Microwave source time-multiplexed ray generating device and method of use and application

Abstract

The application relates to a ray generating device using time division multiplexing of a microwave source and a use method and application, and belongs to the technical field of accelerators. The ray generating device using time division multiplexing of the microwave source comprises a microwave source for generating microwaves, a circulator, a plurality of accelerating tubes and a pulse modulator. The circulator comprises a power input port and at least two power output ports. The power input port is connected with the microwave source. The plurality of accelerating tubes are connected with different power output ports. The resonance frequency ranges of the plurality of accelerating tubes do not overlap with each other. The pulse modulator is connected with a particle source and the microwave source respectively. The particle source is connected with the accelerating tube. The pulse modulator provides pulse power required by the microwave source for generating microwaves with different frequency ranges. The application provides microwave power with different frequency ranges for a plurality of accelerating tubes through time division multiplexing of one microwave source, thereby saving construction cost and space.

Description

Technical Field

[0001] This invention belongs to the field of accelerator technology, specifically relating to a microwave source time-division multiplexing ray generation device, its usage method, and its application. Background Technology

[0002] Flash radiotherapy is a promising radiotherapy method characterized by delivering a high dose of radiation in a very short time. The average and peak doses of X-rays (or other types of radiation) must meet certain requirements to achieve the therapeutic effect. For example, achieving a cumulative X-ray dose of >40 Gy within 1 second. Various approaches can be used, including room-temperature radiofrequency linear accelerators, induction accelerators, laser plasma accelerators, and superconducting accelerators, with room-temperature radiofrequency linear accelerators being the most common. One technical approach involves using multiple radiofrequency accelerators, evenly arranged along the spatial axis and directed towards the axis to achieve an ultra-high dose rate in the central region. However, a drawback is that multiple radiofrequency accelerators constitute multiple accelerator systems, each requiring a separate microwave power source, resulting in high costs. Summary of the Invention

[0003] In view of the various shortcomings of the existing technology, and in order to solve the above problems, a microwave source time-division multiplexing radiation generation device, its usage method and application are proposed.

[0004] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a time-division multiplexing microwave source radiation generating apparatus, comprising: A microwave source, used to generate microwaves; A circulator includes a power input port and at least two power output ports, the power input port being connected to the microwave source; Multiple acceleration tubes are connected to different power output ports. The device includes a pulse modulator connected to a particle source and a microwave source, respectively. The particle source is connected to the accelerating tubes. The pulse modulator provides the microwave source with the pulse power required to generate microwaves of different frequency ranges. During the process of the microwave accelerating the particle beam emitted by the particle source to form a ray, the multiple accelerating tubes operate at the same temperature and their resonant frequency ranges do not overlap, meaning that the multiple accelerating tubes have different structures.

[0005] The present invention is further configured such that the beam exit directions of the multiple accelerating tubes are different, and the beam exit direction is the radiation direction of the rays generated by the accelerating tubes.

[0006] The present invention is further configured such that the power output port has three, two of which are connected to different accelerating tubes, and the remaining power output port is connected to a microwave absorbing load.

[0007] The present invention is further configured such that the circulator includes a primary circulator and a secondary circulator. The primary circulator has three power output ports, two of which are connected to different accelerator tubes, and the remaining power output port is connected to the power input port of the secondary circulator. The secondary circulator has at least two power output ports, and the power output ports of the secondary circulator are connected to different accelerator tubes.

[0008] The present invention is further configured such that the power output ports of the secondary circulator are configured to be two, and the two power output ports of the secondary circulator are connected to different acceleration tubes respectively.

[0009] The present invention is further configured such that the power output ports of the secondary circulator are configured to be three, and the three power output ports of the secondary circulator are connected to different acceleration tubes respectively.

[0010] The present invention is further configured such that the resonant frequency range of the accelerating tube includes a loaded beam-out resonant frequency range and an unloaded beam-out resonant frequency range, and the beam-out center resonant frequency of the accelerating tube under loaded conditions is set to f. bc The on-load Q value of the accelerator tube is Q. bc The resonant frequency range of the accelerator tube with the output beam is then... The resonant frequency of the beam exit center of the accelerator tube under no-load conditions is set to f. bcN The no-load Q value is Q bcN The range of resonant frequencies without load is: .

