A Thermal Surface Ionization Mass Spectrometry Structure

Abstract

The invention discloses a thermal surface ionization mass spectrometer structure. The structure includes a thermal surface ionization ion source, an ion transmission lens, an electrostatic analyzer, a deflection magnet, a multipole lens, a detection system, etc. The thermal ions are generated by the thermal surface ionization ion source; the ion beam is accelerated, focused and transmitted by the ion transmission lens; the ion beam imaging quality is improved by the multipole lens, and the resolution of the instrument is improved; the influence of the acceleration high voltage noise and drift is overcome by matching the electrostatic analyzer with the deflection magnet, and an excellent peak shape factor and long-term stability of the peak center are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of mass spectrometers, and in particular relates to a thermal surface ionization mass spectrometer structure. Background Art

[0002] Since its inception, the mass spectrometer has been an important tool for studying challenging scientific problems in fields such as nuclear science and geology. After nearly a century of development, the application field of mass spectrometers has been further expanded to various fields such as inorganic chemistry, materials science, environmental science and life science. Today, mass spectrometers have developed into an affordable routine analytical tool in many laboratories. Thermal surface ionization mass spectrometry is internationally recognized as the "gold standard" for isotope ratio measurement due to its many advantages such as less background interference, lower mass fractionation effect, and higher measurement precision and accuracy.

[0003] Traditional thermal surface ionization mass spectrometers all use a single magnet structure as a mass analyzer. Due to the noise and drift of the high voltage power supply and the limited focusing ability of the single magnet, single-magnet thermal surface ionization mass spectrometers generally have poor peak shape coefficients and peak center drift, which affects the accuracy of isotope ratio testing. In order to overcome this problem, traditional thermal surface ionization mass spectrometers usually need to perform peak center calibration multiple times during the measurement process, which increases sample consumption and reduces instrument analysis efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide a thermal surface ionization mass spectrometry structure, which improves the ion beam imaging quality and the resolution of the instrument through a multipole lens; overcomes the influence of acceleration high voltage noise and drift by matching an electrostatic analyzer with a deflection magnet, and achieves excellent peak shape coefficient and long-term stability of the peak center, thereby reducing the number of peak center calibration times during the test process, reducing sample consumption and improving instrument analysis efficiency.

[0005] The technical solution of the present invention is as follows:

[0006] A thermal surface ionization mass spectrometer structure includes a thermal surface ionization ion source, an ion transmission lens, an electrostatic analyzer, a deflection magnet and a detection system.

[0007] In the thermal surface ionization mass spectrometry structure, the electrostatic analyzer can be placed before the deflection magnet or after the deflection magnet. When the electrostatic analyzer is placed before the deflection magnet, the detection system adopts a multi-receiving detection system; when the electrostatic analyzer is placed after the deflection magnet, the detection system adopts a single-receiving detection system. The multi-receiving detection system consists of a multi-channel Faraday cup and an electron multiplier, and the detection system can simultaneously measure multiple ion beams with different mass numbers. The single-receiving detection system only receives a single ion beam, and consists of a single Faraday cup and a single electron multiplier, and the two can be switched freely.

[0008] In order to further improve the quality of ion beam imaging and enhance the resolution of the instrument, multipole lenses are installed before and after the electrostatic analyzer. The multipole lenses can be either hexapole lenses or octopole lenses, depending on the final structural parameters of the instrument.

[0009] The multi-receiving detection system consists of a multi-channel Faraday cup and an electron multiplier. The Faraday cups are arranged in sequence on the detection plane, and the electron multiplier is located at the rear end of the Faraday cup.

[0010] It consists of a single Faraday cup and a single electron multiplier, which can be switched freely.

[0011] A first multipole lens is installed in front of the electrostatic analyzer, and a second multipole lens is installed behind the electrostatic analyzer.

[0012] A deflection lens and an ion beam front detection slit are installed in front of the first multipole lens.

[0013] An ion beam rear detection slit is installed after the second multipole lens.

