A small-beam beta ray device and a measurement method of a small-beam beta ray radiation field

Abstract

The application relates to a small-beam beta ray device and a measuring method of a small-beam beta ray radiation field, and the small-beam beta ray device is formed by a horizontal driving sliding table, a vertical driving sliding block, a vertical fixed rod, a vertical screw rod, a baffle and a to-be-measured sample placing table arranged on a supporting platform; the horizontal driving sliding block of the horizontal driving sliding table is slidably connected with a sliding groove, a nut connected with the horizontal driving sliding block and a horizontal screw driving rod form a screw pair, the through holes at the two ends of the upper surface of the vertical driving sliding block penetrate through the two vertical fixed rods of the horizontal driving sliding block, the through hole thread hole of the vertical driving sliding block is threadedly connected with the vertical screw rod, the built-in gear of the horizontal driving sliding block is engaged with the vertical screw rod, and the baffle provided with a small-beam hole is fixedly connected with the vertical driving sliding block. Based on the device and the method, the edge and center position detection efficiency deviation of a beta radiation measuring instrument or a monitoring device can be measured, and the horizontal and vertical ranges meeting the measurement requirements are clear.

Description

Technical Field

[0001] This invention belongs to the field of metrology and testing technology, specifically relating to a small-beam beta-ray device and a method for measuring the radiation field of a small-beam beta-ray. Background Technology

[0002] along with 32 P, 131 I, 90 Y、 177 The widespread use of beta radiotherapy drugs such as Lu both domestically and internationally has led to a gradual refinement of beta radiation dosing. In the field of radiotherapy, the precise measurement of trace beta radionuclide activity, the determination of beta radionuclide dose deposition in local human tissues, and radiation safety monitoring during the handling of trace beta radionuclides by medical personnel have placed new demands on beta radiation dosing and have also guided the improvement of standard beta radiation measuring instruments in new directions.

[0003] Currently, most standard metrology instruments for beta radiation dose use extrapolation ionization chambers or secondary standard ionization chambers. However, due to their physical structure, these planar ionization chambers suffer from problems such as edge distortion of the parallel electric field and "memory effect," resulting in a detection efficiency in the edge region of the ionization chamber that is more than 10% lower than in the central region. Other scintillation detectors also exhibit this problem. Although this issue can be controlled by "limiting the detection area," existing beta standard radiation devices in my country cannot provide precise metrological conditions and lack a small-beam beta-ray standard radiation field, causing this measurement deviation to be amplified step by step during the value transfer process. Summary of the Invention

[0004] In view of the deficiencies in the existing technology, the purpose of this invention is to provide a small-beam beta-ray device and a method for measuring the small-beam beta-ray radiation field, so as to solve the problem of excessive measurement deviation caused by the difference in detection efficiency between the edge and center positions of beta radiation metrology instruments or monitoring equipment.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a small-beam beta-ray device, the device comprising a support platform, a horizontal drive slide, a vertical drive slider, a vertical fixing rod, a vertical screw, a baffle, and a sample placement stage, wherein,

[0006] The support platform includes four support legs, and the distance between any two support legs is not less than 25cm.

[0007] The horizontal drive slide is mounted horizontally on the support platform. The horizontal drive slide includes a housing, a slide groove, a horizontal drive slider, a horizontal helical drive rod, and a horizontal helical drive rod handle. The slide groove is fixedly mounted horizontally within the housing. The horizontal helical drive rod is parallel to the slide groove and mounted horizontally within the housing. The handle of the horizontal helical drive rod is fixedly mounted at one end of the horizontal helical drive rod. The horizontal drive slider is slidably connected to the slide groove, and the nut connected to the horizontal drive slider forms a helical pair with the horizontal helical drive rod.

[0008] The two vertical fixing rods are fixed to the horizontal driving slider in a vertical direction; the upper surface of the vertical driving slider has two through holes at both ends, through which the two vertical fixing rods pass respectively; the center of the vertical driving slider has a through hole threaded opening, which is threadedly connected to the vertical screw.

[0009] The horizontal drive slider is equipped with a gear, which is coaxially connected to the vertical screw handle and meshes with the vertical screw.

[0010] The baffle is fixedly connected to the vertical drive slider, and a small beam hole is provided on the baffle;

[0011] The sample placement platform is placed on the support platform and located behind the baffle.

