Reference radiation field based on accelerator high-energy photons and application method

Abstract

The invention relates to a reference radiation field based on high-energy photons of an accelerator and an application method of the reference radiation field. An accelerator pipeline area is a pipeline of a straight tubular structure and is used for emitting incident particle beams required by a nuclear reaction of the high-energy photons; the target chamber vacuum operation area is connected with the accelerator pipeline area and is a pipeline of a T-shaped structure, a transverse pipeline of the T-shaped structure is connected with the accelerator pipeline area and is parallel to the accelerator pipeline area, and a longitudinal pipeline of the T-shaped structure is connected with a vacuum extraction device; the target chamber nuclear reaction area is connected with the target chamber vacuum operation area, is connected to one end, far away from the accelerator pipeline area, of the transverse pipeline of the T-shaped structure, a nuclear reaction target material is arranged in the target chamber nuclear reaction area, and an incident particle beam penetrates through the target chamber vacuum operation area to react with the nuclear reaction target material to form high-energy photons. According to the invention, the independent high-energy photon radiation field is arranged, and the technical effect of meeting the verification requirement of a domestic nuclear power plant on the high-energy photon dose rate can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of high-energy photons, and in particular to a reference radiation field based on accelerator high-energy photons and an application method thereof. Background Art

[0002] In my country's nuclear power plants, the 16O(n,p)16N nuclear reaction between core fast neutrons and O-16 in the primary cooling water produces high-energy photons with a short lifetime of 7.13 seconds and energies in the 6-7 MeV range. The yield of these high-energy photons is a key monitoring indicator for the safe operation of nuclear power plants. Furthermore, their high penetrating properties contribute significantly to the site / personnel dose rate at certain operating locations outside the reactor containment, reaching up to 50%. Relevant domestic and international standards address the generation and necessity of monitoring these high-energy photons in nuclear power plants. Accurately measuring high-energy gamma radiation dose rates, based on the layout of high-energy photon site / personnel dose (rate) monitoring equipment within nuclear power plants, is crucial for the safe operation of nuclear power plants.

[0003] At present, the existing high-energy photons in my country are directly generated in sealed reactors and used for subsequent use. There is no separate way to obtain the radiation field of high-energy photons for metrological verification of the place / personnel dose (rate) where high-energy photons are generated. This makes it difficult to fully meet the metrological verification needs of high-energy photon dose (rate) monitoring equipment in domestic nuclear power plants, and also brings certain difficulties to the initial verification and subsequent inspections of the monitoring equipment.

[0004] The above problems need to be solved urgently. Summary of the Invention

[0005] The present invention discloses a reference radiation field based on accelerator high-energy photons and an application method, aiming to solve the technical problems existing in the prior art.

[0006] The present invention adopts the following technical solutions:

[0007] On the one hand, the present invention provides a reference radiation field based on accelerator high-energy photons, which includes: an accelerator pipeline area, which is a straight cylindrical structure pipeline used to emit an incident particle beam required for high-energy photon nuclear reaction; a target chamber vacuum operation area, which is connected to the accelerator pipeline area and is a T-shaped structure pipeline, the transverse pipeline of the T-shaped structure is connected to the accelerator pipeline area and is parallel to the accelerator pipeline area, and the longitudinal pipeline of the T-shaped structure is connected to a vacuum extraction device; a target chamber nuclear reaction area, which is connected to the target chamber vacuum operation area and is connected to the transverse pipeline of the T-shaped structure, located at one end away from the accelerator pipeline area, the target chamber nuclear reaction area has a built-in nuclear reaction target material, and the incident particle beam passes through the target chamber vacuum operation area and reacts with the nuclear reaction target material to form high-energy photons.

[0008] Optionally, the accelerator pipeline area includes: an accelerator beam tube, which is a pipeline with a straight cylindrical structure; an accelerator flange, used to connect the accelerator beam tube with the target chamber vacuum operation area; a flange vacuum gate valve, arranged between the accelerator flange and the target chamber vacuum operation area, used to block the vacuum state of the target chamber vacuum operation area.

[0009] Optionally, the accelerator flange is provided with first bolts, and the number of the first bolts is greater than or equal to 16.

[0010] Optionally, the target chamber vacuum operation area includes: a target chamber main pipeline, connected to the accelerator pipeline area; a T-shaped vacuum pipeline, including a transverse pipeline and a longitudinal pipeline, one end of the transverse pipeline is connected to the target chamber main pipeline, and the other end is connected to the target chamber nuclear reaction area, one end of the longitudinal pipeline is connected to the transverse pipeline, and the other end is connected to the vacuum extraction device.

