CN202652821U - Magnetic shielding system - Google Patents
Magnetic shielding system Download PDFInfo
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- CN202652821U CN202652821U CN2012202274356U CN201220227435U CN202652821U CN 202652821 U CN202652821 U CN 202652821U CN 2012202274356 U CN2012202274356 U CN 2012202274356U CN 201220227435 U CN201220227435 U CN 201220227435U CN 202652821 U CN202652821 U CN 202652821U
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- magnetic
- masking layer
- magnetic shielding
- shielding system
- microwave cavity
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Abstract
The utility model provides a magnetic shielding system. The magnetic shielding system comprises an atomic storage bubble; a microwave cavity used for accommodating the atomic storage bubble and formed by connecting a microwave cavity upper cover, a microwave cavity cylinder and a microwave cavity lower cover end to end; and a working magnetic field coil arranged around the outer wall of the microwave cavity. The shielding system further comprises a first magnetic shielding layer, a second magnetic shielding layer and a third magnetic shielding layer, and the three layers are arranged at intervals from inside to outside in an embedded structure and undergo vacuum high-temperature heat treatment, wherein the first magnetic shielding layer is arranged between the working magnetic field coil and the second magnetic shielding layer. With the magnetic shielding system provided by the utility model, the problem that a magnetic shielding system is large in volume and heavy in weight in the prior art is solved, good magnetic shielding performance is ensured, the adaptability to environment magnetic field is improved, and the severe degree of the requirements of the atomic frequency standard for space magnetic field is reduced.
Description
Technical field
The utility model relates to a kind of shielding harness, is specifically related to a kind of magnetic shielding system.
Background technology
At present, domestic magnetic shielding material can be divided into many trades mark.In the atomic frequency standard field, the material that is used for the magnetic masking layer that the shielding external magnetic field adopts is the high initial magnetoconductivity permalloy, and the trade mark is 1J79 and 1J85.
According to the difference of the physical dimension of all kinds of atomic frequency standards, the concrete size of magnetic shielding system also can be different.The magnetic shielding system that atomic frequency standard adopts is that the cylindrical shape magnetic masking layer by the multilayer closure is nested to form mostly, thereby play the to external world shielding action in magnetic field, because aperture area that should be on the end face of the two poles of the earth of each screen is less, so substantially think every layer of magnetic screen or closed.Among Figure 1A 20 shows this class formation.May also can adopt the up and down two-stage end face of cylinder in indivedual fastidious designs is the structure of convex cone face, shown in 30 among Figure 1B.The concrete structure parameter can be different according to actual conditions.The number of plies of the magnetic shielding system that existing atomic frequency standard adopts is generally 4 layers.Consider the requirement of the thickness of each screen according to processing technology, the shock resistance of system own, weight and performance etc.: be followed successively by from inside to outside: 0.6mm, 0.6mm, 0.6mm, 1mm.Because the deviation of processing technology, the thickness of each layer allow ± deviation of 0.1mm.
The process that adopts at present is to be that 1J85(partly adopts 1J79 with the trade mark) magnetic shielding material by physical dimension requirement machine-shaping.Utilize hydrogen protection high temperature furnace to carry out the heat treatment of magnetic screen, take out after the cooling, and integrated on atomic frequency standard, finally adopt corresponding method to demagnetize.The treatment process of each heat treatment producer is basic identical, and high temperature peak is at 1100-1150 ℃.
Magnetic screening coefficient is defined as the ratio in magnetic shielding system external magnetic field and magnetic field, inner space on the stricti jurise, and magnetic screening coefficient is larger, and Magnetic Shielding Effectiveness is then better; Coefficient is less, and then shield effectiveness is poorer.Gn=H
InH
Outward
That is:
Wherein: Gn represents the magnetic screening coefficient of n layer magnetic shielding system;
H
OutwardRepresent near the magnetic field intensity (Gs) of n layer magnetic shielding system space outerpace;
H
InRepresent the magnetic field intensity (Gs) of n layer magnetic shielding system inner space;
By the atomic frequency standard principle as can be known, in the process of work, its frequency output stability that client is provided is the impact that can be subject to environmental magnetic field.The influence degree of environmental magnetic field can be described with magnetic susceptibility coefficient δ v/v usually, δ v/v---refer to the relative variation of the output frequency of the atomic frequency standard that causes because of the variation in external environment magnetic field.Corresponding to formula G
N=H
Outward/ H
In, the changes of magnetic field Δ H in the magnetic shielding system that causes because of the environmental magnetic field respective change as can be known, the magnetic susceptibility coefficient δ v/v=3.9 of atomic clock * 10
-6H
2(Δ H/H)
Yet, the volume and weight that magnetic shielding system of the prior art can not satisfy Shanghai Observatory passive-type Hydrogen Atom Frequency Standard limits this requirement, and the Technology for Heating Processing of existing magnetic shielding system can not satisfy the demand on the performance, Hydrogen Atom Frequency Standard requires comparatively harsh to the space environment magnetic field intensity simultaneously, therefore, be necessary to work out a kind of magnetic shielding system that can address these problems.