[0011] Secondly, the present invention provides a method for using a microwave source time-division multiplexing ray generating device, comprising the following steps: Based on the target radiation direction of the rays within the current time period, determine the accelerator tube that needs to be used and designate that accelerator tube as the target accelerator tube; A microwave source generates microwaves with a frequency range that matches the resonant frequency range of the target accelerating tube, and a pulse modulator synchronously applies a high-voltage pulse to a particle source connected to the target accelerating tube. Microwaves are transmitted to the target accelerating tube via a circulator and accelerate the particle beam emitted by the particle source to form rays; Based on the target radiation direction of the rays in the next time period, the accelerating tubes that need to work are re-determined, and the above steps are repeated to achieve time-division multiplexing of the microwave source.

[0012] The present invention is further configured such that there are multiple accelerating tubes, and the multiple accelerating tubes have different beam emission directions, the beam emission direction being the radiation direction of the rays generated by the accelerating tubes, and all of the multiple accelerating tubes except the target accelerating tube are non-target accelerating tubes, the target accelerating tube and the non-target accelerating tubes having the same operating temperature.

[0013] The present invention is further configured such that the microwave source generates microwaves with a frequency range matching the resonant frequency range of the target accelerating tube, specifically: The resonant frequency range of the accelerating tube includes the resonant frequency range with the beam carried out and the resonant frequency range without the beam carried out. The center frequency of the microwave is equal to the center resonant frequency of the loaded beam, the frequency range of the microwave is within the resonant frequency range of the loaded beam of the target accelerating tube, and the frequency range of the microwave is outside the resonant frequency range of the unloaded beam of the non-target accelerating tube.

[0014] The present invention is further configured such that, under load, the resonant frequency of the beam output center of the accelerating tube is f. bc The on-load Q value of the accelerator tube is Q. bc The resonant frequency range of the accelerator tube with the output beam is then... The resonant frequency of the beam output center of the accelerator tube under no-load conditions is set to f. bcN The no-load Q value is Q bcN The range of resonant frequencies without load is: .

[0015] The present invention is further configured such that the microwaves are transmitted to the target accelerating tube via a circulator, specifically: The microwaves are transmitted directly to the target accelerating tube via the power output port of the circulator; Alternatively, the microwave is transmitted to the non-target accelerating tube via the power output port of the circulator, the non-target accelerating tube reflects the microwave back to the circulator, and the microwave is transmitted again via different power output ports until it reaches the target accelerating tube.

[0016] Thirdly, the present invention provides an application of a microwave source time-division multiplexing ray generating device in flash radiotherapy.

[0017] The beneficial effects of this invention are: 1. A single microwave source can be time-division multiplexed to provide microwave power of different frequency ranges to multiple accelerator tubes, saving construction costs and space.

[0018] 2. By utilizing the narrow-band characteristics of the accelerator tube, the microwave transmission path driving the target accelerator tube can be switched by changing the center frequency of the microwave output from the microwave source.

[0019] 3. The multiple accelerator tubes have different beam output directions, which are the radiation directions of the rays generated by the accelerator tubes, thus meeting the radiation requirements of multiple viewing angles.

[0020] 4. The microwave absorbing load can absorb the microwaves output from its corresponding power output port to achieve isolation and prevent microwaves from returning to the circulator's power input port. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a conventional accelerator; Figure 2 This is a schematic diagram of one embodiment of the time-division multiplexing ray generating device of the microwave source in this invention; Figure 3 This is a schematic diagram of another embodiment of the time-division multiplexing ray generating device of the microwave source in this invention; Figure 4 This is a schematic diagram illustrating the usage method of the time-division multiplexing ray generation device of the microwave source in this invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments in this application, other similar embodiments obtained by those skilled in the art without creative effort should all fall within the scope of protection of this application. Furthermore, directional terms mentioned in the following embodiments, such as "up," "down," "left," and "right," are only for reference to the directions in the accompanying drawings; therefore, the directional terms used are for illustrative purposes and not for limiting the invention.

