Trapezoidal RFQ-IH DTL resonant-coupled radio frequency proton linear accelerating cavity of neutron source in vehicle-mounted accelerator

Abstract

This invention discloses a trapezoidal RFQ-IH DTL resonant-coupled radio-frequency proton linear accelerating cavity for a vehicle-mounted accelerator neutron source. The particle exit end of the RFQ is connected to the particle inlet end of the DTL; a coupling gap exists between the particle exit of the RFQ and the particle inlet of the DTL; the last RFQ support rod is configured as a semi-support rod, which is the structure retained after removing the portion of the RFQ support rod located on the RFQ electrode side of the RFQ; the length of the semi-support rod satisfies the condition that the RFQ and DTL can be coupled at the same frequency. By configuring the last RFQ support rod as a semi-support rod and determining the synchronous phase of the coupling gap, this invention achieves resonant coupling between the RFQ and DTL, thereby eliminating the need for the traditional MEBT transition section between the RFQ and DTL. Power is fed through a single power source, simplifying the power feeding system and significantly reducing weight.

Description

Technical Field

[0001] This invention belongs to the field of particle accelerator technology, specifically relating to a trapezoidal RFQ-IH DTL resonant coupled radio frequency proton linear accelerating cavity for a vehicle-mounted accelerator neutron source. Background Technology

[0002] Neutron imaging is an excellent non-destructive testing technique. Neutrons are uncharged, highly penetrating, and can distinguish isotopes, light elements, and neighboring elements. After passing through the object being tested, differences in the object's structure or material properties cause varying degrees of attenuation. By detecting the intensity distribution of the transmitted neutrons, information such as the object's internal structure and material distribution can be obtained. Accelerator neutron sources are simple, small, lightweight, and relatively easy-to-operate and control neutron generating devices. Further miniaturizing accelerator neutron sources for vehicle-mounted applications allows for convenient on-site neutron non-destructive testing, enabling defect inspection of internal structures in bridges, dams, tunnels, and other buildings; corrosion detection of aerospace components; and the detection and analysis of explosives.

[0003] Mobile accelerator neutron sources typically produce neutrons by bombarding a lithium target with a proton beam. This method requires low proton beam energy, yields high neutrons, and is relatively easy to shield against radiation. The particle accelerator is the core component of a mobile accelerator neutron source, and its size, weight, and performance determine the overall size and effectiveness of the neutron source system. Mobile accelerator neutron sources usually only require the accelerator to accelerate protons to a relatively low energy range (below 4 MeV).

[0004] In the field of small, low-energy, high-current linear accelerators, accelerating particle beams using radio frequency (RF) electromagnetic fields is the most economical and efficient solution. RF accelerators have made significant progress since their inception in the 1960s. Currently, there are many types of proton accelerators internationally. Among them, the radio frequency quadrupole (RFQ) linear accelerator is internationally recognized as the best-performing low-energy accelerating cavity. RFQs can simultaneously focus and accelerate DC beams, featuring a compact structure, high beam quality, and low inlet beam energy, so they are often used directly after the ion source. However, the acceleration efficiency of RFQs decreases with increasing energy. Therefore, when the proton beam energy exceeds 1 MeV, to increase the acceleration gradient, particles are often first extracted to the medium-energy transport band (MEBT) and injected into other high-acceleration-gradient RF accelerating cavities, such as the floating tube linear accelerator (DTL).

[0005] Furthermore, for different operating frequencies, numerous derived structures based on the acceleration principles of RFQ and DTL have been developed internationally. Among them, the "H-type" cavity, operating in TE mode, has advantages such as small size, simple fabrication, and wide operating spectrum, and is widely used in many international accelerator-driven neutron source projects. The "trapezoidal supported H-type RFQ" (denoted as trapezoidal L-RFQ) and the "finger-supported H-type DTL" (denoted as IH-DTL) are two derived structures of the H-type accelerating cavity, respectively. Compared to other cavity types, L-RFQ and IH-DTL have higher mechanical strength, lower power consumption, smaller cavity size, higher quality factor, and are more suitable for operation at moderate frequencies (200MHz).