[0011] Optionally, the target chamber vacuum operation area also includes: a first vacuum chamber flange, installed between the target chamber main pipeline and the accelerator pipeline area, for connecting the target chamber main pipeline and the accelerator pipeline area; a second vacuum chamber flange, installed between the target chamber main pipeline and the T-type vacuum pipeline, for connecting the target chamber main pipeline and the T-type vacuum pipeline; a third vacuum chamber flange, installed between the T-type vacuum pipeline and the target chamber nuclear reaction area, for connecting the T-type vacuum pipeline and the target chamber nuclear reaction area; a fourth vacuum chamber flange, installed between the T-type vacuum pipeline and the vacuum extraction device, for connecting the T-type vacuum pipeline and the vacuum extraction device.

[0012] Optionally, outer diameters of the second vacuum chamber flange, the third vacuum chamber flange, and the fourth vacuum chamber flange are all less than or equal to 55 mm.

[0013] Optionally, the target chamber nuclear reaction area includes: a target chamber beam transport pipeline, connected to the target chamber vacuum operation area, for extending the transport distance of the incident particle beam; a target chamber nuclear reaction substrate, connected to the target chamber beam transport pipeline, with a nuclear reaction target material placed facing one side of the target chamber beam transport pipeline; a target chamber cooling water inlet and outlet, arranged at the center position inside the target chamber nuclear reaction substrate, and facing the nuclear reaction target material, for connecting a cooling water pipe.

[0014] Optionally, the target chamber nuclear reaction zone further includes: a target chamber flange, installed between the target chamber beam transport pipeline and the target chamber nuclear reaction substrate, and used for fixing the target chamber nuclear reaction substrate.

[0015] Optionally, second bolts are provided on the target chamber flange, and the number of the second bolts is less than or equal to 6.

[0016] According to another aspect of an embodiment of the present invention, an application method of a reference radiation field based on accelerator high-energy photons is also provided, including: vacuum extraction of the entire reference radiation field based on a T-type vacuum pipeline; opening a flange vacuum gate valve, and the accelerator beam tube emits an incident particle beam; the incident particle beam is injected into the target chamber main pipeline to reduce the dispersion rate of the incident particle beam; the incident particle beam passes through the T-type vacuum pipeline and the target chamber beam transport pipeline, bombards the nuclear reaction target material, undergoes nuclear reaction to form high-energy photons, and performs high-energy photon dose rate calibration based on the generated high-energy photons.

[0017] The technical solution adopted by the present invention can achieve at least one of the following beneficial effects:

[0018] In an embodiment of the present invention, a straight cylindrical structure pipeline is passed through the accelerator pipeline area, which is used to emit the incident particle beam required for the high-energy photon nuclear reaction; the target chamber vacuum operation area is connected to the accelerator pipeline area, which is a T-shaped structure pipeline, the transverse pipeline of the T-shaped structure is connected to the accelerator pipeline area and is parallel to the accelerator pipeline area, and the longitudinal pipeline of the T-shaped structure is connected to the vacuum extraction device; the target chamber nuclear reaction area is connected to the target chamber vacuum operation area and is connected to the transverse pipeline of the T-shaped structure, located at one end away from the accelerator pipeline area, and the target chamber nuclear reaction area has a built-in nuclear reaction target material. The incident particle beam passes through the target chamber vacuum operation area and reacts with the nuclear reaction target material to form high-energy photons. The purpose of emitting an incident particle beam and transmitting the incident particle beam to the vicinity of a nuclear reaction target in a vacuum environment to cause a nuclear reaction to form high-energy photons, and then detecting the dose rate of the high-energy photons is achieved, thereby achieving the technical effect of setting up an independent high-energy photon radiation field and meeting the domestic nuclear power plant's demand for high-energy photon dose rate verification, thereby solving the technical problem of difficulty in verifying the high-energy photon dose rate due to the lack of an independent radiation field for obtaining high-energy photons. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0020] Figure 1 This is a structural diagram of a reference radiation field based on accelerator high-energy photons in Example 1 of the present invention;

[0021] Figure 2 This is a flow chart of an application method based on an accelerator high-energy photon reference radiation field in Example 2 of the present invention.

