CN202019491U - Continuously Variable Energy Standing Wave Irradiation Accelerator - Google Patents

Abstract

The utility model relates to a standing wave irradiation accelerator with continuously variable energy, which comprises an accelerating cavity section, an electronic gun and a peripheral system, wherein the accelerating cavity section comprises a low-speed accelerating cavity section and a high-speed accelerating cavity section which are connected through beam tubes and are provided with power couplers; the peripheral system comprises a power amplifier, a first loop device, a first direction coupler and a first power divider which are connected in sequence; the first power divider is connected with a second loop device and a second power divider; the second power divider is connected with a third loop device and a high-frequency load; the third loop device is connected with a third direction coupler which is connected with an accelerator; the second loop device is connected with a second direction coupler; the power amplifier, the first direction coupler, the first power divider, the second power divider, the second direction coupler, the third direction coupler and the accelerator are respectively connected with a low-level control system; and the second direction coupler is connected with the accelerator. The standing wave irradiation accelerator disclosed by the utility model has the advantages of simple and compact structure, and high beam current quality, and can continuously adjust the energy in large range.

Description

Continuously Variable Energy Standing Wave Irradiation Accelerator

technical field

The utility model relates to a standing wave irradiation accelerator with continuously variable energy.

Background technique

Like cobalt source irradiation, the irradiation accelerator has the characteristics of normal temperature, no damage, no residual toxicity, environmental protection, low energy consumption, easy operation, high degree of automation, and is suitable for large-scale industrial production. Compared with the cobalt source, its biggest advantage is that the irradiation beam is concentrated and oriented, the energy is fully utilized, the irradiation efficiency is high, and no radioactive waste is produced. With the soaring price of cobalt sources and the rising cost of waste source treatment, electron accelerator irradiators have obvious price and economic advantages.

Different irradiating objects require electron beams of different energies. However, the output energy of the current general-purpose irradiation accelerators either cannot be changed; or the range of change is very small and cannot be changed continuously. Most importantly, the energy change operation process is very cumbersome, non-professionals cannot operate, and there are potential safety hazards. Therefore, multi-purpose users are in urgent need of an irradiation accelerator that can provide continuous changes in output energy.

Utility model content

In order to overcome the problems existing in the above-mentioned prior art, the purpose of this utility model is to provide a standing wave irradiation accelerator with continuously variable energy, which can output electron beams with continuously changing energy in a wide range, and the energy changing operation process is simple, which solves the problem of Problems existing in the prior art.

In order to achieve the above object, the technical solution adopted by the utility model is that the energy continuously variable standing wave irradiation accelerator includes an acceleration chamber section 24, an electron gun 13 and the peripheral system of the acceleration chamber section, and the acceleration chamber section 24 includes a beam tube 20 connected to each other. The low-speed accelerating cavity section 8 and the high-speed accelerating cavity section 10; the low-speed accelerating cavity section 8 and the high-speed accelerating cavity section 10 are respectively provided with power couplers; the peripheral system of the accelerator includes a power amplifier 1 and a first looper 2 connected in sequence , the first direction coupler 3 and the first power divider 4, the first power divider 4 is connected with the second looper 22 and the second power divider 21 respectively; the second power divider 21 is connected with the third loop respectively The looper 23 is connected with the high frequency load 5; the third looper 23 is connected with the third directional coupler 15, and the third directional coupler 15 is connected with the accelerating cavity section 24; the second looper 22 is connected with the second The directional coupler 14 is connected; the power amplifier 1, the first directional coupler 3, the first power divider 4, the second power divider 21, the second directional coupler 14, the third directional coupler 15 and the accelerating cavity section 24 They are respectively connected with the low-level control system 12 ; the second directional coupler 14 is also connected with the acceleration cavity section 24 .

The first power divider 4 is a computer-controlled continuously adjustable power divider.

The second power divider 21 is a computer-controlled continuously adjustable power divider.