[0012] Furthermore, the aperture of the small beam aperture It is 3.0cm;

[0013] The small beam aperture employs a nested ring structure to provide small beams of different sizes to confine β rays to... Within the range.

[0014] Furthermore, the support platform is made of aluminum alloy;

[0015] Both the outer casing and the outer casing of the horizontal drive slider are made of aluminum alloy.

[0016] Furthermore, casters are installed at the bottom of the four support legs.

[0017] Furthermore, the horizontal drive slide also includes a scale, which is mounted on the housing;

[0018] The horizontal movement and positioning of the horizontal drive slider are read by the scale.

[0019] Furthermore, the vertical fixing rod is provided with scale lines, and the vertical driving slider is positioned by the relative position of the scale lines on the vertical fixing rod and the vertical driving slider.

[0020] Furthermore, the baffle is made of PMMA acrylic sheet with a thickness of 1.0cm and a diameter of 20cm x 20cm.

[0021] Furthermore, the front side of the vertical drive slider has a through hole, and the vertical drive slider is connected to the baffle through a fastening screw passing through the through hole.

[0022] The present invention also provides a method for measuring the radiation field of a small-beam beta ray, based on the aforementioned small-beam beta ray device, the method comprising the following steps:

[0023] S1. Measure the dose rate of the small-beam beta-ray radiation field;

[0024] S2. Measure the energy of the small beam β-ray radiation field;

[0025] S3. Measure the repeatability of small-beam β-rays.

[0026] Furthermore, in step S1, the dose rate of β rays passing through the small beam aperture is measured using an RP-1 type extrapolation ionization chamber.

[0027] The beneficial effects of this invention are as follows: Using the small-beam beta-ray device and method for measuring the small-beam beta-ray radiation field provided by this invention, a small-beam beta-ray device can be formed by a horizontal drive slide, a vertical drive slider, a vertical fixed rod, a vertical screw, a baffle, and a sample placement platform mounted on a support platform. The horizontal drive slider of the horizontal drive slide is slidably connected to a groove, and the nut connected to the horizontal drive slider forms a helical pair with the horizontal helical drive rod. Through holes at both ends of the upper surface of the vertical drive slider pass through the two vertical fixed rods of the horizontal drive slider, and the threaded end of the through hole of the vertical drive slider is threadedly connected to the vertical screw. A gear built into the horizontal drive slider meshes with the vertical screw. The handle of the vertical screw drives the gear to rotate, which in turn drives the vertical screw to rotate, forming a gear transmission that drives the vertical screw to rotate, thus enabling the vertical drive slider to move in the vertical direction. A baffle with a small beam aperture is fixedly connected to the vertical drive slider.

[0028] The device provided by this invention converts the rotational motion of a horizontal helical drive rod into the horizontal linear motion of a horizontal drive slider, enabling the slider to move within a horizontal range of 0-20 cm. A gear drives a vertical screw to rotate, converting its rotational motion into the vertical linear motion of a vertical drive slider, enabling the slider to move within a vertical range of 0-20 cm. This, in turn, allows a baffle with a small beam aperture to move linearly within both the horizontal and vertical ranges of 0-20 cm. Combined with the method for measuring the small beam β-ray radiation field, it can measure the edge-to-center position detection efficiency deviation of β-radiation metrology instruments or monitoring equipment, clearly defining the horizontal and vertical ranges that meet metrological measurement requirements. Furthermore, the small beam aperture in this invention employs a "nested ring" structure, which can confine β-rays to... Within the range, and within the allowable lower limit of the measurement of the device under test, a smaller beam aperture can be selected to improve measurement accuracy. Attached Figure Description

[0029] Figure 1 A schematic diagram of the main view structure of a small-beam β-ray device provided for an embodiment of the present invention;

[0030] Figure 2 A right-side view of a small-beam β-ray device provided for an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of a nested ring structure for a small beam aperture provided for an embodiment of the present invention;

[0032] Figure 4 A schematic diagram of the dose rate for measuring a small beam β-ray radiation field, provided for an embodiment of the present invention;

[0033] Figure 5 A flowchart illustrating the method for measuring the small-beam beta-ray radiation field provided for embodiments of the present invention;

