A radiation dose interlock control system for accelerators

Abstract

The present invention discloses a radiation dose interlock control system for an accelerator. The radiation dose interlock control system includes a detector unit, a signal processing unit, an accelerator operation status interface, an indicator light, and a dose interlock device. The detector unit is configured to detect the radiation dose in the accelerator room. The accelerator operation status interface is configured to provide an accelerator operation status signal. The indicator light has different operating states. The dose interlock device is configured to switch the state of the accelerator room protective door under the control of the signal processing unit. The signal processing unit is configured to make a judgment based on the radiation dose in the accelerator room and the accelerator operation status signal, thereby sending corresponding control signals to the indicator light and the dose interlock device. The present invention implements a dose interlock redundancy design and automatic response to system failures, preventing interlock system failures caused by radiation damage to electronic components, and ultimately avoiding overdose irradiation accidents caused by interlock system failures.

Description

Technical Field

[0001] The present invention relates to the field of accelerator radiation safety protection, and in particular to a radiation dose interlocking control system for an accelerator. Background Art

[0002] The radiation fields generated by medium- and high-energy electron, proton, and heavy-ion accelerators differ from those generated by nuclear facilities, radiation devices, and radioactive sources. They are characterized by the generation of prompt neutron and photon radiation with a wide energy range during accelerator operation and the generation of lower-energy slow photon radiation due to activation after accelerator shutdown. Because prompt neutrons and photons contain high-energy components, there are currently no detectors capable of comprehensively monitoring these radiation fields. Conventional detectors are primarily used in the nuclear industry and for radioactive sources. Neutron detector energies typically fall below 15 MeV, while photon detectors typically fall below 3 MeV. Using conventional detectors for accelerator dose interlock control presents the potential for overexposure to personnel.

[0003] Prompt neutron radiation generated during accelerator operation includes relatively low-energy evaporated neutrons (generally below 10 MeV) and cascade neutrons, which can reach energies as high as the incident particle energy. Cascade neutrons account for over 30% of the total neutron flux. Considering the relationship between neutron dose conversion coefficients and energy, neutrons greater than 10 MeV typically contribute over 50% of the total dose. Therefore, using conventional neutron detectors directly will result in significantly underestimating the measured results.

[0004] The prompt photons generated during accelerator operation include higher-energy bremsstrahlung and lower-energy gamma rays produced by the decay and deexcitation of activated nuclides. The energy of electron bremsstrahlung photons can be as high as the energy of the incident electron, and its energy range also far exceeds that of traditional photon dose detectors.

[0005] After the accelerator ceases operation, radioactive nuclides decay due to the activation of accelerator components, shielding, air, and other environmental media within the machine room. This de-excitation produces gamma rays, which form a delayed radiation field. This radiation field is characterized by gamma ray energies primarily concentrated within 2 MeV, and the delayed radiation decays rapidly with downtime. Traditional door interlock systems don't monitor this state, so personnel entering the machine room prematurely after a shutdown could be exposed to excessive radiation.

[0006] The neutron flux in the radiation field when the accelerator is running is high, which can easily cause radiation damage to related electrical equipment in the machine room, especially radiation damage to control system components such as electronic components. This is a common cause of failure of traditional interlocking systems.

[0007] The existing accelerator dose interlock system uses a neutron detector and a photon detector to measure the neutron radiation field and the photon radiation field separately, and uses them as control signals for the dose interlock. This can neither meet the requirements of radiation safety redundancy design nor has the function of responding promptly to detector failure.

[0008] During special operating conditions such as accelerator commissioning, testing, and maintenance, personnel often need to enter certain interlocked control areas. These personnel may manually manipulate the accelerator's operating status signals, potentially exposing personnel to excessive radiation exposure. This is a common occurrence in accelerator nuclear technology applications. Existing dose interlocks are not sufficient to prevent these human-induced accidents.

