A mass analyzer system and a mass spectrometer

Abstract

The present invention discloses a mass analyzer system, including an ion lens group, an analyzing electromagnet, and a detector. The ion lens group, the analyzing electromagnet, and the detector adopt an asymmetric structure. The distance between the ion lens group and the analyzing electromagnet is less than the distance between the analyzing electromagnet and the detector, and the deflection radius of the magnetic field center of the analyzing electromagnet is 200 - 220 mm. The incident angle of the ions output by the ion lens group entering the analyzing electromagnet is less than the exit angle of the ions output by the analyzing electromagnet. The present invention also discloses a mass spectrometer. The present invention has the advantages of compact layout, small occupied space, and light weight, etc.

Description

Technical Field

[0001] The present invention belongs to the field of analytical technologies, and particularly relates to a mass analyzer system and a mass spectrometer including the mass analyzer system. Background Art

[0002] Thermal ionization mass spectrometry (TIMS) is an analytical and testing technology developed in the 1970s for the accurate measurement of elemental isotope abundances and isotope abundance ratios. Compared with other analytical technologies, thermal ionization mass spectrometry has advantages such as high accuracy and high precision. Thermal ionization mass spectrometers have been widely used in fields such as the nuclear industry, environment, geology, and archaeology.

[0003] The mass analyzer system is a place where ions with different mass-to-charge ratios are mass-separated, and is an important component of a thermal ionization mass spectrometer. It directly determines parameters such as the sensitivity, mass resolution, mass dispersion, and aberration of the thermal ionization mass spectrometer, and affects the actual analysis level of the thermal ionization mass spectrometer.

[0004] Currently, the main manufacturers of thermal ionization mass spectrometers worldwide are Thermo Fisher, Ametek, and Isotopx in the UK. The mass analyzer systems of the thermal ionization mass spectrometers produced by these three manufacturers all have their unique ion optical designs. Although they can all achieve the purpose of mass spectrometry analysis, there are problems such as large floor space and large weight, which are not conducive to layout. In addition, these thermal ionization mass spectrometers also have deficiencies such as high energy consumption and low resolution. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a mass analyzer system and a mass spectrometer with advantages such as a compact layout and small floor space in view of the above deficiencies existing in the prior art.

[0006] The technical solution of the present invention to solve the above technical problem is as follows:

[0007] According to one aspect of the present invention, there is provided a mass analyzer system, which includes an ion lens group, an analyzing electromagnet, and a detector. The ion lens group, the analyzing electromagnet, and the detector adopt an asymmetric structure. The distance between the ion lens group and the analyzing electromagnet is less than the distance between the analyzing electromagnet and the detector. Moreover, the magnetic field center deflection radius of the analyzing electromagnet is 200 - 220 mm, and the incident angle of the ions output from the ion lens group entering the analyzing electromagnet is less than the exit angle of the ions output from the analyzing electromagnet.

[0008] Preferably, the distance between the ion lens group and the analyzing electromagnet is 450 - 480 mm, the distance between the analyzing electromagnet and the detector is 570 - 600 mm, the incident angle of the analyzing electromagnet is 27 - 30°, and the exit angle of the analyzing electromagnet is 29 - 32°.

[0009] Preferably, the ion lens group includes an acceleration lens, an extraction lens, a focusing lens, a focusing lens X, a focusing lens Z, an ion source exit slit, an output lens, and a high-voltage power connector. The acceleration lens, the extraction lens, the focusing lens, the focusing lens X, the focusing lens Z, the ion source exit slit, and the output lens are arranged in sequence, and the output lens is located close to the analyzing electromagnet. The high-voltage power connector is electrically connected to the acceleration lens, the extraction lens, the focusing lens, the focusing lens X, the focusing lens Z, and the output lens respectively to provide voltage.

[0010] Preferably, the voltage of the high-voltage power connector is below 10 KV, and the width of the ion source exit slit is 0.2 mm.

