A measurement method and a probe

Abstract

The embodiment of the present application provides a kind of measurement method and detector, detector includes detection device, beam-limiting diaphragm and the shell with vacuum cavity, detection device and beam-limiting diaphragm are arranged in vacuum cavity, detector is used to detect the radioactive source being put into vacuum cavity, the side wall of vacuum cavity has reflection area, reflection area is used to reflect radioactive rays, to make radioactive rays pass through first through-hole and be shot into detection device.Measurement method includes: obtaining first length, radioactive source radius, beam-limiting diaphragm radius and vacuum cavity radius, according to first length, radioactive source radius, beam-limiting diaphragm radius and vacuum cavity radius, determine reflection area.The measurement method of the embodiment of the present application can optimize the size of vacuum cavity radius by the corresponding relationship between the range of reflection area and the radius of vacuum cavity, so as to reduce the range of reflection area, reduce the effect of detector wall scattering, and then improve the measurement accuracy of radioactive source emissivity.

Description

Technical Field

[0001] This application relates to the field of radiation monitoring technology, and in particular to a measurement method and detector. Background Technology

[0002] In related technologies, radioactive sources emit radioactive rays, and the emissivity of radioactive sources can be measured by using detectors.

[0003] For the radioactive rays detected by the detector, part of them are radioactive rays emitted from the radiation source that directly reach the detector's detection device and are received by the detection device. The other part is that the radioactive rays emitted from the radiation source strike the reflection area on the side wall of the vacuum cavity in the detector, causing some of the radioactive rays to be reflected by the reflection area to the detection device, where they are then received by the detection device.

[0004] However, in related technologies, determining the emissivity based on the results of direct and reflected radioactive rays received by the detection device can lead to an overestimation of the emissivity of the obtained radioactive source. Summary of the Invention

[0005] In view of this, the main objective of the embodiments of this application is to provide a measurement method and detector that can reduce the measurement error of the emissivity of a radioactive source.

[0006] To achieve the above objectives, the technical solution of this application embodiment is implemented as follows:

[0007] A first aspect of this application provides a measurement method for measuring a detector used to measure the emissivity of a radioactive source. The detector includes a detection device, a beam-limiting aperture, and a housing having a vacuum cavity. The detection device and the beam-limiting aperture are disposed within the vacuum cavity. The detector is used to detect a radioactive source placed within the vacuum cavity. The sidewall of the vacuum cavity has a reflective area. The beam-limiting aperture has a first through-hole through which radioactive rays emitted from the radioactive source pass. The reflective area reflects the radioactive rays so that the radioactive rays pass through the first through-hole and enter the detection device. The measurement method includes the following steps:

[0008] Obtain a first length, a radiation source radius, a beam-limiting aperture radius, and a vacuum cavity radius; wherein, the first length is the vertical distance between the radiation source and the beam-limiting aperture, and the beam-limiting aperture radius is the radius of the first through-hole;

[0009] The reflection zone is determined based on the first length, the radius of the radiation source, the radius of the beam-limiting aperture, and the radius of the vacuum cavity.

[0010] In one embodiment, the reflection region is determined based on the first length, the radius of the radiation source, the radius of the beam-limiting aperture, and the radius of the vacuum cavity, specifically including:

[0011] Based on the first length, the radius of the radiation source, the radius of the beam-limiting aperture, and the radius of the vacuum cavity, the upper and lower limit points that form the reflection zone are determined at intervals.

[0012] In one embodiment, the upper limit point and the lower limit point are determined by the radioactive rays emitted from a first emission point of the radioactive source, where the first emission point is the nearest point of the radioactive source to the target region of the reflection zone; or,

[0013] The upper limit point and the lower limit point are determined by the radioactive rays emitted from the second emission point of the radioactive source, which is the farthest point of the target area of ​​the radioactive source from the reflection zone.

[0014] In one embodiment, the upper limit point is determined by the radioactive rays emitted from the second emission point of the radioactive source, and the lower limit point is determined by the radioactive rays emitted from the first emission point of the radioactive source; wherein, the first emission point is the near point of the radioactive source near the target area of ​​the reflection zone, and the second emission point is the far point of the radioactive source far from the target area of ​​the reflection zone.