[0009] Therefore, there is a need for a radiation dose interlock control system for an accelerator that can solve the above problems. Summary of the Invention

[0010] The object of the present invention is to provide a radiation dose interlock control system for an accelerator, which realizes dose interlock control and safety protection based on detector signals and accelerator operation status signals.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0012] A radiation dose interlock control system for an accelerator, the radiation dose interlock control system comprising a detector unit, a signal processing unit, an accelerator operation status interface, an indicator light, and a dose interlock device, wherein the detector unit is configured to detect the radiation dose in the accelerator room, the radiation dose including neutron dose, high-energy gamma ray dose, and low-energy gamma ray dose; the accelerator operation status interface is configured to provide an accelerator operation status signal, the accelerator operation status signal including running or shut down; the indicator light is configured to have different working states under the control of the signal processing unit; the dose interlock device is configured to switch the state of the accelerator room protective door under the control of the signal processing unit, the accelerator room protective door state including locked and unlocked; the detector unit, accelerator operation status interface, indicator light, and dose interlock device are respectively electrically connected to the signal processing unit, and the signal processing unit is configured to perform the following judgments based on the radiation dose in the accelerator room and the accelerator operation status signal, thereby sending corresponding control signals to the indicator light and the dose interlock device:

[0013] a. When the neutron dose, high-energy gamma-ray dose, and low-energy gamma-ray dose are all above their respective control thresholds, and the accelerator operating status signal is in operation, the signal processing unit outputs a first control signal. Under the action of the first control signal, the indicator light is in the first operating state and the dose interlock device controls the accelerator room protective door to be in the locked state;

[0014] b. When the neutron dose, high-energy gamma-ray dose and low-energy gamma-ray dose are all lower than their respective control thresholds and the accelerator operation status signal is shutdown, the signal processing unit outputs a second control signal. Under the action of the second control signal, the indicator light is in the second working state and the dose interlock device controls the accelerator room protective door to be in the unlocked state.

[0015] Furthermore, the signal processing unit is further configured to make the following judgments based on the radiation dose in the accelerator room and the accelerator operation status signal, thereby sending corresponding control signals to the indicator light and the dose interlock device:

[0016] c. When the neutron dose and high-energy gamma-ray dose are both lower than their respective control thresholds, and the low-energy gamma-ray dose is higher than the corresponding control thresholds, and the accelerator operation status signal is shutdown, the signal processing system outputs a third control signal. Under the action of the third control signal, the indicator light is in the third working state and the dose interlock device controls the accelerator room protective door to be in a locked state.

[0017] Furthermore, the signal processing unit is further configured to make the following judgments based on the radiation dose in the accelerator room and the accelerator operation status signal, thereby sending corresponding control signals to the indicator light and the dose interlock device:

[0018] d. When the neutron dose, high-energy gamma-ray dose, low-energy gamma-ray dose and accelerator operating status signals do not satisfy conditions a, b, and c, the signal processing unit outputs a fourth control signal. Under the action of the fourth control signal, the indicator light is in a fourth working state and the dose interlock device controls the accelerator room protective door to be in a locked state.

[0019] Furthermore, the detector unit includes a neutron detector assembly, a high-energy gamma-ray detector assembly and a low-energy gamma-ray detector assembly. The neutron detector assembly is configured to detect the neutron dose in the accelerator room, the high-energy gamma-ray detector assembly is configured to detect the high-energy gamma-ray dose in the accelerator room, and the low-energy gamma-ray detector assembly is configured to detect the low-energy gamma-ray dose in the accelerator room.

[0020] Preferably, the neutron detector assembly includes a He-3 neutron counter tube, a polyethylene inner neutron moderation layer, a lead high-energy neutron reaction layer, and a polyethylene outer neutron moderation layer, which are sequentially distributed from the inside to the outside.

[0021] Preferably, the high-energy gamma-ray detector assembly includes a first GM photon counter tube, an X-ray shielding layer made of copper, a gamma-ray shielding layer made of lead, and a first detector neutron protection layer made of polyethylene, which are sequentially distributed from the inside to the outside.