[0006] Existing technologies and shortcomings:

[0007] In vehicle-mounted accelerators, the carrier places extremely stringent requirements on the size and weight of the acceleration cavity. The traditional "RFQ+MEBT+DTL" acceleration scheme not only requires a large vertical space but also two different power sources, making it unsuitable for vehicle-mounted accelerators. Therefore, the internationally accepted approach is a single RFQ cavity for vehicle-mounted acceleration, miniaturizing the cavity by increasing the operating frequency of the RFQ accelerator, such as the RANSIII accelerator at RIKEN in Japan, which operates at 500MHz. While increasing the operating frequency reduces the cavity size, it also increases the required RF power consumption, the volume and weight of the power source, thus complicating the power delivery and cooling systems. Therefore, this single-cavity RFQ acceleration scheme has approached the limits of miniaturization and weight reduction.

[0008] To improve accelerator efficiency at high energies within a compact size, several research institutions both domestically and internationally have proposed coupling structures for radio frequency quadrupole linear accelerators (RFQs) and linear floating tube accelerators (DTLs) based on different electrode support methods. Among these, the "finger-supported H-type radio frequency quadrupole accelerator (IH-RFQ)" coupled with IH-DTL is suitable for frequencies below 100MHz, but its large cavity diameter makes it difficult to meet the size requirements of neutron sources in vehicle-mounted accelerators. The "four-bar supported RFQ" coupled with IH-DTL presents significant challenges in radio frequency coupling, requiring internal quadrupole magnets, resulting in a complex structure, mode spacing of less than 1MHz, and high power consumption. In the RFQ coupled with "radio frequency field finger-electrode floating tube accelerator (RFI)," the floating tube of the RFI incorporates a radio frequency quadrupole lens structure, significantly increasing fabrication difficulty and cost, and leading to poor operational stability. Therefore, research is needed on low-power coupled proton accelerating cavities operating at moderate frequencies for compact accelerator neutron sources. Currently, there are no specific solutions, either domestically or internationally, for resonant-coupled proton accelerating cavities suitable for neutron sources in vehicle-mounted accelerators. Summary of the Invention

[0009] To address the problems existing in the prior art, the present invention aims to provide a trapezoidal RFQ-IH DTL resonant coupled radio frequency proton linear accelerating cavity for a vehicle-mounted accelerator neutron source. The accelerating cavity of the present invention has a compact structure, can operate at a moderate frequency, and has low power consumption.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] The trapezoidal RFQ-IH DTL resonant-coupled radio frequency proton linear accelerator cavity of the neutron source in the vehicle-mounted accelerator includes a radio frequency quadrupole linear accelerator and a floating tube linear accelerator, with the particle exit end of the radio frequency quadrupole linear accelerator connected to the particle inlet end of the floating tube linear accelerator.

[0012] There is a coupling gap between the particle exit of the radio frequency quadrupole linear accelerator and the particle inlet of the floating tube linear accelerator.

[0013] The last RFQ support rod of the radio frequency quadrupole linear accelerator is set as a half support rod. The half support rod is the structure retained after the part of the RFQ support rod located on the RFQ electrode side of the radio frequency quadrupole linear accelerator is removed. The length of the half support rod meets the condition that the radio frequency quadrupole linear accelerator and the floating tube linear accelerator can be coupled at the same frequency.

[0014] Preferably, the synchronization phase of the coupling gap as follows:

[0015]

[0016] In the formula, Lc This represents the length from the midpoint of the Δm element to the midpoint of the coupling gap in a radio frequency quadrupole linear accelerator. This represents the synchronization phase at the midpoint of the Δm element in a radio frequency quadrupole linear accelerator. β For the relativistic velocity of synchronized particles, λ The wavelength of the radio frequency field.