[0011] Preferably, the high-voltage power connector includes a plurality of power supply modules, namely the first module, the second module, the third module, the fourth module, the fifth module, and the sixth module, where:

[0012] The first module is electrically connected to the acceleration lens and is used to provide a voltage range of 9900 ± 100 V to the acceleration lens;

[0013] The second module is electrically connected to the extraction lens and is used to provide a voltage range of 8600 ± 300 V to the extraction lens;

[0014] The third module is electrically connected to the focusing lens and is used to provide a voltage range of 9000 ± 100 V to the focusing lens;

[0015] The fourth module is electrically connected to the focusing lens X and is used to provide a voltage range of 5000 ± 100 V to the focusing lens X;

[0016] The fifth module is electrically connected to the focusing lens Z and is used to provide a voltage range of 450 ± 250 V to the focusing lens Z;

[0017] The sixth module is electrically connected to the output lens and is used to provide a voltage range of 1500 ± 250 V to the output lens.

[0018] Preferably, the analytical electromagnet includes a yoke, pole shoes, a pole coil, and a magnetic induction stabilizing coil. The pole shoes are arranged inside the yoke. The pole coil and the magnetic induction stabilizing coil are sleeved on the pole shoes, and the magnetic induction stabilizing coil is at one end close to the pole shoe gap. The pole coil is used to generate a magnetic field, and the magnetic induction stabilizing coil is used to compensate for the magnetic field generated by the pole coil.

[0019] Preferably, the gap between the pole shoes is 12 - 15 mm, and both the pole coil and the magnetic induction stabilizing coil are wound with low-resistance enameled wires with a current density less than 2 A / mm 2 .

[0020] Preferably, the number of Faraday cups in the detector is more than eight, and each Faraday cup is arranged in a row in sequence to form a focusing plane. Among them, the position of the Faraday cup in the middlemost position is fixed, and the positions of the remaining Faraday cups can move along the direction of the focusing plane.

[0021] Preferably, the angle between the focusing plane and the main optical axis of ion transmission of the analytical electromagnet is 20 - 30°, and the width of the receiving slit of the Faraday cup is 0.8 - 1.0 mm.

[0022] Preferably, the system further includes a second focusing lens and a zoom lens. The second focusing lens is arranged between the ion lens group and the analytical electromagnet and is used to optimize the focusing effect of the ion beam output by the ion lens group. The zoom lens is arranged between the analytical electromagnet and the detector and is used to improve the dispersion distance.

[0023] According to another aspect of the present invention, there is also provided a mass spectrometer, which includes the mass analyzer system described above.

[0024] For the mass analyzer system and the mass spectrometer of the present invention, by adopting an asymmetric ion optical design, relevant parameters such as the central orbit radius of the analytical electromagnet, the distance between the ion lens group and the analytical electromagnet, and the distance between the analytical electromagnet and the detector can be reduced, making the structural layout of the entire system compact, thereby effectively reducing the overall size and weight of the system. In addition, by improving the structural composition and parameters of the ion lens group, the analytical electromagnet, and the detector, not only can performance such as resolution (greater than 500) and ion transmission efficiency (more than 90%) be improved, but also a mass number range of 3 -

[0025] Isotope analysis with a full mass number of 280 amu can also reduce power consumption and achieve environmental protection and energy conservation. By setting the second focusing lens, the ions can be further focused in the X and Y directions before entering the analysis electromagnet. By setting the zoom lens, the mass dispersion distance of the ions after mass separation by the analysis electromagnet can be further adjusted, thereby improving the receiving efficiency of the detector. Description of the Drawings

[0026] Figure 1 Schematic structural diagram of the mass analyzer system in an embodiment of the present invention;

[0027] Figure 2 Schematic structural diagram of the ion lens group in an embodiment of the present invention;

[0028] Figure 3 Schematic structural diagram of the output lens in an embodiment of the present invention;

[0029] Figure 4 Schematic structural diagram of the analysis electromagnet in an embodiment of the present invention;

[0030] Figure 5 Exploded view of the analysis electromagnet in an embodiment of the present invention;

[0031] Figure 6 Schematic structural diagram of the detector in an embodiment of the present invention;

[0032] Figure 7 Schematic structural diagram of another mass analyzer system in an embodiment of the present invention;

[0033] Figure 8 Schematic structural diagram of the second focusing lens in an embodiment of the present invention;

[0034] Figure 9 Cross-sectional view of the second focusing lens in an embodiment of the present invention.

