A method and system for simultaneous and rapid measurement of trace inert gas isotopes

Abstract

The present application relates to the technical field of isotope measurement, and particularly relates to a trace inert gas isotope synchronous rapid measurement method and system, the system comprising: a metastable beam source device, a beam current deceleration device, a first magnetic optical trap, a second magnetic optical trap, an ultrahigh vacuum system, a laser light source module, a first trapping laser module, a second trapping laser module, a first detection module, a second detection module, a synchronous control unit and a data analysis unit; the ultrahigh vacuum system is internally provided with the metastable beam source device, the beam current deceleration device, the first magnetic optical trap and the second magnetic optical trap which are sequentially connected and have coinciding axes; the second magnetic optical trap forms an atomic circulation path through a magnetic suspension vacuum pump pipeline. The present application realizes synchronous measurement of two isotopes without increasing the complexity of the system, does not need to switch the laser wavelength, shortens the measurement time, reduces the influence of system drift, and significantly improves the measurement efficiency and precision.

Description

Technical Field

[0001] This invention relates to the field of isotope measurement technology, and in particular to a method and system for the synchronous and rapid measurement of trace inert gas isotopes. Background Technology

[0002] Radioactive isotopes decay spontaneously, emitting particles or rays. By detecting the decay process of radioactive isotopes, their movement and distribution can be tracked. Radioactive isotopes serve as tracers in fields such as biomedicine and earth sciences. The core of atomic trap trace detection technology is to trap atoms in a magneto-optical trap and then count the trapped atoms to achieve quantitative measurement. This method uses electron collisions to excite inert gas atoms from their ground state to a metastable state. Then, an infrared laser resonates with the two-level system from the metastable to the excited state, achieving cooling and trapping of the inert gas atoms. This approach offers advantages of high selectivity and high sensitivity, making it suitable for measuring trace radioactive isotopes.

[0003] Chinese patent CN103196911B discloses a measurement 85 A systematic approach and method for determining the atomic number of Kr isotopes, proposing the use of cooled lasers to... 85 Kr gas cooling, decelerating laser irradiation 85 Kr gas deceleration, trapping laser pair 85 Kr gas trapping, a single-atom counting device counts the number of atoms within the trapping cavity. Because a specific laser wavelength is used, it only counts... 85 Kr confinement eliminates the need for expensive electronic devices such as particle accelerators, thus saving costs.

[0004] Chinese patent CN113092654B discloses a type of airborne... 85 An automated and continuous measurement system for Kr gas separation, extraction, and content determination is provided. The gas separation process employs activated carbon low-temperature cold trap combined with gas chromatography, and the detection system utilizes an atomic trap trace analysis system for measurement. This measurement system achieves... 85 Continuous separation and automatic continuous measurement of Kr gas content.

[0005] In existing measurement techniques, when detecting two isotopes, the laser system needs to switch back and forth between different isotopes to achieve resonance between the laser wavelength and the isotope being measured. System drift during the measurement process affects the isotope measurement results, leading to problems such as long measurement times and poor accuracy.

[0006] Therefore, how to achieve simultaneous and rapid measurement of two isotopes when there are a large number of samples to be tested is an urgent problem to be solved. Summary of the Invention

[0007] The purpose of this invention is to provide a method and system for the simultaneous and rapid measurement of trace inert gas isotopes, in order to solve the problem of how to achieve simultaneous, rapid and high-precision measurement of two isotopes when there are a large number of samples to be tested.

[0008] To achieve the above objectives, the present invention provides the following technical solution: According to one aspect of the present invention, a system for simultaneous and rapid measurement of trace inert gas isotopes is provided, comprising: Metastable beam source device, beam deceleration device, first magneto-optical trap, second magneto-optical trap, ultra-high vacuum system, laser source module, first trapped laser module, second trapped laser module, first detection module, second detection module, synchronization control unit and data analysis unit; wherein: The metastable beam source device, beam deceleration device, first magneto-optical trap, and second magneto-optical trap are sequentially connected by an ultra-high vacuum pipeline with their axes overlapping, and are placed inside the ultra-high vacuum system; the second magneto-optical trap is connected back to the metastable beam source device through a magnetically levitated vacuum pump pipeline to form an atomic beam circulation path. The first trapping laser module is used to manipulate and trap the first isotope, and the second trapping laser module is used to manipulate and trap the second isotope; the first detection module is used to measure the first isotope trapped in the first magneto-optical trap, and the second detection module is used to measure the second isotope trapped in the second magneto-optical trap; the abundances of the first and second isotopes are different; The first detection module and the second detection module start measurement synchronously under the control of the synchronization control unit. The data analysis unit is used to process the measurement data of the first and second detection modules and calculate the isotope abundance ratio.