[0015] In one embodiment, a first spacing is determined based on the first length, the radius of the radiation source, the radius of the beam-limiting aperture, and the radius of the vacuum cavity to determine the upper limit point; wherein, the first spacing is the distance between the center lines of the radiation source and the beam-limiting aperture and the upper limit point.

[0016] In one embodiment, the first spacing is determined according to a first calculation formula; wherein the first calculation formula is:

[0017]

[0018] Where, ΔZ l+ Let h be the first spacing, h be the first length, R be the radius of the beam-limiting aperture, and r be the radius of the radiation source. in The radius of the vacuum cavity is given.

[0019] In one embodiment, a second spacing is determined based on the first length, the radius of the radiation source, the radius of the beam-limiting aperture, and the radius of the vacuum cavity to determine the lower limit point; wherein, the second spacing is the distance between the center lines of the radiation source and the beam-limiting aperture and the lower limit point.

[0020] In one embodiment, the second spacing is determined according to a second calculation formula; wherein the second calculation formula is:

[0021]

[0022] Where, ΔZ r- h is the second spacing, r is the first length, R is the radius of the beam-limiting aperture, and r is the radius of the radiation source. in The radius of the vacuum cavity is given.

[0023] A second aspect of this application provides a detector, which is any of the detectors described above. The detector includes a detection device, a beam-limiting aperture, and a housing having a vacuum cavity. The detection device and the beam-limiting aperture are disposed within the vacuum cavity. The detector is used to detect a radioactive source placed within the vacuum cavity. The sidewall of the vacuum cavity has a reflective area. The beam-limiting aperture has a first through-hole through which radioactive rays emitted by the radioactive source pass. The reflective area is used to reflect the radioactive rays so that the radioactive rays pass through the first through-hole and enter the detection device.

[0024] In one embodiment, the detector further includes a blocking ring placed inside the vacuum cavity and located between the beam-limiting aperture and the radiation source. The blocking ring has a second through hole, and the first through hole and the second through hole are connected to allow the radioactive rays to directly reach the detection device. The sidewall of the second through hole is located on the line connecting the outer edge of the radiation source and the sidewall of the first through hole.

[0025] This application provides a measurement method and a detector. The measurement method includes the following steps: obtaining a first length, a radiation source radius, a beam-limiting aperture radius, and a vacuum cavity radius; and determining a reflection zone based on the first length, radiation source radius, beam-limiting aperture radius, and vacuum cavity radius. Through the measurement method of this application, the range of the sidewall reflection zone of the vacuum cavity in the detector is determined based on the first length, radiation source radius, beam-limiting aperture radius, and vacuum cavity radius. Therefore, by utilizing the correspondence between the reflection zone range and the vacuum cavity radius, the vacuum cavity radius size can be optimized, thereby reducing the reflection zone range, decreasing the scattering effect of the detector wall, and ultimately improving the measurement accuracy of the radiation source emissivity. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating a measurement method according to an embodiment of this application;

[0027] Figure 2 This is a schematic diagram of a detector structure according to an embodiment of this application;

[0028] Figure 3This is a schematic diagram of the solid angle subtended by the beam-limiting aperture relative to the effective size of the radiation source in an embodiment of this application;

[0029] Figure 4 This is a schematic diagram of the inner diameter of the blocking ring according to an embodiment of this application;

[0030] Figure 5 This is a schematic diagram of the reflection range of the first emission point in the detector vacuum cavity according to an embodiment of this application;

[0031] Figure 6 This is a schematic diagram of the reflection range of the second emission point in the detector vacuum cavity according to another embodiment of this application.

[0032] Explanation of reference numerals in the attached figures

[0033] 1. Detector central axis; 2. Detection device; 3. Beam limiting aperture; 4. First through hole; 5. Side wall of vacuum cavity; 6. Radiation source; 7. Radiation source tray; 8. Vacuum cavity. Detailed Implementation

[0034] One embodiment of this application provides a measurement method; please refer to [link / reference]. Figure 1 , Figure 2 and Figure 3 The detector includes a detection device 2, a beam-limiting aperture 3, and a housing with a vacuum cavity 8. The detection device 2 and the beam-limiting aperture 3 are disposed inside the vacuum cavity 8. The detector is used to detect a radioactive source 6 placed inside the vacuum cavity 8. The side wall 5 of the vacuum cavity has a reflective area. The beam-limiting aperture 3 has a first through-hole 4 through which radioactive rays emitted from the radioactive source 6 pass. The reflective area is used to reflect the radioactive rays so that the radioactive rays pass through the first through-hole 4 and enter the detection device 2. The measurement method includes the following steps:

[0035] Step S1: Obtain the first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8; wherein, the first length is the vertical distance between the radiation source 6 and the beam-limiting aperture 3, and the radius of the beam-limiting aperture 3 is the radius of the first through hole 4;

[0036] Step S2: Determine the reflection zone based on the first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8.

