Atomic gas chamber heating circuit
By using overlapping series flexible circuit boards and thermistor control system in the atomic gas chamber heating circuit, the problem of current-driven magnetic field interference in the prior art is solved, and higher magnetometer measurement accuracy and heating stability are achieved.
Patent Information
- Application Number
- CN202411236880.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-04
- Publication Date
- 2024-12-10
AI Technical Summary
The existing atomic gas chamber heating circuit is difficult to achieve a non-magnetic design, which affects the measurement accuracy of the magnetometer.
Using an outer and inner flexible circuit board with overlapping and series connection, the wire layout pattern is the same but the current direction is opposite, covering the side of the atomic air chamber, pasted by thermal silicone glue, and used with thermistor and controller to achieve uniformity heating.
Effectively offset the magnetic field interference generated by the current, improve the measurement accuracy of the magnetometer, the stability and uniformity of the heating.
Smart Images
Figure CN119110439A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of magnetometers, and in particular to an atomic gas chamber heating circuit. Background Art
[0002] Magnetometers are basic instruments for magnetic detection and ground magnetic field observation, and their performance directly determines the accuracy of magnetic field measurement. OPM (Optical-Pumping Magnetometer) refers to a type of magnetometer that uses the optical pumping effect to polarize atoms and destroys the polarization state by applying an external radio frequency field to achieve magnetic field measurement.
[0003] In an atomic magnetometer, one of the core components is the alkali metal gas chamber. The detection mechanism of the entire magnetometer system is based on the relevant properties of the alkali metal atoms in the gas chamber. For the atomic magnetometer itself, in order to meet the saturated vapor atom number density required for alkali metal operation, a heating source needs to be placed around the gas chamber to heat it to 100 to 200°C, thereby converting the alkali metal atoms into gaseous form.
[0004] In the related art, heating is generally performed by driving an electric heater with electric current to generate heat. However, in this heating method, the electric current will generate a magnetic field, which will affect the measurement accuracy of the magnetometer and make it difficult to achieve a non-magnetic design of the magnetometer atomic gas chamber. Summary of the invention
[0005] In view of this, an embodiment of the present disclosure provides an atomic gas chamber heating circuit to solve the technical problem in the prior art that it is difficult to achieve a non-magnetic design for the atomic gas chamber heating circuit.
[0006] To achieve the above objectives, the technical solution adopted by the present disclosure is:
[0007] An embodiment of the present disclosure provides an atomic gas chamber heating circuit, wherein the atomic gas chamber is cylindrical, and the bottom surface of the cylinder is a light-transmitting surface. The atomic gas chamber heating circuit includes an outer flexible circuit board and an inner flexible circuit board that are overlapped and connected in series, wherein the outer flexible circuit board and the inner flexible circuit board cover the side surfaces of the atomic gas chamber, and the inner flexible circuit board is in contact with the outside of the atomic gas chamber. The patterns of the wire arrangements of the outer flexible circuit board and the inner flexible circuit board overlap, and the current directions of the patterns at corresponding positions of the outer flexible circuit board and the inner flexible circuit board are opposite.
[0008] In one embodiment, the conductive wires are arranged in the outer flexible circuit board and the inner flexible circuit board in the form of two lines, and the current directions in the corresponding two lines are opposite.
[0009] In one embodiment, the conductive wire comprises a connector connected end to end, and the connector comprises a parallel portion and a curved portion.
[0010] In one embodiment, the wire is connected to a heating power source through a twisted pair at the wire extension end of the outer flexible circuit board or the inner flexible circuit board.
[0011] In one embodiment, the outer flexible circuit board and the inner flexible circuit board are glued to the side surface of the cylindrical atomic gas chamber by thermal conductive silicone grease.
[0012] In one embodiment, the wire comprises an electrically heated indium tin oxide wire or a copper foil.
[0013] In one embodiment, the atomic gas chamber heating circuit also includes a thermistor arranged on the atomic gas chamber and a controller outside the atomic gas chamber, and the controller controls the outer flexible circuit board and the inner flexible circuit board to heat the atomic gas chamber according to temperature data collected by the thermistor.
[0014] In one embodiment, the main material of the outer flexible circuit board and the inner flexible circuit board includes polyimide or polyester film.
[0015] In one embodiment, the sizes of the outer flexible circuit board and the inner flexible circuit board are adapted to the size of the side unfolding pattern of the atomic gas chamber.
[0016] In one embodiment, a pitch between parallel portions of conductive lines on the same flexible circuit board is less than or equal to 5 micrometers.