[0009] According to one embodiment of the present invention, the metastable beam source device includes a metastable atom excitation module, a metastable atom collimation module, and a metastable atom focusing module; wherein: the metastable atom excitation module generates metastable atoms using a helical resonant cavity radio frequency gas discharge method; the metastable atom collimation module is used to collimate the generated metastable atom beam; and the metastable atom focusing module is used to focus the collimated atom beam to improve the beam density; The atomic beam generated by the metastable beam source device includes different isotopes to be measured. Its first path is connected to the first trapped laser module, and its second path is connected to the beam deceleration device.

[0010] According to one embodiment of the present invention, the laser source module includes a laser and a frequency stabilization module; the laser is a diode laser, a solid-state laser, or a fiber laser, and the frequency stability of the frequency stabilization module is controlled within ±1MHz; the laser output by the laser source module is divided into two beams, the first beam is transmitted as the first laser beam to the first trapped laser module, and the second beam is transmitted as the second laser beam to the second trapped laser module.

[0011] According to one embodiment of the present invention, the first trapped laser module includes a first frequency shifter, a first modulator, a first amplifier, a first beam splitter, and a second frequency shifter connected in sequence; the first laser beam output from the laser enters the first frequency shifter, the first modulator, and the first amplifier in sequence; the first frequency shifter performs frequency shifting processing on the first laser beam to match the atomic resonance frequency of the first isotope; the first modulator performs amplitude or frequency modulation on the frequency-shifted laser to optimize the beam characteristics; and the first amplifier amplifies the power of the modulated laser. The amplified laser beam is split into four paths by the first beam splitter: The first beam is formed by sequentially passing through the second frequency shifter to adapt to beam deceleration and is then connected to the beam deceleration device. The second path forms the first trapping beam, which is connected to the first magneto-optical trap; the first trapping beam is used to trap and assist in the detection of the atomic beam of the first isotope. The third path forms the first collimated beam; the first collimated beam is used to collimate the atomic beam of the first isotope; The fourth path forms the first focused beam, which is used to focus the atomic beam of the first isotope; Both the first collimated beam and the first focused beam are connected to the metastable beam source device.

[0012] According to one embodiment of the present invention, the second trapped laser module includes a second modulator, a second amplifier, and a second beam splitter connected in sequence; The second laser beam output from the laser enters the second modulator and the second amplifier in sequence. The second modulator modulates the second laser beam to match the atomic resonance frequency of the second isotope. The second amplifier amplifies the power of the modulated laser. The amplified laser is split into three paths by the second beam splitter: the first path forms the second trapped beam and is connected to the second magneto-optical trap; the second path forms the second collimated beam; and the third path forms the second focused beam. Both of these paths are connected to the metastable beam source device. The second collimating beam is used to collimate the atomic beam of the second isotope, the second focusing beam is used to focus the atomic beam of the second isotope, and the second trapping beam is used to trap and assist in the detection of the atomic beam of the second isotope.

[0013] According to one embodiment of the present invention, the first detection module is used to measure and record the single-atom signal of the first isotope, and the second detection module is used to measure and record the single-atom signal of the second isotope; the abundance of the second isotope is higher than that of the first isotope. Each detection module includes an imaging lens module, an image sensor, and a data processing unit; The imaging lens module includes an aspherical lens and a pinhole aperture to reduce stray light interference and improve the clarity of single-atom imaging. The image sensor is an electron multiplication charge-coupled device (EMCCD) or a complementary metal-oxide-semiconductor (CMOS) device, used to capture the fluorescence signal of a single atom; The data processing unit is used to analyze the intensity of single-atom signals, count the single-atom count rate, and transmit the data to the data analysis unit.

[0014] According to one embodiment of the present invention, the synchronization control unit is used to send a synchronization detection control signal to the first detection module and the second detection module, controlling the two detection modules to start signal acquisition at the same time, so as to realize the synchronous measurement of the first isotope and the second isotope; The data analysis unit is used to receive the single-atom count rate transmitted by the data processing units of the first detection module and the second detection module, and calculate the abundance ratio of the first isotope to the second isotope in the gas sample to be tested based on the ratio of the single-atom count rates of the first and second isotopes and in combination with the system calibration parameters.

[0015] According to one embodiment of the present invention, both the first magneto-optical trap and the second magneto-optical trap include a gradient magnetic field and an optical field formed by multiple sets of symmetrical lasers; the gradient magnetic field is formed by an anti-Helmholtz coil, and the magnetic field gradient is 10 to 40 Gs / cm; In the light field, each pair of symmetrical lasers is coaxial and collinear with opposite directions, and the laser directions between groups are perpendicular to each other; The intensity range of the laser is 10 to 20 mW / cm². 2 .

