阅读说明：本技术 一种基于量子自然基准的恒流源装置及实现方法 (Constant current source device based on quantum natural reference and implementation method ) 是由 缪培贤 张金海 廉吉庆 刘志栋 陈江 杨炜 冯浩 史彦超 陈大勇 杨旭红 于 2021-07-16 设计创作，主要内容包括：本公开的一种基于量子自然基准的恒流源装置及实现方法,包括：磁屏蔽筒1、标准线圈2、抽运-检测型原子磁力仪3、电流源4、计算机5和负载6；磁屏蔽筒1用于屏蔽地磁场,标准线圈2轴对称地置于所述磁屏蔽筒1内,电流源4向负载6和标准线圈2通入电流以产生磁场；抽运-检测型原子磁力仪3的探头部分置于标准线圈2的几何中心,用于测量标准线圈2轴线上的均匀磁场；计算机5与所述电流源4相连,用于控制电流源4向负载6和标准线圈2通入的电流。本公开将精密电流源输出的电流锁定至磁共振塞曼跃迁对应的拉莫尔进动频率,有效提升精密电流源输出电流的稳定度,降低漂移,能够获得低漂移的基于量子自然基准的恒流源装置。(The constant current source device based on the quantum natural reference and the realization method thereof comprise the following steps: the device comprises a magnetic shielding cylinder 1, a standard coil 2, a pumping-detection type atomic magnetometer 3, a current source 4, a computer 5 and a load 6; the magnetic shielding cylinder 1 is used for shielding a geomagnetic field, the standard coil 2 is axially and symmetrically arranged in the magnetic shielding cylinder 1, and the current source 4 supplies current to the load 6 and the standard coil 2 to generate the magnetic field; the probe part of the pumping-detection type atomic magnetometer 3 is arranged at the geometric center of the standard coil 2 and is used for measuring a uniform magnetic field on the axis of the standard coil 2; the computer 5 is connected with the current source 4 and is used for controlling the current which is introduced into the load 6 and the standard coil 2 by the current source 4. The constant current source device locks the current output by the precision current source to the Larmor precession frequency corresponding to the magnetic resonance Zeeman transition, effectively improves the stability of the current output by the precision current source, reduces the drift, and can obtain the low-drift constant current source device based on the quantum natural reference.)

1. A quantum natural reference based constant current source device, comprising: the device comprises a magnetic shielding cylinder 1, a standard coil 2, a pumping-detection type atomic magnetometer 3, a current source 4, a computer 5 and a load 6;

the magnetic shielding cylinder 1 is used for shielding a geomagnetic field, the standard coil 2 is axisymmetrically arranged in the magnetic shielding cylinder 1, and the current source 4 supplies current to the load 6 and the standard coil 2 to generate a magnetic field;

the probe part of the pumping-detection type atomic magnetometer 3 is arranged at the geometric center of the standard coil 2 and is used for measuring a uniform magnetic field on the axis of the standard coil 2;

the computer 5 is connected with the current source 4 and is used for controlling the current which is introduced into the load 6 and the standard coil 2 by the current source 4.

2. The constant current source device according to claim 1, wherein the load 6 is a resistor or a coil.

3. The constant current source device according to claim 1, wherein the coil coefficient of the reference coil 2 is traced to three quantum natural references of a josephson effect, a quantized hall effect, and a larmor precession effect.

4. The constant current source device according to claim 1, wherein the pumping-detection type atomic magnetometer 3 is used to measure the magnitude of a uniform magnetic field on the axis of the reference coil 2 and noise.

5. The constant current source device according to claim 1, wherein the magnetic shield cylinder 1 is cylindrical, the cylinder inner diameter is 500mm, and the cylinder inner length is 700mm or more.

6. The constant current source device according to claim 1, wherein the magnetic shield cylinder 1 is replaced with a magnetic shield coefficient of less than 10^-4The magnetic shield room of (1).