The utility model content
The technical problem that the utility model solves just provides a kind of magnetic shielding system, solve that magnetic shielding system volume of the prior art is large, the problem of Heavy Weight, guarantee simultaneously good magnetic shield performance, and reduce the harsh degree that Hydrogen Atom Frequency Standard requires space environment magnetic field.
For achieving the above object, the utility model adopts following technical proposals:
The utility model provides a kind of magnetic shielding system, comprising: atom stores bubble; Accommodating described atom stores the microwave cavity that is joined end to end and surrounded by microwave cavity loam cake, microwave cavity cylinder and microwave cavity lower cover of bubble; Center on the work field coil of the outer wall setting of described microwave cavity; This magnetic shielding system also comprises: heat treated the first magnetic masking layer of process vacuum high-temperature, the second magnetic masking layer and the 3rd magnetic masking layer that are arranged with the nesting type structure each interval from inside to outside; Wherein, described the first magnetic masking layer is between described work field coil and described the second magnetic masking layer.
This magnetic shielding system also comprises the vacuum bell jar that is arranged between described the second magnetic masking layer and the 3rd magnetic masking layer, and described microwave cavity is fixed on the bell jar base plate of described vacuum bell jar by connecting strutting piece.
This magnetic shielding system also comprises the vacuum pump that is arranged on described bell jar floor below.
Preferably, the wall thickness of the cylindrical side wall of described the first magnetic masking layer is 1mm, and the wall thickness of the cylindrical side wall of described the second magnetic masking layer and the 3rd magnetic masking layer is respectively 0.6mm.
The top of each described magnetic masking layer and bottom end face are plane or convex cone face.
Preferably, the wall thickness of the top and bottom end face of each described magnetic masking layer is respectively thickeied respectively one times.
Described magnetic masking layer is the permalloy magnetic masking layer.
The beneficial effect that the utility model brings is: the relative prior art of magnetic masking layer is reduced one deck, realized reducing of volume and weight, because magnetic masking layer carried out vacuum high-temperature heat treatment, so that when the utility model satisfied the restrictive requirement of the volume of Shanghai Observatory passive-type Hydrogen Atom Frequency Standard and weight, magnetic shield performance was up to standard.
Description of drawings
With reference to the accompanying drawing shown in the conduct exemplary embodiments of the present utility model subsequently, this explanation will be more readily understood, but should not be construed as the restriction to the utility model scope.
Figure 1A and Figure 1B show the structural representation of the magnetic shielding system of prior art;
Fig. 2 shows atomic frequency standard structural representation of the present utility model;
Fig. 3 shows the structural representation of the utility model magnetic shielding system;
View when Fig. 4 shows the utility model magnetic shielding system vacuum heat.
Wherein, the implication of main Reference numeral:
1, microwave cavity loam cake 2, work field coil 3, atom store bubble 4, microwave cavity cylinder 5, microwave cavity lower cover 6, the 3rd magnetic masking layer 7, the second magnetic masking layer 8, the first magnetic masking layer 9, vacuum bell jar 10, connect strutting piece 11, bell jar base plate 12, vacuum pump 13, potsherd
Embodiment
Further understand technological means of the present utility model and feature in depth for making, sincerely cooperate accompanying drawing to give again for example and further specify in rear:
As shown in Figure 2, show the magnetic shielding system that is used for atomic frequency standard according to a preferred embodiment of the utility model, this system comprises and setting gradually from inside to outside: atom stores bubble 3; Accommodating described atom stores the microwave cavity of bubble 3, and this microwave cavity is joined end to end by microwave cavity loam cake 1, microwave cavity cylinder 4 and microwave cavity lower cover 5 and surrounds; Center on the work field coil 2 of the outer wall setting of described microwave cavity; The first magnetic masking layer 8; The second magnetic masking layer 7; Vacuum bell jar 9; The 3rd magnetic masking layer 6.Wherein, described the first magnetic masking layer 8 and the 7 adjacent settings of the second magnetic masking layer, microwave cavity is fixed on the bell jar base plate 11 of described vacuum bell jar 9 by connecting strutting piece 10.This system also comprises the vacuum pump 12 that is positioned at bell jar base plate 11 belows.