[0022] Description of reference numerals:

[0023] 1. Accelerator pipeline area; 11. Accelerator beam tube; 12. Accelerator flange; 13. Flange vacuum gate valve;

[0024] 2. Target chamber vacuum operation area; 21. Target chamber main pipeline; 22. T-type vacuum pipeline; 23. First vacuum chamber flange; 24. Second vacuum chamber flange; 25. Third vacuum chamber flange; 26. Fourth vacuum chamber flange;

[0025] 3. Target chamber nuclear reaction area; 31. Target chamber beam transport pipeline; 32. Target chamber nuclear reaction substrate; 33. Target chamber cooling water inlet and outlet; 34. Target chamber flange; 35. Nuclear reaction target material. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and corresponding drawings. In the description of the present invention, it should be noted that the term "or" is generally used in the sense of including "and / or" unless the content clearly indicates otherwise.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or a magnetic connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In addition, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three or more, etc., unless otherwise clearly specified and limited.

[0028] Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] First, to facilitate understanding of the embodiments of the present invention, some of the terms or nouns involved in the present invention are explained below:

[0030] High-energy photons are photons with relatively high energy. Photons are the quantized carriers of electromagnetic waves (such as light, X-rays, and gamma rays), and possess wave-particle duality. Their energy is proportional to their frequency, and they are considered the fundamental particles of electromagnetic radiation.

[0031] To solve the problems existing in the prior art, the embodiments of the present application provide a reference radiation field based on accelerator high-energy photons and an application method.

[0032] Example 1

[0033] This embodiment provides a reference radiation field based on accelerator high-energy photons, such as Figure 1 As shown, Figure 1 This is a structural diagram of a reference radiation field based on accelerator high-energy photons in Example 1 of the present invention. The method includes: an accelerator pipeline area 1, which is a straight cylindrical pipeline connected to the end of the accelerator device and is used to emit an incident particle beam required for a high-energy photon nuclear reaction; a target chamber vacuum operation area 2, which is connected to the accelerator pipeline area 1 and is a T-shaped pipeline. The transverse pipeline of the T-shaped structure is connected to the accelerator pipeline area 1 and is parallel to the accelerator pipeline area 1, and the longitudinal pipeline of the T-shaped structure is connected to a vacuum extraction device; a target chamber nuclear reaction area 3, which is connected to the target chamber vacuum operation area 2 and is connected to the transverse pipeline of the T-shaped structure. It is located at one end away from the accelerator pipeline area 1. The target chamber nuclear reaction area 3 has a built-in nuclear reaction target material 35. The incident particle beam passes through the target chamber vacuum operation area 2 and reacts with the nuclear reaction target material 35 to form high-energy photons.

[0034] Optionally, the accelerator pipeline area 1 can be the end of the accelerator device or a pipeline connected to the end of the accelerator, which is used to provide the incident particle beam required for the high-energy photon reference radiation field. The incident particle beam is emitted by the accelerator end and enters the accelerator pipeline to accelerate the incident particle beam. The target chamber vacuum operation area 2 is connected to the rear of the accelerator pipeline area 1 and has a T-shaped structure. The longitudinal pipeline of the T-shaped structure is connected to the vacuum extraction device, that is, it is directly connected to an external molecular pump, mechanical pump, or other vacuum system, so that the transverse pipeline of the target chamber vacuum operation area 2 forms a vacuum environment. The incident particle beam passes through the target chamber vacuum operation area 2 and moves within this area without generating energy loss.

[0035] Optionally, the target chamber nuclear reaction zone 3 has a built-in nuclear reaction target material 35, which is the area where the incident particle beam and the nuclear reaction target material 35 produce high-energy photon radiation through the (p, γ) nuclear reaction. When the incident particle beam is transmitted in a straight line and bombards the target chamber nuclear reaction zone 3, different types of nuclear reactions occur with different nuclear reaction target materials 35, generating high-energy photon radiation with a variety of energies and dose rates.

[0036] Optionally, based on the setting of the target chamber nuclear reaction zone 3, high-energy photons are generated under the action of the incident particle beam and the nuclear reaction target material 35, and the occurrence is not limited to the reactor. It is convenient to obtain high-energy photons in the target chamber nuclear reaction zone 3 and perform high-energy photon dose rate calibration, thereby meeting the domestic nuclear power plant's demand for high-energy photon dose rate calibration and solving the technical problem of difficulty in calibrating high-energy photon dose rate due to the lack of independent acquisition of the radiation field of high-energy photons.

[0037] In some preferred embodiments, the accelerator pipeline area 1 includes: an accelerator beam tube 11, which is a straight cylindrical pipeline connected to the end of the accelerator device; an accelerator flange 12, used to connect the accelerator beam tube 11 and the target chamber vacuum operation area 2; a flange vacuum gate valve 13, arranged between the accelerator flange 12 and the target chamber vacuum operation area 2, used to block the vacuum state of the target chamber vacuum operation area 2.