[0035] In the figure: 1 - ion lens group; 2 - analysis electromagnet; 3 - detector; 10 - acceleration electrode lens; 11 - extraction electrode lens; 12 - focusing lens; 13 - focusing electrode X lens; 14 - focusing electrode Z lens; 15 - ion source exit slit; 16 - output lens; 20 - yoke;

[0036] 21 - pole shoe; 22 - magnetic induction stabilizing coil; 23 - pole coil; 24 - moving device; 30 - Faraday cup; 31 - secondary electron multiplier; 32 - deflection electrode; 33 - high - voltage connector;

[0037] 41 - pole rod; 161 - first electrode; 162 - second electrode; 163 - third electrode; 164 - fourth electrode. Detailed Embodiments

[0038] To enable those skilled in the art to better understand the technical solution of the present invention, the following will clearly and completely describe the technical solution in the present invention in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0039] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper" is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of description and simplification, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0040] In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0041] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "connected", "arranged", "installed", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0042] Embodiment 1

[0043] As Figure 1 shown, this embodiment discloses a mass analyzer system, which can be used in a thermal ionization mass spectrometer (TIMS), a multi-receiver inductively coupled plasma mass spectrometer (MC-ICP-

[0044] MS), etc. It includes an ion lens group 1, an analyzing electromagnet 2, and a detector 3. Among them, the ion lens group 1, the analyzing electromagnet 2, and the detector 3 adopt an asymmetric structure. The distance between the ion lens group 1 and the analyzing electromagnet 2 is less than the distance between the analyzing electromagnet 2 and the detector 3, and the magnetic field center deflection radius of the analyzing electromagnet 2 is 200 - 220 mm. The incident angle of the ions output by the ion lens group 1 entering the analyzing electromagnet is less than the exit angle of the ions output by the analyzing electromagnet.

[0045] Specifically, the ion lens group 1 is used to adjust and focus ions, the analyzing electromagnet 2 is used to provide a magnetic field with stable and adjustable intensity, and the detector 3 is used to measure the ion beam current intensity. The distance between the ion lens group 1 and the analyzing electromagnet 2 ranges from 450 to 480 mm, and the distance between the analyzing electromagnet 2 and the detector 3 ranges from 570 to 600 mm. The incident angle range of the ions output from the ion lens group 1 entering the analyzing electromagnet is 27 - 30°, and the exit angle range of the ions output from the analyzing electromagnet is 29 - 32°.

[0046] The principle of the mass analyzer system is as follows: Using a uniform magnetic field, according to the different Lorentz forces exerted on ions with different masses entering the analyzing electromagnet, the mass-to-charge ratio m / e is spatially separated according to size;

[0047] According to the ion acceleration equation in an electric field and the Lorentz force equation in a magnetic field:

[0048]

[0049] Then the ion mass-to-charge ratio is:

[0050] where q represents the charge number of the ion, U0 represents the acceleration voltage, m represents the mass of the ion, B represents the magnetic field intensity, V represents the velocity of the ion, and r m represents the deflection radius at the center of the magnetic field;

[0051] When the acceleration voltage U0 and the magnetic field intensity B are adjusted to appropriate values, ions with different mass-to-charge ratios (m / q) achieve different deflection radii, and then reach different Faraday cups, and the detector completes the measurement of the ion beam current intensity.

[0052] In this embodiment, the distance between the ion lens group 1 and the analyzing electromagnet 2 is preferably 430 mm, the distance between the analyzing electromagnet 2 and the detector 3 is preferably 580 mm, the incident angle of the ions output from the ion lens group entering the analyzing electromagnet is preferably 28°, and the exit angle of the ions output from the analyzing electromagnet is preferably 30°.

[0053] Compared with the prior art, an output lens 16 is added to the ion lens group 1 in this embodiment. That is to say, as Figure 2As shown, the ion lens group 1 includes an accelerating electrode lens 10, an extraction electrode lens 11, a focusing lens 12, a focusing electrode X lens 13, a focusing electrode Z lens 14, an ion source exit slit 15, an output lens 16, and a high-voltage power supply connector, where: the accelerating electrode lens 10, the extraction electrode lens 11, the focusing lens 12, the focusing electrode X lens 13, the focusing electrode Z lens 14, the ion source exit slit 15, and the output lens 16 are arranged in parallel in sequence, and the output lens 16 is located close to the analysis electromagnet 2; the high-voltage power supply connector is electrically connected to the accelerating electrode lens 10, the extraction electrode lens 11, the focusing lens 12, the focusing electrode X lens 13, the focusing electrode Z lens 14, and the output lens 16 respectively to provide voltage for these aforementioned lenses.