[0023] Example 1: like Figure 1 As shown, a conventional accelerator typically consists of a microwave source, a circulator, a transmission waveguide, an accelerating tube, a cooling system, and a control system. The circulator is generally a four-port circulator, but a three-port circulator can also be used. If a four-port circulator is used, the first port is connected to the microwave input, the second port to the accelerating tube, and the third and fourth ports to the microwave absorbing load. If a three-port circulator is used, the first port is connected to the microwave input, the second port to the accelerating tube, and the third port to the microwave absorbing load.

[0024] Accelerator tubes are narrowband vacuum microwave devices with a beam-out center resonant frequency f. bc The relationship between the Q value of the vacuum device and the Q value is as follows: , where Δf bc This indicates the bandwidth of the accelerating tube. When the beam is emitted, the Q value of the accelerating tube is generally above 5000. For a current 2998MHz S-band accelerating tube, the bandwidth for the beam emission frequency is approximately 600kHz.

[0025] Taking a klystron as a microwave source as an example, the specific working process of an accelerator is explained: The pulse modulator simultaneously generates high-voltage pulses to drive the klystron, the accelerator tube, and the electron gun, as well as a synchronization signal to control the microwave source. Under the drive of the high-voltage pulse power, the klystron outputs a center frequency of f1 and a bandwidth of [missing value]. The microwave signal is amplified to make the klystron output center frequency f1 and bandwidth... High-power microwaves, ranging from several MW to tens of MHz, enter an accelerating tube via a circulator. The electron gun in the accelerating tube emits an electron beam driven by a high-voltage pulse. This electron beam enters the accelerating tube (at this time, the accelerating tube is under load). If the resonant frequency f of the beam output center in the accelerating tube under load is... bc If the frequency f1 is equal to the center frequency of the high-power microwave, then the accelerating tube will accelerate the electron beam emitted by the electron gun to several MeV or tens of MeV.

[0026] like Figure 2 As shown, compared to conventional accelerators, the present invention provides a microwave source time-division multiplexing ray generating device, including a microwave source, a circulator, multiple accelerating tubes, and a pulse modulator.

[0027] Specifically, a microwave source is used to generate microwaves; preferably, the microwave excitation source is connected to a klystron to generate microwaves. The circulator includes a power input port and at least two power output ports, the power input port being connected to the microwave source. Multiple accelerating tubes are connected to different power output ports, and the resonant frequency ranges of the multiple accelerating tubes do not overlap. Furthermore, the beam emission directions of the multiple accelerating tubes are different, the beam emission direction being the radiation direction of the rays generated by the accelerating tubes. A pulse modulator is connected to both the particle source and the microwave source, the particle source being connected to the accelerating tubes, and the pulse modulator providing the pulse power required for the microwave source to generate microwaves in different frequency ranges.

[0028] The microwave source time-division multiplexing X-ray generating device can be used for flash radiotherapy. When the particle source is an electron gun, it can generate an electron beam to bombard the conversion target and produce X-rays. During the actual operation of the accelerating tube, the center frequency f1 and corresponding bandwidth of the microwaves generated by the microwave source... The following relationship must be satisfied: In this case, most of the microwaves will be absorbed by the accelerator tube.

[0029] Specifically, the resonant frequency of the beam output center of the accelerator tube is set to f. bc The on-load Q value of the accelerator tube is Q. bc If the microwave center frequency driving the accelerator tube is in Within this range, the accelerator tube accelerates the particle beam emitted from the particle source. Under no-load conditions, the accelerator tube's output beam center resonant frequency f...bcN It will be more than f bc Slightly lower, but, no-load Q bcN The value is relatively high, reaching over 10,000. If the microwave center frequency driving the accelerator tube is not... Within this range, most microwaves will be reflected by the accelerating tube. That is, the resonant frequency range of the accelerating tube includes both the resonant frequency range with the output beam and the resonant frequency range without the output beam. The resonant frequency range with the output beam of the accelerating tube is... The range of resonant frequencies without load and without beam is: That is, the resonant frequency ranges of multiple accelerator tubes do not overlap with each other, including the resonant frequency ranges with loaded beams do not overlap with each other, and the resonant frequency ranges with loaded beams and those without loaded beams do not overlap with each other.

