A bottom-up atomic gas cell manufacturing apparatus and method

Abstract

The application belongs to the field of optical precision manufacturing, and relates to a bottom-up atomic gas chamber manufacturing device and manufacturing method. The device is composed of a vacuum cavity, a pumping pipeline, a gas inlet pipeline, a discharge electrode plate set, an insulating support, a gas chamber, a laser, an alkali metal source and a vacuum gauge. The device is used for manufacturing the atomic gas chamber from bottom to top, and can be used for preparing various gas chambers with different gas pressure ratio requirements, thereby helping to realize customized preparation. The device reduces the disadvantages of impurity adsorption on the inner wall of the gas chamber and reduces uncontrollable risks. The device has high integration, high preparation efficiency and large secondary development space, and is favorable for accelerating the technical iteration of the atomic gas chamber and the cross-generation development of key technologies such as nuclear magnetic resonance gyroscopes, atomic clocks and magnetometers.

Description

Technical Field

[0001] This invention belongs to the field of optical precision manufacturing technology, and specifically relates to a bottom-up atomic gas cell manufacturing device and method. Background Technology

[0002] Atomic gas cells, as core components of nuclear magnetic resonance gyroscopes, atomic clocks, and magnetometers, have been widely used in scientific research, military, and metrology fields. Conventional atomic gas cells encapsulate alkali metal atoms within optical glass and are filled with a working gas at a specific pressure.

[0003] Traditional methods for preparing atomic gas chambers have the following problems: First, the inner wall of the chamber is easily contaminated. According to the traditional method, the chamber is first cleaned externally by radio frequency plasma before being connected to a vacuum environment for filling. During the transfer process, the inner wall of the chamber is inevitably exposed to the atmosphere, resulting in contaminants adhering to the inner wall. Second, the traditional method involves long pipeline paths and high flow resistance, severely reducing the accuracy of gas pressure ratios. Third, the traditional method involves sealing the tail tube in an atmospheric environment. The glass, heated to a molten state, automatically collapses and contracts due to the internal pressure being lower than atmospheric pressure, thus sealing the tail tube. Therefore, the traditional method is difficult to prepare positive pressure chambers with an internal pressure higher than one atmosphere. Some literature proposes a method of local liquid nitrogen cooling of the chamber, aiming to reduce the internal pressure using low temperature to ensure that the internal pressure is lower than atmospheric pressure when the tail tube is sealed. However, this method can cause the glass to crack due to excessively drastic local temperature and stress changes, increasing the uncontrollable risks in the preparation of atomic gas chambers. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of conventional methods by adopting a bottom-up manufacturing approach, providing an atomic gas chamber manufacturing apparatus and a method for manufacturing atomic gas chambers using the apparatus. This apparatus and method enable radio frequency plasma cleaning of the gas chamber under vacuum conditions, expand the range of gas pressure filling within the gas chamber, and thus contribute to the development of research capabilities for custom-designed atomic gas chambers.

[0005] The technical solution of the present invention:

[0006] On one hand, the present invention provides a bottom-up atomic gas cell manufacturing apparatus, the apparatus comprising a vacuum chamber 1, a gas extraction pipe 2, a gas inlet pipe 3, a discharge electrode plate assembly 4, an insulating support 5, a gas cell 6, a laser 8, an alkali metal source 9, and a vacuum gauge 10.

[0007] Vacuum chamber 1 is connected to pumping pipe 2 and inlet pipe 3; discharge electrode plate group 4, insulating support 5, gas chamber 6, laser 8, alkali metal source 9, and vacuum gauge 10 are located inside vacuum chamber 1.

[0008] Furthermore,

[0009] (1) The discharge electrode plate group 4 is composed of two parallel metal plates; the two parallel metal plates are fixed on the upper and lower inner surfaces of the vacuum cavity 1; by connecting an external power supply, a radio frequency electric field can be formed between the two parallel metal plates; an insulating support 5 is fixed between the two parallel metal plates.

[0010] (2) The vacuum chamber 1 is connected to the pumping pipe 2 and the inlet pipe 3. The pumping pipe 2 and the inlet pipe 3 are used to change the gas composition and pressure inside the vacuum chamber 1. When the gas pressure inside the vacuum chamber 1 is equal to the atmospheric pressure, the vacuum chamber 1 can be opened and connected to the atmosphere.

[0011] (3) The gas extraction pipeline connects the vacuum chamber 1 and the vacuum pump group; when extracting gas, the internal gas pressure of the vacuum chamber 1 is reduced, and the gas group distribution ratio inside the vacuum chamber 1 is changed.