[0037] Specifically, the measurement method of this application can be a measurement method of a measurement system for measuring a detector.

[0038] The first length, the radius of the radiation source (6), the radius of the beam-limiting aperture (3), and the radius of the vacuum cavity (8) can be measured manually or through the measurement components of the measurement system.

[0039] The processor processes data based on the measured first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8 to determine the reflection zone.

[0040] The shell of vacuum chamber 8 is a sealed structure, which can isolate the influence of radioactive nuclides in the external environment on the detection results.

[0041] The detection device 2 is used to detect the radioactive source 6 placed in the vacuum cavity 8. This means that the detection device 2 receives particles from the radioactive rays emitted by the radioactive source 6. The particles detected by the detection device 2 come from two sources: one part consists of particles whose radioactive rays are reflected by the side wall 5 of the vacuum cavity and pass through the beam-limiting aperture 3 to enter the detection device 2; the other part consists of particles whose radioactive rays pass directly through the beam-limiting aperture 3 to enter the detection device 2.

[0042] It should be noted that "radioactive rays passing through the beam-limiting aperture 3" means that the radioactive rays pass through the first through-hole 4 on the beam-limiting aperture 3.

[0043] The types of particles in radioactive rays are not limited, such as alpha particles and beta particles.

[0044] The materials and types of the detection device 2 are not limited, as long as it has 100% intrinsic efficiency against radioactive rays. For example, a gold-silicon surface barrier detector.

[0045] Intrinsic efficiency refers to the ratio of the recorded pulse to the number of radiation quantum numbers incident on the detector. Therefore, the absolute efficiency of the radioactive particles measured by the detection device 2 is the ratio of the solid angle of the beam-limiting aperture 3 opening to the effective size of the radioactive nuclide source to the solid angle of 4π.

[0046] The source surface of the radiation source (6) and the beam-limiting aperture (3) are both circular.

[0047] It should be noted that you should refer to [link / reference]. Figure 3 and Figure 4 The circumference of the radioactive source 6 and the first through hole 4 forms a frustum. When the radioactive rays are inside the frustum, the particles in the radioactive rays can directly pass through the first through hole 4 and enter the detection device 2. When the radioactive rays are outside the frustum, the particles in the radioactive rays will not directly pass through the first through hole 4 and enter the detection device 2.

[0048] For radioactive rays located outside the frustum, the embodiments of this application show that the particles in the radioactive rays are reflected once through the side wall 5 of the vacuum cavity, pass through the first through hole 4, and enter the detection device 2.

[0049] Specifically, the radius of the vacuum cavity 8 refers to the distance between the central axis 1 of the detector and the side wall 5 of the vacuum cavity. For example, when the housing is a cylinder, the radius of the vacuum cavity 8 is half the inner diameter of the cylinder; when the housing is a rectangular tube, the radius of the vacuum cavity 8 is half the inner diameter of the rectangular tube.

[0050] It should be noted that the beam-limiting aperture 3 has the function of restricting the passage of radioactive nuclides. The statement that radioactive rays pass through the first through-hole 4 and enter the detection device 2 means that only radioactive rays that have passed through the first through-hole 4 can enter the detection device 2.

[0051] The detection device 2 is placed in the direction in which the radioactive rays exit through the first through hole 4.

[0052] The area from which the detection device 2 receives radioactive rays is the area of ​​the first through hole 4.

[0053] In related technologies, the presence of the reflective zone can lead to an overestimation of the emissivity of the radioactive source 6.