[0022] Preferably, the low-energy gamma-ray detector assembly includes a second GM photon counter tube and a second detector neutron shielding layer made of polyethylene, which are sequentially distributed from the inside to the outside.

[0023] Furthermore, the signal processing unit includes an electronic component neutron protection shell and a logic control module based on FPGA.

[0024] Further preferably, the logic control module includes an MC8051 soft core and three detector pulse counters, wherein the three detector pulse counters are arranged in one-to-one correspondence with the neutron detector assembly, the high-energy gamma-ray detector assembly, and the low-energy gamma-ray detector assembly, and the MC8051 soft core is electrically connected to the three detector pulse counters, the accelerator operation status interface, the indicator light, and the dose interlock device, respectively. The MC8051 soft core is configured to perform logical judgment based on the signals sent by the three detector pulse counters and the accelerator operation status interface, thereby outputting corresponding control signals to the indicator light and the dose interlock device.

[0025] Furthermore, the radiation dose interlock control system also includes a PC, which is electrically connected to the signal processing system, and is configured to set the detector dose conversion coefficient and / or dose control threshold and / or detector calibration parameters, as well as to store radiation detector historical data and / or control signal historical data, and to display the operating status of the radiation dose interlock control system.

[0026] The present invention has the advantages of being able to detect detector system failures in the first place, effectively avoiding overdose exposure accidents caused by failure of the radiation dose interlock control system, thereby effectively preventing workers from being overexposed, and making judgments based on the radiation dose in the accelerator room and the accelerator operating status signal, which can further avoid failure of the radiation dose interlock control system caused by human factors, thereby increasing safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 is a schematic block diagram of a radiation dose interlock control system for an accelerator provided by an embodiment of the present invention;

[0029] Figure 2 This is a logic control diagram of a radiation dose interlock control system for an accelerator provided by an embodiment of the present invention.

[0030] Among them, the figure numerals include: 1-detector unit, 2-signal processing unit, 3-accelerator operation status interface, 4-PC, 5-indicator light, 6-dose interlock device, 7-neutron detector assembly, 8-high-energy gamma-ray detector assembly, 9-low-energy gamma-ray detector assembly, 10-neutron outer moderator, 11-high-energy neutron reaction layer, 12-neutron inner moderator, 13-He-3 neutron counter, 14-first detector neutron protection layer, 15-gamma-ray shielding layer, 16-X-ray shielding layer, 17-first GM photon counter, 18-second low-energy gamma-ray detector neutron protection layer, 19-second GM photon counter, 20-electronic component neutron protection shell, 21-FPGA-based logic control module, 22-MC8051 soft core, 23-detector pulse counter. DETAILED DESCRIPTION

[0031] To help those skilled in the art better understand the present invention and more clearly grasp its objectives, technical solutions, and advantages, the following describes the technical solutions in the embodiments of the present invention in a clear and complete manner, in conjunction with specific embodiments and with reference to the accompanying drawings. It should be noted that implementations not depicted or described in the accompanying drawings are known to those skilled in the art. Furthermore, while examples of parameters with specific values may be provided herein, it should be understood that the parameters do not need to be exactly equal to the corresponding values, but rather may be approximated to the corresponding values within acceptable error tolerances or design constraints. Clearly, the described embodiments are merely a portion of the embodiments of the present invention, not all of them. All other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention. Furthermore, the terms "comprising" and "having," and any variations thereof, in the specification and claims of the present invention, are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product, or device comprising a series of steps or units need not be limited to the steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to the process, method, product, or device.

[0032] In one embodiment of the present invention, a radiation dose interlock control system for an accelerator is provided. Figure 1 As shown, the radiation dose interlock control system includes a detector unit 1, a signal processing unit 2, an accelerator operation status interface 3, a PC 4, an indicator light 5, and a dose interlock device 6, wherein the detector unit 1, the accelerator operation status interface 3, the indicator light 5, and the dose interlock device 6 are electrically connected to the signal processing unit 2 respectively.

