Synchrotron high-frequency cavity broadband voltage sampling device and application thereof

Abstract

The invention provides the technical field of particle accelerators, and particularly relates to a broadband voltage sampling device for a high-frequency cavity of a synchrotron and application of the broadband voltage sampling device. The capacitance voltage division circuit is used for adjusting the multiple of the sampling ratio; the broadband impedance converter is connected with the other end of the capacitance voltage division circuit; the first winding wire comprises a first ferrite ring and a multi-core twisted winding wire, and the multi-core twisted winding wire is wound on the periphery of the first ferrite ring; and the radio frequency N-type connector is connected with the other end of the broadband impedance converter, and the radio frequency N-type connector is a voltage sampling output port. Due to the fact that the first ferrite ring has high magnetic conductivity and low quality factor, the broadband impedance converter has excellent broadband characteristics, and can meet the requirement that the working frequency of a high-frequency cavity of a proton synchrotron and a high-frequency cavity of a heavy ion synchrotron is 0.5-10 MHz. The high-frequency cavity is suitable for proton synchrotron high-frequency cavities and heavy ion synchrotron high-frequency cavities.

Description

Technical Field

[0001] The present invention relates to the technical field of particle accelerators, and particularly to a broadband voltage sampling device for a synchrotron high-frequency cavity and its application. Background Art

[0002] Particle synchrotrons generally mainly include proton synchrotrons and heavy-ion synchrotrons. The high-frequency cavities of heavy-ion synchrotrons adopt a broadband frequency-sweeping working mode, with a working frequency range of 0.5 - 6 MHz; the high-frequency cavities of proton synchrotrons adopt a broadband frequency-sweeping working mode, with a working frequency range of 1 - 8 MHz; both heavy-ion synchrotrons and proton synchrotrons require their high-frequency cavities to generate high-precision radio-frequency voltages within the entire working frequency band for beam capture or acceleration.

[0003] The voltage sampling devices in the prior art cannot meet the broadband characteristics of the high-frequency cavity voltage sampling device. Summary of the Invention

[0004] The present invention provides a broadband voltage sampling device for a synchrotron high-frequency cavity to solve at least one of the above technical problems.

[0005] The present invention provides a broadband voltage sampling device for a synchrotron high-frequency cavity, which is used in a synchrotron high-frequency cavity and includes: A capacitive voltage division circuit, one end of which is connected to the acceleration gap of the high-frequency cavity; the capacitive voltage division circuit is used to adjust the multiple of the sampling ratio; A broadband impedance transformer, one end of which is connected to the other end of the capacitive voltage division circuit; and the broadband impedance transformer includes a first ferrite ring and a multi-core twisted wire, and the multi-core twisted wire is wound around the outer periphery of the first ferrite ring; An RF N-type connector, which is connected to the other end of the broadband impedance transformer, and the RF N-type connector is a voltage sampling output port.

[0006] According to a broadband voltage sampling device for a synchrotron high-frequency cavity provided by the present invention, it further includes: A broadband voltage divider, which is connected to the end of the broadband impedance transformer facing away from the capacitive voltage division circuit. The broadband voltage divider includes a second ferrite ring and a twin-core twisted wire, and the twin-core twisted wire is wound around the outer periphery of the second ferrite ring; The RF N-type connector includes two paths, and both paths of the RF N-type connectors are connected to the broadband voltage divider.

[0007] According to a broadband voltage sampling device for a synchrotron high-frequency cavity provided by the present invention, the first ferrite ring is pressed and sintered into a ring shape by ferrite material; the impedance transformation ratio of the broadband impedance transformer is 1:n.

[0008] A broadband voltage sampling device for a synchrotron high-frequency cavity provided by the present invention, wherein the second ferrite ring is pressed and sintered into a ring shape by a ferrite material; the voltage ratio of the two output ports of the broadband voltage divider is 1:1, and the two output ports are respectively connected to the two RF N-type connectors.

[0009] A broadband voltage sampling device for a synchrotron high-frequency cavity provided by the present invention, wherein the capacitive voltage division circuit includes: A small-capacitance high-voltage capacitor for connecting to the acceleration gap of the high-frequency cavity; A large-capacitance low-voltage capacitor, one end of which is connected to the small-capacitance high-voltage capacitor, and the other end is connected to the broadband impedance transformer; and the large-capacitance low-voltage capacitor is grounded.

[0010] A broadband voltage sampling device for a synchrotron high-frequency cavity provided by the present invention, wherein the capacitive voltage division circuit includes two parallel paths, and each capacitive voltage division circuit is connected to the broadband impedance transformer.