[0054] Specifically, the width of the ion source exit slit 15 can be 0.2 - 0.3 mm, preferably 0.2 mm, and the distance between the ion source exit slit 15 and the analysis electromagnet 2 can be 420 - 440 mm, preferably 430 mm. The output lens 16 is connected to the ion source exit slit 15 through components such as a stainless steel support rod, a positioning ceramic, and a fastening bolt. The output lens can adjust and correct the ion beam before it enters the magnetic field in the analysis electromagnet to improve the ion transmission efficiency (more than 90%).

[0055] The range of the voltage that the high-voltage power supply connector can provide is preferably 0 - 10 KV. That is to say, the voltage of the high-voltage power supply connector is below 10 KV, or rather, the maximum voltage of the high-voltage power supply connector is 10 KV, and the maximum ion acceleration voltage of the ion lens group is 10 KV, which can be adjusted according to actual requirements specifically.

[0056] In this embodiment, the high-voltage power connector includes multiple modules, namely the first module, the second module, the third module, the fourth module, the fifth module, and the sixth module (not shown in the figure). Among them: The first module is electrically connected to the acceleration electrode lens 10 and is used to provide a voltage range of 9900 ± 100 V to the acceleration electrode lens, and the preferred voltage is 9900 V; The second module is electrically connected to the extraction electrode lens 11 and is used to provide a voltage range of 8600 ± 300 V to the extraction electrode lens, and the preferred voltage is 8600 V; The third module is electrically connected to the focusing lens 12 and is used to provide a voltage range of 9000 ± 100 V to the focusing lens, and the preferred voltage is 9000 V; The fourth module is electrically connected to the focusing electrode X lens 13 and is used to provide a voltage range of 5000 ± 100 V to the focusing electrode X lens, and the preferred voltage is 5000 V; The fifth module is electrically connected to the focusing electrode Z lens 14 and is used to provide a voltage range of 450 ± 250 V to the focusing electrode Z lens, and the preferred voltage is 450 V; The sixth module is electrically connected to the output lens 16 and is used to provide a voltage range of 1500 ± 250 V to the output lens, and the preferred voltage is 1500 V. By setting multiple modules to provide voltages to the acceleration electrode lens 10, the extraction electrode lens 11, the focusing lens 12, the focusing electrode X lens 13, the focusing electrode Z lens 14, and the output lens 16 respectively, it is beneficial to obtain the best focusing and transmission effects of the ion beam.

[0057] In this embodiment, as Figure 3 shown, the output lens 16 includes four electrodes, namely the first electrode 161, the second electrode 162, the third electrode 163, and the fourth electrode 164. Among them, the first electrode 161 and the second electrode 162 are a group, and the two are opposite and in the first direction. The voltage between the first electrode 161 and the second electrode 162 is preferably 0 - 190 V; The third electrode 163 and the fourth electrode 164 are another group, and the two are opposite and in the second direction, and the second direction is perpendicular to the first direction. The voltage between the third electrode 163 and the fourth electrode 164 is preferably 0 - 190 V.

[0058] Compared with the prior art, the analysis electromagnet 2 in this embodiment is increased with a magnetic induction stabilizing coil 22. As Figure 4 、 Figure 5As shown in the figure, in this embodiment, the analytical electromagnet 2 includes a yoke 20, a pole shoe 21, a pole coil 23, a magnet power supply, and a magnetic induction stabilizing coil 22, where: The pole shoe 21 is arranged inside the yoke 20. The pole coil 23 and the magnetic induction stabilizing coil 22 are sleeved on the pole shoe 21, and the magnetic induction stabilizing coil 22 is at one end close to the pole shoe gap. The pole coil 23 is used to generate a magnetic field; the magnetic induction stabilizing coil 22 is used to make a small compensation during the process of regulating the magnetic field generated by the pole coil 23 to improve the magnetic field stability; the magnet power supply is respectively connected to the pole coil 23 and is used to provide a stable and adjustable current for the pole coil.