7. A method for implementing a constant current source based on a quantum natural reference, which is applied to the constant current source device of any one of claims 1 to 6, the method comprising:

step 1: strictly controlling the magnetic field environment of the experimental device and keeping the magnetic shielding cylinder 1 at a constant temperature;

step 2: the target current is set to I in the measurement software of the computer 5₀Then the target constant magnetic field is set to B₀＝I₀C₂The preset current value output by the current source 4 is I₄＝B₀/C₂Step current Δ I ═ 0, where C₂Is the coil coefficient of the standard coil 2;

and step 3: according to the magnetic field value B measured by the pumping-detection type atomic magnetometer 3, calculating and target magnetic field value B₀Negative deviation delta B ═ B₀B, then Δ I ═ Δ B/(nxc)₂) N is a current compensation speed parameter;

and 4, step 4: the computer 5 controls the current source 4 to input the current I to the standard coil 2₄＝I₄+ΔI；

And 5: repeating the steps 3 and 4, and making the magnetic field value measured by the pumping-detection type atomic magnetometer 3 equal to B in real time by restraining the drift of the constant current output by the current source 4₀The constant current introduced into the load 6 is I ═ B₀/C₂。

Technical Field

The disclosure belongs to the technical field of electromagnetism measurement, and particularly relates to a constant current source device based on a quantum natural reference and an implementation method.

Background

Since the 20 th century, the discovery of the josephson effect and the quantized hall effect has driven the establishment of quantum voltage references and quantum resistance references, where units of current can be derived from ohm's law to achieve indirect quantum currents, but efforts to find a more direct quantum current reference have not been stopped { references: zhang Zhonghua, expecting the electromagnetic measurement of 21 century [ J ]]Measurement and control technique, 2002, 21: 17-22}. Single electron tunneling has been considered as an alternative to current reference devices, however, current based on single electron tunneling is at 10^-12A-order of magnitude, and is not practical. An atomic magnetometer is utilized to measure a uniform magnetic field generated by a current-carrying standard coil, the magnetic field value and a quantum current value (determined by the ratio of quantum voltage to quantum resistance) in the standard coil are in a linear relation, the coil coefficient can be traced to three quantum natural references of a Josephson effect, a quantized Hall effect and a Larmor precession effect, and the current metering based on the quantum natural references can be realized in principle. The current in the current-carrying standard coil is locked to the Larmor precession frequency corresponding to the alkali metal atom magnetic resonance Zeeman transition, the low-drift constant current source function is realized by strictly controlling the physical environment of the experimental device, and the method is a feasible construction scheme of the quantum current reference device. In order to reduce the influence of drift of the earth magnetic field and environmental magnetic noise on the constant recurrent magnetic field, the recurrent magnetic field can be generated in a magnetic shielding cylinder or a magnetic shielding room; to increase the sensitivity of the magnetic field measurement, use may be made ofThe composition and working principle of the pumping-detection type atomic magnetometer for measuring the reproduced magnetic field refer to the patent of 'a rubidium atomic magnetometer and a magnetic field measuring method thereof, CN 107015172B'; in order to reduce the drift of the current source, the current in the current-carrying standard coil can be locked to the Larmor precession frequency corresponding to the alkali metal atom magnetic resonance Zeeman transition by referring to the design idea of an atomic clock, and the standard coil, the high-sensitivity atom magnetometer, the magnetic shielding cylinder or the magnetic shielding chamber and the high-precision current source are integrally designed into a constant current source device.

Disclosure of Invention

The invention provides a constant current source device based on quantum natural reference and an implementation method, the current in a current-carrying standard coil is locked to the Larmor precession frequency corresponding to magnetic resonance Zeeman transition, the experimental environment of the device is strictly controlled, the low-drift constant current source function can be realized, and the device has potential application to the construction of quantum current reference devices.