[0017] Preferably, the power consumption of the floating tube linear accelerator is linearly negatively correlated with the power consumption ratio of the RF quadrupole linear accelerator, which is equal to the square of the half-support rod height.

[0018] Preferably, the radio frequency quadrupole linear accelerator and the floating tube linear accelerator share the same power source.

[0019] Preferably, the radio frequency quadrupole linear accelerator and the floating tube linear accelerator are connected in the outer shell and have interconnected inner cavities at the connection point.

[0020] Preferably, the RFQ electrode of the radio frequency quadrupole linear accelerator is coaxial with the floating tube of the floating tube linear accelerator.

[0021] Preferably, in the radio frequency quadrupole linear accelerator, in the direction from the particle inlet to the particle outlet, there are tuning pads between the first RFQ support rod and the second RFQ support rod, and between the penultimate RFQ support rod and the half support rod. The width of the tuning pad is the same as the width of the RFQ support rod. The tuning pad is attached to the inner wall of the radio frequency quadrupole linear accelerator, and the tuning pad is welded to the RFQ support rod and the inner wall of the radio frequency quadrupole linear accelerator.

[0022] Preferably, the radio frequency quadrupole linear accelerator is equipped with an RFQ cylindrical tuning rod, and the floating tube linear accelerator is equipped with a DTL cylindrical tuner.

[0023] Preferably, the ratio of the average gap voltage of the floating tube linear accelerator to the voltage between the radio frequency quadrupole linear accelerator and the adjacent electrode is 2 to 7.

[0024] The present invention has the following beneficial effects:

[0025] This invention achieves resonant coupling between an RFQ (Radio Frequency Quadrupole) linear accelerator and a DTL (Drift Tube) linear accelerator by setting the last RFQ support rod of the RFQ as a semi-support rod and determining the synchronous phase of the coupling gap. This eliminates the need for the traditional MEBT transition section between the RFQ and DTL, requiring only a single power source for power feeding, simplifying the power feeding system and significantly reducing weight. The resonant coupling accelerator cavity combines the high beam-focusing efficiency of the RFQ and the high acceleration efficiency of the DTL, with a significantly shortened longitudinal length. It also combines the advantages of trapezoidal L-RFQ and IH-DTL cavities, making it suitable for operation at moderate frequencies (around 200 MHz), achieving an electromagnetic coupling of 3%, a mode spacing greater than 5 MHz, and moderate lateral dimensions and power source weight. Therefore, this invention results in a compact accelerator cavity structure that can operate at moderate frequencies with low power consumption. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the beam dynamics of the coupling section of the trapezoidal RFQ-IH DTL resonant coupling radio frequency proton linear accelerating cavity in the vehicle-mounted accelerator of the present invention.

[0027] Figure 2(a) is an internal side view of the trapezoidal RFQ-IH DTL resonant coupled radio frequency proton linear acceleration cavity of the neutron source in the vehicle-mounted accelerator of the present invention.

[0028] Figure 2(b) is a front view of the trapezoidal RFQ-IH DTL resonant coupled radio frequency proton linear accelerating cavity of the neutron source in the vehicle-mounted accelerator of the present invention.

[0029] Figure 3 This is a schematic diagram of the RFQ support rod structure in the trapezoidal RFQ-IH DTL resonant coupling radio frequency proton linear acceleration cavity of the neutron source in the vehicle-mounted accelerator of the present invention.

[0030] Figure 4 This is a schematic diagram of the cylindrical adjustable tuning rod in the trapezoidal RFQ-IH DTL resonant coupling radio frequency proton linear acceleration cavity of the neutron source in the vehicle-mounted accelerator of the present invention.