[0011] A broadband voltage sampling device for a synchrotron high-frequency cavity provided by the present invention, wherein the small-capacitance high-voltage capacitor is composed of two 10 pF RF high-voltage voltages connected in series. The small-capacitance high-voltage capacitor has a capacitance value of 5 pF, and the withstand voltage of a single high-frequency high-voltage capacitor is greater than 20 kV, and the maximum current it can withstand is 10 A.

[0012] A broadband voltage sampling device for a synchrotron high-frequency cavity provided by the present invention, wherein the resistance of the RF N-type connector is 50 Ω.

[0013] A broadband voltage sampling device for a synchrotron high-frequency cavity provided by the present invention, wherein the sampling ratio of the capacitive voltage division circuit is 1500 times.

[0014] The present invention provides an application of a broadband voltage sampling device for a synchrotron high-frequency cavity, which is applied to a heavy-ion medical treatment device or a proton medical treatment device.

[0015] The broadband voltage sampling device for the synchrotron high-frequency cavity provided by the present invention has one end of a capacitive voltage divider connected to the acceleration gap of the high-frequency cavity. The capacitive voltage divider adjusts the multiple of the sampling ratio. One end of the broadband impedance transformer is connected to the other end of the capacitive voltage division circuit. The broadband impedance transformer is formed by winding a multi-core twisted wire around a first ferrite ring. The RF N-type connector is connected to the other end of the broadband impedance transformer, and the RF N-type connector is the voltage sampling output port. Due to the characteristics of the first ferrite ring having high magnetic permeability and low quality factor (Q value), the broadband impedance transformer has excellent broadband characteristics, well meeting the requirements for the broadband characteristics of the voltage sampling device. The working frequency range of the broadband voltage sampling device for the synchrotron high-frequency cavity provided by the present invention is 0.5 - 10 MHz, covering the working frequencies of the proton synchrotron high-frequency cavity and the heavy-ion synchrotron high-frequency cavity. Therefore, it can be applied to the proton synchrotron high-frequency cavity or the heavy-ion synchrotron high-frequency cavity. This type of synchrotron can be used in scientific devices, heavy-ion medical treatment, proton medical treatment, ground simulation of space environment, and experimental devices for simulating proton displacement damage effects, etc.

[0016] In addition, by adjusting the multiple of the sampling ratio of the sampling device through the capacitive voltage division circuit and combining with the voltage division ratio of the broadband impedance transformer, the design requirement of a sampling ratio exceeding 1500 times for the RF voltage sampling device is jointly achieved.

[0017] The broadband voltage divider is connected to the capacitive voltage division circuit, and the broadband voltage divider includes a second ferrite ring and a twin-core twisted wire. The twin-core twisted wire is wound around the outer periphery of the second ferrite ring. Due to the second ferrite ring having high magnetic permeability and a relatively low quality factor Q value, the problem of broadband power distribution is solved, and the design requirement of high-precision port output for the voltage sampling device is achieved. Brief Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a structural composition block diagram of the broadband voltage sampling device for the synchrotron high-frequency cavity provided by the present invention.

[0020] Figure 2 It is a structural diagram of the broadband voltage sampling device for the synchrotron high-frequency cavity provided by the present invention.

[0021] Figure 3 It is a structural schematic diagram of the first ferrite ring or the second ferrite ring provided by the present invention.

[0022] Figure 4 It is a schematic structural diagram of the broadband impedance converter provided by the present invention.

[0023] Figure 5 It is a schematic structural diagram of the broadband voltage divider provided by the present invention.

[0024] Figure 6 It is a schematic structural diagram of the small-capacitance high-voltage capacitor provided by the present invention.

[0025] Figure 7 It is a schematic structural diagram of the RF N-type connector provided by the present invention.

[0026] Reference numerals: 1. Capacitive voltage division circuit; 11. Small-capacitance high-voltage capacitor; 12. Large-capacitance low-voltage capacitor; 2. Broadband impedance converter; 21. First ferrite ring; 22. Multi-core twisted wire; 3. RF N-type connector; 4. Broadband voltage divider; 41. Second ferrite ring; 42. Twin-core twisted wire; 5. Matching resistor. Detailed implementation manners

[0027] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0028] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationships indicated by the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0029] The following combines Figures 1-7 to describe a broadband voltage sampling device for a synchrotron high-frequency cavity provided by the present invention, which is used in a synchrotron high-frequency cavity.