According to an aspect of the present disclosure, there is provided a quantum natural reference-based constant current source device, the device including: the device comprises a magnetic shielding cylinder 1, a standard coil 2, a pumping-detection type atomic magnetometer 3, a current source 4, a computer 5 and a load 6;

the magnetic shielding cylinder 1 is used for shielding a geomagnetic field, the standard coil 2 is axisymmetrically arranged in the magnetic shielding cylinder 1, and the current source 4 supplies current to the load 6 and the standard coil 2 to generate a magnetic field;

the probe part of the pumping-detection type atomic magnetometer 3 is arranged at the geometric center of the standard coil 2 and is used for measuring a uniform magnetic field on the axis of the standard coil 2;

the computer 5 is connected with the current source 4 and is used for controlling the current which is introduced into the load 6 and the standard coil 2 by the current source 4.

In a possible implementation, the load 6 is a resistor or a coil.

In one possible implementation, the coil coefficients of the standard coil 2 are traced to three quantum natural references, the josephson effect, the quantized hall effect and the larmor precession effect.

In a possible implementation, the pumping-detecting type atomic magnetometer 3 is used to measure the magnitude and noise of the uniform magnetic field on the axis of the standard coil 2.

In one possible implementation, the magnetic shield cylinder 1 is cylindrical, the inner diameter of the cylinder is 500mm, and the length of the inner cylinder is greater than or equal to 700 mm.

In a possible realization, the magnetic shielding cartridge 1 is replaced by a magnetic shielding coefficient of less than 10^-4The magnetic shield room of (1).

According to another aspect of the present disclosure, a method for implementing a quantum natural reference based constant current source is provided, which is applied to the above constant current source device, the method includes:

step 1: strictly controlling the magnetic field environment of the experimental device and keeping the magnetic shielding cylinder 1 at a constant temperature;

step 2: the target current is set to I in the measurement software of the computer 5₀Then the target constant magnetic field is set to B₀＝I₀C₂The preset current value output by the current source 4 is I₄＝B₀/C₂Step current Δ I ═ 0, where C₂Is the coil coefficient of the standard coil 2;

and step 3: according to the magnetic field value B measured by the pumping-detection type atomic magnetometer 3, calculating and target magnetic field value B₀Negative deviation delta B ═ B₀B, then Δ I ═ Δ B/(nxc)₂) N is a current compensation speed parameter;

and 4, step 4: the computer 5 controls the current source 4 to input the current I to the standard coil 2₄＝I₄+ΔI；

And 5: repeating the steps 3 and 4, and making the magnetic field value measured by the pumping-detection type atomic magnetometer 3 equal to B in real time by restraining the drift of the constant current output by the current source 4₀The constant current introduced into the load 6 is I ═ B₀/C₂。

The constant current source device based on the quantum natural reference can realize the constant current source function with low drift by locking the current in the current-carrying standard coil to the Larmor precession frequency corresponding to the magnetic resonance Zeeman transition and strictly controlling the experimental environment of the device, and is applied to the construction of the quantum current reference device.

Drawings

The accompanying drawings are included to provide a further understanding of the technology or prior art of the present application and are incorporated in and constitute a part of this specification. The drawings expressing the embodiments of the present application are used for explaining the technical solutions of the present application, and should not be construed as limiting the technical solutions of the present application.

Fig. 1 shows a schematic structural diagram of a quantum natural reference-based constant current source device according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram showing the variation of magnetic induction measured by a pumping-detecting type atomic magnetometer with the output current of a precision current source type B2912A according to one embodiment of the present disclosure;

FIG. 3 shows a schematic diagram of the magnetic field drift measured by a pump-detect atomic magnetometer under an unlocked condition of the current source 4 according to an embodiment of the present disclosure;

fig. 4 shows a schematic diagram of the constant magnetic field measured by the pumping-detection type atomic magnetometer of the current source 4 under the locked condition according to an embodiment of the present disclosure.

Detailed Description

Embodiments of the present disclosure will be described in detail with reference to the accompanying drawings and examples, so that how to apply technical means to solve technical problems and achieve the corresponding technical effects can be fully understood and implemented. The embodiments and various features in the embodiments of the present application can be combined with each other without conflict, and the formed technical solutions are all within the protection scope of the present disclosure.