[0059] Specifically, the deflection radius of the magnetic field center of the analytical electromagnet 2 (also known as the "central orbit radius") can be 200 - 220 mm, preferably 200 mm. Compared with the prior art (above 260 mm), the deflection radius of the magnetic field center is significantly reduced, which is beneficial to reducing the weight of the analytical electromagnet. The materials of the yoke 20 and the pole shoe 21 are preferably DT4 pure iron. The gap (i.e., air gap) of the pole shoe in the analytical electromagnet 2 can be 12 - 15 mm, preferably 14 mm. The incident angle of the ions output by the ion transmission electron microscope entering the analytical electromagnet 2 is preferably 28°, and the exit angle of the ions output by the analytical electromagnet 2 is preferably 30°. The exit surface pole head in the analytical electromagnet 2 adopts an arc surface design, and the radius r of this arc surface can be 600 - 700 mm, preferably 665 mm, to improve the ion focusing effect.

[0060] Both the pole coil 23 and the magnetic induction stabilizing coil 22 are preferably wound with low-resistance enameled wires with a current density less than 2 A / mm 2 . This reduces the winding heat generation. Compared with the prior art, it is not necessary to be equipped with a cooling water machine, thereby reducing the power consumption of the instrument. The number of both the pole coil 23 and the magnetic induction stabilizing coil 22 is two, and the two coils are connected in parallel with each other. The magnet power supply adopts a conventional standard component design, and its output current to the pole coil 23 is preferably 0.2 - 16 A, and the uniformity of the magnetic field generated by the pole coil 23 is less than 50 ppm.

[0061] Through the above settings, the magnification (M) of the analytical electromagnet 2 can reach 1.5, with high precision; it can achieve continuous and stable adjustment between a magnetic field intensity of 0 - 1.24 T; and it can meet the accurate measurement of the abundances and abundance ratios of elements in the full mass number range of 3 - 280 amu.

[0062] Moreover, a moving device 24 can be provided at the bottom of the analytical electromagnet. Driven by the moving device, the analytical electromagnet can be leveled in the horizontal and vertical directions.

[0063] In this embodiment, the mobile device 24 includes a horizontal adjustment unit and a vertical adjustment unit (not shown in the figure). Specifically: the horizontal adjustment unit may include a horizontal guide rail, and the analysis electromagnet is disposed on the horizontal guide rail and can slide along the horizontal guide rail to adjust the position of the analysis electromagnet in the horizontal direction; the vertical adjustment unit may also adopt the same or similar structure as the horizontal adjustment unit, which will not be elaborated here, to adjust the position of the analysis electromagnet in the vertical direction.

[0064] Compared with the prior art, as Figure 6 shown, the detector in this embodiment also includes components such as a Faraday cup 30, a secondary electron multiplier 31, a deflection electrode 32, a high-voltage connector 33, and a detector housing (not shown in the figure). The internal cavity of the detector housing is in a vacuum state. The Faraday cup 30, the secondary electron multiplier 31, the deflection electrode 32, and the high-voltage connector 33 are disposed inside the detector housing, and their wiring methods are the same as those in the prior art, which will not be elaborated here. The difference lies in:

[0065] The gain multiple of the secondary electron multiplier 31 is 10 6 , and the high resistance value of the amplifier of the Faraday cup 30 is 10 11 Ω. In this way, the size of the vacuum cavity inside the detector housing can be reduced as much as possible on the premise of ensuring performance requirements (the diameter of the vacuum cavity can reach about 300 mm), thereby reducing power consumption.

[0066] The number of secondary electron multipliers 31 can be one or more, and a commercially available Daly detector can be used. The number of Faraday cups 30 is multiple, for example, more than 8. Each Faraday cup 30 is arranged in a row in sequence. The orientations of the receiving slits of each Faraday cup are the same to form a focusing plane. Among them, the position of the Faraday cup 30 in the middle order is fixed. Specifically, when the number of Faraday cups 30 is odd, the position of the Faraday cup in the middle order is fixed. When the number of Faraday cups 30 is even, the position of any one of the two Faraday cups 30 in the middle order is fixed. For example, when the number of Faraday cups 30 is 8, the positions of the fourth and / or fifth Faraday cups are fixed. The positions of the remaining Faraday cups 30 can move along the direction of the focusing plane to adjust the positions of each Faraday cup according to different analyzed elements, so as to ensure sensitivity and accuracy.