The low-velocity accelerating cavity section 8 adopts a side-coupled cavity accelerating cavity.

The high-speed accelerating cavity section 10 adopts a side-coupled cavity accelerating cavity.

The utility model standing wave irradiation accelerator has the following advantages:

1) High shunt impedance and high acceleration efficiency.

2) High beam quality (low energy divergence).

3) Compact and simple structure.

4) There is no need for manual adjustment, the variable energy can be automatically controlled, and the energy can be continuously adjusted.

5) The variable energy operation is simple and safe, and non-professionals can perform continuous variable energy operations.

6) Large energy variation range.

Description of drawings

Figure 1 is a graph showing the relationship between electron energy and electron relativistic velocity β.

Fig. 2 is a structural schematic diagram of the radiation accelerator of the present invention.

Fig. 3 is a schematic diagram of the structure of the accelerating chamber section in the radiation accelerator of the present invention.

FIG. 4 is a rear view of FIG. 3 .

Fig. 5 is a right side view of Fig. 3 .

In the figure: 1. Power amplifier, 2. The first looper, 3. The first direction coupler, 4. The first power divider, 5. High-frequency load, 6. High-speed acceleration cavity segment power coupler, 7. Power coupler for low-speed accelerating cavity, 8. Low-speed accelerating cavity, 9. First field probe, 10. High-speed accelerating cavity, 11. Second field probe, 12. Low-level control system, 13. Electron gun, 14. Second directional coupler, 15. Third directional coupler, 16. Accelerating cavity, 17. Coupling cavity, 18. Low-speed accelerating cavity section power coupling hole, 19. High-speed accelerating cavity section power coupling hole, 20. Bundle tube , 21. The second power divider, 22. The second circulator, 23. The third circulator, 24. The acceleration chamber section.

Detailed ways

The utility model will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

The speed of the beam coming out of the electron gun of the irradiation accelerator is lower than the speed of light, and a low-speed acceleration section is required to accelerate the beam and increase its energy so that the speed of the beam is close to the speed of light (energy of about 1.0 MeV), as shown in Figure 1 As shown, β=v/c in the figure, where v is the speed of electrons; c is the speed of light. Then re-accelerate through the high-speed acceleration section, and finally make the beam current reach the designed energy. The simplest way to change the energy is to change the acceleration gradient of the accelerator by controlling the input power, so as to achieve the purpose of changing the energy gain. The disadvantage of this method is that the increase in energy dissipation will lead to the deterioration of the beam quality, and even the electrons cannot be effectively accelerated. . The general-purpose irradiation accelerator is optimized for electron beams with specific energy. After reducing the input power, the acceleration gradient of the entire accelerator is reduced, so that electrons cannot be effectively accelerated in the low-energy section, and the subsequent acceleration section cannot be accelerated. , and longitudinally focus the beam. In the end, the energy dissipation is very large.

In order to overcome the problem of large radiation accelerator energy dispersion, U.S. Patents U.S. Pat. No. 2920228 and U.S. Pat. No. 3070726 disclose a radiation accelerator. The irradiation accelerator uses two sections of traveling wave accelerators to accelerate electron beams. The first section of traveling wave accelerators accelerates electron beams to near the speed of light, and the second section of traveling wave accelerators achieves the purpose of changing the energy gain by changing the high-frequency phase of the accelerator. Since the accelerator uses a traveling wave acceleration structure, if the input power cannot be absorbed by the beam, it must be wasted. In addition, the shunt impedance of the traveling wave acceleration structure is lower than that of the standing wave edge coupling cavity, and the power loss is large; the acceleration efficiency of the accelerator is low.

In order to solve the problem of low efficiency of the above-mentioned traveling wave variable power accelerator, U.S. Patent U.S. Pat. No. 4118653 discloses another kind of irradiation accelerator, which adopts a structure combining traveling wave and standing wave, which improves the acceleration of the accelerator. efficiency. However, the accelerator requires two acceleration structures, resulting in scattered structures and complex peripheral circuits. In order to obtain a compact acceleration structure, U.S. Pat. No. 4024426 proposes a space-side coupling standing wave accelerator, which can change the energy gain by changing the phase difference between the accelerators. However, the structure of the standing wave accelerator is complex and the process is difficult, so no one has adopted it at present.

