CN215415923U - Novel alkali metal optical pump magnetometer - Google Patents
Novel alkali metal optical pump magnetometer Download PDFInfo
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- CN215415923U CN215415923U CN202121173511.5U CN202121173511U CN215415923U CN 215415923 U CN215415923 U CN 215415923U CN 202121173511 U CN202121173511 U CN 202121173511U CN 215415923 U CN215415923 U CN 215415923U
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Abstract
The utility model discloses a novel alkali metal optical pump magnetometer, and relates to the field of magnetic measurement. The utility model creatively designs the single-wavelength reflection cavity, thereby realizing the self-locking of the wavelength of the pumping light and the single-shaft bidirectional pumping. The probe of the optical pump magnetometer has stronger optical pump effect, the magnetic resonance signal of the probe is higher than that of the magnetometer probe with the traditional structure, and meanwhile, the sensitivity of the magnetometer is higher. Meanwhile, the structure simplifies the structure of the pump lamp and the atomic absorption chamber of the optical pumping magnetometer, and realizes the integration of the pump source and the atomic absorption chamber. On the premise of not reducing the performance of the magnetometer, the structure of the optical pump probe and an attached circuit are simplified, and the miniaturization of the optical pump probe is facilitated. The utility model has the advantages of low technical difficulty and low production cost, can meet the practical requirement of miniaturization of the optical pump probe and has practicability.
Description
Technical Field
The utility model relates to the field of magnetic measurement, in particular to a novel alkali metal optical pump magnetometer.
Background
In geological formations, the local geophysical field changes due to differences in density, elasticity, electrical conductivity, magnetism, radioactivity and thermal conductivity of different formation media in the earth's crust. By measuring the distribution and change characteristics of the physical fields, the geological structure analysis is carried out on the physical fields, and then the geological characters are deduced. The main task of geophysical exploration is to measure parameters such as local electrical conductivity, radioactivity, magnetism and gravity of the crust, provide reference information for geological analysis and facilitate future mineral exploration and exploitation. In order to realize the collection of geomagnetism parameters, geophysical prospecting personnel operate various magnetic prospecting equipment to carry out magnetic prospecting so as to collect the crustal magnetism parameters.
A large amount of paramagnetic materials such as iron, chromium, nickel and the like are left in the earth crust. Under the action of earth strong magnetic field, the paramagnetic material has stronger magnetism after being magnetized. Because of good structural strength, material characteristics and rich storage, the iron-chromium-nickel paramagnetic material is widely applied to the field of daily production and life and military use by people. The magnetic field of the surrounding earth changes due to the fact that unexplosive UXO, the ground and objects unknown underwater have a large amount of magnetic bodies. Their magnetic properties are often used as a detection target. Magnetic detection equipment is the main detection and positioning equipment.
The optical pump magnetometer is a high-sensitivity magnetic detection device, and the working principle of the optical pump magnetometer is that specific atoms in a magnetic field generate magnetic resonance under the action of an optical pump, and the tracking measurement of an external magnetic field is realized through a tracking loop with a direction-removing effect or a Larmor magnetic resonance frequency self-excitation loop. The optical pump magnetometer has high sensitivity, so the optical pump magnetometer is a main device for military and civil high-precision and high-performance magnetic prospecting and magnetic anomaly detection. The novel alkali metal optical pump magnetometer adopts a self-excitation magnetometer. And only when the amplitude of the Larmor signal in the self-excited tracking loop is large enough and the phase meets the self-excited condition, the optical pump probe generates self-excited oscillation of the Larmor signal. By measuring the larmor frequency, the value of the external magnetic field can be calculated. In order to realize the optical pumping effect, a pump lamp and an atomic absorption chamber in the traditional optical pumping magnetometer adopt a separation structure. The independent pump lamp generates optical pump effect to the atom in the atom absorption chamber, and the atom in the atom absorption chamber generates magnetic resonance. In this method, the pumping effect is unidirectional pumping, and the pumping probability of the alkali metal atoms is limited. To ensure sufficient pumping intensity, the technician will apply a high frequency excitation of higher power to the pump lamp. Meanwhile, because the spectrum of the pump lamp is wide, the external light wave of the pump light introduces optical noise. If a laser is adopted as a pump source, the structure is more complex, the number of matched circuits is large, the technical difficulty of the laser pump magnetometer is high, and the production cost is high. In addition, in order to ensure the concentration of the metal vapor in the alkali metal pump lamp and the alkali metal atom absorption chamber, designers usually adopt two sets of circuits to respectively heat the lamp and the chamber and preserve heat. Therefore, the conventional optical pump probe has the defects of complicated structure, large size and complex circuit.