[0034] Among them, 100—support platform, 101—support leg, 200—horizontal drive slide, 201—horizontal drive slider, 202—horizontal screw drive rod handle, 203—scale, 300—vertical drive slider, 301—vertical fixing rod, 302—vertical screw, 303—vertical screw handle, 400—baffle, 401—fastening screw, 402—small beam hole, 500—sample placement platform. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be further clearly and completely described below with reference to the accompanying drawings and examples. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that in the description of the embodiments of the present invention, the terms "upper," "lower," "front," "rear," "front," "back," "left," "right," "horizontal," "vertical," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0037] like Figure 1 , Figure 2 As shown in the figure, this embodiment provides a small-beam beta-ray device. The main structure of the device includes a support platform 100, a horizontal drive slide 200, a vertical drive slider 300, a vertical fixing rod 301, a vertical screw 302, a baffle 400, and a sample placement stage 500.

[0038] The support platform 100 is made of aluminum alloy, which can minimize the scattering pollution of the β radiation field. The baffle 400, the baffle driving component, and the sample placement stage 500 are all placed on the support platform 100.

[0039] The support platform includes four support legs 101, with a distance of no less than 25cm between any two support legs 101; the suspended structure design of the four support legs 101 facilitates the passage of the mechanical track of the BSS2 standard device under the support platform 100.

[0040] Optionally, the support platform 100 is rectangular, and four support legs 101 are fixedly installed at the four top corners of the bottom surface of the support platform 100.

[0041] Optionally, if the device is used in many mobile applications, casters can be installed at the bottom of the four support legs 101.

[0042] The horizontal drive slide 200 is mounted horizontally on the support platform 100. The horizontal drive slide 200 includes a housing, a slide groove, a horizontal drive slider 201, a horizontal helical drive rod, and a horizontal helical drive rod handle 202. The slide groove is fixedly mounted horizontally in the housing. The horizontal helical drive rod is parallel to the slide groove and mounted horizontally in the housing. The horizontal helical drive rod handle 202 is fixedly mounted on one end of the horizontal helical drive rod. The horizontal drive slider 201 is slidably connected to the slide groove. The nut connected to the horizontal drive slider 201 forms a helical pair with the horizontal helical drive rod. When the horizontal helical drive rod handle 202 drives the horizontal helical drive rod to rotate, the rotational motion of the horizontal helical drive rod is converted into the horizontal linear motion of the horizontal drive slider 201, so as to realize the movement of the horizontal drive slider 201 within the horizontal range of 0 to 20 cm.

[0043] Both the outer casing and the outer casing of the horizontal drive slider 201 are made of aluminum alloy. The horizontal helical drive rod is a 304 stainless steel helical drive rod.

[0044] The horizontal drive slide 200 also includes a scale 203, which is mounted on the housing; the movement and positioning of the horizontal drive slider 201 are read by the scale 203, and the positioning accuracy is better than ±0.1mm.

[0045] Two vertical fixing rods 301 are welded and fixed to the horizontal drive slider 201 in a vertical direction, serving as slide rails for the vertical drive slider 300 to move up and down in the vertical direction. Specifically, the vertical fixing rods 301 are... Aluminum alloy fixing rod.

[0046] The horizontal drive slider 201 is equipped with a gear inside, which meshes with the vertical screw 302. The gear is coaxially connected to the vertical screw handle 303. By rotating the vertical screw handle 303, the gear is driven to rotate, which in turn drives the vertical screw 302 to rotate, forming a gear transmission, thereby realizing that rotating the vertical screw handle 303 drives the vertical screw 302 to rotate.

[0047] The upper surface of the vertical drive slider 300 has two openings at both ends. The vertical drive slider 300 has through holes through which two vertical fixing rods 301 pass, thus slidably connecting the vertical drive slider 300 to the two vertical fixing rods 301. The vertical drive slider 300 has an M16 threaded through hole at its center, which is threadedly connected to the vertical screw 302, forming a helical pair. When the vertical screw handle 303 drives the gear to rotate, it also drives the vertical screw 302 to rotate. The rotational motion of the vertical screw 302 is converted into the vertical linear motion of the vertical drive slider 300, enabling the vertical drive slider 300 to move within a vertical range of 0–20 cm.