[0033] The detector unit 1 is used to monitor the prompt radiation field when the accelerator is running and the delayed radiation field after the accelerator stops running, that is, to detect the radiation dose in the accelerator room in real time. The radiation dose includes neutron dose, high-energy gamma ray dose and low-energy gamma ray dose. In this embodiment, Figure 1 As shown, the detector unit 1 includes a neutron detector assembly 7, a high-energy gamma-ray detector assembly 8, and a low-energy gamma-ray detector assembly 9, each of which is composed as follows:

[0034] The neutron detector assembly 7 is configured to detect the neutron dose in the accelerator room. The neutron detector assembly 7 includes, arranged from the inside out, a He-3 neutron counter tube 13, an inner neutron moderator layer 12 made of polyethylene, a high-energy neutron reaction layer 11 made of lead, and an outer neutron moderator layer 10 made of polyethylene. High-energy neutrons react with lead to generate lower-energy neutrons, and the polyethylene moderator layer is used to moderate the neutrons to within the energy response range of the He-3 neutron counter tube 13. By appropriately adjusting the thickness of each layer, the energy response range of the He-3 neutron counter tube 13 can be expanded to the GeV level.

[0035] The high-energy gamma-ray detector assembly 8 is configured to detect the high-energy gamma-ray dose in the accelerator room. The high-energy gamma-ray detector assembly 8 includes, arranged from the inside out, a first GM photon counter tube 17, an X-ray shielding layer 16 made of copper, a gamma-ray shielding layer 15 made of lead, and a first detector neutron shielding layer 14 made of polyethylene. The first detector neutron shielding layer 14 is used to reduce radiation damage to the first GM photon counter tube 17 by neutrons. The gamma-ray shielding layer 15 is used to shield gamma photons within 3 MeV. The X-ray shielding layer 16 is used to shield X-rays generated by the interaction between gamma rays and lead. Ultimately, the high-energy gamma-ray detector assembly 8 responds to high-energy gamma photons generated during accelerator operation, but does not respond to lower-energy gamma rays generated after the accelerator is shut down.

[0036] The low-energy gamma-ray detector assembly 9 is configured to detect the low-energy gamma-ray dose in the accelerator room. The low-energy gamma-ray detector assembly 9 includes a second GM photon counter tube 19 and a second detector neutron shielding layer 18 made of polyethylene, which are distributed in sequence from the inside to the outside. Since the second GM photon counter tube 19 is wrapped by the polyethylene shielding layer, namely the second detector neutron shielding layer 18, the polyethylene shielding layer is used to reduce the radiation damage of neutrons to the low-energy gamma-ray detector assembly 9. At the same time, since the polyethylene material has a small blocking ability for gamma photons, the low-energy gamma-ray detector assembly 9 can measure the dose of the slow-emission radiation field after the accelerator stops running.

[0037] The accelerator operation state interface 3 is configured to provide a state signal indicating whether the accelerator is in "operation" or "stop" according to the operation state of the accelerator.

[0038] The PC 4 is electrically connected to the signal processing system 2. The PC 4 is configured to set one or more of the following parameters, including but not limited to a detector dose conversion coefficient, a dose control threshold, and a detector calibration parameter, as well as to store radiation detector historical data and / or control signal historical data, and to display the operating status of the radiation dose interlock control system.

[0039] The indicator light 5 is configured to have different working states under the control of the signal processing unit 2. The working states can be flashing or emitting light of different colors, thereby responding to the control signal of the signal processing unit 2 and displaying the radiation safety status inside the accelerator room in real time outside the accelerator room.

[0040] The dose interlock device 6 is configured to switch the state of the accelerator room protection door under the control of the signal processing unit 2. The accelerator room protection door state includes locked and unlocked, so that the dose interlock device 6 can perform "lock" or "unlock" operations on each shielding door.