[0030] Preferably, the power output port is provided with three ports, two of which are connected to different accelerating tubes, and the remaining power output port is connected to a microwave absorbing load.

[0031] like Figure 3 As shown, in some other embodiments, the circulator includes a primary circulator and a secondary circulator. The primary circulator has three power output ports, two of which are connected to different accelerator tubes, and the remaining power output port is connected to the power input port of the secondary circulator. The secondary circulator has at least two power output ports, and the power output ports of the secondary circulator are connected to different accelerator tubes.

[0032] Preferably, the secondary circulator has two power output ports, and the two power output ports of the secondary circulator are connected to different accelerator tubes. Preferably, the secondary circulator has three power output ports, and the three power output ports of the secondary circulator are connected to different accelerator tubes.

[0033] Figure 2 and Figure 3 The number of accelerating tubes varies. Taking a klystron as a microwave source as an example, under the premise of a certain bandwidth, the maximum number of accelerating tubes that a klystron can theoretically drive can be determined in the following way: Assume the bandwidth of the klystron is Δf kr The bandwidth corresponding to the beam resonant frequency of the accelerator tube under no-load conditions is Δf. bcN Considering a certain interval, the bandwidth is Δf kr Theoretically, the maximum number N of accelerator tubes that a klystron can drive is related to the bandwidth of the klystron and the bandwidth of the unloaded accelerator tubes as follows: 。

[0034] For example, the 1dB bandwidth of a 2998MHz high-power klystron is generally no less than 3MHz, and the Q of the accelerating tube under no-load conditions is... bcN The value will reach over 10,000, and the no-load beam bandwidth is less than 0.3MHz. Therefore, a klystron with a bandwidth of 3MHz can theoretically drive about 5 2998MHz acceleration tubes.

[0035] like Figure 4 As shown, a method of using a microwave source time-division multiplexing ray generating device includes the following steps: S100. Based on the target radiation direction of the rays in the current time period, determine the accelerating tube that needs to work, and use the accelerating tube as the target accelerating tube. The target accelerating tube can generate rays that conform to the target radiation direction in the current time period.

[0036] There are multiple accelerator tubes, and the beam emission directions of the multiple accelerator tubes are different. The beam emission direction is the radiation direction of the rays generated by the accelerator tube. Except for the target accelerator tube, all of the multiple accelerator tubes are used as non-target accelerator tubes.

[0037] Specifically, the resonant frequency range of the accelerating tube includes the resonant frequency range with the loaded beam and the resonant frequency range without the loaded beam. The microwave source generates microwaves with a center frequency that is the same as the center resonant frequency with the loaded beam. The frequency range of the microwaves is within the resonant frequency range with the loaded beam of the target accelerating tube, and the frequency range of the microwaves is outside the resonant frequency range without the loaded beam of the non-target accelerating tube.

[0038] S200, a microwave source generates microwaves with a frequency range matching the resonant frequency range of the target accelerating tube, and a pulse modulator synchronously applies a high-voltage pulse to a particle source connected to the target accelerating tube.

[0039] S300, microwaves are transmitted to the target accelerating tube via a circulator and accelerate the particle beam emitted by the particle source to form rays.

[0040] Specifically, the microwave is transmitted directly to the target accelerator tube via the power output port of the circulator. Alternatively, the microwave is transmitted to the non-target accelerator tube via the power output port of the circulator, the non-target accelerator tube reflects the microwave back to the circulator, and the microwave is transmitted again via different power output ports until it reaches the target accelerator tube.

[0041] S400: Based on the target radiation direction of the ray in the next time period, redetermine the accelerating tube that needs to work, and use the redetermined accelerating tube that needs to work as the target accelerating tube. Repeat steps S200 to S300 to realize time-division multiplexing of microwave source.

