CN211505846U - Low-temperature magnetic field compensation system for superconducting cavity - Google Patents
Low-temperature magnetic field compensation system for superconducting cavity Download PDFInfo
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- CN211505846U CN211505846U CN201921751126.7U CN201921751126U CN211505846U CN 211505846 U CN211505846 U CN 211505846U CN 201921751126 U CN201921751126 U CN 201921751126U CN 211505846 U CN211505846 U CN 211505846U
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Abstract
The utility model discloses a low-temperature magnetic field compensation system for a superconducting cavity, which comprises a magnetic shielding cylinder and a test hanger, wherein the test hanger is used for connecting the superconducting cavity and fixing the superconducting cavity in the magnetic shielding cylinder; it is characterized by also comprising an excitation system; the excitation system is used for being installed on the superconducting cavity and offsetting or compensating residual magnetism of the earth magnetic field and the superconducting cavity tool equipment. The system can reduce the environmental magnetic field of the superconducting cavity region, can realize flexible setting of the superconducting cavity magnetic field environment, and can be used for performance improvement experimental research of the superconducting cavity.
Description
Technical Field
The utility model relates to a superconducting cavity is with low temperature magnetic field compensating system belongs to particle accelerator, superconductive low temperature technical field.
Background
The low-temperature magnetic field compensation system for the superconducting cavity is important experimental equipment for researching the surface resistance characteristic of the superconducting cavity, and is a set of magnetic field shielding and compensation system formed by various materials and equipment. The magnetic field compensation device works in a severe environment with low temperature of 2K (or 4K), high vacuum and radiation, mainly plays a role in shielding a geomagnetic field, compensating the environmental magnetic field of the superconducting cavity, and can set magnetic fields with different strengths to carry out experimental research on the electromagnetic characteristics of the superconducting cavity.
In order to further explore and research the deep structure of a substance, reveal the mysterious course and law of nature and promote the application of basic research in the technical field, the superconducting accelerator becomes the focus of attention of scientists. The superconducting accelerator can accelerate particles to higher energy within a short distance, can enable the high-energy particles to collide to carry out high-energy physical research, and can also utilize rays emitted by the particles to carry out analysis research on structures of living matters and materials. Therefore, many large-scale superconducting accelerator projects at home and abroad are produced, and engineering projects such as a linear accelerator coherent light source project built in the united states, a shanghai hard X-ray free electron laser device, a future international linear collider project planned and built jointly by multiple countries, a future annular collider proposed by high energy of the Chinese academy, and the like need a large number of superconducting cavities for high electron beam energy.
Because the manufacturing process of the superconducting cavity is complex, the equivalent lattice of the matched low-temperature equipment is expensive, and the operation cost is high, the performance of the superconducting cavity needs to be further improved, the number of the superconducting cavities is reduced, and the construction and operation costs of the superconducting accelerator are reduced. An important performance parameter of the superconducting cavity performance is the surface resistance of the superconducting cavity, and the Q of the superconducting cavity can be improved by reducing the surface resistance of the superconducting cavity0The superconducting cavity can work under higher acceleration gradient, thereby achieving the purpose of reducing cost. An important factor influencing the surface resistance of the superconducting cavity is the magnetic field of the environment where the superconducting cavity is located, because the magnetic flux capture occurs when the superconducting cavity performs superconducting transformation, the surface resistance of the superconducting cavity is increased, and the influence of the magnetic flux capture on the performance of the superconducting cavity needs to be further studied, so that a magnetic field compensation system applied to a low-temperature environment is needed to monitor the magnetic field of the superconducting surface in real timeThe change can adjust the environmental magnetic field of the superconducting cavity so as to conveniently research the characteristic experiment of the superconducting cavity and compensate the environmental magnetic field to the acceptable safety limit to ensure the high Q of the superconducting cavity0The performance is not affected by external magnetic fields.
At present, a method for reducing the environmental magnetic field of a superconducting cavity, which is commonly used at home and abroad, is to process a cylinder body by using a material with high magnetic conductivity, and install the cylinder body on a testing Dewar inner layer and a heat insulation vacuum layer of the superconducting cavity, as shown in figure 1.