[0048] Optionally, the vertical screw 302 is an M16 stainless steel screw that matches the size of the through hole thread.

[0049] Optionally, the vertical fixing rod 301 is provided with scale lines, and the vertical driving slider 300 is positioned in the vertical direction by reading the relative position of the scale lines on the vertical fixing rod 301 and the vertical driving slider, with a positioning accuracy better than ±0.1mm.

[0050] The front side of the vertical drive slider 300 has two openings. The vertical drive slider 300 is connected to the baffle 400 through the through hole by two fastening screws 401.

[0051] The lower end of the baffle 400 has two openings. The through hole and the fastening screw 401 are standard M6 screws and nuts, which are used to fix the vertical drive slider 300 and the baffle 400.

[0052] like Figure 3 As shown, the baffle 400 has an aperture. The small beam aperture 402 employs a "nested ring" structure to provide small beams of different sizes. If nested... cm small ring (outer diameter) inner diameter This allows for the constraint of small beam sizes to... Similarly, the small beam aperture 402 can confine β rays to... Within the range.

[0053] Optionally, the baffle 400 is made of a 20cm × 20cm, 1.0cm thick PMMA acrylic sheet to meet the requirements of high-energy β nuclides ( 90 Sr- 90 The maximum β energy (2.27 MeV) of Y will not pass through the baffle 400 outside the small beam hole 402.

[0054] It should be noted that the size of the aperture depends on the measurement lower limit of the device under test. If it is within the allowable range of the measurement lower limit, a smaller beam aperture can be selected to improve the measurement accuracy.

[0055] The sample placement platform 500 is positioned behind the baffle 400 on the support platform 100 and is not fixedly connected to the support platform 100 to facilitate the placement of the test object; its geometric design is relatively flexible, as long as it meets the placement requirements of the test equipment or sample. When placing larger test equipment such as an extrapolation ionization chamber or phantom, the sample placement platform 500 is required to provide a placement area of ​​not less than 20cm × 20cm.

[0056] The sample placement stage 500 is made of a low atomic number material, such as aluminum or plexiglass.

[0057] To use a small-beam beta-ray device for the measurement of beta standard radiation fields, measurements of the beta radiation field are required in three aspects: dose rate, energy, and repeatability. For example... Figure 4 As shown, this embodiment also provides a method for measuring the radiation field of a small-beam beta ray, implemented based on the aforementioned small-beam beta ray device. The method includes the following steps:

[0058] S1. Measure the dose rate of the small-beam beta-ray radiation field;

[0059] To determine the magnitude of the β-ray dose rate through the small beam aperture 402, dose rate measurement is required using an RP-1 type extrapolation ionization chamber, such as... Figure 4 As shown, the β-ray beam, the small beam aperture 402, and the central normal of the extrapolation ionization chamber coincide, and the distance between the front window of the extrapolation ionization chamber and the baffle 400 is no more than 1 cm. During measurement, the baffle 400 is moved horizontally and vertically in a step size of 2 mm, ensuring that the small beam aperture 402 always coincides with the central normal of the extrapolation ionization chamber. The dose rate of the small beam β-rays can be directly reflected by the measurement results of the extrapolation ionization chamber. Finally, the dose rate within ±10 cm of the central normal in both the horizontal and vertical directions is determined. By changing the diameter of the small beam aperture 402, the above operation is repeated to obtain the dose rate of the small beam β-rays corresponding to different diameter small beam apertures 402.

[0060] S2. Measure the energy of the small beam β-ray radiation field;

[0061] To determine whether the beta rays will exhibit any alteration in their original energy spectrum due to scattering after passing through the small beam aperture 402, it is necessary to measure the beta ray energy spectrum using a SiPN detector. When measuring the beta ray energy spectrum using the SiPN detector, a 3 mg·cm³ coating is applied to the surface. 2 The aluminized polyester film is used to shield the light, and the measurement method is consistent with the dose rate measurement method of the small beam β-ray radiation field described in step S1.

[0062] S3. Measure the repeatability of small-beam β-rays;

[0063] To verify the operational stability of the small-beam beta-ray device when used in conjunction with the BSS2 standard device, it is necessary to measure the repeatability of the small-beam beta-ray. An RP-1 type extrapolation ionization chamber was selected, and the dose rate was repeatedly measured 10 times under the same external conditions. The repeatability was calculated according to formula (1).