[0016] According to one embodiment of the present invention, the light field consists of 6 laser beams, which are divided into 3 groups. Each group consists of two coaxial and collinear beams with opposite directions, and the 3 groups of laser beams are perpendicular to each other.

[0017] On the other hand, the present invention also provides a method for simultaneous and rapid measurement of trace inert gas isotopes, based on the aforementioned system, specifically including the following steps: S1: A trace amount of inert gas sample is introduced into the measurement system. Different isotope atoms in the sample enter the metastable atom excitation module of the metastable beam source device and are excited to the metastable state under the action of radio frequency discharge. S2: After being collimated by the metastable atom collimation module and focused by the metastable atom focusing module in sequence, the metastable atom beam flies along the axis towards the beam deceleration device, the first magneto-optical trap, and the second magneto-optical trap. The atoms that are not trapped return to the metastable atom excitation module through the magnetic levitation vacuum pump pipe, forming a cycle. S3: The laser output from the laser source module is split into two beams, which are transmitted to the first trapped laser module and the second trapped laser module respectively. After processing the laser, the two trapped laser modules output collimated, focused and trapped beams. The first trapped laser module also outputs a decelerated beam, which acts on the atomic beam of the corresponding isotope. S4: The first isotope is collimated, focused, and decelerated under the action of the beam of the first confinement laser module and then confined in the first magneto-optical trap; the second isotope is collimated and focused under the action of the beam of the second confinement laser module and then confined in the second magneto-optical trap. S5: The synchronization control unit sends a synchronization signal to trigger the first detection module and the second detection module to synchronously acquire the single-atom signals in the first and second magneto-optical traps. The data processing unit analyzes the signals and transmits them to the data analysis unit. S6: The data analysis unit calculates the abundance ratio based on the single-atom count rates of the first and second isotopes, and completes the measurement.

[0018] This invention provides a method and system for the simultaneous and rapid measurement of trace inert gas isotopes. By employing a laser beam from the same source to trap atoms of different isotopes and simultaneously measuring them separately, it enables the simultaneous and rapid measurement of different isotopes in trace inert gases, shortening measurement time and improving measurement efficiency. Compared with existing technologies, the beneficial effects of this invention are as follows: (1) Low complexity: The trace inert gas isotope synchronous rapid measurement system can measure different isotopes of trace inert gases without increasing the system complexity by adding a small number of devices; only a few devices such as the frequency shifter of the first trap laser module and the second detection module are added, without changing the structural logic of the core components, so the overall complexity is controllable and easy to integrate and mass-produce. (2) High measurement efficiency: The method for synchronous and rapid measurement of trace inert gas isotopes does not require the laser system to switch back and forth between measuring different isotopes, thus shortening the measurement time and improving the measurement efficiency. Through the synchronous design of dual magneto-optical traps and dual trapped laser modules, there is no need to switch laser wavelengths. The measurement time for two isotopes is shortened from 10 to 20 minutes in the existing technology to 2 to 5 minutes, and the efficiency is improved by 4 to 5 times. (3) High measurement accuracy: The method for synchronous and rapid measurement of trace inert gas isotopes is based on the same source laser and adopts synchronous measurement mode to achieve the measurement of different isotopes of trace inert gases, which significantly improves the measurement accuracy. The abundance ratio measurement error of the existing technology is 1%~3%, while the error of the present invention is reduced to less than 0.1% through the same source laser and synchronous control, which meets the high precision requirements of trace detection.

[0019] (4) High atomic utilization: The atomic circulation pathway is formed through the magnetic levitation vacuum pump pipeline, which improves the atomic utilization rate and is suitable for extremely low abundance isotopes (such as...). Measurement of magnitude. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a framework diagram of a trace inert gas isotope synchronous rapid measurement system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the metastable beam source device 101 according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the laser source module and the first and second trapped laser modules according to an embodiment of the present invention; Figure 4 These are schematic diagrams of the first and second detection modules according to an embodiment of the present invention; Figure 5 This is a flowchart of a method for simultaneous and rapid measurement of trace inert gas isotopes according to an embodiment of the present invention.

[0021] The components in the diagram are labeled as follows: 101 - Metastable beam source device; 102 - Beam deceleration device; 103 - First magneto-optical trap; 104 - Second magneto-optical trap; 105 - First trapped laser module; 106 - Second trapped laser module; 107 - First detection module; 108 - Second detection module; 109 - Laser source module; 110 - Ultra-high vacuum system; 1021 - Metastable atom excitation module; 1022 - Metastable atom collimation module; 1023 - Metastable atom focusing module; 1050 - First frequency shifter; 1051 - First modulator; 1052 - First amplifier; 105A - First beam splitter; 1053 - Second frequency shifter; 1054 - First decelerating beam; 1055 - First trapped beam; 1056 - First collimated beam; 1057 - First focused beam; 1061 - Second modulator; 1062 - Second amplifier; 106A - Second beam splitter; 1063 - Second trapped beam; 1064 - Second collimated beam; 1065 - Second focused beam; 1091 - Laser; 1092 - Frequency stabilization module. Detailed Implementation

[0022] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0023] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0024] In this invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c" can represent: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0025] Trace inert gases can be krypton (Kr), xenon (Xe), or neon (Ne). All of these gases have stable inert chemical properties, and their isotopes (especially trace radioactive or low-abundance stable isotopes) have clear requirements in fields such as environmental monitoring, geological dating, and biological tracing. Furthermore, the technical solution of "metastable excitation-magneto-optical trap-synchronous detection" in the adaptation document is compatible with this solution.