SUMMERY OF THE UTILITY MODEL
The utility model aims to overcome the defects in the prior art, and provides a novel alkali metal optical pump magnetometer which has the advantages of self-locking of pumping light wavelength, single-shaft bidirectional pumping, simple structure, smaller technical difficulty and lower production cost.
The purpose of the utility model is achieved by the following technical scheme: the novel alkali metal optical pump magnetometer comprises a probe, a magnetometer host and a magnetic sensor, wherein the probe is electrically connected with the magnetometer host through a cable; the probe comprises a probe outer cover, a magnetic sensor is arranged in an inner cavity of the probe outer cover, a coil is arranged around the periphery of the magnetic sensor and electrically connected with a magnetometer host through a cable and used for applying a Larmor signal radio frequency field to the magnetic sensor; the magnetic sensor is of a tubular structure with two closed ends, alkali metal is filled in the magnetic sensor, heating wires are uniformly wound on the outer wall of the magnetic sensor and used for heating the alkali metal to a gaseous state, and the heating wires are electrically connected with the cable to realize power supply; one end of the electrode is connected with the cable, and the other end of the electrode is inserted into the magnetic sensor and is used for high-frequency excitation of alkali metal steam to enable the alkali metal steam to emit light; a polaroid is arranged in the magnetic sensor and used for converting the alkali metal light into the pumping light; reflectors are arranged at two ends of the magnetic sensor, so that a bidirectional reflection channel is formed in the inner cavity of the magnetic sensor, and the pumping light repeatedly pumps alkali metal vapor atoms along the bidirectional reflection channel to generate a light pump effect; the photoelectric detector is fixed at one end of the magnetic sensor close to the magnetometer host, and is used for detecting an optical signal containing the larmor frequency, converting the optical signal into an electric signal, and transmitting the electric signal to the magnetometer host through a cable, so that the measurement of an external magnetic field is realized.
As a further technical scheme, a heat insulation layer is filled between the outer wall of the magnetic sensor and the inner wall of the probe outer cover.
As a further technical scheme, the tubular structure is a glass outer sleeve, and the glass outer sleeve is sleeved on the periphery of the magnetic resonance glass tube; the magnetic resonance glass tube is provided with a pear-shaped end and a cylindrical end; one end of the glass outer sleeve is welded and sealed with the outer wall of the pear-shaped end of the magnetic resonance glass tube, and the other end of the glass outer sleeve is welded and sealed with the cylindrical port of the magnetic resonance glass tube.
As a further technical scheme, a spherical reflector is welded at the pear-shaped end of the magnetic resonance glass tube in a sealing mode, and a plane reflector is welded and sealed at the cylindrical port of the magnetic resonance glass tube in a sealing mode.
As a further technical scheme, the polaroid is fixed in the magnetic resonance glass tube, and the photoelectric detector is fixed on the plane reflector; alkali metal and buffer gas are filled in the magnetic resonance glass tube, and a magnetic resonance cavity is formed in the magnetic resonance glass tube.
As a further technical scheme, the magnetometer host is electrically connected with external equipment through the external interface module to realize power supply and communication.
As a further technical scheme, the magnetometer host further comprises a high-frequency excitation module, wherein one end of the high-frequency excitation module is electrically connected with the external interface module, and the other end of the high-frequency excitation module is connected with an electrode through a cable and used for providing tunable high-frequency excitation power.
As a further technical scheme, the magnetometer host further comprises a signal processing module and a main control module, wherein one end of the signal processing module is electrically connected with the photoelectric detector through a cable and used for receiving a larmor frequency electric signal, and the other end of the signal processing module is electrically connected with the main control module and used for outputting an analog or TTL frequency signal; the main control module converts the received signals into magnetic field values and outputs the magnetic field values to the external interface module.
As a further technical scheme, the magnetometer host further comprises a temperature control module, one end of the temperature control module is respectively electrically connected with the coil and the heating wire through a cable and used for controlling the heating temperature of the heating wire and the current of the coil, and the other end of the temperature control module is electrically connected with the external interface module.