According to a preferred embodiment of the present utility model, the wall thickness of the first magnetic masking layer 8 is 1mm, and the wall thickness of described the second magnetic masking layer 7 and the 3rd magnetic masking layer 6 is 0.6mm, because the deviation of processing technology, the wall thickness of each layer requires within ± 0.1mm.
According to a preferred embodiment of the present utility model, the top of described magnetic masking layer is the same with prior art with bottom end face, also can be to be selected from a kind of in plane and the convex cone face.
Because atomic clock magnetic field shielding system mainly is the magnetic field of shielding axis direction, therefore as long as the thickness of the top and bottom of each layer of thickening magnetic screen just can bring corresponding effect.According to a preferred embodiment of the present utility model, the wall thickness of the top and bottom of the magnetic masking layer of described each layer is respectively thickeied one times, the wall thickness of the top and bottom of two-layer magnetic masking layer is thickeied to 1.2mm namely, and the wall thickness of the top and bottom of the magnetic masking layer of innermost layer is thickeied to 2mm.
According to a preferred embodiment of the present utility model, the material of described magnetic masking layer adopts permalloy.
The utility model also provides a kind of method that improves the atomic frequency standard magnetic shield performance, and the method comprises: provide atom to store bubble; Described atom is stored bubble be placed in the microwave cavity, this microwave cavity comprises microwave cavity loam cake, microwave cavity cylinder and microwave cavity lower cover; Outer wall around described microwave cavity arranges the work field coil; The method further comprises: turning up the soil with the nesting type structure each interval from inside to outside arranges through heat treated the first magnetic masking layer of vacuum high-temperature, the second magnetic masking layer and the 3rd magnetic masking layer; Wherein, described the first magnetic masking layer is between described work field coil and described the second magnetic masking layer.
Each layer magnetic masking layer carries out vacuum high-temperature heat treatment, after cooling is taken out, integrated on atomic frequency standard, afterwards microwave cavity is connected with external circuitry as conductor and by wire, regulate and control axial demagnetization current, the generation frequency is that the variable alternating magnetic field of the amplitude of 50Hz demagnetizes to each magnetic masking layer, finally improves the magnetic screening coefficient of atomic frequency standard magnetic shielding system.
In the heat treated process of whole vacuum high-temperature, the vacuum degree in the high temperature furnace has been taked strict control measure, satisfy all the time P≤10
-3Pa.And the vacuum degree of this technique does not need strict control in the prior art, only is the hydrogen environment that keeps in the stove, and purpose is isolation from oxygen, thus vacuum degree only need satisfy≤1atm gets final product.
Secondly, according to a preferred embodiment of the present utility model, the high temperature peak during heat treatment is increased to 1200 ℃ by 1100 ~ 1150 ℃ of prior art.
When carrying out vacuum high-temperature heat treatment, the nestable part in described the first magnetic masking layer, the second magnetic masking layer and the 3rd magnetic masking layer bottom adopts refractory ceramics sheet 13 with described each layer isolation, and specific implementation method as shown in Figure 4.The material of described refractory ceramics sheet is Al
2O
3, main purpose is that each screen is spaced from each other, and prevents from producing in the high temperature sticking connection.In whole high-temperature process, all adopted the isolation of refractory ceramics sheet.
According to a preferred embodiment of the present utility model, when arriving 1200 ℃ of high temperature peak, adopt the insulation operation, temperature retention time t 〉=8 hour all are in the desirable temperature atmosphere whole magnetic screen workpiece, and guarantee sufficient action time.