Fig. 1 shows a schematic structural diagram of a quantum natural reference-based constant current source device according to an embodiment of the present disclosure.

The device comprises a magnetic shielding cylinder 1, a standard coil 2, a pumping-detection type atomic magnetometer 3, a current source 4, a computer 5 and a load 6. The magnetic shielding cylinder 1 is used for shielding a geomagnetic field, the standard coil 2 is axisymmetrically arranged in the magnetic shielding cylinder 1, and the current source 4 supplies current to the load 6 and the standard coil 2 to generate a magnetic field; the probe part of the pumping-detection type atomic magnetometer 3 is arranged at the geometric center of the standard coil 2 and is used for measuring a uniform magnetic field on the axis of the standard coil 2; the computer 5 is connected to the current source 4 for controlling the current supplied by the current source 4 to the load 6 and the reference coil 2.

Preferably, the magnetic shield cylinder 1 is cylindrical, and the inner dimension can be selected to be larger than phi 500mm x 700 mm. The magnetic shield cylinder 1 can be replaced with a magnetic shield coefficient of less than 10^-4The magnetic shield room of (1). When the internal size of the magnetic shielding cylinder 1 or the magnetic shielding room is far larger than that of the standard coil 2, the influence of the current-carrying coil on the magnetization state of the magnetic shielding cylinder can be obviously reduced, and further, the influence on the recurring magnetic field is reduced. The standard coil 2 is sized so that the magnetic field gradient in the probe region of the pumping-detection type atomic magnetometer 3 is less than 1% to ensure that the atomic magnetometer measures the magnetic field with high accuracy.

The composition and working principle of the pumping-detection type atomic magnetometer 3 are disclosed in the granted invention patent of "a rubidium atomic magnetometer and a magnetic field measuring method thereof" (patent number: CN 201710270545.8). The range of the pumping-detection type atomic magnetometer 3 is 100 nT-100000 nT, and the ultimate sensitivity is 0.2pT/Hz^1/2Magnetic field noise induced by precision current source noise in the reproduced magnetic field can be measured. As shown in fig. 1, a probe of the pumping-detecting type atomic magnetometer 3 is placed at the geometric center of the standard coil 2, and is used for measuring the size and noise of a uniform magnetic field on the axis of the standard coil 2.

Measurement software carried in the computer 5 is used to control the operation of the pumping-detecting type atomic magnetometer 3 and to control the current supplied by the current source 4 to the load 6 and the reference coil 2.

The load 6 may be a resistor or a coil, and a circuit composed of the resistor or the coil is not limited herein.

As shown in fig. 1, the load 6 is connected in series with the standard coil 2, when the device works stably, the larmor precession frequency corresponding to the magnetic field on the axis of the current-carrying standard coil 2 is locked to a set value, and since the magnetic field on the axis of the standard coil 2 is in proportion to the current passing through the standard coil 2 and the load 6, the device except the other components of the load 6 can be regarded as a constant current source device based on quantum natural reference. The locking loop of the device during stable operation effectively inhibits the drift of the constant current output by the current source 4 along with time, and has potential for construction of quantum current reference devices.

Preferably, the current source 4 can be a 6.5-bit commercial digital current source or a self-developed higher-precision digital current source, and the output current thereof can be set by measurement software in a computer. The current output by the current source 4 is locked to the Larmor precession frequency corresponding to the magnetic resonance Zeeman transition, so that the stability of the current output by the precision current source can be effectively improved, and the drift can be reduced.

The coil coefficients of the standard coil 2 can be traced to three quantum natural references of a Josephson effect, a quantized Hall effect and a Larmor precession effect, and the constant current source device provided based on the disclosure can be used for current metering.