[0038] Optionally, the accelerator beam tube 11 provides the incident particle beam necessary for nuclear reactions associated with the high-energy photon reference radiation field. This incident particle beam is generated by an accelerator device and emitted through the accelerator beam tube 11. The incident particle beam provided by the accelerator device is always proton, with an incident energy ranging from at least 0.2 to 6 MeV and an incident beam intensity of at least 15 μA. Specifically, the accelerator device can be an electrostatic accelerator or a reflow accelerator, ensuring that the emitted incident particle beam has sufficient intensity to strike the opposing target.

[0039] Optionally, the accelerator flange 12 provides a serial interface between the accelerator beam tube 11 and the target chamber vacuum operation area 2, tightly securing the accelerator beam tube 11 to the target chamber vacuum operation area 2 to prevent the accelerator beam tube 11 from being separated from the target chamber vacuum operation area 2 due to a large number of incident particles and a direction deflection. Since the target chamber vacuum operation area 2 requires a vacuum-sealed environment, and both sides of the target chamber vacuum operation area 2 should also be vacuum-sealed from the accelerator pipeline area 1 and the target chamber nuclear reaction area 3, the accelerator flange 12 is used to tightly connect the accelerator beam tube 11 to the target chamber vacuum operation area 2 to ensure a secure connection.

[0040] Specifically, the accelerator flange 12 is a flange structure. A flange is a mechanical component used to connect pipes, valves, pumps and other equipment. It is usually disc-shaped. Two or more flanges are tightly connected together by fasteners such as bolts and nuts, with a sealing gasket in the middle to achieve sealing and fixing.

[0041] Optionally, in order to improve the convenience of experimental operation and the service life of the accelerator beam tube 11, a flange vacuum gate valve 13, i.e., a barrier plate, is installed between the accelerator flange 12 and the target chamber vacuum operation area 2. The flange vacuum gate valve 13 is a valve that is opened or closed by raising or lowering the gate to control the flow of gas in the target chamber vacuum operation area 2 to the accelerator beam tube 11, and can block or allow the incident particle beam to pass through.

[0042] In some preferred embodiments, the accelerator flange 12 is provided with first bolts, and the number of the first bolts is greater than or equal to 16.

[0043] Optionally, a secure connection between the accelerator beam tube 11 and the target chamber vacuum operating area 2 requires more first bolts. The more first bolts installed, the stronger the fixation, better sealing, and better vacuum performance. The accelerator flange 12 can be a CF100 model, which is highly robust. Sixteen first bolts connect the corresponding flanges, securing the flanges very stably to the accelerator beam tube 11 and preventing them from easily separating or damaging under the bombardment of the incident particle beam.

[0044] In some preferred embodiments, the target chamber vacuum operation area 2 includes: a target chamber main pipeline 21, which is connected to the accelerator pipeline area 1; a T-shaped vacuum pipeline 22, which includes a transverse pipeline and a longitudinal pipeline, one end of the transverse pipeline is connected to the target chamber main pipeline 21, and the other end is connected to the target chamber nuclear reaction area 3, and one end of the longitudinal pipeline is connected to the transverse pipeline, and the other end is connected to the vacuum extraction device.

[0045] Optionally, the incident particle beam emitted from the accelerator beam tube 11 is composed of multiple incident particles, and the multiple incident particles may be dispersed during movement due to various factors such as air friction or collisions between the incident particles. Therefore, a target chamber vacuum operation area 2 is set to form a vacuum environment in the target chamber vacuum operation area 2, reducing the phenomenon of particle dispersion caused by friction between the incident particle beam and the air. Moreover, when the incident particle beam moves in a vacuum environment, the energy loss can be ignored. Therefore, when the energy between the multiple particles remains unchanged, the front and back distances and trajectories of the movement remain almost unchanged. Therefore, when the incident particles are all shot vertically, they will not collide with each other when the movement speed and the distance between them remain unchanged. Therefore, the setting of the target chamber vacuum operation area 2 reduces the possibility of collisions between the incident particles, thereby effectively avoiding the dispersion of the incident particle beam, so that the entire incident particle beam is in a beam state when it reaches the target chamber nuclear reaction area 3 from the accelerator beam tube 11.

[0046] It should be noted that the target chamber vacuum operation area 2 is interconnected with the accelerator pipeline area 1 and the target chamber nuclear reaction area 3, so the accelerator pipeline area 1 and the target chamber nuclear reaction area 3 are also in a vacuum state, but the vacuum level is slightly lower than that of the target chamber vacuum operation area 2.

[0047] Optionally, a T-shaped vacuum line 22, i.e., a three-way pipe, connected to a vacuum extraction device can be installed to create a vacuum state in the target chamber vacuum operation area 2. The transverse line of the T-shaped vacuum line 22 is parallel to the accelerator beam tube 11, so that the incident particle beam is transmitted through the transverse line after being emitted from the accelerator beam tube 11, avoiding contact with the transverse line wall.