The general superconducting cavity ambient magnetic field counteracting device mainly comprises an inner magnetic shielding layer and an outer magnetic shielding layer. The inner layer magnetic shield is arranged at the innermost layer of the Dewar, the outer layer magnetic shield is arranged between the Dewar liquid helium cold shield and the outermost layer, and the superconducting cavity is arranged at the central position of the inner layer magnetic shield and close to the bottom.
This solution has the following drawbacks and disadvantages:
(1) the shielding offset of the geomagnetic field in the hoisting area of the superconducting cavity can only reach about 10mGs, and the geomagnetic field is difficult to reduce, and the shielding effect on the geomagnetism can also be reduced because the inner-layer magnetic shielding barrel body is not provided with a top cover;
(2) the magnetic field of the superconducting cavity tool part in the magnetic shielding can not be shielded and compensated;
(3) the environmental magnetic field in the superconducting cavity region cannot be flexibly set and changed, and performance test research on the superconducting cavity can be carried out.
The three points influence the test performance of the superconducting cavity to a certain extent, are not beneficial to the experimental research of improving and improving the performance of the superconducting cavity, and also have certain influence on the development and application of the high-performance superconducting cavity and the cost reduction.
SUMMERY OF THE UTILITY MODEL
To the technical problem who exists among the prior art, the utility model aims to provide a superconducting cavity is with low temperature magnetic field compensating system further reduces the regional environmental magnetic field in superconducting cavity to can realize superconducting cavity magnetic field environment's nimble setting, carry out superconducting cavity's performance promotion experimental study.
The technical scheme of the utility model is that:
a low-temperature magnetic field compensation system for a superconducting cavity comprises a magnetic shielding cylinder and a test hanging bracket, wherein the test hanging bracket is used for connecting the superconducting cavity and fixing the superconducting cavity in the magnetic shielding cylinder; it is characterized by also comprising an excitation system; the excitation system is used for being installed on the superconducting cavity and offsetting or compensating residual magnetism of the earth magnetic field and the superconducting cavity tool equipment.
Furthermore, the excitation system comprises a film heater, a plurality of temperature sensors, a plurality of fluxgate sensors and two excitation coils; the two excitation coils are respectively arranged on the beam tubes at the upper end and the lower end of the superconducting cavity and combined into a whole through a connecting rod; the thin film heater is used for being arranged on the superconducting cavity and changing the temperature of the superconducting cavity; the temperature sensor is arranged on the superconducting cavity and used for monitoring the temperature of the set position of the superconducting cavity in real time and sending the acquired temperature information to the data acquisition and hardware control system; the fluxgate sensor is mounted on the superconducting cavity and used for monitoring a magnetic field at a set position of the superconducting cavity and sending monitored magnetic field information to the data acquisition and hardware control system, and the data acquisition and hardware control system adjusts the current of the excitation coil according to a magnetic field value monitored by the fluxgate sensor.
Further, three sets of the fluxgate sensors are included; three sets of the fluxgate sensors are uniformly distributed on an equatorial plane of the superconducting cavity, and the fluxgate sensors are installed in a direction axially parallel to the superconducting cavity.
Furthermore, the film heater is used for being adhered to the middle of the upper end beam tube of the superconducting cavity.
Furthermore, the film heating resistor is made of polyimide.
And the three temperature sensors are respectively used for being arranged at the root and the equator of the upper beam tube and the lower beam tube of the superconducting cavity.
Further, the test hanging bracket further comprises an inner magnetic shielding top cover, and the inner magnetic shielding top cover is installed above the hanging plate of the test hanging bracket.
Furthermore, the inner magnetic shielding top cover is of a circular structure, and four large holes and four small holes are formed in the outer edge of the inner magnetic shielding top cover; the big hole is used for the vacuum pipeline of the magnetic shielding cylinder to pass through, and the small hole is used as a channel of a radio frequency cable, a heater and a sensor cable.