The effect that this utility model is brought is finally embodied in the complete machine service behaviour of atomic frequency standard, because atomic frequency standard as time and frequency standard equipment, according to customer requirement, is exported a certain road or the metastable characteristic frequency of multichannel outside the reply.By the atomic frequency standard principle as can be known, in the process of work, its frequency output stability that client is provided is the impact that can be subject to environmental magnetic field.The influence degree of environmental magnetic field can be described with magnetic susceptibility coefficient δ v/v usually, δ v/v---refer to the relative variation of the output frequency of the atomic frequency standard that causes because of the variation in external environment magnetic field.The magnetic shield performance that the utility model has promoted magnetic screen is magnetic screening coefficient G, thereby has improved the magnetic susceptibility coefficient of atomic clock, reduces environmental magnetic field to the impact of the output frequency of atomic clock.Its principle is by in the process of high-temperature heat treatment, strictly controls atmosphere vacuum degree, reaches the purpose of the shielding properties of lifting piece magnetic screen.As shown in Figure 3, measure respectively the magnetic field intensity H of this magnetic shielding system inner space
InNear and the magnetic field intensity H this magnetic shielding system space outerpace
OutwardCorresponding to formula G
N=H
Outward/ H
In, the changes of magnetic field Δ H in the magnetic shielding system that causes because of the environmental magnetic field respective change as can be known, the magnetic susceptibility coefficient δ v/v=3.9 of atomic clock * 10
-6H
2(Δ H/H), through experiment confirm, for the atomic clock of 3 layers of present shielding construction, the magnetic susceptibility coefficient now can reach 2 * 10
-13/ Gs.At this moment, the outer amplitude range 0～2Gs of H need be satisfied in the operational environment magnetic field of atomic frequency standard.
The method of magnetic shielding system provided by the utility model and raising atomic frequency standard magnetic shield performance is not only applicable to Hydrogen Atom Frequency Standard, also is applicable to the magnetic shielding system of other atomic frequency standard.
Process provided by the utility model is so that the magnetic shielding system performance of passive-type Hydrogen Atom Frequency Standard has obtained large increase.In the constant situation of other condition, so that the magnetic screening coefficient of magnetic shielding system has improved 1 times, for the structure that provides in the accompanying drawing 2, magnetic screening coefficient reaches 100000.For the structure that provides among the accompanying drawing 1A, magnetic screening coefficient reaches 200000.The utility model is based on the volume that will reduce the original passive-type Hydrogen Atom Frequency Standard of Shanghai Observatory and this specific demand background of weight, thus the structure that adopts than before lack one deck magnetic screen, i.e. real structure with novel middle employing.But process originally can not satisfy the demand on the performance, makes magnetic shield performance up to standard by this utility model.So the primary objective of this utility model is how to satisfy under the situation of performance passive-type Hydrogen Atom Frequency Standard loss of weight in order to solve.We promote the use of this process on 4 layers of shielding construction of original employing again afterwards, and its magnetic screening coefficient is improved, and therefore the coefficient than 3-tier architecture in the utility model is high.And the magnetic susceptibility coefficient of complete machine is from original 1 ~ 2 * 10
-13/ Gs is promoted to 10
-14/ Gs, thus the ability of the anti-external environment magnetic interference of Hydrogen Atom Frequency Standard improved, so that the constraints of external environment magnetostatic field can be relaxed to the scope at 0 ~ 2Gs.The method need to shield Hydrogen Atom Frequency Standard and the time frequency marking of external environment magnetic interference applicable to other.
At present, Shanghai Observatory has been finished application experiment 2 passive-type Hydrogen Atom Frequency Standard altogether, experimental result be 2 passive-type Hydrogen Atom Frequency Standard after tested, the magnetic screening coefficient of magnetic shielding system is all more than 100000, and under the condition in the external environment magnetic field of 0 ~ 2Gs, every test index all can satisfy the correlation technique requirement.Specifically, in Hydrogen Atom Frequency Standard shown in Figure 2, by the to external world shielding of the magnetic of environment of magnetic shielding system, so that the magnetic field in the microwave cavity zone about 10
-10～10
-9NT, the changes of magnetic field even external environment magnetic field changes in (in 0～2Gs) microwave cavity zone also very little (≤2nT).