[0031] Figure 5(a) is a simulation result of the temperature (upper half) distribution of the cooling system of the trapezoidal RFQ-IH DTL resonant coupling radio frequency proton linear acceleration cavity of the neutron source in the vehicle-mounted accelerator of the present invention during operation.

[0032] Figure 5(b) is a simulation result of the thermal deformation (upper half) distribution of the cooling system of the trapezoidal RFQ-IH DTL resonant coupling radio frequency proton linear acceleration cavity of the neutron source in the vehicle-mounted accelerator of the present invention during operation.

[0033] In the diagram: 1 is the RFQ support rod, 2 is the screw hole, 3 is the RFQ cylindrical tuning rod, 4 is the RFQ electrode, 5 is the tuning pad, 6 is the semi-support rod, 7 is the float tube, 8 is the DTL spine, 9 is the DTL support rod, 10 is the DTL cylindrical tuner, 11 is the right cavity plate, 12 is the middle cavity plate, 13 is the connecting screw hole, 14 is the beam channel, 15 is the connecting plate, 16 is the electrode fixing part, 17 is the support ring, 18 is the tuner knob, 19 is the tuner flange, and 20 is the tuner nut. Detailed Implementation

[0034] The specific embodiments of the present invention will now be described in complete and clear detail with reference to the accompanying drawings.

[0035] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the embodiments described herein are merely a part, not all, of the present invention. All other embodiments obtained by other personnel based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0036] refer to Figure 1 As can be seen, the trapezoidal RFQ-IH DTL resonant coupled radio frequency proton linear accelerating cavity of the neutron source in the vehicle-mounted accelerator of this invention is divided into three parts for separate processing, including the end cap. The three parts are connected by screw holes. This invention selects trapezoidal L-RFQ and IH-DTL to form a low-power, easy-to-process, and high-mechanical-strength coupled resonant accelerating cavity. The following is in conjunction with... Figure 1 Figure 5 illustrates a scheme for achieving radio frequency coupling resonance in a cavity.

[0037] First, combined Figure 1 This paper introduces the key points of the dynamic design of the coupling section in this invention. When designing the beam dynamics scheme, the design of RFQ and DTL can be carried out using conventional methods. The key points are: firstly, to achieve RF coupling of the cavity, the ratio of the average gap voltage of the DTL section to the voltage between adjacent electrodes of the RFQ must be controlled within the range of 2 to 7; secondly, in this invention, the phase relationship between RFQ and DTL is determined. Figure 1 The synchronization phase of the coupling gap of the present invention is as follows:

[0038]

[0039] in, Lc This represents the length from the midpoint of the Δm element in the RFQ to the midpoint of the coupling gap. This represents the synchronization phase at the midpoint of the Δm element in the RFQ. β For the relativistic velocity of synchronized particles, λ Where is the wavelength of the radio frequency field. In the design, the synchronization phase of the coupling gap needs to be as low as possible. Obviously, reducing... Lc The length of the gap helps to reduce the synchronization phase of the coupling gap. In this example, the gap length is equal to 6 mm. The bundle synchronization phases of the Δm element and the coupling gap are -40.7° and 26.5°, respectively.