[0067] The structure of the Faraday cup 30 adopts a conventional structure, which is composed of a receiving slit, a suppressor electrode, an insulating block, and a housing, and is in the shape of a rectangular box as a whole. One side of the Faraday cup is open for receiving the ion beam, and the other sides are all sealed.

[0068] In this embodiment, the receiving slit width of the Faraday cup 30 is preferably 0.8 - 1.0 mm; the moving range of the positions of each of the remaining Faraday cups 30 except for the middle position (for example, when the number of Faraday cups is eight, the middle position refers to the fourth Faraday cup and / or the fifth Faraday cup) is preferably 0 - 44 mm; the size of the Faraday cup 30 is preferably 12×2×1 mm; the material of the Faraday cup 30 can be stainless steel or high-purity graphite. The adjustment accuracy of a single Faraday cup 30 can be 10 μm, and the adjustment method can be adjusted by a stepper motor or manually adjusted by a worm gear and worm guide rail; the angle between the focusing plane formed by the arrangement of each Faraday cup 30 and the main ion transmission optical axis of the analyzing electromagnet 2 can be 20 - 30°, preferably 25°.

[0069] With the above settings, when the amplifier high resistance of the Faraday cup 30 is 10 11 Ω, the Faraday cup 30 can detect an ion current of 6.0×10 -14 A - 2.7×10 -10 A, and the secondary electron multiplier 31 (SEM) can detect an ion current as low as 1.6×10 -18 A.

[0070] In the mass analyzer system of this embodiment, by adopting an asymmetric ion optical design, relevant parameters such as the central orbit radius of the analyzing electromagnet, the distance between the ion lens group and the analyzing electromagnet, and the distance between the analyzing electromagnet and the detector can be reduced, making the structural layout of the entire system compact, thereby effectively reducing the overall size and weight of the system. In addition, by improving the structural composition and parameters of the ion lens group, the analyzing electromagnet, and the detector, not only can performance such as resolution (greater than 500) and ion transmission efficiency (more than 90%) be improved, realizing isotope analysis of the entire mass number range from 3 to 280 amu, but also power consumption can be reduced, achieving environmental protection and energy conservation.

[0071] Embodiment 2

[0072] This embodiment discloses a mass analyzer system, which is different from Embodiment 1 in that: as Figure 7 shown, it further includes a second focusing lens 4 and a zoom lens 5. Among them, the second focusing lens 4 is arranged between the ion lens group 1 and the analyzing electromagnet 2 and is used to optimize the focusing effect of the ion beam output by the ion lens group, improve the flat top peak effect, and further improve the transmission efficiency; the zoom lens 5 is arranged between the analyzing electromagnet 2 and the detector 3 and is used to improve the dispersion distance to improve the peak overlapping ability between multiple ion beams and multiple Faraday cup receivers.

[0073] Specifically, the second focusing lens 4 is preferably arranged at a position closer to the inlet of the analyzing electromagnet 2, and the zoom lens 5 is preferably arranged at a position closer to the outlet of the analyzing electromagnet 2. It should be noted that since the second focusing lens 4 and the zoom lens 5 only optimize the focusing effect of the ion beam and improve the dispersion of the mass analyzer system, and do not affect the final focusing image point of the ion beam (i.e., the receiving position of the Faraday cup), therefore, the second focusing lens 4 and the zoom lens 5 can also be arranged at other positions other than the above positions, and can be flexibly selected according to specific requirements.

[0074] As Figure 8 , Figure 9 shown, the second focusing lens 4 is an electrostatic quadrupole lens, which includes four pole rods 41. Among them, two pole rods 41 are arranged oppositely and in the same direction (such as the horizontal direction, i.e., the x-axis direction), and the other two pole rods 41 are arranged oppositely and in another direction (such as the vertical direction, i.e., the y-axis direction). The angle between the center of the adjacent pole rods 41 and the center of the inscribed circle surrounded by the four pole rods 41 is 90°. If a positive voltage is applied to the two pole rods 41 in the horizontal direction, then a negative voltage of the same magnitude is applied to the two pole rods 41 in the vertical direction. Conversely, if a negative voltage is applied to the two pole rods 41 in the horizontal direction, then a positive voltage of the same magnitude is applied to the two pole rods 41 in the vertical direction. The range of the applied voltage is preferably between 0 ± 20V.