[0041] The signal processing unit 2 is used to process the detector signal of the detector unit 1 and complete the logic control of the dose interlock signal. The signal processing unit 2 includes an electronic component neutron protection shell 20 and an FPGA-based logic control module 21, wherein the logic control module 21 includes an MC8051 soft core 22 and three detector pulse counters 23, wherein, Figure 1 As shown, the three detector pulse counters 23 are arranged in one-to-one correspondence with the neutron detector assembly 7, the high-energy gamma-ray detector assembly 8, and the low-energy gamma-ray detector assembly 9. The MC8051 soft core 22 is electrically connected to the three detector pulse counters 23, the accelerator operation status interface 3, the indicator light 5, and the dose interlock device 6 respectively. The MC8051 soft core 22 is configured to perform logical judgment based on the signals sent by the three detector pulse counters 23 and the accelerator operation status interface 3, thereby outputting corresponding control signals to the indicator light 5 and the dose interlock device 6. Specifically, the MC8051 soft core 22 is used to convert the detector pulse count information into radiation dose information in real time, and perform logical judgment on the status signals of each detector component and the signals of the accelerator operation status interface, thereby outputting control signals to the dose interlock device 6 and the indicator light 5 control signal, so that the dose interlock device 6 responds to the control signal to control the "lock" and "unlock" states of the protective doors of each accelerator room, and causes the indicator light 5 to indicate one of the following states: the accelerator is in operation, the accelerator is in shutdown but the radiation dose in the room is higher than the control threshold, the accelerator is in shutdown and the radiation dose in the room is lower than the control threshold, or it indicates that there is a fault in the radiation dose interlock control system.

[0042] In this embodiment, the signal processing unit 2 makes the following judgments based on the radiation dose in the accelerator room and the accelerator operating status signal, and sends corresponding control signals to the indicator light 5 and the dose interlock device 6:

[0043] a. When the neutron dose, high-energy gamma-ray dose, and low-energy gamma-ray dose are all above their respective control thresholds, and the accelerator operating state signal is in operation, the signal processing unit 2 outputs a first control signal. Under the action of the first control signal, the indicator light 5 is in the first operating state (e.g., red light) and the dose interlock device 6 controls the accelerator room protective door to be in the locked state;

[0044] b. When the neutron dose, high-energy gamma-ray dose and low-energy gamma-ray dose are all lower than their respective control thresholds and the accelerator operation status signal is shutdown, the signal processing unit 2 outputs a second control signal. Under the action of the second control signal, the indicator light 5 is in the second working state (for example, emitting green light) and the dose interlock device 6 controls the accelerator room protective door to be in the unlocked state.

[0045] c. When the neutron dose and high-energy gamma-ray dose are both lower than their respective control thresholds, and the low-energy gamma-ray dose is higher than the corresponding control thresholds, and the accelerator operation status signal is shutdown, the signal processing system 2 outputs a third control signal. Under the action of the third control signal, the indicator light 5 is in the third working state (for example, emitting yellow light) and the dose interlock device 6 controls the accelerator room protective door to be in the locked state.

[0046] d. When the neutron dose, high-energy gamma-ray dose, low-energy gamma-ray dose and accelerator operating status signals do not satisfy conditions a, b, and c, the signal processing unit 2 outputs a fourth control signal. Under the action of the fourth control signal, the indicator light 5 is in a fourth operating state (for example, flashing) and the dose interlock device 6 controls the accelerator room protective door to be in a locked state.

[0047] In one embodiment of the present invention, the detector unit 1 of the radiation dose interlock control system, i.e., three detector assemblies, is installed in areas frequently visited by personnel in the accelerator room; the signal processing unit 2 is installed in areas with low radiation doses, such as the accelerator room maze; the indicator light 5 is installed outside the entrance of each protective door and in the accelerator control room; and the dose interlock device 6 is installed on each protective door.