Further, the magnetic shielding cylinder comprises an inner magnetic shielding cylinder and an outer magnetic shielding cylinder; the inner magnetic shielding cylinder is arranged in the Dewar inner layer and is soaked in the liquid helium, and the outer magnetic shielding cylinder is arranged in the heat insulation vacuum between the Dewar liquid nitrogen cold shield and the Dewar outer layer; install the supporting shoe between inlayer magnetism shielding barrel and the dewar inlayer, install the supporting shoe between dewar inlayer and the liquid nitrogen cold screen, install the supporting shoe between liquid nitrogen cold screen and the outer magnetism shielding barrel, install the supporting shoe between outer magnetism shielding barrel and the dewar skin.
Fig. 2 is a schematic diagram showing a design scheme of the cryogenic magnetic field compensation system for a superconducting cavity according to the present application. The low-temperature magnetic field compensation system for the superconducting cavity is mainly composed of a magnetic shielding cylinder, a top cover, an excitation system and the like. The requirements of the superconducting cavity on the geomagnetic field environment can be met, and the environmental magnetic field parameters can be flexibly set to improve and promote the research on the performance of the superconducting cavity.
Firstly, a magnetic shielding cylinder body and an inner layer magnetic shielding top cover:
fig. 3 is a schematic view showing the installation of the magnetic shielding cylinder and the top cover. The inner magnetic shielding cylinder body is arranged on the innermost layer of the Dewar and soaked in liquid helium, the outer magnetic shielding cylinder body is arranged in a heat insulation vacuum between the Dewar liquid nitrogen cold shield and the Dewar outer layer, and the inner magnetic shielding top cover is arranged above a hanging plate of the test hanging bracket. The inner layer magnetic shielding top cover and the inner layer magnetic shielding barrel form a relatively closed space, so that the shielding effect on the geomagnetic field is improved. The supporting blocks are installed on the magnetic shields, so that the uniform gap between the magnetic shield barrel and the Dewar is ensured, and the barrel is prevented from deforming. As shown in fig. 4, which is a schematic structural view of the inner layer magnetic shield top cover, the inner layer magnetic shield top cover is a circular structure, and eight holes are opened on the outer side of the shield plate: four large holes and four small holes. The vacuum pipe passes through four large holes, and the small holes are used as channels of radio frequency cables, heaters and other sensor cables.
Excitation system:
fig. 5 is a schematic structural diagram of an excitation system of a low-temperature magnetic field compensation system for a superconducting cavity. The two excitation coils are respectively arranged on the beam tubes at the upper end and the lower end of the superconducting cavity and are combined into a whole through four connecting rods; the thin film heater is adhered to the middle part of the upper end beam tube of the superconducting cavity; the three sets of fluxgate sensors are uniformly distributed on the equatorial plane of the superconducting cavity at included angles of 120 degrees, and the installation direction of the fluxgate sensors is parallel to the axial direction of the superconducting cavity; the three temperature sensors are respectively arranged on the root parts and the middle equator positions of the upper beam tube and the lower beam tube of the superconducting cavity. All the equipment and sensor signal wires are led out to an external PC data acquisition control system and corresponding driving current sources through the test hanging bracket. The temperature sensor is used for monitoring the temperatures of different positions of the superconducting cavity in real time and judging the superconducting transition condition of the superconducting cavity; the fluxgate sensor monitors magnetic fields at different positions of the equator of the superconducting cavity, the data acquisition and hardware control system feeds back according to the magnetic field value monitored by the fluxgate sensor, adjusts the current of the excitation coil, and adjusts the environmental magnetic field of the superconducting cavity according to the set magnetic field parameter value (the magnetic field adjustment range is 0-200mGs, the adjustment precision is less than 0.5mGs, and the coil uniformity error is less than 2%); the film heater is used for improving the surface temperature gradient when the superconducting cavity generates superconducting transition and is matched with the excitation coil, so that experimental research of trapping magnetic flux and discharging of the superconducting cavity is facilitated. The excitation system can realize the precise adjustment and control of the environmental magnetic field of the superconducting cavity, further reduce the influence of residual magnetism on the performance of the superconducting cavity, and can set various magnetic field environments to carry out experimental research.