[0026] If the trace inert gas is krypton (Kr), then the isotope is a gas. (First isotope, extremely low abundance, approximately) (magnitude, radioactive isotope) and (The second isotope, with the highest abundance, about 99.6%, is a stable isotope); This combination conforms to the technical logic of "low abundance requires deceleration, high abundance requires direct imprisonment".

[0027] If the trace inert gas is xenon (Xe), then the isotope is a gas. (First isotope, extremely low abundance, approximately) (magnitude, radioactive isotope) and (The second isotope, with the highest abundance, about 26.9%, a stable isotope); this combination is often used for nuclear environment monitoring and atmospheric circulation tracing.

[0028] If the trace inert gas is neon (Ne), then the isotope is a gas. (First isotope, low abundance, approximately 9.25%, stable isotope, requires high-precision differentiation in trace concentration scenarios) and (The second isotope, with the highest abundance, approximately 90.48%, is a stable isotope); this combination is often used for dating geological samples (such as groundwater dating) and can be applied in the field of earth sciences.

[0029] like Figure 1 The diagram shows a framework diagram of a system for the simultaneous and rapid measurement of trace inert gas isotopes. The system includes: The metastable beam source device 101, beam deceleration device 102, first magneto-optical trap 103, second magneto-optical trap 104, ultra-high vacuum system 110, laser source module 109, first trapped laser module 105, second trapped laser module 106, first detection module 107, second detection module 108, synchronization control unit, and data analysis unit are described below, along with their interconnections. The ultra-high vacuum system 110 provides a low-impact environment (vacuum degree ≤ 1000) for the entire measurement process. The device internally comprises a metastable beam source device 101, a beam deceleration device 102, a first magneto-optical trap 103, and a second magneto-optical trap 104. These four devices are sealed together by an ultra-high vacuum pipeline, and their axes are completely coincident. The order is metastable beam source device 101, beam deceleration device 102, first magneto-optical trap 103, and second magneto-optical trap 104. The second magneto-optical trap 104 is connected back to the metastable beam source device 101 through a magnetic levitation vacuum pump pipeline, forming a circulating path for the atomic beam and improving the atomic utilization rate.

[0030] like Figure 2 As shown, the metastable beam source device 101 includes a metastable atom excitation module 1021, a metastable atom collimation module 1022, and a metastable atom focusing module 1023 connected in sequence. The metastable atom excitation module 1021 employs a spiral resonant cavity radio frequency gas discharge method. The radio frequency frequency of 200~230MHz can efficiently excite inert gas to a metastable state. The radio frequency power of 20~50W is matched with the pressure in the excitation region to ensure the metastable atom yield. The pressure in the excitation region... This module is used to excite different isotope atoms (such as 85Kr and 84Kr) in an inert gas sample from the ground state to a metastable state; the metastable atom collimation module 1022 consists of a precision slit and a collimating lens to reduce the divergence angle of the metastable atom beam (≤1°); the metastable atom focusing module 1023 uses an electrostatic lens group to focus the collimated atomic beam, increasing the beam density. (atoms / cm²)

[0031] The metastable beam source device 101 has two beam paths: the first path is used to receive the first collimated beam and the first focused beam from the first trapped laser module 105; the second path is used to transport the atomic beam to the beam deceleration device 102 to enter the deceleration stage.

[0032] like Figure 3 As shown, the laser source module 109 includes a laser 1091 and a frequency stabilization module 1092. The laser 1091 is a diode laser, a solid-state laser, or a fiber laser, and its output wavelength matches the metastable-excited state resonance wavelength of the isotope being measured, such as the 811nm band for krypton isotopes. The frequency stabilization module 1092 employs saturated absorption frequency stabilization technology to control the laser frequency stability within ±1MHz, avoiding frequency drift that could affect the trapping effect. The laser output from the laser source module 109 is divided into two beams: the first laser beam is transmitted to the first trapping laser module 105, and the second laser beam is transmitted to the second trapping laser module 106.