[0048] Optionally, since the longitudinal pipeline of the T-shaped vacuum pipeline 22 is connected to a vacuum extraction device, the extraction effect of the vacuum extraction device may affect the emission direction of the incident particle beam. Therefore, the extraction hole directly facing the vacuum extraction device needs to be moved away from the accelerator beam tube 11 to prevent the extraction force from changing the initial emission direction of the incident particle beam. The target chamber main pipeline 21 is set to extend the distance between the T-shaped vacuum pipeline 22 and the accelerator beam tube 11. After the accelerator beam tube 11 emits the incident particle beam, the emission direction of the incident particle beam is parallel to the internal axis of the pipeline. When passing through the T-shaped vacuum pipeline 22, since the entire device is in a vacuum environment, the extraction force of the vacuum extraction device will no longer have an impact on the incident particle beam.

[0049] Specifically, in order to reduce the scattering of the incident particles of the accelerator in the target chamber and improve the vacuum required for the nuclear reaction in the target chamber, the main body of the target chamber pipeline is made of 304 stainless steel with an inner diameter of Φ40mm.

[0050] In some preferred embodiments, the target chamber vacuum operation area 2 further includes: a first vacuum chamber flange 23, installed between the target chamber main pipeline 21 and the accelerator pipeline area 1, for connecting the target chamber main pipeline 21 and the accelerator pipeline area 1; a second vacuum chamber flange 24, installed between the target chamber main pipeline 21 and the T-type vacuum pipeline 22, for connecting the target chamber main pipeline 21 and the T-type vacuum pipeline 22; a third vacuum chamber flange 25, installed between the T-type vacuum pipeline 22 and the target chamber nuclear reaction area 3, for connecting the T-type vacuum pipeline 22 and the target chamber nuclear reaction area 3; a fourth vacuum chamber flange 26, installed between the T-type vacuum pipeline 22 and the vacuum extraction device, for connecting the T-type vacuum pipeline 22 and the vacuum extraction device.

[0051] In some preferred embodiments, the outer diameters of the second vacuum chamber flange 24 , the third vacuum chamber flange 25 , and the fourth vacuum chamber flange 26 are all less than or equal to 55 mm.

[0052] The first vacuum chamber flange 23 adopts the CF100 model; the second vacuum chamber flange 24 adopts the KF40 model; the third vacuum chamber flange 25 adopts the KF40 model; and the fourth vacuum chamber flange 26 adopts the KF40 model.

[0053] Optionally, the first vacuum chamber flange 23 is used to connect the target chamber main pipeline 21 and the accelerator beam tube 11. The first vacuum chamber flange 23 is a flange plate, which needs to be the same model and size as the accelerator flange 12. The CF100 model flange can be selected and installed together with the accelerator flange 12 to effectively fix the target chamber main pipeline 21 and the accelerator beam tube 11.

[0054] Optionally, the T-shaped vacuum pipe 22 requires the installation of a vacuum extraction device, which is relatively large and occupies some installation space, potentially impacting the installation of the connectors at both ends of the transverse pipe of the T-shaped vacuum pipe 22. Specifically, the presence of the vacuum extraction device reduces the space available there. For example, if a flange with many bolts and a large size is used, tools such as wrenches for tightening the bolts cannot reach both sides of the second vacuum chamber flange 24, making it impossible to secure the second vacuum chamber flange 24. Therefore, the second vacuum chamber flange 24 should be a flange with an outer diameter of less than or equal to 55 mm, specifically, the KF40 model. The third and fourth vacuum chamber flanges 25 and 26 are the same model as the second vacuum chamber flange 24, and similarly, due to limited installation space, the KF40 model can be used.

[0055] The optional KF40 model has a smaller flange size and requires fewer bolts for installation, making it easier to disassemble and install, and suitable for locations with limited installation space.

[0056] Optionally, a standard manual pressure relief valve can be installed between the second vacuum chamber flange 24 and the target chamber main pipeline 21. This allows for pressure relief after completing an experiment or when replacing the nuclear reaction target 35 in the target chamber nuclear reaction zone 3. This prevents cracks in components within the reference radiation field due to high internal and external pressures. The standard manual pressure relief valve slowly injects air into the reference radiation field. This component requires manual operation to prevent the electronic valve from automatically opening in the event of a control failure, potentially leaking radiation from the internal radioactive material through the leak port and affecting the safety of surrounding personnel.