[0012] (4) The air inlet pipe connects the vacuum chamber 1 to the working gas and cleaning gas sources; when the air is inlet, the internal air pressure of the vacuum chamber 1 is increased, and the gas composition ratio inside the vacuum chamber 1 is changed.

[0013] (5) An air chamber tail pipe 7 structure is provided at the upper end of the air chamber, and the air chamber 6 is connected to the outside through the air chamber tail pipe 7; the air chamber 6 is placed on the insulating support 5.

[0014] (6) The laser emits laser light; the optical path passes through the gas chamber tail tube 7 and is used to sinter the gas chamber tail tube 7 material.

[0015] (7) The alkali metal source can be connected to an external power source for heating and evaporating alkali metal atoms.

[0016] (8) The vacuum gauge is located inside the vacuum chamber 1 and is used to monitor the gas pressure inside the vacuum chamber 1.

[0017] On the other hand, the present invention also provides a bottom-up method for manufacturing atomic gas chambers, the method being implemented based on the above-described apparatus, the method comprising the following steps:

[0018] Open the vacuum chamber 1 and place the gas chamber 6 on the insulating support 5;

[0019] Close vacuum chamber 1, remove air from vacuum chamber 1 through evacuation pipe 2, and inject cleaning gas into vacuum chamber 1 through inlet pipe 3, so that vacuum chamber 1 and gas chamber 6 both reach a specific pressure state, which is monitored by vacuum gauge 10.

[0020] The discharge electrode plate group 4 is connected to an external power supply. The discharge electrode plate group 4 can form a radio frequency electric field. The cleaning gas forms plasma in the radio frequency electric field and performs radio frequency plasma cleaning on the inside of the gas chamber 6.

[0021] The cleaning gas in the vacuum chamber 1 is removed by the evacuation pipe 2, and a vacuum is achieved in the vacuum chamber 1.

[0022] Alkali metal source 9 is connected to an external power source to heat and evaporate alkali metal atoms. The alkali metal atoms diffuse into the gas chamber 6 and deposit. After the set time is reached, the heating and evaporation of alkali metal atoms is stopped.

[0023] Working gas is injected into vacuum chamber 1 through air inlet pipe 3, so that vacuum chamber 1 and gas chamber 6 both reach a specific pressure state, which is monitored by vacuum gauge 10.

[0024] The laser is connected to an external power source to emit laser light, which sinters the material of the gas chamber tail tube 7. After sintering, the gas chamber tail tube 7 is no longer connected to the outside world.

[0025] Adjust the air pressure inside the vacuum chamber 1 by using the suction pipe 2 and the intake pipe 3 to make it equal to atmospheric pressure, open the vacuum chamber 1, and remove the air chamber 6.

[0026] Advantages of this invention:

[0027] (1) This invention adopts the approach of "cleaning the inner wall first, then filling with materials". The atomic gas chamber is placed in a vacuum environment before radio frequency plasma cleaning. After the radio frequency plasma cleaning is completed, the residual cleaning gas in the gas chamber is evacuated, and then alkali metal and working gas are filled from the alkali metal source and the gas inlet pipe. Compared with the traditional method of filling the gas chamber into a vacuum environment after radio frequency plasma cleaning, this invention avoids the disadvantage of the gas chamber wall being exposed to the atmosphere and causing pollution during the transfer process, and greatly reduces the uncontrollable risks in the preparation of atomic gas chambers;

[0028] (2) This invention adopts a bottom-up approach to material synthesis to prepare atomic gas chambers, abandoning the traditional method of fusing the gas chamber onto a glass tube and then removing it after processing. Instead, the gas chamber is prepared directly in a vacuum environment by interacting with cleaning gas, a radio frequency electric field, alkali metal, working gas, and laser, following the assembly sequence. This invention can prepare gas chambers with various pressure ratios, overcoming the limitation of traditional methods in preparing positive pressure gas chambers, and facilitating the customized preparation of atomic gas chambers.

[0029] (3) This invention employs an integrated manufacturing device, combining the separate glass pipelines, radio frequency plasma cleaning machine, and sintering device of the traditional scheme into one unit. This greatly simplifies the preparation steps of the atomic gas chamber, overcomes the drawbacks of the traditional scheme that heavily relies on manual glass welding, and reduces the requirements for operators. At the same time, this invention leaves room for secondary development, and can add personalized functions such as gas chamber baking and degassing, anti-relaxation film deposition, and residual gas mass spectrometry analysis as needed.