[0040] The principle of this invention will be explained below with reference to Figure 2. After the particles exit the beam extraction system and collimator, they pass through the beam inlet. The electrodes in the RFQ section are modulated to achieve beam focusing and acceleration. At the particle exit of the RFQ, the beam energy can reach 0.6 MeV. After acceleration through the gaps of the IHDTL, the beam energy can be increased to 2.5 MeV. In Figure 2(a), part A of the cavity operates in TE. 210 In mode B, the cavity operates in TE. 110In the design, firstly, according to the dynamic requirements, the height and width of the cavity, the width and thickness of the RFQ support rod 1 (all support rods are the same size), and the height and width of the DTL spine 8 are adjusted until the intrinsic mode frequency of the cavity is close to the design frequency (200MHz in this example). At this time, in order to ensure the flatness of the longitudinal electric field of the RFQ section, the height of the tuning pad 5 needs to be adjusted until the electric field is sufficiently flat. Similarly, in order to ensure the flatness of the DTL section cavity, a portion needs to be cut off at the front end (left end shown in Figure 2(a)) and the end end (right end shown in Figure 2(a)) of the DTL spine 8, forming an undercut structure. The height and length of the undercut are positively correlated with the local electric field; the higher the height or length of the local undercut, the higher the electric field near the DTL. Therefore, in the design, the undercut dimensions need to be adjusted until the DTL electric field distribution is sufficiently flat. In addition, to achieve coupling of the two cavities at the same frequency, a semi-support rod 6 structure is required. The square of the height of the semi-support rod 6 and the power consumption ratio of the DTL section are linearly negatively correlated. In this example, the power consumption ratio decreases by a factor of approximately -0.005 per square millimeter as the height of the semi-support rod 6 increases squarely. Therefore, in the cavity design, the ratio of the average gap voltage of the cavity DTL section to the voltage between adjacent electrodes of the RFQ can be adjusted to match the dynamic design by adjusting the height of the semi-support rod 6, according to the dynamic design.

[0041] All dimensions are fixed and cannot be adjusted after processing. Machine debugging after processing can be achieved using the RFQ cylindrical tuning rod 3 and DTL cylindrical tuner 10 shown in Figures 2(a) and 2(b). The cylindrical tuning rod 3 is positioned in the gap between adjacent RFQ support rods, with one rod placed every two gaps, alternating between the left and right sides (perpendicular to the paper in Figure 2(a)). The diameter of the RFQ cylindrical tuning rod 3 is 1mm smaller than the gap length between the RFQ support rods, and its initial depth is 20mm. The DTL cylindrical tuner 10 is positioned on the side of the DTL cavity, with the center of its bottom surface on the axis. There are two sets, one on each side (perpendicular to the paper in Figure 2(a) and one in the left-right direction in Figure 2(b)). The longitudinal position of the DTL cylindrical tuner 10 (left-right direction in Figure 2(a)) is not fixed. Taking a 200MHz example, each DTL cylindrical tuner 10 can achieve a frequency tuning capability of approximately 0.1MHz / mm. When the frequency is adjusted to 200MHz and the electric field unevenness is adjusted to below 3%, the cavity function can be successfully realized.

[0042] The installation process and debugging method of the cavity are described in detail below. The trapezoidal RFQ-IH-DTL coupling cavity is processed and assembled in the following manner.

[0043] First, the modulated RFQ electrode needs to be passed through Figure 3The screw holes on the electrode fixing part 16 shown are mounted on the RFQ support rod 1. In Figure 2(a), the cavity parts of parts A and B are machined as a whole, and the upper and lower surfaces of the middle cavity of the RFQ part are provided with grooves, which are consistent with... Figure 3 Align the screw holes on the connecting plate 15 and secure it with screws to install the RFQ support rod 1. Finally, install the tuning pad 5 onto the cavity in one go to complete the installation of the RFQ section.

[0044] Secondly, the upper and lower DTL spines 8 of the IH-DTL section are integrated with the middle part of the cavity and the floating tube, and the DTL cylindrical tuner 10 is installed on the side cavity. Finally, the cavities are merged to complete the installation.

[0045] Figures 5(a) and 5(b) show the temperature field distribution of the cavity after water cooling (upper half) and the deformation distribution of the cavity due to thermal effects (lower half) respectively, simulated using CST. In the simulation examples shown in Figures 5(a) and 5(b), the cross-sectional dimensions of the cavity are 240 mm × 289.2 mm, the width of RFQ support rod 1 and half-support rod 6 is 34 mm, and the height of RFQ half-support rod 6 is 170 mm. At room temperature, with 20°C liquid water cooling and a coolant flow rate of 1.8 m / s, the highest temperature of the cavity occurs in the coupling section, near half-support rod 6 as shown in Figure 2(a). In addition, the maximum deformation also occurs near the highest temperature part, with a maximum value of 58.2 μm. According to the simulation calculation, after water cooling, the frequency drift of the entire cavity due to thermal deformation is 41.69 kHz, which is less than 100 kHz. Therefore, the cooling effect is very ideal.