[0054] The measurement method of this application specifically includes obtaining the first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8; determining the reflection zone based on the first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8; thereby optimizing the radius size of the vacuum cavity 8 by the correspondence between the range of the reflection zone and the radius of the vacuum cavity 8, thereby reducing the range of the reflection zone, reducing the effect of scattering from the detector wall, and thus improving the measurement accuracy of the emissivity of the radiation source 6.

[0055] Please refer to the implementation details. Figure 1 The measurement method includes the following steps:

[0056] Step S1: Obtain the first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8; wherein, the first length is the vertical distance between the radiation source 6 and the beam-limiting aperture 3, and the radius of the beam-limiting aperture 3 is the radius of the first through hole 4;

[0057] Step S2: Determine the reflection zone based on the first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8.

[0058] Step S3: Determine the correspondence between the range of the reflection zone and the radius of the vacuum cavity.

[0059] Step S4: Optimize the radius of the vacuum cavity to reduce the range of the reflection zone, reduce the effect of scattering from the detector wall, and thus improve the measurement accuracy of the radioactive source emissivity.

[0060] In one embodiment, please refer to Figure 2 , Figure 5 and Figure 6 Based on the first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8, the reflection zone is determined, specifically including:

[0061] Based on the first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8, the upper and lower limit points of the interval forming the reflection zone are determined.

[0062] Specifically, the reflection zone refers to a region on the side wall 5 of the vacuum cavity after the radioactive source 6 emits radioactive rays in various directions, which are then reflected and received by the detection device 2. This is the general term for that region. In other words, radioactive rays hitting the reflection zone of the side wall 5 of the vacuum cavity can be reflected, pass through the first through-hole 4, and enter the detection device 2 for reception. However, radioactive rays hitting outside the reflection zone of the side wall 5 of the vacuum cavity cannot pass through the first through-hole 4 after a single reflection and enter the detection device 2 for reception.

[0063] The upper limit point refers to the upper boundary of the reflection zone. In other words, the upper limit point is a line distributed along the side wall 5 of the vacuum cavity.

[0064] The lower limit point refers to the lower boundary of the reflection zone. In other words, the lower limit point is a line distributed along the side wall 5 of the vacuum cavity.

[0065] In fact, for the sidewall 5 of the vacuum cavity, the reflection zone is an annular region on the sidewall 5. The upper limit point is the upper ring line of the annular region, and the lower limit point is the lower ring line of the annular region. Therefore, by determining the upper and lower ring lines, the range of the annular region can be determined, that is, the range of the reflection zone can be determined.

[0066] In one embodiment, please refer to Figure 5 The upper and lower limits are determined by the radioactive rays emitted from the first emission point of the radioactive source 6, which is the nearest point of the target area of ​​the radioactive source 6 near the reflection zone.

[0067] Specifically, since the launch zone is actually a ring-shaped area, the relative position of the first launch point with respect to different areas of the launch zone is different. The target area is the region closest to the first launch point. Therefore, when determining the range of the target area of ​​the reflection zone, the first launch point is the nearest point corresponding to the target area.

[0068] The first emission point is the point on the edge of the radiation source 6, in the vertical section of the detector, that is closest to the side wall 5 of the vacuum cavity. The distance between the first emission point and the central axis 1 of the detector is the radius of the radiation source 6.

[0069] For example, in Figure 5 In the detector cross-section shown, the first emission point is point H, point J is the center point of the first through-hole 4, and point K is the center point of the radiation source 6. The detector's central axis 1 intersects the first through-hole 4 at point J and the radiation source 6 at point K. Assume the radius of the radiation source 6 is r, the radius of the first through-hole 4 is R, and the radius of the vacuum cavity 8 is R. in Then KH = r.

[0070] The first emission point is point H. The ray emitted from point H is reflected by point X on the side wall 5 of the vacuum cavity and intersects the first through hole 4 at point C. Point X is the intersection of the center line of the radiation source 6 and the beam-limiting aperture 3 with the side wall 5 of the vacuum cavity. OX is the center line of the radiation source 6 and the beam-limiting aperture 3, and OX = R. in -r.

[0071] The first emission point is point H. The ray emitted from point H is reflected by the extreme point A on the side wall 5 of the vacuum cavity and intersects the first through hole 4 at point D. The extension of AD intersects the extension of CH at point B. Point D is the point on the side of the first through hole 4 that is closest to the reflection zone of the side wall 5 of the vacuum cavity in the same cross section as the first emission point. JD = R, CD = Rr.