Compared with the prior art, the utility model discloses an actively the effect does:
(1) and (3) adding an inner magnetic shielding top cover: an inner magnetic shielding top cover is arranged on the test hanging frame and is not directly contacted with the inner magnetic shielding cylinder body, so that a relatively sealed space for the geomagnetic field is formed, and the shielding effect on the geomagnetic field in the superconducting cavity area is further improved.
(2) And (3) adding a magnet exciting coil: the excitation coil is arranged around the superconducting cavity, and the residual magnetism of the earth magnetic field and the superconducting cavity tool equipment is offset and compensated through the magnetic field generated by the excitation coil;
(3) and (3) adding a thin film heater: the surface temperature gradient of the superconducting cavity during superconducting transformation is improved, and the superconducting cavity is matched with the excitation coil, so that experimental research on magnetic flux capture and discharge of the superconducting cavity is facilitated.
Drawings
FIG. 1 is a diagram of a general superconducting cavity ambient magnetic field cancellation arrangement;
FIG. 2 is a schematic diagram of a design scheme of a low-temperature magnetic field compensation system for a superconducting cavity;
FIG. 3 is a schematic view of the installation of the magnetic shielding cylinder and the inner magnetic shielding top cover structure;
FIG. 4 is a schematic view of an inner magnetic shield top cover construction;
FIG. 5 is a schematic diagram of an excitation system;
the device comprises a test hanger, a 2-hanger plate, a 3-clamp plate, a 4-hanger rod, a 5-superconducting cavity, a 6-inner layer magnetic shielding cylinder, a 7-outer layer magnetic shielding cylinder, an 8-Dewar inner layer, a 9-Dewar outer layer, a 10-liquid nitrogen cold screen, an 11-supporting block, a 12-inner layer magnetic shielding top cover, a 13-excitation coil, a 14-thin film heater, a 15-fluxgate sensor, a 16-temperature sensor, a 17-large hole and an 18-small hole.
Detailed Description
For better understanding of the technical solutions of the present invention, the present invention will be described in detail with reference to the following embodiments.
The utility model discloses an outer magnetic screen barrel adopts permalloy 1J85 to process the preparation, and inlayer magnetic screen barrel and inlayer magnetic screen top cap can adopt permalloy 1J79 preparation owing to soak in liquid helium to guarantee the shielding effect of material. The excitation coil is wound by polyimide enameled wires, and a support tool of the coil can be made of G10 material which is non-magnetic and has good low-temperature performance. The film heating resistor is made of polyimide and can work in the low-temperature environment of liquid helium. The uniaxial fluxgate can be selected from commercial sensor probes of Bartington in England and can also be specially developed and developed. The temperature sensor can adopt a cernox low-temperature sensor.
In summary, the above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. A low-temperature magnetic field compensation system for a superconducting cavity comprises a magnetic shielding cylinder and a test hanging bracket, wherein the test hanging bracket is used for connecting the superconducting cavity and fixing the superconducting cavity in the magnetic shielding cylinder; it is characterized by also comprising an excitation system; the excitation system is used for being installed on the superconducting cavity and offsetting or compensating residual magnetism of the earth magnetic field and the superconducting cavity tool equipment.
2. The cryogenic magnetic field compensation system for a superconducting cavity of claim 1, wherein the excitation system comprises a thin film heater, a plurality of temperature sensors, a plurality of fluxgate sensors, and two excitation coils; the two excitation coils are respectively arranged on the beam tubes at the upper end and the lower end of the superconducting cavity and combined into a whole through a connecting rod; the thin film heater is used for being arranged on the superconducting cavity and changing the temperature of the superconducting cavity; the temperature sensor is arranged on the superconducting cavity and used for monitoring the temperature of the set position of the superconducting cavity in real time and sending the acquired temperature information to the data acquisition and hardware control system; the fluxgate sensor is mounted on the superconducting cavity and used for monitoring a magnetic field at a set position of the superconducting cavity and sending monitored magnetic field information to the data acquisition and hardware control system, and the data acquisition and hardware control system adjusts the current of the excitation coil according to a magnetic field value monitored by the fluxgate sensor.