In order to obtain a simple acceleration structure and high acceleration efficiency, U.S. Pat. No. 4286192 discloses an accelerator, which adds an adjustable phase perturbation to the side-coupled cavity of the side-coupled linear accelerator Rod (the perturbation rod and the side coupling cavity are sealed with bellows), the phase of the acceleration cavity in the high acceleration section is adjusted by changing the insertion depth of the perturbation rod, and the energy gain is changed. Due to the limited phase adjustment of the perturbation bar, the range of energy gain of the accelerator cannot be changed very much; moreover, manual adjustment is required every time, the procedure is complicated, and it is not easy for non-professionals to operate.

In order to increase the phase adjustment effect of the perturbation rod in the above-mentioned accelerator, the US Patent U.S. Pat. No. 4382208 has improved the above-mentioned accelerator, and set an adjustable phase micrometer on both sides of the side-coupled cavity of the side-coupled linear accelerator. Spoiler. However, the energy gain range of the accelerator is still not very large; manual adjustment is required every time, the procedure is complicated, and it is not easy for non-professionals to operate.

In order to solve the problems of complex structure, small energy variation range and complicated operation procedures of the existing variable energy irradiation accelerators, the utility model provides a combination of connected low-speed side coupling cavity groups (the electron beam from the electron gun is accelerated to 1.0 MeV ) and high-speed side-coupling cavity group, there is no coupling between the low-speed side-coupling cavity group and the high-speed side-coupling cavity group. The structure of the standing-wave radiation accelerator, as shown in Figure 2, includes sequentially The power amplifier 1, the first looper 2, the first direction coupler 3 and the first power divider 4; the first power divider 4 is connected with the second looper 22 and the second power divider 21 respectively; The second power divider 21 is connected with the third circulator 23 and the high-frequency load 5 respectively; catch. The second circulator 22 is connected to the second directional coupler 14 . The power amplifier 1, the first directional coupler 3, the first power divider 4, the second power divider 21, the second directional coupler 14, the third directional coupler 15 and the accelerator 24 are connected with the low-level control system 12 respectively. connection; the second directional coupler 14 is also connected to the acceleration cavity segment 24 .

Both the first power divider 4 and the second power divider 21 are computer-controlled continuously adjustable power dividers.

As shown in Fig. 3, Fig. 4 and Fig. 5, the structure of the accelerating chamber section 24 in the standing wave irradiation accelerator of the present invention includes the connected low-speed accelerating chamber section 8 and the high-speed accelerating chamber section 10, the low-speed accelerating chamber section 8 and the high-speed accelerating chamber section Accelerating chamber sections 10 are all provided with coupling chambers 17 coupled to each other; the other end of low-speed accelerating chamber section 8 is provided with electron gun 13, and electron gun 13 communicates with accelerating chamber 16 in low-speed accelerating chamber section 8; The chamber 16 is connected to the acceleration chamber 16 in the low-speed acceleration chamber section 8 through the beam tube 20; the acceleration chamber 16 adjacent to the high-speed acceleration chamber section 10 in the low-speed acceleration chamber section 8 is respectively provided with a low-speed acceleration chamber section power coupling hole 18 and The first field probe 9 and the power coupling hole 18 of the low-velocity accelerating cavity section are connected to the power coupler 7 of the low-velocity accelerating cavity section. In the high-speed accelerating cavity section 10, the accelerating cavity 16 adjacent to the low-speed accelerating cavity section 8 is provided with a high-speed accelerating cavity section power coupling hole 19, and the high-speed accelerating cavity section power coupling hole 19 is connected with the high-speed accelerating cavity section power coupler 6; A second field probe 11 is installed on the acceleration chamber 16 disposed at the end of the acceleration chamber section 10 away from the low-velocity acceleration chamber section 8 .