[0072] The first emission point is point H. The ray emitted from point H is reflected by the lower limit point G of the side wall 5 of the vacuum cavity and intersects the first through hole 4 at point F. The line connecting GF intersects CH at point E. Point F is the point on the side of the first through hole 4 that is farthest from the reflection area of ​​the side wall 5 of the vacuum cavity in the same cross section as the first emission point. That is to say, points F and D are symmetrically distributed along the central axis 1 of the detector, i.e., JF = JD = R.

[0073] The range between the upper limit point A and the lower limit point G is the reflection zone of the first emission point.

[0074] AO1 is a straight line passing through the upper limit point A and parallel to OX, AO1 = R. in -r, CH represents the vertical distance between the radiation source 6 and the beam-limiting aperture 3, which is the first length, that is, CH = h.

[0075] GO2 is a straight line passing through the lower limit point G and parallel to OX, and GO2 = R. in -r.

[0076] Specifically, assume AX = ΔZ r+ GX = ΔZ r- According to the laws of specular reflection, BO1 = HO1 (Equation 1), BO1 = BC + CO1 (Equation 2). From equations 1, 2, and 3, we can obtain that From equations 1, 2, 3, and 4, we can obtain BC = 2ΔZ r+ .

[0077] Based on the similarity between triangle BCD and triangle BO1A, we can obtain... Also, CD = JD - JC = Rr (Equation 7). From Equations 5, 6 and 7, we can obtain... Therefore, the upper limit point obtained from the first emission point is the center line between the radiation source 6 and the beam-limiting aperture 3. point.

[0078] Specifically, according to the laws of specular reflection, CE = CO2 - EO2 (Equation 11). From Equations 9, 10, and 11, we can obtain CE = 2ΔZ. r- (Equation 12)

[0079] Based on the similarity between triangle ECF and triangle EO2G, we can obtain Also, CF = CJ + JF = R + r (Equation 15), and from Equations 12, 13, 14 and 15, we can obtain... Therefore, the lower limit point obtained from the first emission point is the center line between the radiation source 6 and the beam-limiting aperture 3. point.

[0080] In one embodiment, please refer to Figure 6 The upper and lower limits are determined by the radioactive rays emitted from the second emission point of the radioactive source 6, which is the farthest point of the target area of ​​the radioactive source 6 away from the sidewall.

[0081] Specifically, since the launch zone is actually a ring-shaped area, the relative position of the second launch point with respect to different areas of the launch zone varies. The target area is the region furthest from the second launch point. Therefore, when determining the range of the target area of ​​the reflection zone, the second launch point is the farthest point corresponding to the target area.

[0082] The second emission point is the point on the edge of the radiation source 6, in the vertical section of the detector, that is farthest from the reflection zone of the side wall 5 of the vacuum cavity. The distance between the second emission point and the central axis 1 of the detector is the radius of the radiation source 6.

[0083] For example, in Figure 6 In the detector cross-section shown, the second emission point is point I, point J is the center point of the first through-hole 4, and point K is the center point of the radiation source 6. The detector's central axis 1 intersects the first through-hole 4 at point J and the radiation source 6 at point K. Assume the radius of the radiation source 6 is r, the radius of the beam-limiting aperture 3 is R, and the radius of the vacuum cavity 8 is R. in , then KI=r.

[0084] The second emission point, i.e., point I, is where the ray emitted from point I is reflected by point X on the side wall 5 of the vacuum cavity and intersects the first through-hole 4 at point C. Here, X is the intersection of the center line of the radiation source 6 and the beam-limiting aperture 3 with the side wall 5 of the vacuum cavity, and OX is the center line of the radiation source 6 and the beam-limiting aperture 3. OX = R in +r.

[0085] The second emission point, i.e., point I, is reflected by the extreme point A on the side wall 5 of the vacuum cavity and intersects the first through hole 4 at point D. The extension of AD intersects the extension of CI at point B. Point D is the point on the side of the first through hole 4 that is closest to the reflection zone of the side wall 5 of the vacuum cavity in the same cross section as the second emission point. JD = R, CD = R + r.