[0014] The upper pole shoe and the lower pole shoe of the deflection magnet are respectively installed on the upper and lower sides of the yoke, the upper excitation coil and the lower excitation coil surround the upper pole shoe and the lower pole shoe respectively and are installed on the yoke, and the front magnetic shield and the rear magnetic shield are respectively installed in front and behind the pole shoe.

[0015] The beneficial effect of the present invention is that, by matching the electrostatic analyzer with the magnet, the influence of the acceleration high voltage noise and drift can be overcome, and the peak center stability can be improved. The number of peak center calibrations can be reduced during the analysis and testing process, thereby improving sample utilization and instrument analysis efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a diagram of the structure of a hot surface ionization mass spectrometer according to an embodiment of the present invention, with an electrostatic analyzer in the front and a deflection magnet in the back;

[0017] Figure 2 This is a diagram of the structure of a hot surface ionization mass spectrometer according to an embodiment of the present invention, with an electrostatic analyzer at the back and a deflection magnet at the front;

[0018] Figure 3 The structure diagram of the electrostatic analyzer equipped with octopole, deflection lens and ion detection slit;

[0019] Figure 4 A diagram of a deflection magnet in an embodiment;

[0020] Figure 5 The mass spectrometry peak profiles produced for the embodiments;

[0021] Figure 6 To realize the simultaneous peak mapping of multiple mass numbers for the embodiment; DETAILED DESCRIPTION

[0022] The present invention is further described below through the accompanying drawings and specific embodiments. It should be noted that the embodiments described here are to help readers understand the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific statements and embodiments.

[0023] like Figure 1 As shown, a hot surface ionization mass spectrometer structure is shown, with an electrostatic analyzer 3 in front and a deflection magnet 4 in the back. In addition to the mass analyzer, the mass spectrometer structure also includes a hot surface ionization ion source 1, an ion transmission lens 2 and a multi-receiving detection system 5.

[0024] The most significant feature of this structure is that the influence of acceleration high voltage noise and drift is overcome by matching the electrostatic analyzer 3 with the deflection magnet 4, achieving excellent peak shape factor and long-term stability of the peak center, avoiding frequent calibration of the peak center during the instrument measurement process, and thus improving the analysis efficiency of the instrument.

[0025] like Figure 2 As shown, a hot surface ionization mass spectrometer structure is shown, with an electrostatic analyzer 3 at the back and a deflection magnet 4 at the front. In addition to the mass analyzer, the mass spectrometer structure also includes a hot surface ionization ion source 1, an ion transmission lens 2, and a single receiving detection system.

[0026] The characteristic of this structure is that the signals of ions with different mass numbers are measured in different time periods through magnetic field scanning, thereby realizing the analysis of sample components.

[0027] like Figure 3 As shown, the electrostatic analyzer 3 is composed of an inner electrode 9 and an outer electrode 10, both of which are cylindrical electrodes. The first multipole lens 6 and the second multipole lens 7 installed before and after the electrostatic analyzer 3 are octopole lenses, a deflection lens and a front ion beam detection slit 11 are installed before the first multipole lens 6, and an ion beam rear detection slit 12 is installed after the second multipole lens 7.

[0028] The octopole lens is used to improve the imaging quality of the ion beam, the deflection lens 10 is used to correct the direction of the ion beam incident on the electrostatic analyzer 3, and the purpose of setting the front detection slit 11 and the rear detection slit 12 of the ion beam is to detect and diagnose the intermediate state of the ion beam.

[0029] like Figure 4 As shown, the structure and composition of the deflection magnet 4 are shown, and the magnet is composed of an upper excitation coil 13, a lower excitation coil 14, a yoke 15, an upper pole shoe 16, a lower pole shoe 17, a front magnetic shield 18, a rear magnetic shield 19, etc.

[0030] By applying a stable excitation current to the upper excitation coil 13 and the lower excitation coil 14, a stable magnetic field is generated between the upper pole shoe 16 and the lower pole shoe 17, thereby achieving the deflection and separation of ion beams of different mass numbers. The front magnetic shield 18 and the rear magnetic shield 19 are used to weaken the diffuse field distribution of the magnet, thereby improving the imaging quality of the ion beam.