[0064]

[0065] Ultimately, it was determined that, compared to the center normal of the beta rays, the horizontal and vertical movement distances within which the dose rate change does not exceed ±5%, the energy spectrum change does not exceed 5%, and the repeatability change does not exceed 1% are sufficient for metrological measurements of small-beta rays.

[0066] According to the device provided in this embodiment, a baffle with a small beam aperture can be made to move linearly within a horizontal range of 0 to 20 cm and a vertical range of 0 to 20 cm. Combined with the measurement method of the small beam β-ray radiation field, the detection efficiency deviation between the edge and center positions of the β-radiation metrology instrument or monitoring equipment can be measured, and the horizontal and vertical ranges that meet the metrology measurement requirements can be clearly defined.

[0067] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention is also intended to include these modifications and variations.

Claims

1. A small-beam beta-ray device, characterized in that, The device includes a support platform, a horizontal drive slide, a vertical drive slider, a vertical fixing rod, a vertical screw, a baffle, and a sample placement stage. The support platform includes four support legs, and the distance between any two support legs is not less than 25 cm; The horizontal drive slide is mounted horizontally on the support platform. The horizontal drive slide includes a housing, a slide groove, a horizontal drive slider, a horizontal helical drive rod, and a horizontal helical drive rod handle. The slide groove is fixedly mounted horizontally within the housing. The horizontal helical drive rod is parallel to the slide groove and mounted horizontally within the housing. The handle of the horizontal helical drive rod is fixedly mounted at one end of the horizontal helical drive rod. The horizontal drive slider is slidably connected to the slide groove, and the nut connected to the horizontal drive slider forms a helical pair with the horizontal helical drive rod. The two vertical fixing rods are fixed to the horizontal driving slider in a vertical direction; the upper surface of the vertical driving slider has two through holes at both ends, through which the two vertical fixing rods pass respectively; the center of the vertical driving slider has a through hole threaded opening, which is threadedly connected to the vertical screw. The horizontal drive slider is equipped with a gear, which is coaxially connected to the vertical screw handle and meshes with the vertical screw. The baffle is fixedly connected to the vertical drive slider, and a small beam hole is provided on the baffle; The sample placement platform is placed on the support platform and located behind the baffle.

2. The small-beam β-ray device according to claim 1, characterized in that, The aperture φ of the small beam aperture is 3.0 cm; The small beam aperture employs a nested ring structure to provide small beams of different sizes to confine β rays to the range of φ1.0 cm to φ3.0 cm.

3. A small-beam beta-ray device according to claim 1, characterized in that, The support platform is made of aluminum alloy. Both the outer casing and the outer casing of the horizontal drive slider are made of aluminum alloy.

4. A small-beam beta-ray device according to claim 1, characterized in that, The bottom of each of the four support legs is equipped with casters.

5. A small-beam beta-ray device according to claim 1, characterized in that, The horizontal drive slide also includes a scale, which is mounted on the housing; The horizontal movement and positioning of the horizontal drive slider are read by the scale.

6. A small-beam beta-ray device according to claim 1, characterized in that, The vertical fixed rod is provided with scale lines, and the vertical drive slider is positioned by the relative position of the scale lines on the vertical fixed rod and the vertical drive slider.

7. A small-beam beta-ray device according to claim 1, characterized in that, The baffle is made of PMMA acrylic sheet with a thickness of 20 cm × 20 cm and a thickness of 1.0 cm.

8. A small-beam beta-ray device according to claim 1, characterized in that, The front side of the vertical drive slider has a through hole, and the vertical drive slider is connected to the baffle through a fastening screw passing through the through hole.

9. A method for measuring the radiation field of a small-beam beta-ray, implemented based on the small-beam beta-ray device described in claims 1-8, characterized in that, The method includes the following steps: S1. Measure the dose rate of the small-beam beta-ray radiation field; S2. Measure the energy of the small beam β-ray radiation field; S3. Measure the repeatability of small-beam β-rays.

10. The method for measuring a small-beam beta-ray radiation field according to claim 9, characterized in that, In step S1, the dose rate of β rays passing through the small beam aperture is measured using an RP-1 type extrapolation ionization chamber.

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