[0048] The accelerator operation status signal "1" at the accelerator operation status interface 3 indicates that the accelerator is in the operation state, and "0" indicates that the accelerator is in the shutdown state; the detector signal "1" of the neutron detector assembly 7 indicates that the neutron dose in the accelerator room is higher than its control threshold, and "0" indicates that the neutron dose is lower than its control threshold; the detector signal "1" of the high-energy gamma-ray detector assembly 8 indicates that the high-energy gamma radiation dose in the accelerator room is higher than its control threshold, and "0" indicates that the high-energy gamma radiation dose is lower than its control threshold; the detector signal "1" of the low-energy gamma-ray detector assembly 9 indicates that the low-energy gamma radiation dose in the accelerator room is higher than its control threshold, "0" indicates that the low-energy gamma radiation dose is lower than its control threshold; the status signal "1" of the dose interlock device 6 indicates that the accelerator room protective door is in the "locked" state, and "0" indicates that the accelerator room protective door is in the "unlocked" state; the indicator light 5 is in "red" to indicate that the accelerator is in operation; the indicator light 5 is in "yellow" to indicate that the accelerator is in shutdown but the radiation dose in the room is higher than the control threshold; the indicator light 5 is in "green" to indicate that the accelerator is in shutdown and the radiation dose in the room is lower than the control threshold; the indicator light 5 is in "flashing" to indicate that there is a fault in the radiation dose interlock control system. Based on the above settings and combined with Figure 2 Make the following specific instructions:

[0049] For a typical 230MeV medical proton accelerator, the radiation field during operation is characterized by: a neutron radiation field consisting of cascade neutrons with energies up to 230MeV and evaporated neutrons with energies within 10MeV; and a photon radiation field consisting of high-energy gamma rays with energies approaching 100MeV and low-energy gamma rays within 3MeV. At this point, the energies of neutrons of varying energies are reduced to within the response range of the He-3 neutron counter tube 13 by the action of the neutron outer moderator 10, the high-energy neutron reaction layer 11, and the neutron inner moderator 12. The neutron dose rate exceeds the control threshold, resulting in a detector response signal of "1." Furthermore, because the gamma-ray shielding layer 15 cannot completely block high-energy gamma photons, the photon dose rate of the high-energy gamma-ray detector assembly 8 and the low-energy gamma-ray detector assembly 9 exceeds the control threshold, resulting in detector response signals of "1." At the same time, the accelerator is in the running state, and the accelerator running state interface 3 sends a state signal of "1". Then the logic control module 21 makes a judgment and processing based on the combination of the above state signals, and sends a control signal "1" to the dose interlock device 6 to lock each accelerator protection door. At the same time, a control signal is sent to the indicator light 5 to make the indicator light 5 in "red", that is, the indicator light 5 is displayed as a red light at this time.

[0050] After the accelerator stops operating, the neutron radiation field disappears. The radiation field at this point is dominated by gamma photon radiation from the decay of activated nuclides. Activated nuclides are typically Fe-59, Co-57, and Co-58, and the gamma ray energy is generally below 2 MeV. At this point, due to the absence of neutron radiation, the dose response of the He-3 neutron counter 13 falls below the control threshold and outputs a status signal of "0." Furthermore, because the gamma ray shield 15 shields gamma rays below 2 MeV, the dose response of the high-energy gamma ray detector assembly 8 falls below the threshold and outputs a status signal of "0." Meanwhile, the low-energy gamma ray detector assembly 9 responds normally, with the radiation dose rate exceeding the control threshold and outputting a status signal of "1." Simultaneously, the accelerator is in shutdown mode, and the accelerator operating status interface 3 outputs a status signal of "0." The logic control module 21 then determines and processes the combination of these status signals, issuing a control signal of "1" to the dose interlock 6 to lock the accelerator protective doors. Simultaneously, a control signal is sent to the indicator light 5, turning it to "yellow."

[0051] As downtime increases, the photon radiation dose rate decreases due to the decay of activated nuclides in the slow-emission radiation field. When the photon radiation dose falls below the control threshold of the low-energy gamma-ray detector assembly 9, the low-energy gamma-ray detector assembly 9 emits a status signal of "0." The logic control module 21 then determines and processes the combination of these status signals, sending a control signal of "0" to the dose interlock device 6 to unlock the accelerator protective doors. Simultaneously, a control signal is sent to the indicator light 5, turning it green. This means that personnel can now enter the accelerator room.