[0030] As Figures 1-4As shown in the figure, the broadband voltage sampling device for the synchrotron high-frequency cavity provided by the embodiment of the present invention includes a capacitive voltage division circuit 1, a broadband impedance converter 2, and a radio frequency N-type connector 3. One end of the capacitive voltage division circuit 1 is connected to the acceleration gap of the high-frequency cavity for directly obtaining the voltage signal in the high-frequency cavity. The capacitive voltage division circuit 1 is used to adjust the multiple of the sampling ratio so as to meet different measurement requirements. One end of the broadband impedance converter 2 is connected to the other end of the capacitive voltage division circuit 1; and the broadband impedance converter 2 includes a first ferrite ring 21 and a multi-core winding wire 22, and the multi-core winding wire 22 is wound around the outer periphery of the first ferrite ring 21. The radio frequency N-type connector 3 is connected to the other end of the broadband impedance converter 2, and the radio frequency N-type connector 3 is the voltage sampling output port.

[0031] Among them, the first ferrite ring 21 is made of ferrite material, has high magnetic permeability, can effectively gather and guide the magnetic field, can enhance the magnetic field effect, and improve the performance of the device. In addition, the ferrite material also has a low quality factor, so that the broadband impedance converter 2 has excellent broadband characteristics, which well solves the requirements for the broadband characteristics of the voltage sampling device. The multi-core winding wire is tightly wound around the outer periphery of the first ferrite ring 21 to form a stable electromagnetic coupling structure, which not only improves the electrical performance of the impedance converter, but also enhances its mechanical stability, ensuring reliable operation in a high-frequency and high-power environment.

[0032] The radio frequency N-type connector 4 adopts a standard radio frequency connector structure, has excellent electrical performance and mechanical stability, and is suitable for the transmission of high-frequency and high-power radio frequency signals. The radio frequency N-type connector 4 outputs the voltage signal after capacitive voltage division and impedance transformation to an external measurement device or system. More specifically, the resistance of the radio frequency N-type connector 3 is 50Ω.

[0033] The working frequency range of the broadband voltage sampling device for the synchrotron high-frequency cavity provided by the embodiment of the present invention is 0.5 - 10 MHz, covering the working frequencies of proton synchrotrons and heavy ion synchrotrons. Therefore, it can be applied to the high-frequency cavities of proton synchrotrons and heavy ion synchrotrons at the same time; this type of synchrotron can be used in heavy ion medical treatment, proton medical treatment, space environment ground simulation, and proton displacement damage effect simulation experimental devices, etc.

[0034] Such as Figures 5-7As shown, in a feasible embodiment of the present invention, it further includes a broadband voltage divider 4, which is connected to one end of the back-to-back capacitive voltage division circuit of the broadband impedance transformer 2. The broadband voltage divider 4 includes a second ferrite ring 41 and a twin-core winding wire 42, and the twin-core winding wire 42 is wound around the outer periphery of the second ferrite ring 41. The RF N-type connector 3 has two paths, and both paths of the RF N-type connector 3 are connected to the broadband voltage divider 4. Through the above embodiment settings, it can meet the requirements of cavity voltage amplitude, phase control and cavity sampling waveform monitoring. Moreover, by using the second ferrite ring 41 with high magnetic permeability and low quality factor Q value in the broadband voltage divider 4, combined with the twin-core winding wire 42 wound around the outer periphery of the second ferrite ring 41, and adopting the transmission line transformer technology, the requirement of high broadband amplitude flatness (<±0.05dB) of the broadband transmission line transformer is achieved; at the same time, by using the transmission line broadband voltage division technology, two high-precision port outputs of the RF voltage sampling device can be realized. Among them, one sampling signal is used for the closed-loop control of the amplitude and phase stability of the cavity; the other sampling signal is used for the monitoring of the cavity voltage waveform, and two high-precision voltage sampling signals are output simultaneously under broadband working conditions.

[0035] Among them, the broadband voltage divider 4 is also used in cooperation with a matching resistor 5.

[0036] In a feasible embodiment of the present invention, the first ferrite ring 21 is pressed and sintered into a ring shape by ferrite material; the impedance transformation ratio of the broadband impedance transformer 2 is 1:n. More specifically, the broadband impedance transformer 2 can use the multi-core winding wire 22 to wind the first ferrite ring 21 for a total of 10 turns, and the impedance transformation ratio is 1:4. It can also use the multi-core winding wire 22 to wind the first ferrite ring 21 with other numbers of turns to achieve other impedance transformation ratios, such as 1:4 or 1:9, so as to select a suitable impedance transformation ratio to meet the usage requirements.