The utility model has the beneficial effects that:
1. by adopting the technical scheme of self-locking of the wavelength of the pumping light, the defects of wider spectrum of the pumping light source, weaker optical pumping effect and higher optical noise in the optical pumping probe of the optical pumping magnetometer can be overcome;
2. the optical axis bidirectional pumping mode is adopted, so that the pumping probability of alkali metal atoms can be increased, and the defects of reduced size of a magnetic sensor, reduced magnetic resonance signal and reduced performance of a magnetometer can be overcome;
3. the optical pump source and the atomic absorption chamber are integrally designed, so that the simplification of the optical pump probe structure and the auxiliary circuit is facilitated;
4. the device has the advantages of small volume, strong sensitivity and the like, and can be widely applied to magnetic measurement tasks in various fields.
Drawings
FIG. 1 is a schematic structural diagram of the present invention.
Fig. 2 is a schematic structural view of the probe.
Fig. 3 is a schematic structural view of the magnetic sensor.
Fig. 4 is a schematic structural diagram of a magnetometer host.
Description of reference numerals: the device comprises a probe 1, a cable 2, a magnetometer host 3, a magnetic sensor 4, a coil 5, an electrode 6, a heat insulation layer 7, a heating wire 8, a spherical reflector 9, a polaroid 10, a magnetic resonance glass tube 11, a glass outer sleeve 12, a plane reflector 13, a photoelectric detector 14, a high-frequency excitation module 15, a signal processing module 16, a temperature control module 17, a main control module 18, an external interface module 19 and a probe outer cover 20.
Detailed Description
The utility model will be described in detail below with reference to the following drawings:
example (b): as shown in the attached drawings 1-4, the novel alkali metal optical pump magnetometer comprises a probe 1, a magnetometer host 3 and a magnetic sensor 4, wherein the probe 1 is electrically connected with the magnetometer host 3 through a cable 2; the probe 1 comprises a probe outer cover 20, a magnetic sensor 4 is arranged in an inner cavity of the probe outer cover 20, a coil 5 is arranged around the periphery of the magnetic sensor 4, and the coil 5 is electrically connected with a magnetometer host 3 through a cable 2 and used for applying a Larmor signal radio frequency field to the magnetic sensor 4; the magnetic sensor 4 is of a tubular structure with two closed ends, alkali metal is filled in the magnetic sensor 4, heating wires 8 are uniformly wound on the outer wall of the magnetic sensor 4 and used for heating the alkali metal to a gas state, and the heating wires 8 are electrically connected with the cable 2 to realize power supply; one end of the electrode 6 is connected with the cable 2, and the other end of the electrode 6 is inserted into the magnetic sensor 4 and is used for high-frequency excitation of alkali metal steam to enable the alkali metal steam to emit light; a polaroid 10 is arranged in the magnetic sensor 4 and used for converting alkali metal light into pump light; reflectors are arranged at two ends of the magnetic sensor 4, so that a bidirectional reflection channel is formed in the inner cavity of the magnetic sensor 4, and the pumping light repeatedly pumps alkali metal vapor atoms along the bidirectional reflection channel to generate a light pump effect; the photoelectric detector 14 is fixed at one end of the magnetic sensor 4 close to the magnetometer host 3, and is used for detecting an optical signal containing larmor frequency, converting the optical signal into an electrical signal, and transmitting the electrical signal to the magnetometer host 3 through the cable 2, so as to realize measurement of an external magnetic field.
Further, as shown in fig. 3, the tubular structure is a glass outer sleeve 12, and the glass outer sleeve 12 is sleeved on the periphery of the magnetic resonance glass tube 11; the magnetic resonance glass tube 11 has a pear-shaped end and a cylindrical end; one end of the glass outer sleeve 12 is welded and sealed with the outer wall of the pear-shaped end of the magnetic resonance glass tube 11, and the other end of the glass outer sleeve 12 is welded and sealed with the cylindrical port of the magnetic resonance glass tube 11. The pear-shaped end of the magnetic resonance glass tube 11 is welded with the spherical reflector 9 in a sealing mode, and the plane reflector 13 is welded and sealed at the cylindrical port of the magnetic resonance glass tube 11 in a sealing mode. The polaroid 10 is fixed in the magnetic resonance glass tube 11, and the photoelectric detector 14 is fixed on the plane reflector 13; the magnetic resonance glass tube 11 is filled with alkali metal and buffer gas, and a magnetic resonance cavity is formed in the magnetic resonance glass tube 11.
