Portable ultra-high vacuum quantum measurement device and application method

Abstract

The application relates to the technical field of vacuum measurement, in particular to a portable ultrahigh vacuum quantum measurement device and an application method, the device comprises a shell, a handle and a grating magnetic optical trap system, wherein: the handle is arranged at the top of the shell, and the grating magnetic optical trap system is arranged in the shell; eight corresponding interfaces are arranged on the outer wall of the shell and the cavity of the grating magnetic optical trap system, which are respectively: three laser inlets for connecting a laser deflection and shaping module; a camera mounting port for connecting a CMOS camera module; a wiring port for connecting a cable assembly; a vacuum interface for connecting a vacuum to be measured; a vacuum pump mounting port for connecting a non-evaporative getter pump; and an observation port for connecting an observation window end cover. The quantum vacuum measurement vacuum degree method adopted by the application does not need to be calibrated, has high accuracy, excellent space-time reproducibility, can effectively reduce the volume of a cold atom trapping system, and has high system reliability and strong anti-interference capability.

Description

Technical Field

[0001] This application relates to the field of vacuum measurement technology, and more specifically, to a portable ultra-high vacuum quantum measurement device and its application method. Background Technology

[0002] With the development of aerospace technology, especially the development of deep space exploration activities, there is a need to directly explore the extremely high vacuum environment of interplanetary space, interstellar space and the lunar surface, which requires solving the problem of extremely high vacuum measurement technology.

[0003] Currently, the measurement of ultra-high vacuum is generally carried out using vacuum gauges based on the principle of ionization or cold atom ultra-high vacuum measurement equipment based on the theory of atomic collisions. However, the former requires regular and precise calibration during use, and the vacuum being measured is affected by the gas absorption and desorption effects during use, resulting in inaccurate results. The latter is mostly laboratory-scale equipment to date, which is difficult to put into practical application.

[0004] Compared to the aforementioned vacuum measuring instruments, portable ultra-high vacuum quantum measuring devices retain the advantages of traditional quantum vacuum measurements, such as high accuracy, no calibration required, and minimal disturbance to the vacuum environment. Furthermore, they optimize the size and structure of the device, improving its portability and performance under extreme dynamic conditions. Therefore, the miniaturization and precision of ultra-high vacuum quantum measuring devices have enormous development potential, and they are expected to replace traditional ultra-high vacuum measurement methods, achieving quantum-level ultra-high vacuum metrology.

[0005] However, most existing ultra-high vacuum measurement devices belong to the ionization type. These devices measure vacuum based on the relationship between the number of ions generated by the ionization of gas molecules and the gas pressure. The measurement results of these devices are affected by various factors, such as mechanical vibration, gauge sensitivity, and thermal exhaust effects, leading to low measurement accuracy and poor long-term stability. Furthermore, due to their inherent limitations, these devices require periodic calibration using vacuum standards, making true absolute measurement impossible. In addition, laboratory-scale ultra-high vacuum quantum measurement devices have numerous mechanical structures and control units, resulting in a large, complex, and extremely poorly portable system with high production costs and difficulties in use and maintenance. They cannot replace traditional ionization vacuum gauges in the field of ultra-high vacuum measurement and lack practical application. Moreover, the optical systems of current laboratory-scale ultra-high vacuum quantum measurement devices contain numerous optical components, resulting in complex structures and many degrees of mechanical freedom. This makes it difficult for laboratory-scale ultra-high vacuum quantum measurement devices to maintain high performance under extreme dynamic conditions, such as high vibration and harsh temperature conditions. Summary of the Invention

[0006] This application provides a portable ultra-high vacuum quantum measurement device and its application method, which does not require calibration and has excellent operability, portability, stability and accuracy. It overcomes the shortcomings of traditional ultra-high vacuum measurement devices, such as large uncertainty and the need for periodic calibration, as well as the large scale and complex operation of current laboratory-scale ultra-high vacuum quantum measurement devices.