[0033] The first trapped laser module 105 is used to adapt to the first isotope with a low abundance and includes a first frequency shifter 1050, a first modulator 1051, a first amplifier 1052, a first beam splitter 105A and a second frequency shifter 1053 connected in sequence.

[0034] The first frequency shifter 1050 is an acousto-optic frequency shifter that shifts the frequency of the first laser beam (by a certain amount). ), matching the first isotope (e.g., 85Kr, abundance ≈ The atomic resonance frequency of ) The first modulator 1051 uses an electro-optic modulator to perform amplitude modulation (modulation depth ≥90%) on the frequency-shifted laser, thereby optimizing the trapping stability of the beam. The first amplifier 1052 uses a semiconductor optical amplifier to amplify the laser power to 50~100mW to meet the requirements of multi-beam output. The first beam splitter is used to divide the amplified laser into four paths: ① The first path passes through the second frequency shifter 1053 (frequency shift amount) The first deceleration beam 1054 is formed and connected to the beam deceleration device 102 to reduce the beam velocity of the first isotope atom from 300~500m / s to 5~10m / s. ② The second path forms the first trapping beam 1055, which is connected to the first magneto-optical trap 103 and participates in the trapping of the first isotope; ③ The third path forms the first collimated beam 1056, which is connected to the metastable beam source device 101 to assist in the collimation of the first isotope atom beam; ④ The fourth path forms the first focused beam 1057, which is connected to the metastable beam source device 101 to assist in focusing the first isotope atomic beam.

[0035] The second trapped laser module 106 is used to adapt to the second isotope with higher abundance, and specifically includes a second modulator 1061, a second amplifier 1062 and a second beam splitter 106A connected in sequence.

[0036] The second modulator 1061 employs an electro-optic modulator to modulate the second laser beam (matching the second isotope, such as 84Kr, with a resonance frequency of approximately 99.6% abundance). The second amplifier 1062 uses a semiconductor optical amplifier to amplify the laser power to 30~80mW; Because the second isotope has a high abundance, no additional deceleration is needed. The second beam splitter 106A splits the amplified laser into three paths: ① The first path forms the second trapping beam 1063, which is connected to the second magneto-optical trap 104 and participates in the trapping of the second isotope; ② The second collimated beam 1064 is formed and connected to the metastable beam source device 101 to assist in the collimation of the second isotope atomic beam; ③ The third path forms a second focused beam 1065, which is connected to the metastable beam source device 101 to assist in focusing the second isotope atomic beam.

[0037] The first magneto-optical trap 103 and the second magneto-optical trap 104 have the same structure, both consisting of a gradient magnetic field and an optical field composed of six laser beams. The gradient magnetic field uses an anti-Helmholtz coil with a magnetic field gradient of 10~40 Gs / cm, providing the gradient force for atomic confinement. The six laser beams in the optical field are divided into three groups, with two laser beams in each group coaxial and collinear with opposite directions. The three groups of laser beams are perpendicular to each other (along the x, y, and z axes), with a laser intensity of 10~20 mW / cm². The Doppler cooling effect confines the atoms to the center of the trap (confinement volume ≤ 1 mm³).

[0038] like Figure 4 As shown, the first detection module 107 and the second detection module 108 have the same structure, both including an imaging lens module, an image sensor, and a data processing unit. The imaging lens module consists of an aspherical lens (focal length f=20~50mm) and a pinhole aperture (aperture 50~100μm) to reduce stray light interference and improve image clarity; the image sensor uses an electron multiplication charge-coupled device (EMCCD) or complementary metal-oxide semiconductor (CMOS) with a quantum efficiency ≥90% and can capture the fluorescence signal of a single atom; the data processing unit is used to analyze the single atom signal intensity, count the single atom count rate (counting accuracy ≤1 atom), and transmit the data to the data analysis unit.

[0039] The synchronization control unit triggers the first detection module 107 and the second detection module 108 with a pulse signal (pulse width 10~100ns) to ensure that the two modules start signal acquisition at the same time, with a synchronization error ≤1μs.

[0040] The data analysis unit is used to receive the single-atom count rate from the first and second detection modules, and, in conjunction with system calibration parameters (such as trapping efficiency and detection efficiency), calculate the abundance ratio of the first isotope to the second isotope in the sample to be tested (calculation accuracy ≤ 0.1%).

[0041] like Figure 5 As shown, based on the above system, the method for simultaneous and rapid measurement of trace inert gas isotopes includes the following steps: S501: Sample excitation and beam pretreatment; A trace amount of inert gas sample (such as a krypton sample containing 85Kr and 84Kr) is introduced into the metastable beam source device 101 of the ultra-high vacuum system 110; the metastable atom excitation module 1021 excites different isotope atoms in the sample to a metastable state through radio frequency discharge; the metastable atom beam is collimated by the metastable atom collimation module 1022 and focused by the metastable atom focusing module 1023 in sequence, and then transmitted along the axis to the beam deceleration device 102; atoms that are not trapped by subsequent stages flow back to the metastable atom excitation module 1021 through the magnetic levitation vacuum pump pipe to form a cycle.