Taking the example that the pumping-detection type atomic magnetometer 3 measures the coil coefficient of the standard coil 2, the magnetic induction B of the current-carrying standard coil 2 measured by the pumping-detection type atomic magnetometer 3 has the following relationship with the larmor precession frequency f of the atomic magnetic moment:

b ═ (2 pi/gamma) × f formula (1), wherein gamma is⁸⁷Gyromagnetic ratio of Rb.

When current passes through the standard coil 2, the magnetic induction intensity B generated by the standard coil 2 is related to the current I by: b ═ C × I formula (2), where C is the coil coefficient of the standard coil.

From equations (1) and (2), the relationship of the current I to the larmor precession frequency f can be obtained: i ═ 2 pi f/(γ C) formula (3).

A quantum voltage reference device based on the Josephson effect and a quantum resistance reference device based on the quantized Hall effect are built in China, quantum current is obtained by adopting the ratio of quantum voltage to quantum resistance in electrical measurement, the current is pumped into a standard coil 2 and then is detected by a pumping-detection type atomic magnetometer 3 to obtain magnetic induction intensity B, a series of quantum currents I are set to obtain corresponding magnetic induction intensity B, a coil coefficient C of the standard coil 2 can be obtained according to the formula (2) linear fitting experimental data, and the coil coefficient is traced to three quantum natural references of the Josephson effect, the quantized Hall effect and the Larmor precession effect. After the coil coefficient C of the standard coil is obtained and the Larmor precession frequency f is measured by the pumping-detection type atomic magnetometer, the constant current led into the standard coil can be obtained according to the formula (3), and the current value output by the current source 4 can be traced to three quantum natural references of a Josephson effect, a quantized Hall effect and a Larmor precession effect by the method. Therefore, the current output by the constant current source device is traced to three quantum natural references, namely, the josephson effect, the quantized hall effect and the larmor precession effect.

The constant current source device based on the quantum natural reference can effectively improve the stability of the output current of the precise current source 4 and reduce the drift.

The following describes a constant current source device based on quantum natural reference and an implementation method thereof in detail with reference to embodiments.

The first embodiment is as follows:

step 1: the experimental environment is strictly controlled, the constant temperature of the magnetic shielding cylinder 1 (or the magnetic shielding room) is kept, no obvious magnetic field fluctuation and magnetic noise source exist around the magnetic shielding cylinder, the influence of the change of the magnetization state of the magnetic shielding material and the environmental magnetic noise on the magnetic field measurement is reduced, and the remanence in the magnetic shielding cylinder 1 (or the magnetic shielding room) tends to zero after the magnetic shielding cylinder is strictly demagnetized.

Step 2: starting a constant current source device, setting a target current as I in the measurement software of the computer 5₀Then the target constant magnetic field is set to B₀＝I₀C₂The preset current value output by the current source 4 is I₄＝B₀/C₂Step current Δ I ═ 0, where C₂Is the coil coefficient of the standard coil 2. In this embodiment, the current source 4 is a 6.5-bit precision current source of a delta Technology (keylight Technology) B2912A type, and since the transfer condition of the quantum current is not met in the present application, the current of 2mA to 5mA output by the current source is directly regarded as the quantum current. FIG. 2 shows the variation of magnetic field value measured by the pump-detection type atomic magnetometer with the output current of the B2912A type precision current source, the current is increased from 2mA to 5mA in steps of 0.05mA, the coil coefficient average value of the standard coil 2 is 52426.5nT/A (or 52.4265nT/mA) and the relative standard deviation is 8.3927 × 10^-5. By calculation ofThe measurement software in the machine 5 sets the initial value of the constant magnetic field to be B₀20000nT, coil coefficient C of standard coil 2₂Is 52426.5nT/A, I₄＝B₀/C₂＝0.381486A，ΔI＝0。

And step 3: according to the magnetic field value B measured by the pumping-detection type atomic magnetometer 3, the magnetic field value B and the target magnetic field value B are calculated₀Negative deviation delta B ═ B₀B, then Δ I ═ Δ B/(nxc)₂) Wherein n is a current compensation speed parameter, the larger n is, the slower the compensation speed is, but the smaller n is, the smaller the fluctuation of the magnetic field and the compensation current is, and the faster the compensation speed is, but the fluctuation of the magnetic field and the compensation current is slightly larger during stabilization, n may generally be set to be greater than or equal to 2, n is set to be 10 in the measurement software of this embodiment, and the magnetic field sampling rate of the pumping-detection type atomic magnetometer 3 is 10 Hz.