[0086] The second emission point, i.e., point I, is reflected by the extreme point G on the side wall 5 of the vacuum cavity and intersects the first through hole 4 at point F. The line connecting GF intersects CI at point E. Point F is the point on the side of the first through hole 4 that is farthest from the reflection area of ​​the side wall 5 of the vacuum cavity in the same cross section as the second emission point. That is to say, points F and D are symmetrically distributed along the central axis 1 of the detector, i.e., JF = JD = R.

[0087] The range between the upper limit point A and the lower limit point G is the reflection zone of the second emission point.

[0088] AO1 is a straight line passing through the upper limit point A and parallel to OX, AO1 = R. in +r, CI represents the vertical distance between the radiation source 6 and the beam-limiting aperture 3, which is the first length, that is, CI = h.

[0089] GO2 is a straight line passing through the lower limit point G and parallel to OX, and GO2 = R. in +r.

[0090] Specifically, assume AX = ΔZ l+ GX = ΔZ l- According to the laws of specular reflection, BO1 = IO1 (Equation 1) and BO1 = BC + CO1 (Equation 2). From equations 1, 2, and 3, we can obtain that From equations 1, 2, 3, and 4, we can obtain BC = 2ΔZ l+ .

[0091] Based on the similarity between triangle BCD and triangle BO1A, we can obtain... Also, CD = CG + JD = R + r (Equation 7). From Equations 5, 6, and 7, we can obtain... Therefore, the upper limit point obtained from the second emission point is the center line between the radiation source 6 and the beam-limiting aperture 3. point.

[0092] Specifically, according to the laws of specular reflection, CE = CO2 - EO2 (Equation 11). From Equations 9, 10, and 11, we can obtain CE = 2ΔZ. l- (Equation 12)

[0093] Based on the similarity between triangle ECF and triangle EO2G, we can obtain Also, CF = FD - CD = Rr (Equation 15), and from Equations 12, 13, 14 and 15, we can obtain... Therefore, the lower limit point obtained from the second emission point is the center line between the radiation source 6 and the beam-limiting aperture 3. point.

[0094] In one embodiment, the upper limit point is determined by the radioactive rays emitted from the second emission point of the radioactive source 6, and the lower limit point is determined by the radioactive rays emitted from the first emission point of the radioactive source 6; wherein, the first emission point is the near point of the target area of ​​the radioactive source 6 near the sidewall, and the second emission point is the far point of the target area of ​​the radioactive source 6 away from the sidewall.

[0095] Specifically, since the launch zone is actually a ring-shaped area, the relative positions of the first and second launch points with respect to different areas of the launch zone are different. The target area is the region furthest from the second launch point and closest to the first launch point. Therefore, when determining the range of the target area of ​​the reflection zone, the first launch point is the near point corresponding to the target area, and the second launch point is the far point corresponding to the target area.

[0096] The upper limit point is determined based on the radioactive rays emitted from the second emission point; that is, the upper limit point is the center line between the radiation source 6 and the beam-limiting aperture 3. point.

[0097] The lower limit point is determined based on the radioactive rays emitted from the first emission point; that is, the lower limit point is the distance from the center line between the radioactive source 6 and the beam-limiting aperture 3. point.

[0098] In one embodiment, a first spacing is determined based on a first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8, in order to determine the upper limit point; wherein, the first spacing is the distance between the center lines of the radiation source 6 and the beam-limiting aperture 3 and the upper limit point.

[0099] Specifically, the first interval is the larger of the upper limit point determined by the radioactive rays emitted from the first emission point and the upper limit point determined by the radioactive rays emitted from the second emission point, i.e. and The larger value in the range.

[0100] Specifically, By finding a common denominator in equation 16, we obtain From equation 17, we can obtain... Because of R in It is always greater than or equal to R and r, therefore, 2·h·r·(RR) in )≤0,(2·Rin -Rr)·(2·R in -R+r)≥0, therefore ΔZ r+ -ΔZ l+ ≤0, i.e., ΔZ r+ ≤ΔZ l+ If and only if R = R in At that time, ΔZ r+ =ΔZ l+ .

[0101] Therefore, the first spacing is determined according to the first calculation formula; where the first calculation formula is:

[0102]

[0103] Where, ΔZ l+ Let h be the first spacing, h be the first length, R be the radius of the beam-limiting aperture 3, and r be the radius of the radiation source 6. in The radius of the vacuum cavity is 8.