[0046] Using the L-RFQ-IH DTL resonant-coupled radio frequency proton-heavy ion linear accelerator cavity of the embodiment, the proton energy is accelerated from tens of keV to a lower energy range (such as below 4 MeV, the specific energy depending on the analyte and application) over a short length range. The proton beam bombards a lithium target, and through... 7 Li(p, n) 7 The Be reaction produces neutrons.

[0047] Combination Figure 1 As shown in Figure 2(a), the cavity in this embodiment has a quadrilateral cross-section, consisting of a trapezoidal L-RFQ, a resonant coupling section, and an IH DTL. The particle beam is injected and accelerated from the RFQ end. The trapezoidal L-RFQ uses RFQ support rods 1 to alternately support four electrodes. Each RFQ support rod 1 plate is directly connected and fixed to the upper and lower surfaces of the cavity, forming a TE 210 Field distribution. The IH DTL uses DTL support rods 9 to alternately support the floating tubes 7. All DTL support rods 9 are fixed to the spine 8, and the spine 8 is connected to the DTL cavity to form a TE. 110Field distribution. The trapezoidal L-RFQ electrode support rod of the resonant coupling section is only connected to one end of the RFQ cavity—the other end needs to have a certain length removed, forming a semi-support rod 6; thus realizing TE 210 Pattern and TE 110 The mode is RF-coupled in a single cavity with a mode spacing greater than 5 MHz. This invention incorporates adjustable tuners (RFQ cylindrical tuning rods 3) in both the RFQ and DTL, providing a 3 MHz frequency adjustment range to address frequency drift and reduced electric field flatness after fabrication due to issues such as processing accuracy, material deformation, and material aging. The RFQ cavity is fixed to the bottom using fixed "square" tuning pads 5, while adjustable RFQ cylindrical tuning rods 3 are installed on the side of the cavity. The DTL cavity uses a larger-radius adjustable DTL cylindrical tuner 10, fixed to the side of the cavity. The entire cavity is constructed of oxygen-free copper, which helps reduce heat loss and improve the cavity's quality factor. During operation, liquid water is used to cool all cavity components except the electrodes. In this embodiment, the entire cavity is divided into three axially sections—the middle and two sides—and the end caps are machined as a single unit to address vacuum and RF leakage issues caused by three-sided contact. The RFQ section has grooves of a certain depth on the upper and lower inner surfaces of the middle cavity to fix the connecting plates 15 at both ends of the RFQ support rod. The RFQ support rod is fixed to the RFQ electrode with screws, and the support ring in the center of the RFQ support rod rotates 90 degrees sequentially from the first end to the last. The upper and lower ridges of the IH-DTL section and the middle cavity are machined together, and screw holes are provided to fix the float tube support rod.

[0048] This invention's resonant coupling accelerator cavity combines the advantages of trapezoidal L-RFQ and IH-DTL cavities, offering high mechanical strength and low power consumption. The entire cavity is manufactured as a single unit, making it more suitable for vehicle-mounted accelerator neutron sources. Tuners are provided at both the RFQ and DTL ends, allowing for independent tuning of frequency and field distribution. Operation is safe and convenient, and it can handle various complex working environments in vehicle-mounted neutron sources. This invention simplifies the cavity's cooling system, requiring only cooling of the RFQ electrode support plate and DTL spine, eliminating the need for water channels within the electrodes and float tubes. In summary, the coupling cavity of this invention has a compact structure, is simple to manufacture, and has low power consumption, meeting the requirements of vehicle-mounted neutron sources and enabling long-term, safe, and reliable operation.