[0042] S502: Laser beam splitting and beam processing; The laser 1091 of the laser source module 109 outputs laser light, which is then frequency-stabilized by the frequency stabilization module 1092 and split into two beams: The first laser beam enters the first trapped laser module 105, and is subsequently frequency-shifted by the first frequency shifter 1050, modulated by the first modulator 1051, and amplified by the first amplifier 1052. It is then split into a first decelerated beam, a first trapped beam, a first collimated beam, and a first focused beam by the first beam splitter. The second laser beam enters the second trapped laser module 106, and after being modulated by the second modulator 1061 and amplified by the second amplifier 1062, it is split into the second trapped beam, the second collimated beam, and the second focused beam by the second beam splitter.

[0043] S503: Synchronous Isotope Trapping; After being optimized by the first collimated beam and the first focused beam, the first isotope (such as 85Kr) enters the beam deceleration device 102 and is decelerated under the action of the first deceleration beam; the decelerated first isotope atoms enter the first magneto-optical trap 103 and are trapped under the action of the first trapping beam and the gradient magnetic field. After being optimized by the second collimating beam and the second focusing beam, the second isotope (such as 84Kr) directly enters the second magneto-optical trap 104 and is trapped under the action of the second trapping beam and the gradient magnetic field. The trapping processes of the two isotopes occur simultaneously, without the need to switch laser wavelengths.

[0044] S504: Synchronous detection and data processing; The synchronization control unit sends a synchronization signal, triggering the first detection module 107 and the second detection module 108: The imaging lens modules of the first and second detection modules capture the fluorescence signals of atoms in the magneto-optical trap, the image sensor converts the light signals into electrical signals, and the data processing unit analyzes the signals and counts the single atom count rate. The data analysis unit receives the count rate data from the first and second detection modules, calculates the abundance ratio of the first isotope to the second isotope by combining the system calibration parameters, and completes the measurement.

[0045] In existing technologies, laser systems switch wavelengths to match the resonance of different isotopes (e.g., the resonance wavelength difference between 85Kr and 84Kr is about 0.1nm), and a single switch takes 5-10 seconds, resulting in a total measurement time of 15-25 minutes for a single measurement of the two isotopes. Furthermore, the laser frequency drifts (≥±2MHz) during the switching process, leading to an abundance ratio measurement error of 1.5%-3%, which cannot meet the requirements for trace isotopes (e.g., The requirement for high-precision detection (on the order of 85Kr).

[0046] When using this invention for isotope measurement, the first isotope, with lower abundance, is collimated, focused, and slowed down by the laser beam, ultimately confined in the first magneto-optical trap and measured by the first detection module. Simultaneously, the second isotope, with higher abundance, is collimated, focused, and slowed down by the laser beam, ultimately confined in the second magneto-optical trap and measured synchronously by the second detection module. Therefore, when simultaneously measuring two isotopes, there is no need to switch the laser wavelength in the laser system, shortening the measurement time, increasing efficiency by 4-5 times, and improving accuracy to 0.1%. This invention is applicable to biomedical tracing (such as monitoring radioisotope drug metabolism), earth science dating (such as groundwater / glacier dating), and nuclear environment monitoring (such as trace fission gas detection).

[0047] The first and second magneto-optical traps are aligned on the same axis and sequentially arranged in the same ultra-high vacuum system, forming an atomic circulation path via a vacuum pump. The first magneto-optical trap is used to trap the low-abundance first isotope, and the second magneto-optical trap is used to trap the high-abundance second isotope. This ensures the homogeneity of the atomic beams from the two magneto-optical traps. Simultaneously, the circulation path allows atoms to flow back to the beam source, thus achieving dynamic and synchronous replenishment of atomic consumption and beam source supply. In particular, it solves the problem of insufficient atomic quantity for low-abundance isotopes, improving atomic utilization.

[0048] This invention employs co-source lasers to ensure synchronized frequency drift between the two laser beams. After beam splitting, the lasers undergo differential processing to adapt to isotopes of varying abundances, achieving synchronized measurement without increasing system complexity. In the first trapped laser module, dual frequency shifters achieve synchronized adaptation between deceleration and trapping. The first frequency shifter matches the resonant frequency of the first isotope, while the second frequency shifter adapts to beam deceleration. In the second trapped laser module, a single modulator directly matches the resonant frequency of the second isotope. Because the second isotope is highly abundant and has sufficient atomic mass, deceleration is unnecessary.