[0042] Example 2: like Figure 3As shown, four accelerator tubes (accelerator tube A, accelerator tube B, accelerator tube C, and accelerator tube D) can output rays that are uniformly distributed in four directions at 90-degree intervals. The resonant frequency ranges of the four accelerator tubes do not overlap, and the resonant frequencies of the beam exit centers are spaced 0.75MHz apart. 0.75MHz is approximately twice the resonant frequency of the beam exit center of the accelerator tube.

[0043] Let's take the 2998MHz S-band accelerator as an example to illustrate the entire working process: Let the start time of beam emission be T0, and the center frequency of the microwave source output be f during the time interval from T0 to T1. A1 The microwave, after being amplified by a klystron, is sent to the power input port a of the first-stage circulator, and the microwave is output from the power output port b, with the center resonant frequency of the output beam equal to f. A1 Accelerator tube A is activated, and at the same time, the particle source connected to accelerator tube A is simultaneously subjected to a high-voltage pulse and outputs a particle beam. Meanwhile, the particle sources connected to accelerator tubes B, C and D are not subjected to a high-voltage pulse (they are in an unloaded state). At this time, only accelerator tube A outputs rays.

[0044] At times T1 to T2, the center frequency of the microwave source output is f. B1 The microwave, after being amplified by the klystron, is sent to the power input port a of the first-stage circulator, and then transmitted to the accelerating tube A through the power output port b. Due to f B1 Not located within the resonant frequency range of the loaded beam of accelerating tube A, and f B1 Since the microwave is not located within the no-load non-beam resonant frequency range of accelerating tube A, it will be entirely transmitted back to the power output port b of the first-stage circulator. From there, it is output from the power output port c of the first-stage circulator, then sent to the power input port a' of the second-stage circulator. From the power output port b' of the second-stage circulator, the microwave is output to the beam center resonant frequency, which is equal to f. B1 Accelerator tube B is connected to the particle source connected to accelerator tube B. At this time, accelerator tubes A, C and D are in an unloaded state, and only accelerator tube B outputs rays.

[0045] At times T2 to T3, the center frequency of the microwave source output is f. C1 The microwave, after being amplified by the klystron, is sent to the power input port a of the first-stage circulator, and then transmitted to the accelerating tube A through the power output port b. Due to f C1 Not located within the resonant frequency range of the loaded beam of accelerating tube A, and f C1Since the microwave is not located within the no-load non-beam resonant frequency range of accelerating tube A, it will be entirely emitted back to the power output port b of the first-stage circulator, and output from the power output port c of the first-stage circulator. This microwave is then sent to the power input port a' of the second-stage circulator, and output to accelerating tube B via the power output port b' of the second-stage circulator. Because f C1 Not located within the resonant frequency range of the loaded beam of accelerator tube B, and f C1 Since the microwave is not located within the no-load non-beam resonant frequency range of accelerating tube B, it will be totally reflected back to the power output port b' of the second-stage circulator, and then output through the power output port c' of the second-stage circulator to the beam center resonant frequency equal to f. C1 Accelerator tube C is connected to the particle source connected to accelerator tube C. At this time, accelerator tubes A, B and D are in an unloaded state. Only accelerator tube C outputs rays.

[0046] At times T3 to T4, the center frequency of the microwave source output is f. D1 The microwave, after being amplified by a klystron, will follow the following path: power output port b of the first-stage circulator -> accelerator tube A -> power output port b of the first-stage circulator -> power output port c of the first-stage circulator -> power input port a' of the second-stage circulator -> power output port b' of the second-stage circulator -> accelerator tube B -> power output port b' of the second-stage circulator -> power output port c' of the second-stage circulator -> accelerator tube C -> power output port c' of the second-stage circulator -> power output port d' of the second-stage circulator -> beam center frequency equal to f D1 Accelerator tube D is connected to the particle source connected to accelerator tube D. At this time, accelerator tubes A, B and C are in an unloaded state, and only accelerator tube D outputs rays.

[0047] Furthermore, when the center frequency of the microwaves output by the microwave source is not within the resonant frequency range of each accelerating tube, the microwaves will be transmitted to the power output port d of the first-stage circulator and absorbed by the microwave absorption load.