The power coupler 6 of the high-speed accelerating cavity section is connected to the third directional coupler 15 ; the power coupler 7 of the low-speed accelerating cavity section is connected to the second directional coupler 14 . The first field probe 9 and the second field probe 11 are respectively connected to the low-level control system 12 .

Since the relationship between the acceleration gradient Ea of the standing wave accelerating cavity and the input power Pin is: Ea=K(Pin)1/2 (where K is a constant related to the characteristics of the accelerating cavity), therefore, by changing the input power of the high-energy accelerating cavity can change the acceleration gradient of the high-energy acceleration cavity segment, thereby achieving the purpose of changing the energy gain.

The accelerating chamber section 24 of the radiation accelerator of the utility model is composed of a high-speed accelerating chamber section 10 and a low-speed accelerating chamber section 8, and both the high-speed accelerating chamber section 10 and the low-speed accelerating chamber section 8 adopt side-coupled cavity accelerators, so that the accelerating chamber section 24 has a high shunt impedance and high acceleration efficiency. The high-speed acceleration chamber section 10 and the low-speed acceleration chamber section 8 are connected by a beam tube 20 with a small aperture. Since the cut-off frequency of the beam tube 20 is much higher than the operating frequency of the cavity TM010 mode, there is no mutual coupling between the high-speed accelerating cavity section 10 and the low-speed accelerating cavity section 8, and the two accelerating cavity sections can change the acceleration gradient independently. Accelerating cavity section power coupler 6 and low-speed accelerating cavity section power coupler 7 respectively supply high-speed high-speed accelerating cavity section 10 and low-speed accelerating cavity section 8 high-frequency power, and can control the acceleration gradient of the two accelerating cavity sections respectively.

Determine the highest output energy E (MeV) and beam intensity Ib (mA) of the required accelerator according to user needs. Select the power source according to the required power P (kW) of the accelerator. Generally speaking, the high-frequency loss of an accelerator at room temperature is 1.2 times the beam power. Beam power Pb(kW)=E(MeV)×Ib(mA). In this way, the output power of the power source required by the accelerator should be P(kW)≈2.5×Pb(kW). Then select the power amplifier available in the market according to P(kW), so as to determine the operating frequency f and the working mode (pulse or continuous) of the accelerator. According to the accelerator output energy E (MeV), beam intensity Ib (mA), operating frequency f and operating mode, optimize and design the high-frequency and beam dynamic parameters of the low-speed accelerating cavity section 8 and the high-speed accelerating cavity section 10 respectively, and determine their power Coupling coefficient β1 (the coupling coefficient of the power coupler 7 of the low-speed accelerating cavity section) and β2 (the coupling coefficient of the power coupler 6 of the high-speed accelerating cavity section). According to the power coupling coefficients β1 and β2, the power coupling aperture is designed. Finalize the design of the accelerator cavity. According to the cavity shape design, mechanical analysis is carried out to determine the cavity wall thickness. According to the high-frequency parameters of the cavity shape, determine the power loss Pd(kW)=Vc2/[(R/Q)×Qo] of the accelerating cavity. In the formula, Vc is the total accelerating voltage of the accelerating cavity segment, for the low-speed accelerating cavity segment 8: Vc1 ≈ 1.0 MV, for the high-speed accelerating cavity 10: Vc2 ≈ (E-1.0) MV. R/Q is the geometric shunt impedance of the accelerating cavity section, which is obtained from the optimal design of the cavity shape. Qo is the quality factor of the accelerating cavity, and it is generally about 40,000 for an oxygen-free copper cavity. According to Pd(kW), the water-cooling circuit of the acceleration cavity section is designed, and the mechanical design is finally completed.