[0049] The synchronization control unit can perform dynamic timing compensation to ensure synchronized detection startup. Specifically, the deceleration beam of the first trapping laser module is triggered first, for example, 50 to 100 microseconds in advance. After the first isotope decelerates to a predetermined speed range and enters the first magneto-optical trap to stabilize, the trapping beam of the second trapping laser module is triggered synchronously to ensure that the atoms in the first and second magneto-optical traps reach a stable trapping state simultaneously.

[0050] The synchronization control unit then triggers the two detection modules via pulse signals, controlling the trigger time difference to within 1 microsecond, thus avoiding technical deviations caused by asynchronous detection startup. By dynamically synchronizing the trapping and detection, the synchronization accuracy can be improved from milliseconds to microseconds, thereby reducing the error in the measured abundance ratio.

[0051] In summary, since laser wavelength switching is not required, measurement time is significantly shortened and measurement efficiency is improved compared to existing technologies. Dynamic synchronization control can significantly reduce measurement errors. Furthermore, targeted trapping methods for isotopes of different abundances reduce system complexity. Utilizing atomic recycling pathways can significantly improve atom utilization, especially ensuring reliable measurements of extremely low abundance isotopes.

[0052] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, disclosure, and other materials. In this specification, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple components. A single processor or other unit can implement several functions listed in the specification. While certain measures are described in different embodiments, this does not mean that these measures cannot be combined to produce good results.

[0053] Although the invention has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made therein without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the invention and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if such modifications and modifications fall within the scope of the invention and its equivalents, the invention is also intended to include such modifications and modifications.

Claims

1. A system for synchronous and rapid measurement of trace inert gas isotopes, characterized in that, include: Metastable beam source device, beam deceleration device, first magneto-optical trap, second magneto-optical trap, ultra-high vacuum system, laser source module, first trapped laser module, second trapped laser module, first detection module, second detection module, synchronization control unit and data analysis unit; wherein: The metastable beam source device, beam deceleration device, first magneto-optical trap, and second magneto-optical trap are sequentially connected by an ultra-high vacuum pipeline with their axes coinciding, and are placed inside the ultra-high vacuum system; the second magneto-optical trap is connected back to the metastable beam source device through a magnetically levitated vacuum pump pipeline to form an atomic beam circulation path. The first trapping laser module is used to manipulate and trap the first isotope, and the second trapping laser module is used to manipulate and trap the second isotope; the first detection module is used to measure the first isotope trapped in the first magneto-optical trap, and the second detection module is used to measure the second isotope trapped in the second magneto-optical trap; the abundances of the first and second isotopes are different; The first detection module and the second detection module start measurement synchronously under the control of the synchronization control unit. The data analysis unit is used to process the measurement data of the first and second detection modules and calculate the isotope abundance ratio.

2. The trace inert gas isotope synchronous rapid measurement system according to claim 1, characterized in that, The metastable beam source device includes a metastable atom excitation module, a metastable atom collimation module, and a metastable atom focusing module; wherein: the metastable atom excitation module generates metastable atoms using a helical resonant cavity radio frequency gas discharge method; the metastable atom collimation module is used to collimate the generated metastable atom beam; and the metastable atom focusing module is used to focus the collimated atom beam to improve the beam density; The atomic beam generated by the metastable beam source device includes different isotopes to be measured. Its first path is connected to the first trapped laser module, and its second path is connected to the beam deceleration device.

3. The trace inert gas isotope synchronous rapid measurement system according to claim 1, characterized in that, The laser source module includes a laser and a frequency stabilization module; the laser is a diode laser, a solid-state laser, or a fiber laser, and the frequency stability of the frequency stabilization module is controlled within ±1MHz; The laser output from the laser source module is divided into two beams. The first beam is transmitted to the first confined laser module as the first laser beam, and the second beam is transmitted to the second confined laser module as the second laser beam.

4. The trace inert gas isotope synchronous rapid measurement system according to claim 3, characterized in that, The first trapped laser module includes a first frequency shifter, a first modulator, a first amplifier, a first beam splitter, and a second frequency shifter connected in sequence. The first laser beam output from the laser enters the first frequency shifter, the first modulator, and the first amplifier in sequence. The first frequency shifter performs frequency shifting on the first laser beam to match the atomic resonance frequency of the first isotope. The first modulator modulates the amplitude or frequency of the frequency-shifted laser to optimize the beam characteristics. The first amplifier amplifies the power of the modulated laser. The amplified laser beam is split into four paths by the first beam splitter: The first beam is formed by sequentially passing through the second frequency shifter to adapt to beam deceleration and is then connected to the beam deceleration device. The second path forms the first trapping beam, which is connected to the first magneto-optical trap; the first trapping beam is used to trap and assist in the detection of the atomic beam of the first isotope. The third path forms the first collimated beam; the first collimated beam is used to collimate the atomic beam of the first isotope; The fourth path forms the first focused beam, which is used to focus the atomic beam of the first isotope; Both the first collimated beam and the first focused beam are connected to the metastable beam source device.