[0048] The present invention has been described in detail above. The above description is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of this application should still fall within the scope of the present invention.

Claims

1. A time-division multiplexing radiation generating device for a microwave source, comprising a microwave source, a circulator, an accelerating tube, and a pulse modulator, characterized in that, The acceleration tubes are configured as multiple tubes, and the multiple acceleration tubes are respectively connected to different power output ports of the circulator, and the resonant frequency ranges of the multiple acceleration tubes do not overlap. The accelerator tube includes a target accelerator tube and non-target accelerator tubes. The target accelerator tube is the accelerator tube that needs to work. Among the multiple accelerator tubes, all except the target accelerator tube are non-target accelerator tubes. In the initial state, the target accelerator tube and the non-target accelerator tubes have the same operating temperature. The pulse modulator is connected to the microwave source to provide the pulse power required for the microwave source to generate microwaves in different frequency ranges. The resonant frequency range of the accelerating tube includes the resonant frequency range with the loaded beam and the resonant frequency range without the loaded beam. The center frequency of the microwave is equal to the center resonant frequency with the loaded beam. The frequency range of the microwave is within the resonant frequency range with the loaded beam of the target accelerating tube, and the frequency range of the microwave is outside the resonant frequency range without the loaded beam of the non-target accelerating tube. The microwave source is time-division multiplexed to provide microwave power of different frequency ranges to multiple accelerating tubes. During the process of the microwave accelerating the particle beam emitted by the particle source to form a ray, the target accelerating tube and the non-target accelerating tube have the same operating temperature, and the beam output direction of the multiple accelerating tubes is different. The beam output direction is the radiation direction of the ray generated by the accelerating tube, which meets the radiation requirements of multiple angles in flash radiotherapy.

2. The microwave source time-division multiplexing radiation generating device according to claim 1, characterized in that, The power output port is provided with three ports, two of which are connected to different accelerating tubes, and the remaining power output port is connected to a microwave absorption load.

3. The microwave source time-division multiplexing radiation generating device according to claim 1, characterized in that, The circulator includes a primary circulator and a secondary circulator. The primary circulator has three power output ports, two of which are connected to different accelerator tubes, and the remaining power output port is connected to the power input port of the secondary circulator. The secondary circulator has at least two power output ports, and each power output port of the secondary circulator is connected to a different accelerator tube.

4. A method of using a radiation generating device employing time-division multiplexing of a microwave source as described in any one of claims 1-3, characterized in that, Includes the following steps: Based on the target radiation direction of the rays within the current time period, determine the accelerator tube that needs to be used and designate that accelerator tube as the target accelerator tube; A microwave source generates microwaves with a frequency range that matches the resonant frequency range of the target accelerating tube, and a pulse modulator synchronously applies a high-voltage pulse to a particle source connected to the target accelerating tube. Microwaves are transmitted to the target accelerating tube via a circulator and accelerate the particle beam emitted by the particle source to form rays; Based on the target radiation direction of the rays in the next time period, the accelerating tubes that need to work are re-determined, and the above steps are repeated to achieve time-division multiplexing of the microwave source.

5. The method of using the microwave source time-division multiplexing radiation generating device according to claim 4, characterized in that, The accelerator tube is set to have a beam center resonant frequency of f under load. bc The on-load Q value of the accelerator tube is Q. bc The resonant frequency range of the accelerator tube with the output beam is then... The resonant frequency of the beam output center of the accelerator tube under no-load conditions is set to f. bcN The no-load Q value is Q bcN The range of resonant frequencies without load is: .

6. The method of using the microwave source time-division multiplexing radiation generating device according to claim 4, characterized in that, The microwaves are transmitted to the target accelerating tube via a circulator, specifically as follows: The microwaves are transmitted directly to the target accelerating tube via the power output port of the circulator; Alternatively, the microwave is transmitted to the non-target accelerating tube via the power output port of the circulator, the non-target accelerating tube reflects the microwave back to the circulator, and the microwave is transmitted again via different power output ports until it reaches the target accelerating tube.

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