[0007] To achieve the above objectives, this application provides a portable ultra-high vacuum quantum measurement device, including a housing, a handle, and a grating magneto-optical trap system, wherein: the handle is located on the top of the housing, and the grating magneto-optical trap system is located inside the housing; the outer wall of the housing and the cavity of the grating magneto-optical trap system are provided with eight corresponding interfaces, namely: three laser inlets for connecting to a laser polarization and shaping module; a camera mounting port for connecting to a CMOS camera module; a wiring port for connecting to a cable assembly; a vacuum interface for connecting to the vacuum being measured; a vacuum pump mounting port for connecting to a non-evaporative suction pump; and an observation port for connecting to the observation window end cap.

[0008] Furthermore, the cavity of the grating magneto-optical trap system is made of Ti alloy material and includes a base, a diffraction grating, an electromagnetic coil, a mounting frame, a differential tube, and an alkali metal distributor. The electromagnetic coil is fixed to the base by the mounting frame; the diffraction grating is located above the electromagnetic coil; the alkali metal distributor is located below the base and is connected to the internal cavity through the differential tube; and a non-evaporative suction pump is located below the alkali metal distributor.

[0009] Furthermore, the three laser inlets include a cooling light inlet, an imaging light inlet, and a kick light inlet. The cooling light inlet is located above the cavity of the grating magneto-optical trap system, while the imaging light inlet and the kick light inlet are located on the sides of the cavity of the grating magneto-optical trap system. Each laser inlet is connected to a laser polarization and shaping module.

[0010] Furthermore, the laser polarization and shaping module includes a first housing, a first lens, a filter, a half-wave plate, and a first end cap, wherein: the first lens, the filter, and the half-wave plate are sequentially fixedly disposed on a groove inside the first housing; the first end cap covers one end of the first housing and is mated with the outer wall of the housing; and an optical fiber coupling head is disposed at the center of the first end cap.

[0011] Furthermore, the CMOS camera module includes a second housing, a second lens, a filter, a camera mounting flange, a CMOS camera, and a second end cap, wherein: the second end cap covers one end of the second housing and abuts against the outer wall of the housing; the camera mounting flange is disposed inside the second housing; the CMOS camera is disposed between the camera mounting flange and the second end cap and is fixed inside the second housing by a lug; the filter and the second lens are disposed between the camera mounting flange and the grating magneto-optical trap system cavity and are fixed inside the second housing by a groove.

[0012] Furthermore, the cable assembly includes a wiring flange, cable conduit, and conductors, wherein: the wiring flange is located on the outer wall of the housing, and a wiring rod is provided on it. The wiring rod is covered with insulating ceramic, and both ends are fitted with expansion alloy sealing caps; the cable conduit is located between the wiring flange and the cavity of the grating magneto-optical trap system; the conductors connect to the wiring rod from the outside of the housing, enter the cavity of the grating magneto-optical trap system through the cable conduit, and connect to the electromagnetic coil and alkali metal distributor.

[0013] Furthermore, the alkali metal distributor serves as the atom source, with Li atoms selected as the working cold atoms.

[0014] Furthermore, ultra-high vacuum indicates a vacuum level <10. -9 Pa.

[0015] Furthermore, the observation window is made of Pyrex optical glass.

[0016] Furthermore, this application also provides a method for using a portable ultra-high vacuum quantum measurement device, comprising the following steps: Step 1: Installation and wiring, connecting the power cord to the cable assembly, connecting the fiber optic patch cord to the fiber optic coupler of the laser polarization and shaping module through the cable assembly, and connecting the vacuum to be measured to the vacuum interface through a corrugated tube; Step 2: Evacuating the cavity of the grating magneto-optical trap system; Step 3: Introducing the gas to be measured into the cavity of the grating magneto-optical trap system; Step 4: Loading cold atoms into the grating magneto-optical trap system; Step 5: Measuring the number and loss rate of atomic clusters in the grating magneto-optical trap system; Step 6: Measuring the potential well depth of the grating magneto-optical trap; Step 7: Obtaining the vacuum degree to be measured by inversion based on atomic collision theory.