[0017] Compared with the prior art, the embodiments of the present disclosure have the following beneficial effects: the technical solution of the embodiments of the present disclosure provides overlapping and series-connected flexible circuit boards with the same conductor arrangement pattern, and covers the side of the atomic gas chamber to heat the atomic gas chamber. Since the two flexible circuit boards are connected in series, the directions of the currents flowing in the corresponding positions of the two flexible circuit boards are opposite, so that the magnetic fields generated by the currents cancel each other out, which helps to reduce the interfering magnetic field of the magnetometer and improve the measurement accuracy of the magnetometer. In addition, the flexible circuit board covers the side of the atomic gas chamber, which can uniformly heat the atomic gas chamber, improve the stability and uniformity of the heating, and further improve the measurement accuracy of the magnetometer.
[0018] Specifically, the outer flexible circuit board and the inner flexible circuit board overlap and are connected in series, the conductor arrangement patterns are the same, and the current directions of the patterns at corresponding positions are opposite, so that the magnetic fields generated by the currents in the conductors can offset each other as much as possible, and the influence of the magnetic field generated by the current drive can be reduced to the greatest extent, thereby improving the measurement accuracy of the magnetometer. The outer flexible circuit board and the inner flexible circuit board cover the side of the atomic gas chamber, so that the alkali metal atoms inside the atomic gas chamber are at the same energy level and polarization state, which is conducive to providing stable and uniform heating in the magnetometer measurement to improve the stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0020] Figure 1 is a structural schematic diagram of an atomic gas chamber heating circuit provided by an embodiment of the present disclosure;
[0021] Figure 2 is a schematic diagram of an atomic gas chamber heating circuit and a relative position of an atomic gas chamber provided by an embodiment of the present disclosure;
[0022] Figure 3 It is a schematic diagram of a flexible circuit board provided in an embodiment of the present disclosure. DETAILED DESCRIPTION
[0023] The disclosed embodiments will now be described more fully with reference to the accompanying drawings in which the embodiments are shown. However, the disclosed embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments specifically set forth herein; rather, the purpose of providing these embodiments is to make the disclosure exhaustive and complete and to fully convey the concepts of the embodiments to those skilled in the art so that they can implement the invention. The same reference numerals in the drawings represent the same elements, and therefore their descriptions will be omitted.
[0024] It should be understood that when an element is referred to as being connected to another element or being connected with another element, the element can be directly connected to another element, or there may be intervening elements between them. On the contrary, when an element is referred to as being directly connected to another element, there are no intervening elements.
[0025] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the disclosed embodiments belong. It should also be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant field, and unless explicitly defined as such in this article, will not be interpreted in an idealized or overly rigid sense.
[0026] The term "device" used in the embodiments may be a software component or a hardware component configured to perform a specific function. The hardware component may include a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC). A software component may refer to data used by an executable code and / or data stored in an addressable storage medium and used by the executable code. Therefore, a software component may be, for example, an object-oriented software component, a class component, and a working component, and may include a process, a function, a property, a procedure, a subroutine, a program code segment, a driver, firmware, microcode, a circuit, data, a database, a data structure, a table, an array, or a variable.
[0027] The words used herein are for the purpose of describing specific embodiments and are not intended to be limiting of the present disclosure. It should be understood that the terms "include", "comprises", "comprising", "having", etc., when used in this specification, indicate the presence and characteristics, quantities, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other characteristics, quantities, steps, operations, elements, components and / or groups thereof.
[0028] The atomic gas chamber heating circuit according to an embodiment of the present disclosure will be described in detail below with reference to the accompanying drawings.
[0029] Figure 1 is a structural schematic diagram of an atomic gas chamber heating circuit provided by an embodiment of the present disclosure; Figure 2 is a schematic diagram of an atomic gas chamber heating circuit and a relative position of an atomic gas chamber provided by an embodiment of the present disclosure; Figure 3 Schematic diagram of a flexible circuit board provided by an embodiment of the present disclosure. Figures 1 to 3 Let us now describe the atomic gas chamber heating circuit provided by the embodiments of the present disclosure.
[0030] like Figure 1 and Figure 2 As shown, an embodiment of the present disclosure provides an atomic gas chamber heating circuit, wherein the atomic gas chamber is cylindrical, and the bottom surface of the cylinder is a light-transmitting surface. The atomic gas chamber heating circuit includes an outer flexible circuit board 100 and an inner flexible circuit board 200 which are overlapped and connected in series, wherein the outer flexible circuit board and the inner flexible circuit board cover the side surfaces of the atomic gas chamber 300, and the inner flexible circuit board is in contact with the outside of the atomic gas chamber, and the patterns of the conductor arrangements of the outer flexible circuit board and the inner flexible circuit board overlap, and the current directions of the patterns at corresponding positions of the outer flexible circuit board and the inner flexible circuit board are opposite.