3. The cryogenic magnetic field compensation system for a superconducting cavity of claim 2, comprising three sets of the fluxgate sensors; three sets of the fluxgate sensors are uniformly distributed on an equatorial plane of the superconducting cavity, and the fluxgate sensors are installed in a direction axially parallel to the superconducting cavity.
4. The cryogenic magnetic field compensation system for a superconducting cavity of claim 2, wherein the thin film heater is configured to be attached to a middle portion of an upper end bundle tube of the superconducting cavity.
5. The system of claim 2, wherein the thin film heater resistor is made of polyimide.
6. The cryogenic magnetic field compensation system for a superconducting cavity according to claim 2, comprising three temperature sensors for mounting on the upper and lower beam tubes at the root and equator positions of the superconducting cavity, respectively.
7. The cryogenic magnetic field compensation system for a superconducting cavity of claim 1, further comprising an inner magnetic shield top cap mounted over a hanger plate of the test hanger.
8. The cryogenic magnetic field compensation system for a superconducting cavity of claim 7, wherein the inner magnetic shielding top cover has a circular structure, and four large holes and four small holes are formed in the outer edge of the inner magnetic shielding top cover; the big hole is used for the vacuum pipeline of the magnetic shielding cylinder to pass through, and the small hole is used as a channel of a radio frequency cable, a heater and a sensor cable.
9. The cryogenic magnetic field compensation system for a superconducting cavity of claim 1, wherein the magnetic shielding cylinder comprises an inner magnetic shielding cylinder and an outer magnetic shielding cylinder; the inner magnetic shielding cylinder is arranged in the Dewar inner layer and is soaked in the liquid helium, and the outer magnetic shielding cylinder is arranged in the heat insulation vacuum between the Dewar liquid nitrogen cold shield and the Dewar outer layer; install the supporting shoe between inlayer magnetism shielding barrel and the dewar inlayer, install the supporting shoe between dewar inlayer and the liquid nitrogen cold screen, install the supporting shoe between liquid nitrogen cold screen and the outer magnetism shielding barrel, install the supporting shoe between outer magnetism shielding barrel and the dewar skin.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921751126.7U CN211505846U (en) | 2019-10-18 | 2019-10-18 | Low-temperature magnetic field compensation system for superconducting cavity |
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| CN201921751126.7U CN211505846U (en) | 2019-10-18 | 2019-10-18 | Low-temperature magnetic field compensation system for superconducting cavity |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113176525A (en) * | 2021-04-23 | 2021-07-27 | 中国科学院空天信息创新研究院 | Aviation low-temperature superconducting magnetic gradient full-tension magnetometer support frame and temperature control method |
| CN113586940A (en) * | 2021-07-30 | 2021-11-02 | 中科富海(中山)低温装备制造有限公司 | Liquid nitrogen cold shield structure |
| CN115087342A (en) * | 2022-07-25 | 2022-09-20 | 之江实验室 | Double-layer vacuum superconducting magnetic shielding system and atomic magnetometer |
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2019
- 2019-10-18 CN CN201921751126.7U patent/CN211505846U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113176525A (en) * | 2021-04-23 | 2021-07-27 | 中国科学院空天信息创新研究院 | Aviation low-temperature superconducting magnetic gradient full-tension magnetometer support frame and temperature control method |
| CN113176525B (en) * | 2021-04-23 | 2023-03-31 | 中国科学院空天信息创新研究院 | Aviation low-temperature superconducting magnetic gradient full-tension magnetometer support frame and temperature control method |
| CN113586940A (en) * | 2021-07-30 | 2021-11-02 | 中科富海(中山)低温装备制造有限公司 | Liquid nitrogen cold shield structure |
| CN113586940B (en) * | 2021-07-30 | 2023-08-18 | 中科富海(中山)低温装备制造有限公司 | Liquid nitrogen cold screen structure |
| CN115087342A (en) * | 2022-07-25 | 2022-09-20 | 之江实验室 | Double-layer vacuum superconducting magnetic shielding system and atomic magnetometer |
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