[0017] The portable ultra-high vacuum quantum measurement device and its application method provided by this invention have the following beneficial effects: The quantum vacuum measurement method used in this application requires no calibration, has high accuracy, and excellent spatiotemporal reproducibility. The grating magneto-optical trap system uses a grating chip to replace the three opposing laser beams in the traditional magneto-optical trap, which can effectively reduce the size of the cold atom trapping system. By utilizing the strong confinement effect of the micro-nano optical structure on the chip on the light field, the laser power required to excite and manipulate atoms can be reduced, reducing system power consumption and thus achieving more efficient atom trapping and capture. Furthermore, the optical components are directly integrated into the CMOS camera module and the laser polarization and shaping module, which is different from the optical platform used in laboratory-scale quantum vacuum measurement systems. This simplifies a large number of optical components in the cold atom trapping and capture system, reduces unnecessary mechanical degrees of freedom, and results in high system reliability, strong anti-interference ability, and operation under high vibration and harsh temperature conditions. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 This is a schematic diagram of a portable ultra-high vacuum quantum measurement device provided according to an embodiment of this application; Figure 2 This is a schematic diagram of the cavity interior and various interfaces of the grating magneto-optical trap system provided according to an embodiment of this application; Figure 3 This is a schematic diagram of a laser polarization and shaping module provided according to an embodiment of this application; Figure 4 This is a schematic diagram of a CMOS camera module provided according to an embodiment of this application; In the diagram: 1-Housing, 2-Handle, 3-Grating magneto-optical trap system, 31-Base, 32-Diffraction grating, 33-Electromagnetic coil, 34-Mounting bracket, 35-Differential tube, 36-Alkali metal distributor, 4-Cooling light inlet, 5-Imaging light inlet, 6-Kick light inlet, 7-Camera mounting port, 8-Wiring port, 9-Observation window end cap, 10-Vacuum interface, 11-Vacuum pump mounting port, 12-Observation port, 13-Laser polarization and shaping module, 131-First housing, 1 32-First lens, 133-Filter, 134-Half-wave plate, 135-First end cap, 136-Fiber optic coupler, 14-CMOS camera module, 141-Second housing, 142-Second lens, 143-Filter, 144-Camera mounting flange, 145-CMOS camera, 146-Second end cap, 15-Cable assembly, 151-Wiring flange, 152-Cable conduit, 153-Wire, 154-Connecting rod, 16-Non-evaporative suction pump. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0022] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0023] In addition, the term "multiple" should mean two or more.

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] like Figure 1 As shown, this application provides a portable ultra-high vacuum quantum measurement device, including a housing 1, a handle 2, and a grating magneto-optical trap system 3, wherein: the handle 2 is located on the top of the housing 1, and the grating magneto-optical trap system 3 is located inside the housing 1; the outer wall of the housing 1 and the cavity of the grating magneto-optical trap system 3 are provided with 8 corresponding interfaces, namely: 3 laser inlets for connecting to the laser polarization and shaping module 13; camera mounting port 7 for connecting to the CMOS camera module 14; wiring port 8 for connecting to the cable assembly 15; vacuum interface 10 for connecting to the vacuum to be measured; vacuum pump mounting port 11 for connecting to the non-evaporative suction pump 16; and observation port 12 for connecting to the observation window end cover 9.

[0026] Specifically, the portable ultra-high vacuum quantum measurement device provided in this application embodiment is mainly based on the cold atom collision theory. It inverts the vacuum degree to be measured by the loss rate of the cold atom cluster trapped in the magneto-optical trap and the loss rate coefficient at a certain potential trap depth. The grating magneto-optical trap system 3 replaces the three-dimensional magneto-optical trap commonly used in current atom cooling trap systems. The grating magneto-optical trap is composed of a beam of incident cooling laser and the magnetic field generated by the diffraction beam generated by the diffraction grating 32 combined with the magnetic field generated by the electromagnetic coil 33, thereby avoiding the use of three beams of opposing cooling light and effectively reducing the size of the optical system. Furthermore, eight interfaces are set between the housing 1 and the cavity of the grating magneto-optical trap system 3, integrating functions such as cable connection, laser incident, connection of the vacuum to be measured, camera imaging, vacuum pumping, and real-time observation, thus realizing the measurement of portable ultra-high vacuum. The housing 1 is mainly used to fix and support the various interfaces and house the internal grating magneto-optical trap system 3. The handle 2 is located on the top of the housing 1 for picking up the entire device, facilitating its movement and docking with the vacuum to be measured, and making it easy to carry. The grating magneto-optical trap system 3 is fixedly installed inside the housing 1 with screws and is mainly used to cool and trap cold atoms. The laser polarization and shaping module 13 is mainly used to polarize and shape the incident laser to ensure that it meets the polarization and shape requirements for cold atom trapping. The CMOS camera module 14 is mainly used to record images of the cold atom clusters trapped in the grating magneto-optical trap system 3. The cable assembly 15 is mainly used to dock with external cables. The non-evaporative suction pump 16 is mainly used to extract gas from the cavity of the grating magneto-optical trap system 3 to maintain the vacuum level inside the cavity. The observation window is mainly used to observe the atomic clusters inside the cavity of the grating magneto-optical trap system 3 in real time.