[0031] Specifically, the outer flexible circuit board and the inner flexible circuit board are both flexible printed circuit boards (Flexible Printed Circuit, referred to as FPC). Figure 1In the two flexible circuit boards shown, the wire extension end 11 of the outer flexible circuit board 100 is the current input end of the atomic gas chamber heating circuit, and the wire extension end 12 of the outer flexible circuit board 100 is connected to the wire extension end 22 of the inner flexible circuit board 200, so as to realize the series connection of the outer flexible circuit board and the inner flexible circuit board. The wire extension end 21 of the inner flexible circuit board 200 is the current output end of the atomic gas chamber heating circuit. It can be seen that when the wire layout patterns of the outer flexible circuit board and the inner flexible circuit board are exactly the same, the wire extension end 21 of the inner circuit board corresponding to the wire extension end 11 of the outer flexible circuit board is respectively the current inflow end and the current outflow end, so the current directions of the patterns at the corresponding positions of the outer flexible circuit board and the inner flexible circuit board are opposite, which will cause the magnetic fields generated by the currents at the corresponding positions in the two layers of flexible circuit boards to cancel each other out.
[0032] In the technical solution of the embodiment of the present disclosure, the outer flexible circuit board and the inner flexible circuit board are overlapped and connected in series, the conductor arrangement pattern is the same, and the current direction of the pattern at the corresponding position is opposite, so that the magnetic field generated by the current in the conductor can offset each other as much as possible, and the influence of the magnetic field generated by the current drive is reduced to the greatest extent, thereby improving the measurement accuracy of the magnetometer. The outer flexible circuit board and the inner flexible circuit board cover the side of the atomic gas chamber, so that the alkali metal atoms inside the atomic gas chamber are at the same energy level and polarization state, which is conducive to providing stable and uniform heating in the magnetometer measurement to improve the stability of the system.
[0033] In the embodiment of the present disclosure, the atomic gas chamber can be a cylindrical cesium absorption chamber with a bottom diameter of 8 mm and a vertical height of 8 mm. The material is high borosilicate glass. The pressure in the gas chamber is 101 kPa and is filled with nitrogen (N 2 )760torr. The sizes of the outer flexible circuit board and the inner flexible circuit board are adapted to the size of the side unfolded pattern of the atomic gas chamber. Therefore, the size of the flexible circuit boards such as the outer flexible circuit board and the inner flexible circuit board should be 8mm*25.1mm to cover the side of the atomic gas chamber without overlapping, so as to uniformly heat the atomic gas chamber.
[0034] The temperature range of the atomic gas chamber is 80℃ to 150℃, which is conducive to the generation of cesium atomic vapor. However, the higher the temperature of the cesium atomic gas chamber, the better, because the spin relaxation of the cesium atoms in the gas chamber and the collision with the instrument wall will increase with the increase of the gas chamber temperature; and too high relaxation will cause the polarized cesium atoms to depolarize, reducing the sensitivity of the magnetometer system; therefore, the cesium atomic gas chamber needs to be maintained at a constant optimal temperature. In addition, the atomic gas chamber is packaged with a thermistor, and the thermistor can be selected with a resistance of 10kΩ and a B value of 3950K+ / -1%@25 degrees Celsius.
[0035] The working principle of thermistor is based on Seebeck effect or Pilz effect. In thermistor, NTC (Negative Temperature Coefficient thermistor) or PTC (Positive Temperature Coefficient thermistor) materials are usually used. When the temperature of NTC material increases, the resistance value decreases, while when the temperature of PTC material increases, the resistance value increases. By measuring the change of the resistance value of the thermistor, the corresponding temperature change can be calculated. Thermistors can be classified according to their structure, material, purpose, etc. Thermistors can be divided into direct heating type and surface type according to structure, and can be divided into ceramic thermistors and metal thermistors according to materials. Different types of thermistors have different characteristics and application ranges.
[0036] In an embodiment of the present disclosure, the atomic gas chamber heating circuit also includes a thermistor arranged on the atomic gas chamber and a controller outside the atomic gas chamber. The controller controls the outer flexible circuit board and the inner flexible circuit board to heat the atomic gas chamber according to temperature data collected by the thermistor.