[0037] In a feasible embodiment of the present invention, the second ferrite ring 41 is pressed and sintered into a ring shape by a ferrite material, which can effectively aggregate and guide the magnetic field. The high magnetic permeability characteristic of the ferrite material enables it to maintain stable electromagnetic characteristics within a wide frequency range, thereby enhancing the stability and reliability of the entire sampling system. The second ferrite ring 41 can also effectively reduce the influence of external electromagnetic interference on the sampling device, protect the internal circuit from external interference, and ensure the accuracy and precision of sampling. The voltage ratio of the two output ports of the broadband voltage divider 4 is 1:1, and the signal received from the input port can be evenly distributed to the two output ports with the same voltage amplitude. This characteristic of equal voltage output enables the sampling device to simultaneously and accurately acquire voltage signals at two different positions, improving the diversity and flexibility of sampling. The two output ports are respectively connected to two RF N-type connectors 3, enabling the sampling device to easily connect to multiple external measurement devices or systems, which not only improves the flexibility of sampling but also provides convenience for subsequent expansion and integration. For example, two oscilloscopes or data acquisition systems can be connected simultaneously to monitor voltage signals at two different positions.

[0038] Furthermore, the manufacturing process of the first ferrite ring 21 and the second ferrite ring 41 is as follows: It is mainly composed of metal elements such as iron (Fe), manganese (Mn), and zinc (Zn) to form oxide or carbonate compounds, and its basic structure is Fe3O4, also known as magnetic iron oxide. The ferrite material becomes semi-finished products with different shapes after pressing and becomes ferrite components after being sintered at a high temperature of 1300°C; the size of the ferrite ring (outer diameter * inner diameter * thickness) is: φ26×φ14×10mm; the key performance parameters of the ferrite ring: the magnetic permeability at 0.3 MHz is about 8000, and the Q value at 0.3 MHz is about 1.2.

[0039] As Figure 6 shown, in a feasible embodiment of the present invention, the capacitive voltage division circuit 1 includes a small-capacitance high-voltage capacitor 11 and a large-capacitance low-voltage capacitor 12. The small-capacitance high-voltage capacitor 11 is used to connect to the acceleration gap of the high-frequency cavity. Since the acceleration gap usually bears high voltage, selecting a small-capacitance high-voltage capacitor can ensure its stable operation in a high-voltage environment. One end of the large-capacitance low-voltage capacitor 12 is connected to the small-capacitance high-voltage capacitor 11, and the other end is connected to the broadband impedance converter 2; and the large-capacitance low-voltage capacitor 12 is grounded. The large-capacitance low-voltage capacitor 12 has a better filtering effect at low-frequency signals and can reduce the influence of low-frequency noise on the circuit.

[0040] It should be noted that the radio frequency voltage of the high-frequency cavity of the proton synchrotron exceeds 3 kV at most for effective beam acceleration; while the output voltage signal of the cavity sampling device is usually required to be less than 2 V to improve the beam capture efficiency, facilitate the control of the low-level voltage amplitude and phase, or directly connect to an oscilloscope for voltage waveform monitoring. The above conditions require the sampling device to have a voltage sampling ratio circuit of about 1500 times to meet the sampling requirements. The capacitive voltage division circuit of the sampling device is designed to adjust the multiple of the sampling ratio of the sampling device, and together with the voltage division ratio of the impedance transformation circuit, it jointly realizes the design requirement of the 1500-fold sampling ratio of the radio frequency voltage sampling device.

[0041] In a feasible embodiment of the present invention, the capacitive voltage division circuit 1 includes two parallel paths, each path serving as an independent capacitive voltage division circuit, and each capacitive voltage division circuit 1 is connected to the broadband impedance converter 2. By paralleling two capacitive voltage division circuits, the voltage stress on a single circuit can be dispersed, thereby improving the voltage withstand capacity of the entire circuit system. At the same time, since the two circuits work simultaneously, they can compensate and balance each other, further improving the stability of the output voltage.

[0042] Furthermore, in order to minimize the impact of the radio frequency voltage sampling device on the performance parameters of the cavity itself (such as resonant frequency, quality factor Q value, and shunt impedance) after being connected to the high-frequency cavity, the capacitance value of the high-voltage capacitor paralleled to the cavity acceleration gap is minimized as much as possible. The small-capacitance high-voltage capacitor 11 is composed of two 10 pF (5 pF in series) radio frequency high-voltage voltage series combinations. The capacitance value of the small-capacitance high-voltage capacitor is 5 pF. The 5 pF capacitance has little impact on the distributed capacitance of the high-frequency cavity itself, and the impact on the performance parameters of the cavity itself can be ignored. All capacitors selected for the voltage division circuit need to be measured, tested, and performance-screened, and finally combined into two combined capacitors with basically the same capacitance value and connected to the high-frequency cavity. In addition, the series use of capacitors can also increase the overall voltage withstand performance of the combined capacitor. Through the above settings, the high voltage withstand of a single high-frequency high-voltage capacitor is increased to be greater than 20 kV, and the maximum current it can withstand is 10 A.