[0031] like Figure 5 The mass spectrum peak shape produced by this embodiment is shown in FIG. 1 , which has a relatively wide flat top and an excellent peak shape factor. The steep rising edge and the relatively wide flat top area of ​​the "trapezoidal peak" both reflect that this embodiment achieves excellent ion beam imaging quality for the ion beam.

[0032] like Figure 6 The figure shows the simultaneous peak matching of multiple mass numbers achieved in this embodiment. The figure reflects that different detection channels simultaneously detect two ion beams with different mass numbers.

[0033] The working mode of the hot surface ionization mass spectrometer structure is as follows: the hot surface ionization ion source generates ions, which are accelerated and focused by the ion transmission lens, and then pass through the electrostatic analyzer, magnet, or magnet and electrostatic analyzer to achieve focused imaging on the detection plane, and finally are received by the Faraday cup or electron multiplier to achieve signal output. According to the strength of the collected signal, the composition and content of the sample can be analyzed.

[0034] To further evaluate the peak center stability achieved by the example, the index was tested, as shown in Table 1. The peak center stability of the example was less than 10 ppm.

[0035] Table 1 Peak center stability of the examples

[0036]

[0037]

Claims

1. A thermal surface ionization mass spectrometry structure, characterized in that: The invention comprises a hot surface ionization ion source (1), an ion transmission lens (2), an electrostatic analyzer (3), a deflection magnet (4), and a detection system (5). Ions generated by the hot surface ionization ion source (1) are accelerated and focused through the ion transmission lens (2), and then pass through the electrostatic analyzer (3) and then the deflection magnet (4), or pass through the deflection magnet (4) and then the electrostatic analyzer (3) to achieve separation and imaging of ions with different mass numbers, and are finally received by the detection system (5) to achieve signal output. The deflection magnet (4) comprises an upper excitation coil (13), a lower excitation coil (14), a yoke (15), an upper pole shoe (16), a lower pole shoe (17), a front magnetic shield (18), and a rear magnetic shield The invention relates to a magnetic field detector (19), an upper pole shoe (16) and a lower pole shoe (17) are respectively mounted on the upper and lower sides of the yoke (15), an upper excitation coil (13) and a lower excitation coil (14) surround the upper pole shoe (16) and the lower pole shoe (17) respectively, and are mounted on the yoke (15), a front magnetic shield (18) and a rear magnetic shield (19) are respectively mounted on the front and rear of the pole shoe, when the electrostatic analyzer (3) is placed before the deflection magnet (4), the detection system (5) is a multi-receiving detection system, when the electrostatic analyzer (3) is placed after the deflection magnet (4), the detection system (5) is a single-receiving detection system, a first multipole lens (6) is mounted in front of the electrostatic analyzer (3), and a second multipole lens (7) is mounted behind the electrostatic analyzer (3).

2. The thermal surface ionization mass spectrometry structure according to claim 1, characterized in that: The multi-receiving detection system is composed of a multi-channel Faraday cup (5.1) and an electron multiplier (5.2). The Faraday cups are arranged in sequence on the detection plane, and the electron multiplier is located at the rear end of the Faraday cup.

3. The thermal surface ionization mass spectrometry structure according to claim 1, characterized in that: The single receiving detection system is composed of a single Faraday cup (5.3) and a single electron multiplier (5.4), and the two can be switched freely.

4. The thermal surface ionization mass spectrometry structure according to claim 1, characterized in that: The first multipole lens (6) and the second multipole lens (7) are sextupole lenses or octupole lenses.

5. The thermal surface ionization mass spectrometry structure according to claim 1, characterized in that: A deflection lens (10) and an ion beam front detection slit (11) are installed in front of the first multipole lens.

6. The thermal surface ionization mass spectrometry structure according to claim 4, characterized in that: An ion beam rear detection slit (12) is installed behind the second multipole lens.

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