[0057] In some preferred embodiments, the target chamber nuclear reaction area 3 includes: a target chamber beam transport pipeline 31, which is connected to the target chamber vacuum operation area 2 and is used to extend the transportation distance of the incident particle beam; a target chamber nuclear reaction substrate 32, which is connected to the target chamber beam transport pipeline 31, and a nuclear reaction target material 35 is placed on one side of the target chamber beam transport pipeline 31; a target chamber cooling water inlet and outlet 33, which is arranged at the center position inside the target chamber nuclear reaction substrate 32 and is directly opposite to the nuclear reaction target material 35, and is used to connect a cooling water pipe.

[0058] Optionally, to minimize disturbances to the nuclear reaction caused by the vacuum extraction device, a target chamber beam delivery line 31 is installed to extend the distance between the nuclear reaction target 35 and the target chamber vacuum operation area 2 by 15 to 25 cm. This effectively reduces the disturbance of the vacuum extraction device to the nuclear reaction. The target chamber beam delivery line 31 is constructed of 304 stainless steel with an inner diameter of 40 mm.

[0059] Optionally, the target chamber nuclear reaction substrate 32 provides a securement area for the nuclear reaction target 35 and a cooling water circulation area. To reduce the difficulty of component manufacturing, the target chamber nuclear reaction substrate 32 can be constructed by hollowing out a hollow area (target chamber cooling water inlet and outlet 33) with a diameter of Φ30mm and a thickness of 4mm on a standard KF40 flange. This hollow area is connected to two Φ4mm hollow 304 stainless steel tubes, allowing the injection and outflow of cooling water to control the nuclear reaction temperature of the nuclear reaction target 35. Four M2×4 threaded holes are evenly drilled on the concentric circles of the Φ35mm KF40 flange, avoiding the cooling water circulation area to secure the nuclear reaction target 35.

[0060] Optionally, the target chamber nuclear reaction substrate 32 uses a 0.2mm tantalum metal substrate or a 2mm high-purity carbon substrate, and four Φ2.2mm small holes are evenly drilled at positions with an outer diameter of Φ40mm and a center diameter of Φ35mm on the substrate. The nuclear reaction target 35 is fixed on the target chamber nuclear reaction substrate 32 by tantalum M2×4 screws.

[0061] Optionally, the target chamber cooling water inlet and outlet 33 provides an external interface for cooling water required by the target chamber nuclear reaction substrate 32. The interface pipe uses two Φ4mm 304 stainless steel hollow pipe standard parts, which are directly connected to a universal water chiller to maintain 18℃~24℃.

[0062] Optionally, the nuclear reaction target 35 is the target material carrier that undergoes the target nuclear reaction with the accelerator's incident particles. The target material 35 can be selected based on the radiation quality, and the material can also be determined based on metrological verification requirements. The target material 35 is determined based on radiation quality as follows: For RF radiation quality, the target material 35 is an analytically pure CaF2 compound with a thickness of 18.9μm to 25.2μm and a diameter of Φ40mm. For RC radiation quality, the target material 35 is a high-purity carbon element (purity above 99%) with a thickness of 2mm and a diameter of Φ40mm. Four Φ2.2mm holes are evenly drilled on a Φ35mm center diameter. The target material and substrate are secured to the substrate flange using tantalum M2×4 screws. Based on metrological verification requirements, the target material 35 can be made of either Na2WO4 or boron. The Na2WO4 target material has a thickness of 1.0μm and a diameter of Φ40mm.

[0063] Optionally, different types of nuclear reaction targets 35 materials may be used to generate different types of nuclear reactions, producing high-energy photon radiation with various energies and dose rates, as shown in Table 1. Table 1 shows four commonly used types of nuclear reaction targets 35 and the energy and air kerma rate of high-energy photon radiation generated, where the size of the air kerma rate can be continuously adjusted by the strength of the accelerator beam tube 11.

[0064] Table 1

[0065] Target type <![CDATA[CaF2]]> High-purity carbon <![CDATA[Na2WO4]]> Boron accelerator beam 2.7 MeV protons 5.8MeV protons 1.7 MeV protons 240keV protons Nuclear reaction type <![CDATA[ 19 F(p,αγ) 16 O]]> <![CDATA[ 12 C(p,pγ) 12 C]]> <![CDATA[ 23 On(p,γ) 24 Mg]]> <![CDATA[ 11 B(p,γ) 12 C]]> High-energy photon energy (6~7)MeV 4.4MeV (1~12)MeV 240keV, 7.2MeV Air kerma rate 0.1μGy / h~1.5mGy / h 0.1μGy / h~1.5mGy / h 0.1μSv / h~10μSv / h 1μSv / h~100μSv / h