[0030] (4) The present invention abandons the pipe-type structure in the traditional scheme and adopts a cubic structure, which has the advantages of small volume and low flow resistance. It is beneficial to ensure the uniformity of filling alkali metal and the accuracy of gas pressure ratio, thereby further improving the stability of atomic gas chamber performance and helping to realize the mass production of atomic gas chamber. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the apparatus used to create a gas chamber from the bottom up.

[0032] Figure 2 Detailed images of the glass tail tube before and after laser sintering;

[0033] Figure 3 A flowchart for manufacturing an atomic gas cell using this invention;

[0034] Explanation of reference numerals in the attached drawings: 1-vacuum chamber, 2-evacuation line, 3-inlet line, 4-discharge electrode plate assembly, 5-insulating support, 6-gas chamber, 7-gas chamber tailpipe, 8-laser, 9-alkali metal source, 10-vacuum gauge. Detailed Implementation

[0035] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0036] This invention provides a bottom-up precision manufacturing apparatus for atomic gas cells, such as... Figure 1 As shown, the device includes a vacuum chamber, a pumping pipeline, an inlet pipeline, a discharge electrode plate assembly, an insulating support, a gas chamber, a laser, an alkali metal source, and a vacuum gauge.

[0037] The vacuum chamber is connected to the pumping and inlet pipes; the pumping and inlet pipes can change the gas composition and pressure inside the vacuum chamber; when the internal gas pressure is equal to atmospheric pressure, the vacuum chamber can be opened to connect with the atmosphere; the discharge electrode plate assembly, insulating support, gas chamber, laser, alkali metal source, and vacuum gauge are located inside the vacuum chamber.

[0038] The evacuation pipeline connects the vacuum chamber and the vacuum pump unit; during evacuation, the internal gas pressure of the vacuum chamber is reduced, changing the gas distribution ratio inside the vacuum chamber.

[0039] The air intake pipe connects the vacuum chamber to the working gas and cleaning gas sources; when air is intaked, the internal air pressure of the vacuum chamber is increased, and the gas composition ratio inside the vacuum chamber is changed.

[0040] The discharge electrode plate assembly consists of two parallel metal plates; the two parallel metal plates are fixed on the upper and lower inner surfaces of the vacuum chamber; by connecting an external power supply, a radio frequency electric field can be formed between the two parallel metal plates.

[0041] An insulating support is fixed between two parallel metal plates. The gas chamber is placed on the insulating support.

[0042] The air chamber includes an air chamber tail tube structure, which is connected to the outside world. The air chamber tail tube can receive laser irradiation.

[0043] After the laser emits a laser beam, the optical path passes through the gas chamber tail tube. The laser power is high, which melts and sinters the gas chamber tail tube material.

[0044] The alkali metal source can be connected to an external power source to heat and evaporate the alkali metal atoms.

[0045] Vacuum gauges are used to monitor the gas pressure inside a vacuum chamber.

[0046] Optionally, the air chamber is square, and the air chamber tailpipe is cylindrical.

[0047] Optionally, the air chamber and air chamber tailpipe may be made of quartz or borosilicate glass material as needed.

[0048] Alternatively, a carbon dioxide laser may be used.

[0049] Optionally, the alkali metal source may be K, Cs, or Rb, as needed.

[0050] Optionally, the cleaning gas includes hydrogen and nitrogen, and the working gas includes... 129 Xe, 131 Xe and nitrogen.

[0051] This invention also provides a bottom-up method for manufacturing atomic gas cells, utilizing the manufacturing apparatus described above, the method comprising the following steps:

[0052] Open the vacuum chamber and place the gas chamber on the insulating support.

[0053] The vacuum chamber is closed, the air inside the vacuum chamber is evacuated through the evacuation line, and the cleaning gas is injected into the vacuum chamber through the inlet line, so that the vacuum chamber and the gas chamber reach a specific pressure state, which is monitored by the vacuum gauge.

[0054] Connect the discharge electrode plate group to an external power source. After power is applied, a radio frequency electric field can be formed between the discharge electrode plate group. The cleaning gas forms plasma in the radio frequency electric field and performs radio frequency plasma cleaning on the inside of the gas chamber.

[0055] The cleaning gas inside the vacuum chamber is removed by the evacuation line, and a vacuum is achieved inside the vacuum chamber.

[0056] An alkali metal source is connected to an external power source to heat and evaporate alkali metal atoms. The alkali metal atoms diffuse into the gas chamber and deposit. After a set time is reached, the heating and evaporation of alkali metal atoms is stopped.

[0057] Working gas is injected into the vacuum chamber through the air inlet pipe to bring both the vacuum chamber and the gas chamber to a specific pressure state, which is monitored by a vacuum gauge.