[0027] Furthermore, such as Figure 2 As shown, the cavity of the grating magneto-optical trap system 3 is made of Ti alloy material. Internally, it includes a base 31, a diffraction grating 32, an electromagnetic coil 33, a mounting frame 34, a differential tube 35, and an alkali metal distributor 36. The electromagnetic coil 33 is fixed to the base 31 via the mounting frame 34; the diffraction grating 32 is positioned above the electromagnetic coil 33; the alkali metal distributor 36 is positioned below the base 31 and communicates with the internal cavity via the differential tube 35; a non-evaporative suction pump 16 is located below the alkali metal distributor 36. The magneto-optical trap of the grating magneto-optical trap system 3 uses a single incident cooling laser beam combined with the diffracted beam generated by the diffraction grating 32 to form a magnetic field within the coil, replacing the three opposing laser beams in traditional magneto-optical traps. This effectively reduces the volume of the cold atom trapping system and achieves higher efficiency in atom trapping and capture.

[0028] Furthermore, the three laser inlets include a cooling light inlet 4, an imaging light inlet 5, and a kick light inlet 6. The cooling light inlet 4 is located above the cavity of the grating magneto-optical trap system 3, while the imaging light inlet 5 and the kick light inlet 6 are located on the side of the cavity of the grating magneto-optical trap system 3. Each laser inlet is connected to a laser polarization and shaping module 13. Cooling light inlet 4 is located above the cavity of the grating magneto-optical trap system 3. The top laser polarization and shaping module 13 emits cooling light, which enters the cavity of the grating magneto-optical trap system 3 vertically through cooling light inlet 4 and irradiates the diffraction grating 32, forming an optical trap together with the diffraction beam. The side laser polarization and shaping module 13 emits imaging light, which enters the cavity of the grating magneto-optical trap system 3 through imaging light inlet 5, and will obtain a signal frame containing atomic information. Similarly, the side laser polarization and shaping module 13 emits kick light, which enters the cavity of the grating magneto-optical trap system 3 through kick light inlet 6, and is used to apply a pushing force to the atoms to make them escape the potential trap.

[0029] Furthermore, such as Figure 3 As shown, the laser polarization and shaping module 13 includes a first housing 131, a first lens 132, a filter 133, a half-wave plate 134, and a first end cap 135. The first lens 132, filter 133, and half-wave plate 134 are sequentially fixed in a groove inside the first housing 131, the groove primarily serving a positioning and fixing function. The first end cap 135 covers one end of the first housing 131 and abuts against the outer wall of the housing 1. A fiber optic coupling head 136 is positioned at the center of the first end cap 135, ensuring the collimation of the incident laser. In this embodiment, the filter 133, half-wave plate 134, and lens, among other optical components, are directly integrated into the housing of the laser polarization and shaping module 13, eliminating unnecessary mechanical degrees of freedom, ensuring the compactness and reliability of the device, and improving its adaptability to ambient temperature and vibration resistance, enabling it to operate normally under harsh temperature and high vibration conditions.