The irradiation accelerator is powered by a power source. Through the first power divider 4 , the two acceleration cavity sections have different power inputs. Through the second power divider 21 , the control of the input power of the high-speed accelerating cavity section 10 is realized. Since the first work divider 4 and the second work divider 21 are continuously adjustable, the acceleration gradient of the high-speed accelerating cavity section 10 can be continuously changed, thereby realizing continuous change of beam energy gain. The radiation accelerator is controlled by the low-level control system 12 to realize the automatic control of beam energy output, and it is no longer necessary for professionals to set the phase of the accelerator.

The acceleration gradient of the high-speed accelerating cavity section 10 can continuously change the energy gain of the electron beam with the continuous change of the input power. Therefore, a large-scale continuous change of the beam energy is realized, and it is no longer necessary to change the beam energy gain by adjusting the phase of the accelerator resonant cavity. The low-speed accelerating cavity section 8 accelerates the electron beam to near the speed of light (1.0MeV). Since the velocity of the electron beam output by the low-speed accelerating cavity section 8 is the speed of light, the energy dispersion is small; the acceleration gradient of the high-speed accelerating cavity section 10 has little influence on the beam quality of the electron beam, which ensures good quality of the electron beam.

The first field probe 9 and the second field probe 11 are used to detect the high-frequency frequency and acceleration gradient of the low-velocity acceleration cavity section 8 and the high-speed acceleration cavity section 10 respectively. The low-level control system 12 controls the resonant frequency of the accelerator, the phase and output power of the power source, and the first power divider 4 and the second power divider 21 according to the signals of the first field probe 9 and the second field probe 11 The proportion of power points is adjusted. Finally, the output energy can meet the requirements, and at the same time, the goal of high acceleration efficiency can be achieved.

The radiation accelerator of the utility model has compact and simple structure, high beam quality, and can continuously adjust energy in a wide range.

Structural design of continuously variable energy standing wave accelerator. Regardless of whether the low-speed acceleration section is one or more standing wave cavities, or whether the high-speed acceleration section has one or more standing wave acceleration cavities, as long as the two acceleration sections are connected by a beam tube, they are considered to belong to the structure of the acceleration cavity section of the accelerator. .

Claims (5)

1. A standing wave irradiation accelerator with continuously variable energy, including an acceleration cavity section (24), an electron gun (13) and a peripheral system of the acceleration cavity section, characterized in that the acceleration cavity section (24) includes a beam tube (20) The connected low-speed accelerating cavity section (8) and the high-speed accelerating cavity section (10); the low-speed accelerating cavity section (8) and the high-speed accelerating cavity section (10) are respectively equipped with power couplers; the peripheral system of the accelerating cavity section includes sequentially Connected power amplifier (1), first looper (2), first directional coupler (3) and first power divider (4), the first power divider (4) and the second loop The device (22) is connected with the second power divider (21); the second power divider (21) is connected with the third looper (23) and the high frequency load (5) respectively; the third looper ( 23) It is connected with the third directional coupler (15), and the third directional coupler (15) is connected with the accelerating cavity section (24); the second circulator (22) is connected with the second directional coupler (14) Connection; power amplifier (1), first directional coupler (3), first power divider (4), second power divider (21), second directional coupler (14), third directional coupler ( 15) and the accelerating cavity section (24) are respectively connected with the low-level control system (12); the second direction coupler (14) is also connected with the accelerating cavity section (24). 2. The standing wave irradiation accelerator according to claim 1, characterized in that, the first power divider (4) is a computer controllable and continuously adjustable power divider. 3. The standing wave irradiation accelerator according to claim 1, characterized in that, the second power divider (21) is a computer controllable and continuously adjustable power divider. 4. The standing wave irradiation accelerator according to claim 1, characterized in that, the low-velocity accelerating cavity section (8) adopts an edge-coupled cavity accelerator. 5. The standing wave irradiation accelerator according to claim 1, characterized in that, the high-speed accelerating cavity section (10) adopts a side-coupled cavity accelerating cavity.

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