[0052] If the status signals sent by the neutron detector assembly 7, the high energy gamma ray detector assembly 8, the low energy gamma ray detector assembly 9 and the accelerator operation status interface 3 are not the above three combinations, it means that there is a fault in the radiation dose interlock control system. Figure 2 As shown, the components that may fail can be inferred based on the combination of the status signals, so that the accelerator can be shut down as soon as the system failure occurs to avoid excessive exposure of personnel.

[0053] Compared to existing technologies, the present invention expands the detector's energy response range by utilizing a specially structured outer layer of detectors made of materials such as polyethylene, lead, and copper. This allows conventional He-3 neutron counters and GM photon counters to be used to monitor the complex radiation fields generated by accelerators. This provides an accelerator dose interlock solution for hospitals, enterprises, and other organizations that lack the capacity to independently develop high-energy response detectors, effectively preventing the potential for personnel overexposure from direct use of conventional detectors. Furthermore, due to the low cost of GM photon counters, the present invention utilizes a combination of two GM counters and one He-3 neutron counter, replacing the traditional single GM counter and one He-3 neutron counter. This achieves a redundant interlock design for the radiation dose interlock control system. Furthermore, by determining the signal relationship between the three detectors, detector system failures can be detected immediately, effectively preventing overdose accidents caused by failure of the radiation dose interlock control system. Furthermore, by integrating the detector's signal processing circuitry into an FPGA chip within the polyethylene neutron shield, separating it from the probe located in the high radiation field, the failure of electronic components due to neutron radiation damage can be effectively avoided. At the same time, by simultaneously using the detector status signal and the accelerator operation status signal emitted by the accelerator operation status interface to form the control signal for the dose interlock control and indicator light, human factors can further prevent the dose interlock system from failing due to human factors. As a result, the present invention broadens the energy response range of traditional neutron and photon detectors, solves the problem of low accelerator radiation field dose response, implements dose interlock redundancy and automatic response to system failures, and prevents interlock system failures caused by radiation damage to electronic components, ultimately avoiding overdose accidents caused by interlock system failure.

[0054] The above description is only a preferred embodiment of the present invention and does not limit the scope of the patent. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, directly or indirectly applied in other related technical fields, is also included in the scope of patent protection of the present invention.

Claims

1. A radiation dose interlock control system for an accelerator, characterized in that: The radiation dose interlock control system performs dose interlock control based on a detector signal and an accelerator operation state signal, and comprises a detector unit (1), a signal processing unit (2), an accelerator operation state interface (3), an indicator light (5), and a dose interlock device (6). The detector unit (1) is configured to detect the radiation dose in the accelerator room, wherein the radiation dose includes a neutron dose, a high-energy gamma-ray dose, and a low-energy gamma-ray dose; the accelerator operation state interface (3) is configured to provide an accelerator operation state signal, wherein the accelerator operation state signal includes operation or shutdown; the indicator light (5) is configured to indicate the accelerator operation state when the accelerator is in operation or shutdown mode. The accelerator room protective door has different working states under the control of the signal processing unit (2); the dose interlock device (6) is configured to switch the accelerator room protective door state under the control of the signal processing unit (2), and the accelerator room protective door state includes locking and unlocking; the detector unit (1), the accelerator operation state interface (3), the indicator light (5), and the dose interlock device (6) are electrically connected to the signal processing unit (2) respectively, and the signal processing unit (2) is configured to make the following judgments based on the radiation dose in the accelerator room and the accelerator operation state signal, thereby sending corresponding control signals to the indicator light (5) and the dose interlock device (6): The detector unit (1) comprises a high-energy gamma-ray detector assembly (8) for detecting a high-energy gamma-ray dose in an accelerator room, wherein the high-energy gamma-ray detector assembly (8) comprises a first GM photon counter tube (17), an X-ray shielding layer (16) made of copper, a gamma-ray shielding layer (15) made of lead, and a first detector neutron shielding layer (14) made of polyethylene, which are sequentially distributed from the inside to the outside. a. When the neutron dose, high-energy gamma-ray dose, and low-energy gamma-ray dose are all higher than their respective control thresholds, and the accelerator operation state signal is in operation, the signal processing unit (2) outputs a first control signal. Under the action of the first control signal, the indicator light (5) is in a first working state, and the dose interlock device (6) controls the accelerator room protective door to be in a locked state; b. When the neutron dose, high-energy gamma-ray dose, and low-energy gamma-ray dose are all lower than their respective control thresholds, and the accelerator operation status signal is shutdown, the signal processing unit (2) outputs a second control signal. Under the action of the second control signal, the indicator light (5) is in a second working state, and the dose interlock device (6) controls the accelerator room protective door to be in an unlocked state; c. When the neutron dose and the high-energy gamma-ray dose are both lower than their respective control thresholds, and the low-energy gamma-ray dose is higher than the corresponding control thresholds, and the accelerator operation status signal is shutdown, the signal processing system (2) outputs a third control signal. Under the action of the third control signal, the indicator light (5) is in a third working state and the dose interlock device (6) controls the accelerator room protective door to be in a locked state; d. When the neutron dose, high-energy gamma-ray dose, low-energy gamma-ray dose and accelerator operation status signals do not satisfy the three conditions a, b and c, the signal processing unit (2) outputs a fourth control signal. Under the action of the fourth control signal, the indicator light (5) is in the fourth working state and the dose interlock device (6) controls the state of the accelerator room protective door to be in the locked state.