[0075] The zoom lens 5 can adopt any one of a quadrupole lens, a hexapole lens, an octopole lens, and a dodecapole lens to finely adjust the mass dispersion of the ion beam within ±5%. The voltage application method of the zoom lens 5 is similar to that of the second focusing lens. Taking the hexapole lens as an example, it includes six second pole rods, an x terminal, and a y terminal. One end of each second pole rod is connected to the x terminal, and the other end of each second pole rod is connected to the y terminal. If a positive voltage is applied to the six pole rods on the x terminal, then a negative voltage of the same magnitude is applied to the six pole rods on the y terminal. Conversely, if a negative voltage is applied to the six pole rods on the x terminal, then a positive voltage of the same magnitude is applied to the six pole rods on the y terminal. The range of the applied voltage is preferably between 0 ± 50V.

[0076] More specifically, each pole rod in the second focusing lens 4 and the zoom lens 5 can be a circular pole rod, a semi-circular pole rod, or any one of a hyperbolic pole rod, a rod-shaped pole rod, and a planar pole rod. And, when the pole rod is a cylindrical pole rod, the radius of the cylindrical pole rod is 1.1 - 1.2 times the radius of the inscribed circle surrounded by each pole rod, and the length of the pole rod should not be less than 3 times the radius of its inscribed circle; when the pole rod is of other types, the radius and length of the pole rod can also be designed according to a design equivalent to that of the (cylindrical pole rod), which will not be elaborated here one by one.

[0077] The mass analyzer system of this embodiment has all the advantages of the mass analyzer system in Embodiment 1. Moreover, due to the addition of the second focusing lens and the zoom lens, since the second focusing lens can further focus the ions in the X and Y directions before they enter the analysis electromagnet, and the zoom lens can further adjust the mass dispersion distance of the ions after mass separation by the analysis electromagnet, the reception efficiency of the detector can be ultimately improved.

[0078] Embodiment 3

[0079] This embodiment discloses a mass spectrometer, which includes an ion source, a shielding glove box, and the mass analyzer system described in Embodiment 1.

[0080] Specifically, the mass spectrometer of this embodiment can be a thermal ionization mass spectrometer (TIMS) or a multi-receiver inductively coupled plasma mass spectrometer (MC-ICP-MS). Its detection process is as follows: the ions generated by the ion source are extracted, accelerated, focused, and shaped by the ion lens group 1 and then reach the analysis electromagnet 2. Ions of different masses are mass-separated in the sector magnetic field generated by the analysis electromagnet 2, and finally the ions reach the detector 3 for ion beam intensity detection.

[0081] Among them, the ion lens group 1, the analysis electromagnet 2, and the detector 3 in the mass analyzer system are preferably arranged in sequence from right to left. Compared with the arrangement of the ion lens group 1, the analysis electromagnet 2, and the detector 3 in the prior art, which are all arranged from left to right, since the ion source all uses a right-side opening door, it is convenient for the sealing between the ion source and the shielding glove box.

[0082] The mass spectrometer of this embodiment, due to adopting the mass analyzer system described in Embodiment 1, has the following advantages: compact structure layout, small volume, and the overall machine size can be reduced to 1750 х 1050 х 1600 mm; light weight, and the overall machine weight can be reduced to 1000 Kg; low power consumption, and the rated power of the whole machine can be reduced to 3.5 kW, which is about half lower than that of the prior art; high resolution, which can reach more than 500; high ion transmission efficiency, which can reach more than 90%; the magnification (M) can reach 1.5, and isotope analysis of the full mass number range from 3 to 280 amu can be realized.