[0030] Furthermore, such as Figure 4As shown, the CMOS camera module 14 includes a second housing 141, a second lens 142, a filter 143, a camera mounting flange 144, a CMOS camera 145, and a second end cap 146. The second end cap 146 covers one end of the second housing 141 and abuts against the outer wall of the housing 1. The camera mounting flange 144 is disposed inside the second housing 141. The CMOS camera 145 is disposed between the camera mounting flange 144 and the second end cap 146 and is fixed inside the second housing 141 by a lug. The filter 143 and the second lens 142 are disposed between the camera mounting flange 144 and the cavity of the grating magneto-optical trap system 3 and are fixed inside the second housing 141 by a groove. Similarly, by integrating all optical components into the housing of the CMOS camera module 14, unnecessary mechanical degrees of freedom are eliminated, ensuring the compactness and reliability of the device, and making the imaging of atomic clusters clearer and more reliable.

[0031] Furthermore, the cable assembly 15 includes a wiring flange 151, a cable conduit 152, and a wire 153. The wiring flange 151 is located on the outer wall of the housing 1 and has a wiring rod 154 on it. The wiring rod 154 is covered with insulating ceramic and has expansion alloy sealing caps at both ends. The cable conduit 152 is located between the wiring flange 151 and the cavity of the grating magneto-optical trap system 3. The wire 153 connects to the wiring rod 154 from the outside of the housing 1, enters the cavity of the grating magneto-optical trap system 3 through the cable conduit 152, and connects to the electromagnetic coil 33 and the alkali metal distributor 36. The cable assembly 15 adopts a vacuum sealing method of stainless steel-ceramic-sealing metal welding, which can effectively reduce vacuum leakage. It is mainly used for connecting with external cables, such as introducing power lines to connect with the electromagnetic coil 33 and alkali metal distributor 36 inside the cavity of the grating magneto-optical trap system 3 for power supply, introducing fiber optic jumpers to connect with the fiber optic coupler 136 on the laser polarization and shaping module 13, etc. All wires 153 entering the interior of the grating magneto-optical trap system 3 and each docking device are introduced through the cable assembly 15.

[0032] Furthermore, the alkali metal distributor 36 serves as the atomic source, with Li atoms selected as the working cold atom. In this embodiment, the alkali metal distributor 36 is used as the atomic source, replacing the atomic furnace used in a typical atomic cooling trap system, effectively reducing the system size. A differential pipe 35 connects the alkali metal distributor 36 to the internal chamber of the grating magneto-optical trap system 3, reducing the impact on the vacuum level within the magneto-optical trap chamber. A non-evaporative suction pump is also installed below the alkali metal distributor 36 to absorb any impurities released during operation.

[0033] Furthermore, extremely high vacuum indicates a vacuum level <10. -9 Pa. In the embodiments of this application, the described ultra-high vacuum environment means a vacuum degree << 10. -9Pa.

[0034] Furthermore, the observation window is made of Pyrex optical glass. The observation window is also connected to the internal cavity of the grating magneto-optical trap system 3 via the observation end cap 9 and the observation port 12, for real-time observation of the atomic cluster trapping situation inside the cavity of the grating magneto-optical trap system 3.

[0035] Furthermore, this application also provides a method for measuring vacuum using a portable ultra-high vacuum quantum measurement device. The core principle of this method is based on the law governing the loss of cold atoms caused by collisions between neutral particles and trapped cold atoms within a potential well. According to a mathematical model, the loss rate coefficient required to invert the vacuum level is determined. It depends only on the potential well depth and the type of collision system, and specifically includes the following steps: Step 1: Installation and wiring. Connect the power cord to the cable assembly 15. Connect the fiber optic patch cord to the fiber optic coupler 136 of the laser polarization and shaping module 13 through the cable assembly 15. Connect the vacuum to be tested to the vacuum interface 10 through the corrugated tube.

[0036] Step 2: Evacuate the cavity of the grating magneto-optical trap system 3; first, use the mechanical pump and molecular pump of the vacuum system to be tested to evacuate the cavity of the grating magneto-optical trap system 3 to a rough vacuum; then, use a non-evaporative getter pump to evacuate the cavity of the grating magneto-optical trap system 3 to a high vacuum.

[0037] Step 3: Introduce the gas to be tested into the cavity of the grating magneto-optical trap system 3; introduce the gas to be tested into the cavity of the grating magneto-optical trap system 3 through the vacuum system to be tested.