[0058] The laser is connected to an external power source and emits laser light to sinter the material of the gas chamber tail tube. After sintering, the gas chamber tail tube is no longer connected to the outside world. Detailed images of the glass tail tube before and after laser sintering are shown below. Figure 2 As shown.

[0059] Adjust the air pressure inside the vacuum chamber by using the extraction and intake pipes to make it equal to atmospheric pressure, then open the vacuum chamber and remove the gas chamber.

[0060] This invention also provides a bottom-up alkali metal atom gas chamber, wherein the alkali metal atom gas chamber has few internal impurities, and the material of the alkali metal atom gas chamber includes alkali metal and working gas.

[0061] Example 1

[0062] Combination Figure 3 As shown, this embodiment uses the aforementioned bottom-up atomic gas cell precision manufacturing apparatus to manufacture the atomic gas cell. The specific implementation steps are as follows:

[0063] Step 1:

[0064] Open the vacuum chamber and place the five borosilicate glass gas chambers on the insulating support.

[0065] Step Two:

[0066] Air is removed from the vacuum chamber through the evacuation line, and cleaning gas N2 is injected into the vacuum chamber through the inlet line, so that the N2 pressure inside the vacuum chamber reaches 100Pa.

[0067] Step 3:

[0068] After connecting the discharge electrode plate group to an external power supply and adjusting the voltage and frequency, a 110V, 100Hz radio frequency electric field can be formed between the discharge electrode plate groups. The cleaning gas N2 forms plasma in the radio frequency electric field. The plasma bombards the impurities on the inner wall of the gas chamber, and the vacuum pump removes the impurities, thus performing radio frequency plasma cleaning.

[0069] Step Four:

[0070] The cleaning gas inside the vacuum chamber is removed through the evacuation line, achieving a vacuum level of 10. -6 Pa;

[0071] Step 5:

[0072] An alkali metal source is connected to an external power source to heat and evaporate alkali metal atoms. The alkali metal atoms diffuse into the gas chamber and deposit. After a set time is reached, the heating and evaporation of alkali metal atoms is stopped.

[0073] Step Six:

[0074] Working gas is injected into the vacuum chamber through the intake pipe.129 Xe, 131 Xe and N2, mixed for 24 hours;

[0075] Step Seven:

[0076] The laser is connected to an external power source to emit laser light, which sinters the material of the gas chamber tail tube. After sintering, the gas chamber tail tube becomes a glass block with a sealing function, and the inside of the gas chamber is no longer connected to the outside.

[0077] Step 8:

[0078] The air pressure inside the vacuum chamber is adjusted by pumping air in or out to make it equal to atmospheric pressure.

[0079] Step Nine:

[0080] Open the vacuum chamber and remove the gas chamber.

[0081] Example 2

[0082] All five gas chambers are square chambers, each 5mm x 5mm x 5mm. The glass tubes within the chambers have a diameter of 1.5mm. Four of the chambers were cleaned, dried, and then placed into an insulating support within the vacuum chamber. Isotopes 87 The Rb metal source was manufactured by the Italian company SEAS.

[0083] The vacuum chamber should be evacuated to a vacuum level better than 10. -6 Pa; isotopes 87 An external current source connected to the Rb metal source is used to complete degassing, with a current of 5.5A. Cleaning gas H2 is injected into the vacuum chamber to bring the H2 pressure inside the chamber to 100Pa.

[0084] When the discharge electrode plate assembly is connected to an external power supply, a radio frequency electric field can be formed between the discharge electrode plates. The cleaning gas H2 forms plasma H in the radio frequency electric field. + Plasma H + The plasma bombardment of the chamber wall causes impurities to desorb, which are then removed by a vacuum pump, achieving the effect of radio frequency plasma cleaning. After 30 minutes of cleaning, the cleaning gas is removed through the extraction line, restoring the vacuum level in the chamber to 10°C. -6 Pa

[0085] Using an external current source to realize isotopes 87 The isotopes are heated and evaporated using an Rb metal source with a current of 5A for 5-10 minutes, causing the isotopes to evaporate. 87 The Rb metal source enters the gas chamber.

[0086] Turn on the air supply separately to 10 kPa 129 Xe gas, 20kPa 131Xe gas and 100kPa N2 gas are introduced into the vacuum chamber and mixed for 24 hours to ensure that the gas pressure ratio inside the gas chamber is the same as that inside the vacuum chamber.

[0087] The laser is connected to an external power source to emit laser light, which sinters the material of the gas chamber tail tube. After sintering, the gas chamber tail tube becomes a glass block with a sealing function, and the inside of the gas chamber is no longer connected to the inside of the vacuum chamber.