[0037] Among them, the controller can be the STM32F3 series microcontroller, which integrates a 32-bit ARMCortex-M4 core with DSP and FPU instructions and an operating frequency of 72MHz and advanced analog peripherals, thereby improving flexibility. This series realizes embedded DSC design innovation by integrating the Cortex-M4 core, fast 12-bit 5MSPS and precision 16-bit sigma-delta ADC, programmable gain amplifier, fast 50ns comparator and a multi-function clock control unit with an operating frequency of 144MHz, thereby achieving optimal integration. It includes a series of 32-bit products with high performance, real-time functions, digital signal processing, low power consumption and low voltage operation characteristics, while maintaining high integration and easy development. The unparalleled and complete range of STM32 products are based on industry-standard cores and provide a large number of tools and software options, making this series of products an ideal choice for small projects and complete platforms. Specifically, the STM32F373CCT6 of this series can be selected as the processor.
[0038] The temperature information acquisition circuit is realized by thermistor temperature measurement principle. Thermistors are sensitive to temperature and have different resistance values at different temperatures. When voltage is applied to the circuit, the temperature changes, that is, the voltage changes. Usually, the temperature characteristics of thermistors are known, and the current temperature can be obtained by measuring and calculating the voltage.
[0039] The temperature acquisition of the constant temperature room provides real-time feedback data for the closed-loop temperature control. The temperature is converted by an external high-performance ADC chip. The temperature is calculated by reading the conversion result of the ADC chip through the SPI interface. The constant temperature room temperature control circuit uses MAX9711 for power amplification. The input end of MAX9711 is a sinusoidal signal with a fixed frequency and a variable amplitude. The technical solution of the embodiment of the present disclosure uses a digital potentiometer MAX5482 to modulate the sinusoidal signal with a fixed frequency and amplitude and then output it to MAX9711, which controls the current entering the flexible circuit board after power amplification by MAX9711.
[0040] In the embodiment of the present disclosure, the main material of the outer flexible circuit board and the inner flexible circuit board includes polyimide or polyester film.
[0041] Flexible circuit boards are lightweight, thin, and can be bent and folded freely. They are printed circuits with high reliability and excellent flexibility made of polyester film or polyimide as the substrate. By embedding the circuit design on a bendable thin plastic sheet, a large number of precision components can be stacked in a narrow and limited space, thus forming a bendable flexible circuit. This type of circuit can be bent and folded at will, is lightweight, small in size, has good heat dissipation, and is easy to install, breaking through traditional interconnection technology. Polyimide materials are non-flammable, have stable geometric dimensions, have high tear strength, and have the ability to withstand welding temperatures. Polyester, also known as polyethylene terephthalate (PET for short), has physical properties similar to polyimide, has a lower dielectric constant, and absorbs very little moisture.
[0042] Specifically, in the technical solution of the embodiment of the present disclosure, a polyimide FPC double-layer flexible circuit board can be used, the maximum current Imax of the heating current of the circuit board is 600mA; the heating voltage is 0 to 12V. The outer flexible circuit board and the inner flexible circuit board are glued to the side of the cylindrical atomic gas chamber by thermal conductive silicone grease.
[0043] like Figure 1 and Figure 3 As shown, the conductors are arranged in double-wire form in the outer flexible circuit board and the inner flexible circuit board, and the current directions in the corresponding double wires are opposite, so as to further make the magnetic fields generated by the currents in the conductors offset each other as much as possible, minimize the influence of the magnetic field generated by the current drive, and thus improve the measurement accuracy of the magnetometer.
[0044] In order to further offset the magnetic field, the wire is connected to the heating power source through a twisted pair at the wire extension end of the outer flexible circuit board or the inner flexible circuit board. Twisted pair is the most commonly used transmission medium in integrated wiring engineering, which is composed of two copper wires with an insulating protective layer. The two insulated copper wires are twisted together at a certain density, and the radio waves radiated by each wire during transmission will be offset by the radio waves emitted by the other wire, effectively reducing the degree of signal interference.
[0045] In one embodiment, the conductor includes a connector connected end to end, and the connector includes a parallel portion and a curved portion. The spacing between the parallel portions of the conductors on the same flexible circuit board is less than or equal to 5 microns. The length of the curved portion is in the order of microns, and the length of the parallel portion is in the order of mm. For example, Figure 1 In the flexible circuit board shown, when the pitch of the parallel parts is 5 microns, the length of the curved part is about 8 microns, and the length of the parallel part is about 25 mm. Figure 3 In the flexible circuit board shown, when the interval between the parallel parts is 5 micrometers, the length of the curved part is about 8 micrometers, while the length of the parallel part is about 8 millimeters. It can be seen that the length of the parallel part is much greater than the length of the curved part.