[0038] Step 4: Load cold atoms into the grating magneto-optical trap system 3; First, heat the alkali metal distributor 36 to generate alkali metal vapor, which enters the cavity of the grating magneto-optical trap system 3 through the differential tube 35. Then, turn on the cooling light, which enters the cavity of the grating magneto-optical trap system 3 in a vertical direction and forms an optical trap together with the diffraction beam; then, energize the electromagnetic coil 33 to generate a gradient magnetic field, which combines with the optical trap to form a magneto-optical trap, thereby cooling and capturing the alkali metal vapor to obtain cold atom clusters; after loading is completed, turn off the alkali metal distributor 36.

[0039] Step 5: Measure the number and loss rate of atomic clusters in the grating magneto-optical trap system 3. First, turn on the imaging light to perform the first imaging and obtain a signal frame containing atomic information. Then, turn off all beams and gradient magnetic fields to allow the atomic clusters to be completely destroyed. Then, turn on the imaging light again to perform the second imaging and obtain a reference frame containing background information inside the cavity of the grating magneto-optical trap system 3. Finally, process the reference frame and information frame images. Based on the size of the atomic cluster, the number of atoms it contains can be estimated. Then, record the curve of the number of atoms in the atomic cluster decaying over time and calculate the corresponding loss rate.

[0040] Step 6: Measure the potential well depth of the grating magneto-optical trap; First, repeat steps 4 and 5 to load atoms into the grating magneto-optical trap system 3 and measure the initial number of atoms in the atomic cluster; then turn on the Kick light to apply a thrust to the atoms, causing them to escape the potential well; immediately turn off the cooling light so that atoms below the minimum escape velocity are recaptured; repeat step 5 to measure the number of recaptured atoms in the atomic cluster; process the data of the initial number of atoms and the number of recaptured atoms to obtain the escape velocity of the atoms in the grating magneto-optical trap system 3, i.e., the potential well depth.

[0041] Step 7: Obtain the vacuum level to be measured by inversion based on atomic collision theory; first, calculate the loss rate coefficient of the atomic cluster based on the potential well depth, as shown in the following formula: , In the formula, κ and ζ are fixed coefficients; m cold The mass of a cold atom is given; m and T represent the mass and temperature of different neutral particle compositions of the background gas, respectively; μ is the reduced mass; x σ E is the van der Waals length. σ For van der Waals energy, C σ is the diffusion coefficient; U is the potential well depth for trapping cold atoms; The loss rate coefficient of the atomic group at a certain potential well depth; Then, the loss rate of the atomic group is calculated using the following formula: , In the formula, N0 is the initial number of atoms in the atomic group; N (t) The number of atoms in the atomic group at a certain moment; The loss rate of atomic clusters at a certain potential well depth; Finally, the vacuum degree to be measured is obtained using the following formula: , In the formula, P is the vacuum degree to be measured, and n is the density of the reference gas; Let k be the velocity-average collision loss cross section at a pit depth of U; B is Boltzmann's constant; T is the temperature of the atomic group.

[0042] More specifically, the portable ultra-high vacuum quantum measurement device and application method provided in this application solve the problems of large measurement uncertainty caused by various effects in the measurement process of traditional ionization vacuum meters, as well as the large scale, complex structure, poor portability, and difficult operation and maintenance of current laboratory-scale ultra-high vacuum quantum measurement equipment. Based on the basic physical properties of cold atoms, it reduces the size of the system and enhances its portability while retaining the unique advantages of current ultra-high vacuum quantum measurement equipment, such as no calibration required, high accuracy, and good spatiotemporal reproducibility.