[0083] It can be understood that the above embodiments are only exemplary embodiments adopted to illustrate the principle of the present invention. However, the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A mass analyzer system, comprising an ion lens group (1), an analyzing electromagnet (2), and a detector (3), characterized in that, The ion lens group, the analyzing electromagnet, and the detector adopt an asymmetric structure. The distance between the ion lens group and the analyzing electromagnet is less than the distance between the analyzing electromagnet and the detector. The magnetic field center deflection radius of the analyzing electromagnet is 200 - 220 mm. The incident angle of the ions output from the ion lens group entering the analyzing electromagnet is less than the exit angle of the ions output from the analyzing electromagnet. The distance between the ion lens group and the analyzing electromagnet is 450 - 480 mm, the distance between the analyzing electromagnet and the detector is 570 - 600 mm. The incident angle of the analyzing electromagnet is 27 - 30°, and the exit angle of the analyzing electromagnet is 29 - 32°.

2. The mass analyzer system according to claim 1, wherein The ion lens group includes an accelerating lens (10), an extraction lens (11), a focusing lens (12), a focusing X lens (13), a focusing Z lens (14), an ion source exit slit (15), an output lens (16), and a high - voltage power connector. The accelerating lens, the extraction lens, the focusing lens, the focusing X lens, the focusing Z lens, the ion source exit slit, and the output lens are arranged in sequence. The output lens is located close to the analyzing electromagnet. The high - voltage power connector is electrically connected to the accelerating lens, the extraction lens, the focusing lens, the focusing X lens, the focusing Z lens, and the output lens respectively to provide voltage.

3. The mass analyzer system according to claim 2, characterized in that, The voltage of the high - voltage power connector is below 10 KV, and the width of the ion source exit slit is 0.2 mm.

4. The mass analyzer system according to claim 2, wherein The high - voltage power connector includes a plurality of power supply modules, namely the first module, the second module, the third module, the fourth module, the fifth module, and the sixth module. The first module is electrically connected to the accelerating lens and is used to provide a voltage range of 9900 ± 100 V to the accelerating lens. The second module is electrically connected to the extraction lens and is used to provide a voltage range of 8600 ± 300 V to the extraction lens. The third module is electrically connected to the focusing lens and is used to provide a voltage range of 9000 ± 100 V to the focusing lens. The fourth module is electrically connected to the focusing X lens and is used to provide a voltage range of 5000 ± 100 V to the focusing X lens. The fifth module is electrically connected to the focusing Z lens and is used to provide a voltage range of 450 ± 250 V to the focusing Z lens. The sixth module is electrically connected to the output lens and is used to provide a voltage range of 1500 ± 250 V to the output lens.

5. The mass analyzer system according to claim 1, wherein The analyzing electromagnet includes a yoke (20), pole shoes (21), a pole - piece coil (23), and a magnetic induction stabilizing coil (22). The pole shoes are arranged inside the yoke. The pole - piece coil and the magnetic induction stabilizing coil are sleeved on the pole shoes. The magnetic induction stabilizing coil is at one end close to the pole - shoe gap. The pole - piece coil is used to generate a magnetic field, and the magnetic induction stabilizing coil is used to compensate the magnetic field generated by the pole - piece coil.

6. The mass analyzer system according to claim 5, wherein The clearance of the pole shoe is 12 - 15 mm, and both the magnetic pole coil and the magnetic induction stabilizing coil are wound with low-resistance enameled wires with a current density less than 2 A / mm 2 .

7. The mass analyzer system according to claim 1, characterized in that, The number of Faraday cups (30) in the detector is more than eight, and each Faraday cup is arranged in a row in sequence to form a focusing plane. Among them, the position of the Faraday cup at the middlemost position is fixed, and the positions of the remaining Faraday cups can move along the direction of the focusing plane.

8. The mass analyzer system according to claim 7, wherein, The included angle between the focusing plane and the main optical axis of ion transmission of the analyzing electromagnet is 20 - 30°, and the width of the receiving slit of the Faraday cup is 0.8 - 1.0 mm.

9. The mass analyzer system according to any one of claims 1-8, characterized in that, It further includes a second focusing lens (4) and a zoom lens (5). The second focusing lens is arranged between the ion lens group and the analyzing electromagnet and is used to optimize the focusing effect of the ion beam output by the ion lens group. The zoom lens is arranged between the analyzing electromagnet and the detector and is used to improve the dispersion distance.

10. A mass spectrometer, characterized in that, It includes the mass analyzer system according to any one of claims 1 - 9.

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