[0046] In various embodiments of the present disclosure, Figure 1 The flexible circuit board shown and Figure 3 The parallel sections of the flexible circuit board shown run in different directions. Figure 1 The parallel parts of the flexible circuit board are arranged along the length direction of the flexible circuit board, such as Figure 3 The parallel portions of the flexible circuit board are shown arranged along the width direction of the flexible circuit board.
[0047] In the disclosed embodiments, the conductor may be an electrically heated indium tin oxide conductor or copper foil, but is not limited thereto. Copper foil is suitable for use in flexible circuits, and it can be formed by electrodeposition or plating. One side of the copper foil that is electrodeposited has a glossy surface, while the other side of the processed surface is dull and matte. It is a flexible material that can be made into a variety of thicknesses and widths. The matte side of the electrodeposited copper foil is often specially treated to improve its bonding ability. In addition to being flexible, forged copper foil is also hard and smooth, and is suitable for use in applications that require dynamic flexing.
[0048] According to the atomic gas chamber heating circuit provided by the embodiment of the present disclosure, flexible circuit boards which are overlapped and connected in series and have the same conductor arrangement pattern are arranged, and the flexible circuit boards are covered on the sides of the atomic gas chamber to heat the atomic gas chamber. Since the two flexible circuit boards are connected in series, the directions of the currents flowing in the corresponding positions of the two flexible circuit boards are opposite, so that the magnetic fields generated by the currents cancel each other out, which helps to reduce the interference magnetic field of the magnetometer and improve the measurement accuracy of the magnetometer. In addition, the flexible circuit boards cover the sides of the atomic gas chamber, which can uniformly heat the atomic gas chamber, improve the stability and uniformity of the heating, and further improve the measurement accuracy of the magnetometer.
[0049] The above are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.
Claims
1. An atomic gas chamber heating circuit, wherein the atomic gas chamber is cylindrical, and the bottom surface of the cylinder is a light-transmitting surface, characterized in that: The atomic gas chamber heating circuit includes an outer flexible circuit board and an inner flexible circuit board that are overlapped and connected in series, the outer flexible circuit board and the inner flexible circuit board cover the sides of the atomic gas chamber, the inner flexible circuit board is in contact with the outside of the atomic gas chamber, the patterns of the conductor arrangements of the outer flexible circuit board and the inner flexible circuit board overlap, and the current directions of the patterns at corresponding positions of the outer flexible circuit board and the inner flexible circuit board are opposite.
2. The atomic gas chamber heating circuit according to claim 1, characterized in that: The conductive wires are arranged in the outer flexible circuit board and the inner flexible circuit board in a double-wire form, and the current directions in the corresponding double-wires are opposite.
3. The atomic gas chamber heating circuit according to claim 1, characterized in that: The conductor includes a connector connected end to end, and the connector includes a parallel portion and a curved portion.
4. The atomic gas chamber heating circuit according to claim 1, characterized in that: The lead is connected to a heating power source through a twisted pair at the lead extending end of the outer flexible circuit board or the inner flexible circuit board.
5. The atomic gas chamber heating circuit according to claim 1, characterized in that: The outer flexible circuit board and the inner flexible circuit board are glued to the side surface of the cylindrical atomic gas chamber by heat-conducting silicone grease.
6. The atomic gas chamber heating circuit according to claim 1, characterized in that: The wires include electrically heated indium tin oxide wires or copper foils.
7. The atomic gas chamber heating circuit according to claim 1, characterized in that: The atomic gas chamber heating circuit also includes a thermistor arranged on the atomic gas chamber and a controller outside the atomic gas chamber. The controller controls the outer flexible circuit board and the inner flexible circuit board to heat the atomic gas chamber according to temperature data collected by the thermistor.
8. The atomic gas chamber heating circuit according to claim 1, characterized in that: The main materials of the outer flexible circuit board and the inner flexible circuit board include polyimide or polyester film.
9. The atomic gas chamber heating circuit according to claim 1, characterized in that: The sizes of the outer flexible circuit board and the inner flexible circuit board are adapted to the size of the side unfolding pattern of the atomic gas chamber.
10. The atomic gas chamber heating circuit according to claim 1, characterized in that: The spacing between parallel portions of the conductive lines on the same flexible circuit board is less than or equal to 5 microns.