And 4, step 4: the computer 5 controls the current source 4 to input the current I to the standard coil 2₄＝I₄+ΔI；

And 5: repeating the steps 3 and 4, and making the magnetic field value measured by the pumping-detection type atomic magnetometer 3 equal to B in real time by restraining the drift of the constant current output by the current source 4₀The constant current introduced into the load 6 is I ═ B₀/C₂。

FIG. 3 shows a schematic diagram of the magnetic field drift measured by a pump-detect atomic magnetometer under an unlocked condition of the current source 4 according to an embodiment of the present disclosure; fig. 4 shows a schematic diagram of the constant magnetic field measured by the pumping-detection type atomic magnetometer of the current source 4 under the locked condition according to an embodiment of the present disclosure.

As shown in figure 3, the current source 4 is controlled by the measuring software in the computer to input the current I to the standard coil 2₄Current source 4 drifts from 20004.8nT to 20005.2nT on average in 1 second of the magnetic field values measured by pump-test type atomic magnetometer 3 in 20 minutes under unlocked condition 0.381486 a. Intercepting 5 minutes of stable magnetic field data, calculating the power spectral density of the magnetic field values, taking the average value of 21 amplitudes near the 1Hz frequency point as the magnetic field noise, and then the magnetic field noise measured by the pumping-detection type atomic magnetometer 3 is 17.3pT/Hz^1/2。

As shown in fig. 4, computer testThe quantity software controls the current source 4 to input the current I to the standard coil 2₄0.381486A, when the current source 4 is in a locked condition, the average value of the magnetic field values measured by the pumping-detection type atomic magnetometer 3 within 1 second is locked to 20000nT, 5-minute stable magnetic field data is intercepted, the power spectral density of the magnetic field values is calculated, the average value of 21 amplitude values near the 1Hz frequency point is taken as the magnetic field noise, the magnetic field noise measured by the pumping-detection type atomic magnetometer 3 is 28.3pT/Hz1/2, and the noise measured by the pumping-detection type atomic magnetometer 3 directly reflects the noise of the current source 4 when the current source 4 is not locked; the digital lock loop also introduces additional noise when the current source 4 is locked, and therefore the magnetic field noise measured in fig. 4 is larger than the magnetic field noise measured in fig. 3. Since the magnetic field on the axis of the standard coil 2 is in direct proportion to the current of the current source 4 to the standard coil 2 and the load 6, the locking loop effectively restrains the drift of the current output by the current source 4 along with the time when the constant current source device works stably.

The constant current source device disclosed by the invention locks the current in the current-carrying standard coil to the Larmor precession frequency corresponding to the magnetic resonance Zeeman transition by adopting a digital negative feedback mode, so that the stability of the output current of the constant current source is effectively improved, and the drift is reduced. Since the coil coefficients of the standard coil can be traced to three quantum natural references of the josephson effect, the quantized hall effect and the larmor precession effect, the current output by the constant current source device of the present disclosure is traced to the three quantum natural references.

In summary, the first embodiment is a preliminary testing method for the quantum-based natural-reference-based constant current source device, and a great deal of work is required in the future when a current reference device is built, for example, the drift and noise of the constant current source are reduced at the same time, and the influence of residual magnetism in the magnetic shielding cylinder 1 (or the magnetic shielding chamber) on the accuracy of the output current of the constant current source is reasonably analyzed. The embodiment is merely a preferred embodiment of the disclosure, and is not intended to limit the scope of the disclosure. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.