[0066] Optionally, since the target chamber nuclear reaction zone 3 does not have independent beam focusing analysis capabilities, and an excessively large cavity volume within the target chamber nuclear reaction zone 3 (the region with the middle inner diameter of the target chamber nuclear reaction substrate 32) will interfere with the regional vacuum level of the nuclear reaction target material 35 undergoing nuclear reaction, the sum of the length of the target chamber beam transport pipeline 31 and the length of the target chamber nuclear reaction substrate 32 within the target chamber nuclear reaction zone 3 should be preferably controlled within 30 to 50 cm. Considering that high-energy photon radiation can cause air ionization and generate a large amount of high-energy electron radiation, in order to prevent the electron radiation from colliding with the surrounding walls, ground, etc. to generate bremsstrahlung photons and contaminating the target high-energy photon reference radiation, it is necessary to ensure that the target chamber nuclear reaction zone 3 is at least 5 meters away from the surrounding walls.

[0067] In some preferred embodiments, the target chamber nuclear reaction zone 3 further includes: a target chamber flange 34 installed between the target chamber beam transport pipeline 31 and the target chamber nuclear reaction substrate 32 for fixing the target chamber nuclear reaction substrate 32 .

[0068] In some preferred embodiments, second bolts are provided on the target chamber flange 34 , and the number of the second bolts is less than or equal to 6.

[0069] Optionally, a target chamber flange 34 is installed between the target chamber beam transport pipeline 31 and the target chamber nuclear reaction substrate 32, so that the target chamber nuclear reaction substrate 32 can be fixed on the target chamber beam transport pipeline 31, and the target chamber nuclear reaction substrate 32 can be disassembled through the target chamber flange 34, and the internal nuclear reaction target material 35 can be replaced, so that the radiation field can be adapted to different nuclear reactions based on the replacement of the nuclear reaction target material 35, and the effect of the high-energy photon dose rate after different nuclear reactions can be tested.

[0070] Optionally, in order to facilitate the disassembly of the target chamber nuclear reaction substrate 32 for replacing the nuclear reaction target material 35, the target chamber flange 34 needs to be easy to disassemble, that is, the number of fixed second bolts needs to be small. The target chamber flange 34 can use a KF40 model flange. The KF40 model flange has fewer bolts and four second bolts, which can be quickly replaced during disassembly and installation.

[0071] Example 2

[0072] Based on the above embodiments and optional embodiments, the present invention further proposes a method implementation method: Figure 2 This is a flow chart of an application method based on an accelerator high-energy photon reference radiation field in Example 2 of the present invention, such as Figure 2 As shown, the method includes:

[0073] Step S1, vacuum extraction of the entire reference radiation field based on the T-shaped vacuum pipeline 22;

[0074] Step S2, opening the flange vacuum gate valve 13, and the accelerator beam tube 11 emits an incident particle beam;

[0075] Step S3, the incident particle beam is injected into the target chamber main pipeline 21 to reduce the dispersion rate of the incident particle beam;

[0076] Step S4: The incident particle beam passes through the T-shaped vacuum pipe 22 and the target chamber beam transport pipeline 31, bombards the nuclear reaction target 35, and undergoes nuclear reaction to generate high-energy photons.

[0077] Step S5: performing high-energy photon dose rate verification based on the generated high-energy photons.

[0078] Through the above steps S1 to S5, the purpose of emitting an incident particle beam and transmitting the incident particle beam to the vicinity of the nuclear reaction target 35 in a vacuum environment to cause a nuclear reaction to form high-energy photons, and then detecting the dose rate of the high-energy photons is achieved, thereby achieving the technical effect of setting up an independent high-energy photon radiation field, which can meet the domestic nuclear power plant's demand for high-energy photon dose rate verification, and thus solves the technical problem of difficulty in verifying the high-energy photon dose rate due to the lack of an independent high-energy photon radiation field.

[0079] The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A reference radiation field based on accelerator high-energy photons, characterized in that: include: The accelerator pipeline area (1) is a straight cylindrical pipeline used to emit the incident particle beam required for high-energy photon nuclear reaction; The target chamber vacuum operation area (2) is connected to the accelerator pipeline area (1) and is a T-shaped pipeline. The transverse pipeline of the T-shaped structure is connected to the accelerator pipeline area (1) and is parallel to the accelerator pipeline area (1). The longitudinal pipeline of the T-shaped structure is connected to the vacuum extraction device. The target chamber nuclear reaction zone (3) is connected to the target chamber vacuum operation zone (2) and is connected to a transverse pipeline of a T-shaped structure and is located at one end away from the accelerator pipeline zone (1). The target chamber nuclear reaction zone (3) has a built-in nuclear reaction target material (35). The incident particle beam passes through the target chamber vacuum operation zone (2) and reacts with the nuclear reaction target material (35) to form high-energy photons.