Further, as shown in fig. 4, the magnetometer host 3 is electrically connected to an external device through the external interface module 19, so as to implement power supply and communication. The magnetometer host 3 further comprises a high-frequency excitation module 15, a signal processing module 16, a temperature control module 17 and a main control module 18, wherein one end of the high-frequency excitation module 15 is electrically connected with an external interface module 19, and the other end of the high-frequency excitation module 15 is connected with the electrode 6 through a cable 2 and used for providing tunable high-frequency excitation power. One end of the signal processing module 16 is electrically connected with the photoelectric detector 14 through the cable 2 and is used for receiving a larmor frequency electric signal, and the other end of the signal processing module 16 is electrically connected with the main control module 18 and is used for outputting an analog or TTL frequency signal; the main control module 18 converts the received signal into a magnetic field value and outputs the magnetic field value to the external interface module 19. One end of the temperature control module 17 is electrically connected with the coil 5 and the heating wire 8 through the cable 2 respectively, and is used for controlling the heating temperature of the heating wire 8 and the current of the coil 5, and the other end of the temperature control module 17 is electrically connected with the external interface module 19.
Preferably, referring to fig. 2, an insulating layer 7 is filled between the outer wall of the magnetic sensor 4 (i.e., the glass outer sleeve 12) and the inner wall of the probe housing 20. The magnetic sensor 4 is prevented from being heated inside and being transmitted outside, and is prevented from being influenced by the external temperature.
The working principle of the utility model is as follows: the utility model relates to a self-excited alkali metal optical pump magnetometer, wherein alkali metal in a magnetic resonance glass tube 11 emits light under the influence of a buffer gas and high-frequency excitation, and forms polarized light pump light under the action of a polarizing film 10. The pump light reciprocally pumps alkali metal atoms (cesium atoms for example) between the spherical mirror 9 and the plane mirror 13. When the frequency of a radio frequency field generated by the coil 5 at the periphery of the magnetic sensor 4 in the magnetic resonance glass tube 11 (i.e. the magnetic resonance cavity) is consistent with the larmor frequency generated by an external magnetic field in cesium atomic energy level transition, the optical pump probe of the cesium optical pump magnetometer generates a self-excitation phenomenon under the action of the phase shifter. Cesium atoms generate magnetic resonance in a magnetic resonance cavity, larmor frequency signals of atomic transition are collected by a photoelectric detector 14 and transmitted to a magnetometer host 3, a signal processing module 16 of the magnetometer host 3 receives larmor frequency electric signals and outputs analog or TTL frequency signals to a main control module 18, and the main control module 18 converts the received signals into magnetic field values and outputs the magnetic field values to an external interface module 19. In practice, magnetic resonance is only generated when the frequency generated by the coil 5 is identical to the larmor frequency, but self-excitation cannot be achieved. The self-excitation can be realized only by shifting the phase of the received larmor frequency signal. At this time, the larmor frequency is counted and substituted into a relational expression between the larmor frequency and the external magnetic field, so that the magnetic field value of the position where the optical pump magnetometer is located can be deduced.
It should be understood that equivalent alterations and modifications of the technical solution and the inventive concept of the present invention by those skilled in the art should fall within the scope of the appended claims.