Claims

1. A trapezoidal RFQ-IH DTL resonant-coupled radio frequency proton linear accelerating cavity for a vehicle-mounted accelerator neutron source, characterized in that, It includes a radio frequency quadrupole linear accelerator and a floating tube linear accelerator, with the particle exit end of the radio frequency quadrupole linear accelerator connected to the particle inlet end of the floating tube linear accelerator. There is a coupling gap between the particle exit of the radio frequency quadrupole linear accelerator and the particle inlet of the floating tube linear accelerator. The last RFQ support rod of the radio frequency quadrupole linear accelerator is set as a half support rod (6). The half support rod (6) is the structure retained after the part of the RFQ support rod (1) located on the side of the RFQ electrode (4) of the radio frequency quadrupole linear accelerator is removed. The length of the half support rod (6) satisfies the condition that the radio frequency quadrupole linear accelerator and the floating tube linear accelerator can be coupled at the same frequency. Synchronization phase of the coupling gap as follows: In the formula, Lc This represents the length from the midpoint of the Δm element to the midpoint of the coupling gap in a radio frequency quadrupole linear accelerator. This represents the synchronization phase at the midpoint of the Δm element in a radio frequency quadrupole linear accelerator. β For the relativistic velocity of synchronized particles, λ The wavelength of the radio frequency field; The sum of the squares of the height of the semi-support rod (6) and the power consumption of the floating tube linear accelerator are linearly negatively correlated with the power consumption of the radio frequency quadrupole linear accelerator.

2. The trapezoidal RFQ-IH DTL resonant-coupled radio frequency proton linear accelerating cavity of the neutron source in the vehicle-mounted accelerator according to claim 1, characterized in that, The radio frequency quadrupole linear accelerator and the floating tube linear accelerator share the same power source.

3. The trapezoidal RFQ-IH DTL resonant-coupled radio frequency proton linear accelerating cavity of the neutron source in the vehicle-mounted accelerator according to claim 1, characterized in that, The radio frequency quadrupole linear accelerator and the floating tube linear accelerator are connected by their outer shells and have interconnected inner cavities at the connection point.

4. The trapezoidal RFQ-IH DTL resonant-coupled radio frequency proton linear accelerating cavity of the neutron source in the vehicle-mounted accelerator according to claim 1, characterized in that, The RFQ electrode (4) of the radio frequency quadrupole linear accelerator is coaxial with the floating tube (7) of the floating tube linear accelerator.

5. The trapezoidal RFQ-IH DTL resonant-coupled radio frequency proton linear accelerating cavity of the neutron source in the vehicle-mounted accelerator according to claim 1, characterized in that, In the radio frequency quadrupole linear accelerator, a tuning pad (5) is provided between the first RFQ support rod and the second RFQ support rod, and between the penultimate RFQ support rod and the half support rod (6) in the direction from the particle inlet to the particle outlet. The width of the tuning pad (5) is the same as the width of the RFQ support rod. The tuning pad (5) is attached to the inner wall of the radio frequency quadrupole linear accelerator and is welded to the RFQ support rod and the inner wall of the radio frequency quadrupole linear accelerator.

6. The trapezoidal RFQ-IH DTL resonant-coupled radio frequency proton linear accelerating cavity of the neutron source in the vehicle-mounted accelerator according to claim 1, characterized in that, The radio frequency quadrupole linear accelerator is equipped with an RFQ cylindrical tuning rod, while the floating tube linear accelerator is equipped with a DTL cylindrical tuner.

7. The trapezoidal RFQ-IH DTL resonant-coupled radio frequency proton linear accelerating cavity of the neutron source in the vehicle-mounted accelerator according to claim 1, characterized in that, The ratio of the average gap voltage of the floating tube linear accelerator to the voltage between the radio frequency quadrupole linear accelerator and the adjacent electrode is 2 to 7.

Images