[0104] In one embodiment, a second spacing is determined based on a first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8 to determine the lower limit point; wherein, the second spacing is the distance between the center lines of the radiation source 6 and the beam-limiting aperture 3 and the lower limit point.

[0105] Specifically, the second spacing is the larger of the lower limit point determined by the radioactive rays emitted from the first emission point and the lower limit point determined by the radioactive rays emitted from the second emission point, i.e. and The larger value in the range.

[0106] Specifically, Analysis of Equation 18 shows that (R+r)>(Rr), (2·R in +Rr)<(2·R in +R+r), therefore, That is, ΔZ r- >ΔZ l- .

[0107] Therefore, the second spacing is determined according to the second calculation formula; wherein the second calculation formula is:

[0108]

[0109] Where, ΔZ r- The second spacing is h, the first length is r, the radius of the beam-limiting aperture 3 is r, and the radius of the radiation source 6 is r. in The radius of the vacuum cavity is 8.

[0110] Another embodiment of this application provides a detector, which is the detector of any embodiment of this application. The detector includes a detection device 2, a beam-limiting aperture 3, and a housing with a vacuum cavity 8. The detection device 2 and the beam-limiting aperture 3 are disposed inside the vacuum cavity 8. The detector is used to detect a radioactive source 6 placed inside the vacuum cavity 8. The side wall 5 of the vacuum cavity has a reflective area. The beam-limiting aperture 3 has a first through-hole 4 through which radioactive rays emitted from the radioactive source 6 pass. The reflective area is used to reflect the radioactive rays so that the radioactive rays pass through the beam-limiting aperture 3 and enter the detection device 2. Thus, the wall scattering effect can be reduced, and the measurement accuracy of the radioactive nuclide emissivity of the radioactive source 6 can be improved.

[0111] Specifically, as shown by the first and second calculation formulas, the first spacing is inversely proportional to the radius of the vacuum cavity 8, and the second spacing is also inversely proportional to the radius of the vacuum cavity 8. Therefore, the larger the first and second spacings are, the smaller the radius of the vacuum cavity 8; conversely, the smaller the first and second spacings are, the larger the radius of the vacuum cavity 8. However, the spacing between the upper and lower limit points should not be too large. If it is too large, more radioactive particles will be reflected by the reflection zone and pass through the first through-hole 4 into the detector, resulting in lower measurement accuracy of the radioactive nuclide emissivity of the radioactive source 6.

[0112] In one embodiment, please refer to Figure 4 The detector also includes a blocking ring placed inside the vacuum cavity 8, between the beam-limiting aperture 3 and the radioactive source 6. The blocking ring has a second through-hole, which connects to the first through-hole 4, allowing direct radiation to the detection device 2. The sidewall of the second through-hole is located on the line connecting the outer edge of the radioactive source 6 and the sidewall of the first through-hole 4. This reduces the impact of particles in the radioactive rays reflected by the sidewall 5 of the vacuum cavity, passing through the first through-hole 4 and entering the detection device 2, on the measurement accuracy of the radioactive nuclide emissivity of the radioactive source 6.

[0113] Specifically, the diameter of the second through hole refers to the inner diameter of the blocking ring.

[0114] The radioactive source 6 is circular in the horizontal plane, and the first through-hole 4 is also circular in the horizontal plane. The line connecting the circumferences of the radioactive source 6 and the first through-hole 4 forms a frustum. Particles in the radioactive rays located inside the frustum can directly pass through the first through-hole 4 and enter the detection device 2. The inner diameter of the blocking ring is the diameter of the frustum surface at the axial position where the blocking ring is placed. That is to say, the diameter of the second through-hole is determined by the axial position of the blocking ring inside the frustum.

[0115] The outer diameter of the blocking ring is the same as the diameter of the vacuum cavity 8, which can better reduce the influence of particles in the radioactive rays reflected by the sidewall 5 of the vacuum cavity.

[0116] It should be noted that the blocking ring blocks particles in radioactive rays in two ways: one part of the particles in the radioactive rays directly hit the blocking ring and are blocked by the blocking ring, and the other part of the particles in the radioactive rays are reflected by the side wall 5 of the vacuum cavity and then reflected onto the blocking ring and blocked by the blocking ring.