2. The reference radiation field based on accelerator high-energy photons according to claim 1, characterized in that: The accelerator pipeline area (1) includes: The accelerator beam tube (11) is a pipe with a straight cylindrical structure; An accelerator flange (12) is used to connect the accelerator beam tube (11) and the target chamber vacuum operation area (2); A flange vacuum gate valve (13) is provided between the accelerator flange (12) and the target chamber vacuum operation area (2) and is used to block the vacuum state of the target chamber vacuum operation area (2).

3. The reference radiation field based on accelerator high-energy photons according to claim 2, characterized in that: The accelerator flange (12) is provided with first bolts, and the number of the first bolts is greater than or equal to 16.

4. The reference radiation field based on accelerator high-energy photons according to claim 1, characterized in that: The target chamber vacuum operation area (2) comprises: The target chamber main pipeline (21) is connected to the accelerator pipeline area (1); The T-shaped vacuum pipeline (22) comprises a transverse pipeline and a longitudinal pipeline, wherein one end of the transverse pipeline is connected to the target chamber main pipeline (21) and the other end is connected to the target chamber nuclear reaction zone (3); one end of the longitudinal pipeline is connected to the transverse pipeline and the other end is connected to the vacuum extraction device.

5. The reference radiation field based on accelerator high-energy photons according to claim 4, characterized in that: The target chamber vacuum operation area (2) also includes: A first vacuum chamber flange (23) is installed between the target chamber main pipeline (21) and the accelerator pipeline area (1) and is used to connect the target chamber main pipeline (21) and the accelerator pipeline area (1); a second vacuum chamber flange (24), installed between the target chamber main pipeline (21) and the T-shaped vacuum pipeline (22), and used for connecting the target chamber main pipeline (21) and the T-shaped vacuum pipeline (22); a third vacuum chamber flange (25), installed between the T-shaped vacuum pipeline (22) and the target chamber nuclear reaction zone (3), and used for connecting the T-shaped vacuum pipeline (22) and the target chamber nuclear reaction zone (3); A fourth vacuum chamber flange (26) is installed between the T-shaped vacuum pipeline (22) and the vacuum extraction device, and is used to connect the T-shaped vacuum pipeline (22) and the vacuum extraction device.

6. The reference radiation field based on accelerator high-energy photons according to claim 5, characterized in that: The outer diameters of the second vacuum chamber flange, the third vacuum chamber flange, and the fourth vacuum chamber flange are all less than or equal to 55 mm.

7. The reference radiation field based on accelerator high-energy photons according to claim 1, characterized in that: The target chamber nuclear reaction zone (3) comprises: A target chamber beam transport pipeline (31) is connected to the target chamber vacuum operation area (2) and is used to extend the transport distance of the incident particle beam; A target chamber nuclear reaction substrate (32) is connected to the target chamber beam transport pipeline (31), and a nuclear reaction target material (35) is placed on one side of the target chamber beam transport pipeline (31); The target chamber cooling water inlet and outlet (33) is arranged at the center position inside the target chamber nuclear reaction substrate (32) and directly facing the nuclear reaction target material (35) for connecting a cooling water pipe.

8. The reference radiation field based on accelerator high-energy photons according to claim 7, characterized in that: The target chamber nuclear reaction zone (3) further comprises: The target chamber flange (34) is installed between the target chamber beam transport pipeline (31) and the target chamber nuclear reaction substrate (32) and is used to fix the target chamber nuclear reaction substrate (32).

9. The reference radiation field based on accelerator high-energy photons according to claim 8, characterized in that: Second bolts are provided on the target chamber flange (34), and the number of the second bolts is less than or equal to 6.

10. An application method of an accelerator high-energy photon reference radiation field, applied to an accelerator high-energy photon reference radiation field according to any one of claims 1 to 9, characterized in that: include: The entire reference radiation field is vacuum-extracted based on a T-type vacuum line (22); The flange vacuum gate valve (13) is opened, and the accelerator beam tube (11) emits an incident particle beam; The incident particle beam is injected into the target chamber main pipeline (21), thereby reducing the dispersion rate of the incident particle beam; The incident particle beam passes through a T-shaped vacuum pipeline (22) and a target chamber beam transport pipeline (31), bombards a nuclear reaction target (35), and undergoes a nuclear reaction to generate high-energy photons; High-energy photon dose rate verification is performed based on the generated high-energy photons.

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