Claims (9)
1. A novel alkali metal optical pump magnetometer is characterized in that: the device comprises a probe (1), a magnetometer host (3) and a magnetic sensor (4), wherein the probe (1) is electrically connected with the magnetometer host (3) through a cable (2); the probe (1) comprises a probe outer cover (20), a magnetic sensor (4) is placed in an inner cavity of the probe outer cover (20), a coil (5) is arranged on the periphery of the magnetic sensor (4) in a surrounding mode, and the coil (5) is electrically connected with a magnetometer host (3) through a cable (2) and used for applying a Larmor signal radio frequency field to the magnetic sensor (4); the magnetic sensor (4) is of a tubular structure with two closed ends, alkali metal is filled in the magnetic sensor (4), heating wires (8) are uniformly wound on the outer wall of the magnetic sensor (4) and used for heating the alkali metal to a gaseous state, and the heating wires (8) are electrically connected with the cable (2) to realize power supply; one end of the electrode (6) is connected with the cable (2), and the other end of the electrode (6) is inserted into the magnetic sensor (4) and is used for high-frequency excitation of alkali metal steam to enable the alkali metal steam to emit light; a polaroid (10) is arranged in the magnetic sensor (4) and is used for converting alkali metal light into pump light; reflectors are arranged at two ends of the magnetic sensor (4), so that a bidirectional reflection channel is formed in the inner cavity of the magnetic sensor (4), and the pumping light repeatedly pumps alkali metal vapor atoms along the bidirectional reflection channel to generate a light pump effect; the photoelectric detector (14) is fixed at one end of the magnetic sensor (4) close to the magnetometer host (3) and used for detecting an optical signal containing larmor frequency, converting the optical signal into an electric signal and transmitting the electric signal to the magnetometer host (3) through the cable (2) so as to realize the measurement of an external magnetic field.
2. The novel alkali metal optical pumping magnetometer of claim 1, wherein: and an insulating layer (7) is filled between the outer wall of the magnetic sensor (4) and the inner wall of the probe outer cover (20).
3. The novel alkali metal optical pumping magnetometer of claim 1, wherein: the tubular structure is a glass outer sleeve (12), and the glass outer sleeve (12) is sleeved on the periphery of the magnetic resonance glass tube (11); the magnetic resonance glass tube (11) is provided with a pear-shaped end and a cylindrical end; one end of the glass outer sleeve (12) is welded and sealed with the outer wall of the pear-shaped end of the magnetic resonance glass tube (11), and the other end of the glass outer sleeve (12) is welded and sealed with the cylindrical port of the magnetic resonance glass tube (11).
4. The novel alkali metal optical pumping magnetometer of claim 3, wherein: the pear-shaped end of the magnetic resonance glass tube (11) is hermetically welded with the spherical reflector (9), and the plane reflector (13) is hermetically welded at the cylindrical port part of the magnetic resonance glass tube (11).
5. The novel alkali metal optical pumping magnetometer of claim 4, wherein: the polaroid (10) is fixed in the magnetic resonance glass tube (11), and the photoelectric detector (14) is fixed on the plane reflector (13); alkali metal and buffer gas are filled in the magnetic resonance glass tube (11), and a magnetic resonance cavity is formed in the magnetic resonance glass tube (11).
6. The novel alkali metal optical pumping magnetometer of claim 1, wherein: the magnetometer host (3) is electrically connected with external equipment through an external interface module (19) to realize power supply and communication.
7. The novel alkali metal optical pumping magnetometer of claim 6, wherein: the magnetometer host (3) further comprises a high-frequency excitation module (15), one end of the high-frequency excitation module (15) is electrically connected with the external interface module (19), and the other end of the high-frequency excitation module (15) is connected with the electrode (6) through the cable (2) and used for providing tunable high-frequency excitation power.
8. The novel alkali metal optical pumping magnetometer of claim 6, wherein: the magnetometer host (3) further comprises a signal processing module (16) and a main control module (18), one end of the signal processing module (16) is electrically connected with the photoelectric detector (14) through a cable (2) and used for receiving a larmor frequency electric signal, and the other end of the signal processing module (16) is electrically connected with the main control module (18) and used for outputting an analog or TTL frequency signal; the main control module (18) converts the received signals into magnetic field values and outputs the magnetic field values to the external interface module (19).
9. The novel alkali metal optical pumping magnetometer of claim 6, wherein: the magnetometer host (3) further comprises a temperature control module (17), one end of the temperature control module (17) is respectively electrically connected with the coil (5) and the heating wire (8) through a cable (2) and is used for controlling the heating temperature of the heating wire (8) and the current of the coil (5), and the other end of the temperature control module (17) is electrically connected with the external interface module (19).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121173511.5U CN215415923U (en) | 2021-05-28 | 2021-05-28 | Novel alkali metal optical pump magnetometer |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121173511.5U CN215415923U (en) | 2021-05-28 | 2021-05-28 | Novel alkali metal optical pump magnetometer |
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| CN215415923U true CN215415923U (en) | 2022-01-04 |
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| CN202121173511.5U Active CN215415923U (en) | 2021-05-28 | 2021-05-28 | Novel alkali metal optical pump magnetometer |
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