The beneficial effect that the utility model brings is: the relative prior art of magnetic masking layer is reduced one deck, realized reducing of volume and weight, simultaneously when the processing of this magnetic shielding system is processed, adopt vacuum high-temperature heat treatment, so that in the restrictive requirement of the volume that satisfies Shanghai Observatory passive-type Hydrogen Atom Frequency Standard and weight, magnetic shield performance is up to standard;
Secondly, system and method provided by the utility model so that extraneous space environment magnetic field when in a certain size scope, changing Hydrogen Atom Frequency Standard preferably service behaviour can both be arranged, namely improve the adaptability to environmental magnetic field, reduced simultaneously the harsh degree that Hydrogen Atom Frequency Standard requires space environment magnetic field.Be not only applicable to Hydrogen Atom Frequency Standard, equally also be applicable to other atomic frequency standard.
More than although embodiment of the present utility model has been described, it will be understood by those of skill in the art that these only illustrate, protection range of the present utility model is limited by appended claims.Those skilled in the art can make various changes or modifications to these execution modes under the prerequisite that does not deviate from principle of the present utility model and essence, but these changes and modification all fall into protection range of the present utility model.
Claims (7)
1. magnetic shielding system comprises:
Atom stores bubble;
Accommodating described atom stores the microwave cavity that is joined end to end and surrounded by microwave cavity loam cake, microwave cavity cylinder and microwave cavity lower cover of bubble;
Center on the work field coil of the outer wall setting of described microwave cavity; It is characterized in that this magnetic shielding system also comprises: heat treated the first magnetic masking layer of process vacuum high-temperature, the second magnetic masking layer and the 3rd magnetic masking layer that are arranged with the nesting type structure each interval from inside to outside; Wherein, described the first magnetic masking layer is between described work field coil and described the second magnetic masking layer.
2. magnetic shielding system as claimed in claim 1, it is characterized in that, this magnetic shielding system also comprises the vacuum bell jar that is arranged between described the second magnetic masking layer and the 3rd magnetic masking layer, and described microwave cavity is fixed on the bell jar base plate of described vacuum bell jar by connecting strutting piece.
3. magnetic shielding system as claimed in claim 1 is characterized in that, also comprises the vacuum pump that is arranged on described bell jar floor below.
4. magnetic shielding system as claimed in claim 1 is characterized in that, the wall thickness of the cylindrical side wall of described the first magnetic masking layer is 1mm, and the wall thickness of the cylindrical side wall of described the second magnetic masking layer and the 3rd magnetic masking layer is respectively 0.6mm.
5. magnetic shielding system as claimed in claim 1 is characterized in that, the top of each described magnetic masking layer and bottom end face are plane or convex cone face.
6. magnetic shielding system as claimed in claim 1 is characterized in that, the wall thickness of the top and bottom end face of each described magnetic masking layer is respectively thickeied respectively one times.
7. magnetic shielding system as claimed in claim 1 is characterized in that, described magnetic masking layer is the permalloy magnetic masking layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012202274356U CN202652821U (en) | 2012-05-17 | 2012-05-17 | Magnetic shielding system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2012202274356U CN202652821U (en) | 2012-05-17 | 2012-05-17 | Magnetic shielding system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202652821U true CN202652821U (en) | 2013-01-02 |
Family
ID=47421835
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2012202274356U Expired - Lifetime CN202652821U (en) | 2012-05-17 | 2012-05-17 | Magnetic shielding system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202652821U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112786324A (en) * | 2021-01-29 | 2021-05-11 | 北京双杰电气股份有限公司 | Low-voltage direct-current circuit breaker arc extinguish chamber and circuit breaker |
| CN117015224A (en) * | 2023-09-28 | 2023-11-07 | 国网江苏省电力有限公司营销服务中心 | Electromagnetic shielding device and system for keeping superconducting state of Josephson junction |
-
2012
- 2012-05-17 CN CN2012202274356U patent/CN202652821U/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112786324A (en) * | 2021-01-29 | 2021-05-11 | 北京双杰电气股份有限公司 | Low-voltage direct-current circuit breaker arc extinguish chamber and circuit breaker |
| CN117015224A (en) * | 2023-09-28 | 2023-11-07 | 国网江苏省电力有限公司营销服务中心 | Electromagnetic shielding device and system for keeping superconducting state of Josephson junction |
| CN117015224B (en) * | 2023-09-28 | 2024-02-20 | 国网江苏省电力有限公司营销服务中心 | Electromagnetic shielding device and system for keeping superconducting state of Josephson junction |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130102 |
|
| CX01 | Expiry of patent term |