[0088] Remove the residual gas from the vacuum chamber until the internal pressure equals atmospheric pressure. Open the vacuum chamber and remove the gas chamber.

[0089] The method described in this embodiment is used to perform radio frequency plasma cleaning on the inner wall of the atomic gas chamber in a vacuum environment to remove impurities from the chamber. 129 The signal-to-noise ratio of Xe atoms is higher than that of traditional methods. 129 The signal-to-noise ratio of Xe atoms increased by 2 times.

Claims

1. A bottom-up atomic cell manufacturing method, the method uses a bottom-up atomic cell manufacturing device to manufacture an atomic cell, characterized in that, the device comprises a vacuum chamber (1), a gas exhaust pipeline (2), a gas inlet pipeline (3), a discharge electrode plate group (4), an insulating support (5), a cell (6), a laser (8), an alkali metal source (9), a vacuum gauge (10); the vacuum chamber (1) is communicated with the gas exhaust pipeline (2) and the gas inlet pipeline (3); the discharge electrode plate group (4), the insulating support (5), the cell (6), the laser (8), the alkali metal source (9) and the vacuum gauge (10) are located inside the vacuum chamber (1); the discharge electrode plate group (4) is composed of two parallel metal electrode plates; the two parallel metal electrode plates are fixed on the upper and lower inner surfaces of the vacuum chamber (1); a radio frequency electric field can be formed between the two parallel metal electrode plates by connecting an external power supply; the insulating support (5) is fixed between the two parallel metal electrode plates; the vacuum chamber (1) is communicated with the gas exhaust pipeline (2) and the gas inlet pipeline (3), and the gas exhaust pipeline (2) and the gas inlet pipeline (3) are used to change the gas composition and pressure inside the vacuum chamber (1); when the internal pressure of the vacuum chamber (1) is equal to the atmospheric pressure, the vacuum chamber (1) can be opened and communicated with the atmosphere; the gas exhaust pipeline communicates the vacuum chamber (1) and a vacuum pump group; the internal pressure of the vacuum chamber (1) is reduced during gas exhaust, and the gas composition ratio inside the vacuum chamber (1) is changed; the gas inlet pipeline communicates the vacuum chamber (1) with the working gas and the cleaning gas source; the internal pressure of the vacuum chamber (1) is increased during gas inlet, and the gas composition ratio inside the vacuum chamber (1) is changed; a cell tail pipe (7) structure is arranged at the upper end of the cell, and the cell (6) is communicated with the outside through the cell tail pipe (7); the cell (6) is placed on the insulating support (5); the laser emits laser; the light path passes through the position of the cell tail pipe (7) and is used for sintering the material of the cell tail pipe (7); the alkali metal source can be connected to an external power supply and is used for heating and evaporating alkali metal atoms; the vacuum gauge is located inside the vacuum chamber (1) and is used for monitoring the gas pressure inside the vacuum chamber (1); the method comprises the following steps: opening the vacuum chamber (1) and placing the cell (6) on the insulating support (5); closing the vacuum chamber (1), removing the air in the vacuum chamber (1) through the gas exhaust pipeline (2), and injecting the cleaning gas into the vacuum chamber (1) through the gas inlet pipeline (3) so that the internal pressure of the vacuum chamber (1) and the cell (6) reaches a specific pressure state, which is monitored by the vacuum gauge (10); connecting the discharge electrode plate group (4) to an external power supply, the discharge electrode plate group (4) can form a radio frequency electric field, and the cleaning gas forms a plasma in the radio frequency electric field to perform radio frequency plasma cleaning on the inside of the cell (6); removing the cleaning gas in the vacuum chamber (1) through the gas exhaust pipeline (2) to achieve vacuum in the vacuum chamber (1); connecting the alkali metal source (9) to an external power supply to heat and evaporate alkali metal atoms, and the alkali metal atoms diffuse into the inside of the cell (6) and deposit, after a set time, stopping heating and evaporating the alkali metal atoms; ​ ​ The working gas is injected into the vacuum cavity (1) through the gas inlet pipeline (3) to make the vacuum cavity (1) and the gas chamber (6) reach a specific pressure state, which is monitored by the vacuum gauge (10); The laser is connected to an external power supply to emit laser to sinter the material of the gas chamber tail pipe (7), and the sintered gas chamber tail pipe (7) is no longer in communication with the outside world; The internal gas pressure of the vacuum cavity (1) is adjusted through the air exhaust pipeline (2) and the gas inlet pipeline (3) to be equal to the atmospheric pressure, the vacuum cavity (1) is opened, and the gas chamber (6) is taken away.

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