2. The radiation dose interlock control system for an accelerator according to claim 1, characterized in that: The detector unit (1) further comprises a neutron detector assembly (7) and a low-energy gamma-ray detector assembly (9); the neutron detector assembly (7) is configured to detect the neutron dose in the accelerator room; and the low-energy gamma-ray detector assembly (9) is configured to detect the low-energy gamma-ray dose in the accelerator room.

3. The radiation dose interlock control system for an accelerator according to claim 2, characterized in that: The neutron detector assembly (7) comprises a He-3 neutron counter tube (13), a polyethylene inner neutron moderation layer (12), a lead high-energy neutron reaction layer (11), and a polyethylene outer neutron moderation layer (10), which are sequentially distributed from the inside to the outside.

4. The radiation dose interlock control system for an accelerator according to claim 2, characterized in that: The low-energy gamma-ray detector assembly (9) comprises a second GM photon counter tube (19) and a second detector neutron shielding layer (18) made of polyethylene, which are sequentially distributed from the inside to the outside.

5. The radiation dose interlock control system for an accelerator according to claim 1, characterized in that: The signal processing unit (2) comprises an electronic component neutron protection housing (20) and an FPGA-based logic control module (21).

6. The radiation dose interlock control system for an accelerator according to claim 5, characterized in that: The logic control module (21) includes an MC8051 soft core (22) and three detector pulse counters (23), wherein the three detector pulse counters (23) are arranged in a one-to-one correspondence with the neutron detector assembly (7), the high-energy gamma-ray detector assembly (8), and the low-energy gamma-ray detector assembly (9); the MC8051 soft core (22) is electrically connected to the three detector pulse counters (23), the accelerator operation status interface (3), the indicator light (5), and the dose interlock device (6), respectively; the MC8051 soft core (22) is configured to perform logic judgment based on the signals sent by the three detector pulse counters (23) and the accelerator operation status interface (3), thereby outputting corresponding control signals to the indicator light (5) and the dose interlock device (6).

7. The radiation dose interlock control system for an accelerator according to claim 1, characterized in that: The radiation dose interlock control system further comprises a PC (4), the PC (4) being electrically connected to the signal processing system (2), the PC (4) being configured to set a detector dose conversion coefficient and / or a dose control threshold and / or a detector calibration parameter, and to store radiation detector history data and / or control signal history data, and to display an operating status of the radiation dose interlock control system.

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