[0043] The second aspect embodiment of the present invention lies in providing an application of a broadband voltage sampling device for a synchrotron high-frequency cavity, which can be applied to a heavy ion medical treatment device or a proton medical treatment device.

[0044] In the description of the embodiments of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0045] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or mode are included in at least one embodiment or mode of the embodiments of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or modes in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or modes described in this specification and the features of different embodiments or modes.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A synchrotron high-frequency cavity broadband voltage sampling device, used in a synchrotron high-frequency cavity, characterized in that: include: A capacitive voltage divider circuit (1), one end of which is connected to the acceleration gap of the high-frequency cavity; the capacitive voltage divider circuit (1) is used to adjust the multiple of the sampling ratio; A broadband impedance converter (2), one end of which is connected to the other end of the capacitive voltage divider circuit (1); the broadband impedance converter (2) comprises a first ferrite ring (21) and a multi-core twisted wire (22), the multi-core twisted wire (22) being wound around the outer periphery of the first ferrite ring (21); A radio frequency N-type connector (3) is connected to the other end of the wide-band impedance converter (2), and the radio frequency N-type connector (3) is a voltage sampling output port.

2. The synchrotron high-frequency cavity broadband voltage sampling device according to claim 1, characterized in that: Also includes: A wideband voltage distributor (4) is connected to an end of the wideband impedance converter (2) facing away from the capacitive voltage divider circuit, the wideband voltage distributor (4) comprising a second ferrite ring (41) and a double-core twisted wire (42), the double-core twisted wire (42) being wound around the outer periphery of the second ferrite ring (41); The radio frequency N-type connector (3) comprises two paths, and the two paths of the radio frequency N-type connector (3) are both connected to the wide-band voltage distributor (4).

3. The synchrotron high-frequency cavity broadband voltage sampling device according to claim 1, characterized in that: The first ferrite ring (21) is made of ferrite material pressed and sintered into a ring shape; the variable impedance ratio of the wide-band impedance transformer (2) is 1:n.

4. The synchrotron high-frequency cavity broadband voltage sampling device according to claim 2, characterized in that: The second ferrite ring (41) is made of ferrite material pressed and sintered into a ring shape; the voltage ratio of the two output ports of the wide-band voltage distributor (4) is 1:1, and the two output ports are respectively connected to the two radio frequency N-type connectors (3).

5. The synchrotron high-frequency cavity broadband voltage sampling device according to claim 1, characterized in that: The capacitive voltage divider circuit (1) comprises: A small-capacitance high-voltage capacitor (11) used to connect the acceleration gap of the high-frequency cavity; A large-capacitance low-voltage capacitor (12) has one end connected to the small-capacitance high-voltage capacitor (11) and the other end connected to the wide-band impedance converter (2); and the large-capacitance low-voltage capacitor (12) is grounded.

6. The synchrotron high-frequency cavity broadband voltage sampling device according to claim 5, characterized in that: The capacitive voltage divider circuit (1) comprises two paths connected in parallel, and each path of the capacitive voltage divider circuit (1) is connected to the wide-band impedance converter (2).

7. The synchrotron high-frequency cavity broadband voltage sampling device according to claim 5, characterized in that: The small-capacitance high-voltage capacitor (11) comprises two 10pF radio frequency high-voltage capacitors connected in series, the capacitance of the small-capacitance high-voltage capacitor is 5pF, the high-voltage resistance of a single high-frequency high-voltage capacitor is greater than 20kV, and the maximum current it can withstand is 10A.

8. The synchrotron high-frequency cavity broadband voltage sampling device according to claim 1, characterized in that: The resistance of the radio frequency N-type connector (3) is 50Ω.

9. The synchrotron high-frequency cavity broadband voltage sampling device according to claim 1, characterized in that: The sampling ratio of the capacitive voltage divider circuit (1) is 1500 times.

10. An application of a synchrotron high-frequency cavity broadband voltage sampling device, characterized in that: Applicable to heavy ion medical treatment devices or proton medical treatment devices.

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