[0117] Another embodiment of this application provides a measurement system, which includes a measurement component, a memory, and a processor;

[0118] The measuring components are used to obtain the first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8;

[0119] The memory stores computer-executable instructions;

[0120] The processor is used to execute computer-executable instructions to implement the steps of any of the above measurement methods.

[0121] Specifically, the first length, the radius of the radiation source 6, the radius of the beam-limiting aperture 3, and the radius of the vacuum cavity 8 are measured by the measuring components, and the relevant data is stored in the memory. The processor processes the relevant data to obtain the range of the reflective zone in the detection device 2 through the first through-hole 4.

[0122] 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.

[0123] 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 measurement method for measuring a detector, said detector being used to measure the emissivity of a radioactive source, characterized in that, The detector includes a detection device, a beam-limiting aperture, and a housing with a vacuum cavity. The detection device and the beam-limiting aperture are disposed within the vacuum cavity. The detector is used to detect a radioactive source placed within the vacuum cavity. The sidewall of the vacuum cavity has a reflective area. The beam-limiting aperture has a first through-hole through which radioactive rays emitted from the radioactive source pass. The reflective area is used to reflect the radioactive rays, allowing the radioactive rays to pass through the first through-hole and enter the detection device. The measurement method includes the following steps: Obtain a first length, a radiation source radius, a beam-limiting aperture radius, and a vacuum cavity radius; wherein, the first length is the vertical distance between the radiation source and the beam-limiting aperture, and the beam-limiting aperture radius is the radius of the first through-hole; The reflection zone is determined based on the first length, the radius of the radiation source, the radius of the beam-limiting aperture, and the radius of the vacuum cavity; the upper and lower limit points that form the reflection zone are determined based on the first length, the radius of the radiation source, the radius of the beam-limiting aperture, and the radius of the vacuum cavity. The upper limit point is determined by the radioactive rays emitted from the second emission point of the radioactive source, and the lower limit point is determined by the radioactive rays emitted from the first emission point of the radioactive source; wherein, the first emission point is the near point of the target area of ​​the radioactive source close to the reflection zone, and the second emission point is the far point of the target area of ​​the radioactive source far from the reflection zone. A first spacing is determined based on the first length, the radius of the radiation source, the radius of the beam-limiting aperture, and the radius of the vacuum cavity, in order to determine the upper limit point; wherein, the first spacing is the distance between the center lines of the radiation source and the beam-limiting aperture and the upper limit point; The first spacing is determined according to a first calculation formula; wherein the first calculation formula is: Where, ΔZ l+ Let h be the first spacing, h be the first length, R be the radius of the beam-limiting aperture, and r be the radius of the radiation source. in The radius of the vacuum cavity; A second spacing is determined based on the first length, the radius of the radiation source, the radius of the beam-limiting aperture, and the radius of the vacuum cavity, in order to determine the lower limit point; wherein, the second spacing is the distance between the center lines of the radiation source and the beam-limiting aperture and the lower limit point; The second spacing is determined according to a second calculation formula; wherein the second calculation formula is: Where, ΔZ r- h is the second spacing, r is the first length, R is the radius of the beam-limiting aperture, and r is the radius of the radiation source. in The radius of the vacuum cavity is given.

2. A detector, characterized in that, The detector is the detector described in claim 1. The detector includes a detection device, a beam-limiting aperture, and a housing with a vacuum cavity. The detection device and the beam-limiting aperture are disposed inside the vacuum cavity. The detector is used to detect a radioactive source placed inside the vacuum cavity. The sidewall of the vacuum cavity has a reflective area. The beam-limiting aperture has a first through-hole through which radioactive rays emitted by the radioactive source can pass. The reflective area is used to reflect the radioactive rays so that the radioactive rays pass through the first through-hole and enter the detection device.

3. The detector according to claim 2, characterized in that, The detector also includes a blocking ring placed inside the vacuum cavity and located between the beam-limiting aperture and the radiation source. The blocking ring has a second through hole, and the first through hole and the second through hole are connected to allow the radioactive rays to directly hit the detection device. The sidewall of the second through hole is located on the line connecting the outer edge of the radiation source and the sidewall of the first through hole.

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