[0043] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A portable ultra-high vacuum quantum measurement device, characterized in that, Includes the housing, handle, and grating magneto-optical trap system, wherein: The handle is located on the top of the housing, and the grating magneto-optical trap system is located inside the housing; The outer wall of the housing and the cavity of the grating magneto-optical trap system are provided with eight corresponding interfaces, namely: Three laser inlets are used to connect to the laser polarization and shaping module; Camera mounting port for connecting CMOS camera modules; Connection port, used for connecting cable assemblies; Vacuum interface, used for receiving vacuum measurements; Vacuum pump mounting port, for connecting to a non-evaporative suction pump; Observation port, used to connect with the observation window end cap; The cavity of the grating magneto-optical trap system is made of Ti alloy and includes a base, a diffraction grating, an electromagnetic coil, a mounting bracket, a differential tube, and an alkali metal distributor, wherein: The electromagnetic coil is fixed to the base by the mounting bracket; The diffraction grating is disposed above the electromagnetic coil; The alkali metal distributor is located below the base and is connected to the internal chamber through the differential pipe; Below the alkali metal distributor is a non-evaporative suction pump; The magneto-optical trap of the grating magneto-optical trap system is composed of a magnetic field of a coil combined with an incident cooled laser beam and a diffraction beam generated by a diffraction grating.

2. The portable ultra-high vacuum quantum measurement device according to claim 1, characterized in that, The three laser inlets include a cooling light inlet, an imaging light inlet, and a kick light inlet. The cooling light inlet is located above the cavity of the grating magneto-optical trap system, while the imaging light inlet and the kick light inlet are located on the side of the cavity of the grating magneto-optical trap system. Each laser inlet is connected to a laser polarization and shaping module.

3. The portable ultra-high vacuum quantum measurement device according to claim 2, characterized in that, The laser polarization and shaping module includes a first housing, a first lens, a filter, a half-wave plate, and a first end cap, wherein: The first lens, filter, and half-wave plate are sequentially fixed in a groove inside the first housing; The first end cap covers one end of the first outer shell and is aligned with the outer wall of the shell. An optical fiber coupling head is located at the center of the first end cap.

4. The portable ultra-high vacuum quantum measurement device according to claim 1, characterized in that, The CMOS camera module includes a second housing, a second lens, a filter, a camera mounting flange, a CMOS camera, and a second end cap, wherein: The second end cap covers one end of the second outer shell and is aligned with the outer wall of the shell. The camera mounting flange is located inside the second housing; The CMOS camera is positioned between the camera mounting flange and the second end cap, and is fixed inside the second housing by lugs. The filter and the second lens are disposed between the camera mounting flange and the cavity of the grating magneto-optical trap system, and are fixed inside the second housing by a groove.

5. The portable ultra-high vacuum quantum measurement device according to claim 1, characterized in that, The cable assembly includes a wiring flange, cable conduit, and conductors, wherein: The wiring flange is located on the outer wall of the housing, and a wiring rod is installed on it. The wiring rod is covered with insulating ceramic, and both ends are fitted with expansion alloy sealing caps. The cable conduit is installed between the wiring flange and the cavity of the grating magneto-optical trap system; The wires connect to the wiring rod from the outside of the housing, enter the cavity of the grating magneto-optical trap system through the cable conduit, and connect to the electromagnetic coil and the alkali metal distributor.

6. The portable ultra-high vacuum quantum measurement device according to claim 5, characterized in that, The alkali metal distributor serves as the atom source, with Li atoms selected as the working cold atoms.

7. The portable ultra-high vacuum quantum measurement device according to claim 1, characterized in that, Extremely high vacuum means a vacuum level of <10. -9 Pa.

8. The portable ultra-high vacuum quantum measurement device according to claim 1, characterized in that, The observation window is made of Pyrex optical glass.

9. A method for using the portable ultra-high vacuum quantum measurement device according to any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Installation and wiring. Connect the power cord to the cable assembly. Connect the fiber optic patch cord to the fiber optic coupler of the laser polarization and shaping module through the cable assembly. Connect the vacuum to be tested to the vacuum interface through the corrugated tube. Step 2: Evacuate the cavity of the grating magneto-optical trap system; Step 3: Introduce the gas to be tested into the cavity of the grating magneto-optical trap system; Step 4: Load cold atoms into the grating magneto-optical trap system; Step 5: Measure the number and loss rate of atomic clusters in the grating magneto-optical trap system; Step 6: Measure the potential well depth of the grating magneto-optical trap; Step 7: Obtain the vacuum degree to be measured by inversion based on atomic collision theory.

Images