5. The trace inert gas isotope synchronous rapid measurement system according to claim 3, characterized in that, The second trapped laser module includes a second modulator, a second amplifier, and a second beam splitter connected in sequence; The second laser beam output from the laser enters the second modulator and the second amplifier in sequence. The second modulator modulates the second laser beam to match the atomic resonance frequency of the second isotope. The second amplifier amplifies the power of the modulated laser. The amplified laser is split into three paths by the second beam splitter: the first path forms the second trapped beam and is connected to the second magneto-optical trap; the second path forms the second collimated beam; and the third path forms the second focused beam. Both of these paths are connected to the metastable beam source device. The second collimating beam is used to collimate the atomic beam of the second isotope, the second focusing beam is used to focus the atomic beam of the second isotope, and the second trapping beam is used to trap and assist in the detection of the atomic beam of the second isotope.

6. The trace inert gas isotope synchronous rapid measurement system according to claim 1, characterized in that, The first detection module is used to measure and record the single-atom signal of the first isotope, and the second detection module is used to measure and record the single-atom signal of the second isotope; the abundance of the second isotope is higher than that of the first isotope. Each detection module includes an imaging lens module, an image sensor, and a data processing unit; The imaging lens module includes an aspherical lens and a pinhole aperture to reduce stray light interference and improve the clarity of single-atom imaging. The image sensor is an electron multiplication charge-coupled device (EMCCD) or a complementary metal-oxide-semiconductor (CMOS) device, used to capture the fluorescence signal of a single atom; The data processing unit is used to analyze the intensity of single-atom signals, count the single-atom count rate, and transmit the data to the data analysis unit.

7. The trace inert gas isotope synchronous rapid measurement system according to claim 6, characterized in that, The synchronization control unit is used to send a synchronization detection control signal to the first detection module and the second detection module, controlling the two detection modules to start signal acquisition at the same time, so as to realize the synchronous measurement of the first isotope and the second isotope. The data analysis unit is used to receive the single-atom count rate transmitted by the data processing units of the first detection module and the second detection module, and calculate the abundance ratio of the first isotope to the second isotope in the gas sample to be tested based on the ratio of the single-atom count rates of the first and second isotopes and in combination with the system calibration parameters.

8. The trace inert gas isotope synchronous rapid measurement system according to claim 1, characterized in that, Both the first magneto-optical trap and the second magneto-optical trap include a gradient magnetic field and an optical field formed by multiple sets of symmetrical lasers; the gradient magnetic field is formed by an anti-Helmholtz coil, and the magnetic field gradient is 10 to 40 Gs / cm. In the light field, each pair of symmetrical lasers is coaxial and collinear with opposite directions, and the laser directions between groups are perpendicular to each other; The intensity range of the laser is 10 to 20 mW / cm2.

9. The trace inert gas isotope synchronous rapid measurement system according to claim 8, characterized in that, The light field consists of 6 laser beams, which are divided into 3 groups. Each group consists of two coaxial and collinear beams with opposite directions, and the 3 groups of laser beams are perpendicular to each other.

10. A method for simultaneous and rapid measurement of trace inert gas isotopes, implemented based on the system described in any one of claims 1 to 9, characterized in that, The method includes the following steps: S1: A trace amount of inert gas sample is introduced into the measurement system. Different isotope atoms in the sample enter the metastable atom excitation module of the metastable beam source device and are excited to the metastable state under the action of radio frequency discharge. S2: After being collimated by the metastable atom collimation module and focused by the metastable atom focusing module in sequence, the metastable atom beam flies along the axis towards the beam deceleration device, the first magneto-optical trap, and the second magneto-optical trap. The atoms that are not trapped return to the metastable atom excitation module through the magnetic levitation vacuum pump pipe, forming a cycle. S3: The laser output from the laser source module is split into two beams, which are transmitted to the first trapped laser module and the second trapped laser module respectively. After processing the laser, the two trapped laser modules output collimated, focused and trapped beams. The first trapped laser module also outputs a decelerated beam, which acts on the atomic beam of the corresponding isotope. S4: The first isotope is collimated, focused, and decelerated under the action of the beam of the first confinement laser module and then confined in the first magneto-optical trap; the second isotope is collimated and focused under the action of the beam of the second confinement laser module and then confined in the second magneto-optical trap. S5: The synchronization control unit sends a synchronization signal to trigger the first detection module and the second detection module to synchronously acquire the single-atom signals in the first and second magneto-optical traps. The data processing unit analyzes the signals and transmits them to the data analysis unit. S6: The data analysis unit calculates the abundance ratio based on the single-atom count rates of the first and second isotopes, and completes the measurement.

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