value of the fifth transmittance as the first transmittance into the second relational expression, and obtains the second surface density based on the surface density calculation result of the second relational expression; wherein, the fifth transmittance is the difference between the third transmittance and the second calculated transmittance; The processor averages the first areal density with the second areal density to obtain a third areal density.
5. The detection method of the detection system according to claim 2, characterized in that, The formulas for calculating the first transmittance, the second transmittance, and the third transmittance are as follows: Wherein, T is the first transmittance, the second transmittance, or the third transmittance; N1 is the first count, the second count, or the third count; N2 is the background count; and N3 is the direct beam count.
6. The detection method of the detection system according to any one of claims 1 to 5, characterized in that, The processor determines a first relationship between the first transmittance and the first thickness of the boron carbide sample based on the direct beam count, the background count, and the first count, and determines a second relationship between the first transmittance and the boron 10 areal density, including: The processor determines a plurality of first transmittances based on the direct beam count, the background count, and a plurality of first counts; wherein the plurality of first counts are detection results received by the detection component from the first transmitted neutron beams passing through a plurality of boron carbide samples respectively; The processor fits multiple first transmittance values with the logarithm of the first thickness of the corresponding boron carbide sample to form the first relationship; The processor determines multiple boron 10 areal densities corresponding to the first thickness of the multiple boron carbide samples, and logarithmically fits the multiple first transmittances with the corresponding boron 10 areal densities to form the second relationship.
7. The detection method of the detection system according to any one of claims 1 to 5, characterized in that, The processor determines a third relationship between the second transmittance and the second thickness of the second phase sample based on the direct beam count, the background count, and the second count, including: The processor determines a plurality of second transmittances based on the direct beam count, the background count, and a plurality of second counts; wherein the plurality of second counts are detection results received by the detection component from the second transmitted neutron beams passing through a plurality of second phase samples respectively; The processor fits multiple second transmittance values with the second thickness of the corresponding second phase sample to form the third relationship.
8. A detection system characterized by, The detection system includes a neutron monochromator, a detection component, a memory, and a processor. The neutron monochromator is used to monochromate a white neutron beam into a monochromatic neutron beam. The detection component is placed on one side of the neutron monochromator along the direction of motion of the monochromatic neutron beam. At least a portion of the structure of the detection component is spaced apart from the neutron monochromator to form a sample mounting space. The sample mounting space can be used to place a boron carbide sample, a second-phase sample, a boron-containing alloy sample, or a neutron-absorbing sample. The memory stores computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the steps of the detection method of the detection system according to any one of claims 1 to 7.
9. The detection system of claim 8, wherein, The detection assembly includes a detector and a monitor. The monitor is disposed between the neutron monochromator and the detector. The detector and the monitor are spaced apart to form the sample mounting space. The monitor is used to allow the monochromatic neutron beam to pass through in order to obtain the neutron count of the monochromatic neutron beam.
10. The detection system of claim 9, wherein, The detection system further includes a shielding assembly comprising a first shielding plug, a second shielding plug, and a shielding cover. The first shielding plug is disposed between the neutron monochromator and the monitor. The first shielding plug can calibrate the neutron count of the monochromatic neutron beam passing through the monitor by adjusting the size of the monochromatic neutron beam spot. The shielding cover includes a receiving cavity with an entrance port. The detector is disposed within the receiving cavity. The second shielding plug is disposed at the entrance port to limit the size of the monochromatic neutron beam spot incident on the detector.