A desktop continuous wave paramagnetic resonance spectrometer probe

Abstract

The present invention discloses a desktop continuous wave paramagnetic resonance spectrometer probe, comprising a resonant cavity and a microwave coupling structure and a high-frequency modulation magnetic field coupling structure arranged on the resonant cavity, wherein the resonant cavity adopts a flat structure and a rectangular cavity arranged vertically, and the microwave coupling structure is a first small hole arranged on the waveguide access side of the rectangular cavity; a second small hole for accessing an external signal source is arranged on the side opposite to the first small hole of the rectangular cavity, and the high-frequency modulation magnetic field coupling structure comprises two copper rods vertically penetrating the rectangular cavity and arranged oppositely, and the copper rods are externally connected to a modulation field driving circuit. The two copper rods form a Helmholtz coil, which is externally connected to a modulation field driving circuit, and the modulation field is driven by a large current to achieve high-efficiency high-frequency modulation magnetic field coupling and better distribution of the modulation field; the copper rod is used as a Helmholtz coil, and no coil winding is required, which is more conducive to mass production.

Description

Technical Field

[0001] The invention relates to the technical field of electron paramagnetic resonance, in particular to a desktop continuous wave paramagnetic resonance spectrometer probe. Background Art

[0002] Electron paramagnetic resonance (EPR) is a magnetic resonance technique originated from the magnetic moment of unpaired electrons. It can be used to detect the unpaired electrons contained in atoms or molecules of substances from qualitative and quantitative aspects, and explore the structural characteristics of their surroundings. Electron paramagnetic resonance spectrometers are mainly divided into two types: pulsed type and continuous wave type. Continuous wave paramagnetic resonance spectrometers obtain continuous wave EPR spectral lines by placing the sample to be tested in a microwave field of constant frequency and changing the frequency of the external magnetic field.

[0003] In the electron paramagnetic resonance experiment, the resonant cavity plays an important role. Different forms of resonant cavities have been developed according to different experimental requirements. Commonly used ones include rectangular cavities, cylindrical cavities, dielectric cavities, slit cavities, etc. In the continuous wave electron paramagnetic resonance experiment, the design requirements of the resonant cavity are: 1. Ensure that the direction of the magnetic field B1 is perpendicular to the direction of the external static magnetic field; 2. Ensure that the magnetic field B1 in the sample placement area is as large as possible; 3. Have high-frequency modulation field coupling capability to meet the requirements of the high-frequency modulation field number detection method of the continuous wave paramagnetic resonance spectrometer; 4. Have a standard sample comparison measurement function to facilitate the accurate measurement of the g factor and the spin number of the sample to be tested.

[0004] The existing continuous wave paramagnetic resonance spectrometers on the market are relatively large in size. In order to meet the market demand for lightweight and portable continuous wave paramagnetic resonance spectrometers, miniaturized desktop continuous wave paramagnetic resonance spectrometers have become the development direction of continuous wave paramagnetic resonance spectrometers, and reducing the space occupied by the probe also plays a crucial role. Summary of the invention

[0005] Based on the design requirements of the continuous wave paramagnetic resonance spectrometer for the resonant cavity and combined with the development direction of desktop miniaturization, the present invention proposes a desktop continuous wave paramagnetic resonance spectrometer probe.

[0006] A desktop continuous wave paramagnetic resonance spectrometer probe comprises a resonant cavity and a microwave coupling structure and a high-frequency modulation magnetic field coupling structure arranged on the resonant cavity. The resonant cavity adopts a flat structure and is a rectangular cavity arranged vertically. The microwave coupling structure is a first small hole arranged on the waveguide access side of the rectangular cavity. A second small hole for accessing an external signal source is arranged on the side of the rectangular cavity opposite to the first small hole. The high-frequency modulation magnetic field coupling structure comprises two copper rods vertically penetrating the rectangular cavity and arranged oppositely. The copper rods are externally connected to a modulation field drive circuit.

[0007] Furthermore, the first small hole is a waist hole arranged parallel to the copper rod, and a tuning unit is provided on the side of the first small hole of the rectangular cavity. The tuning unit is composed of a tuning motor, a tuning screw that moves back and forth driven by the tuning motor, and a tuning block fixed to the top of the tuning screw. During the back and forth movement of the tuning screw, the tuning block moves relative to the first small hole.

[0008] Furthermore, a sample tube to be tested is vertically arranged through the middle of the rectangular cavity; the copper rod is symmetrically arranged relative to the sample tube to be tested; and a standard sample tube is arranged beside the sample tube to be tested.

[0009] Furthermore, a waveguide access unit is detachably connected to the first small hole side of the rectangular cavity, and an external signal source access unit is detachably connected to the second small hole side; the placement groove of the tuning unit, the sample tube to be tested and the rectangular cavity are integrally formed to form a probe main body structure.

[0010] Furthermore, one side of the copper rod is welded to a driving adapter plate, through which an external modulation field driving circuit is connected, and the other side is fixed to the probe main structure through a copper rod base; the driving adapter plate is detachably fixed to one side of the probe main structure.

[0011] The invention has the following beneficial effects: 1. Two copper rods form a Helmholtz coil, which is externally connected to a modulation field driving circuit. The modulation field is driven by a large current to achieve high-efficiency high-frequency modulation magnetic field coupling and better distribution of the modulation field; 2. The copper rod is used as the Helmholtz coil, and no coil winding is required, which is more conducive to mass production; 3. A rectangular cavity with a flat structure arranged vertically and a through-type sample tube to be tested are used, which reduces the thickness of the probe and ensures sufficient space in the sample area; 4. The probe width is only 14 mm, which meets the space limitation of 15 mm of the magnet gap of a desktop continuous wave paramagnetic resonance spectrometer; 5. A standard sample tube is added to facilitate real-time comparison during the sample detection process, and the g factor and the spin number can be tested more accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a stereoscopic view of one side of the probe main structure;

[0013] Figure 2 This is a three-dimensional view of the other side of the probe main structure;

[0014] Figure 3 This is a side view of the probe of a desktop continuous wave paramagnetic resonance spectrometer;

[0015] Figure 4 for Figure 3 AA surface section view in;

[0016] Figure 5 Schematic diagram of the probe structure of a desktop continuous wave paramagnetic resonance spectrometer. DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention are provided for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

[0018] Example 1

[0019] A desktop continuous wave paramagnetic resonance spectrometer probe, such as Figure 1-4 As shown, it includes a resonant cavity 1 and a microwave coupling structure and a high-frequency modulated magnetic field coupling structure arranged on the resonant cavity. The microwave signal is coupled into the resonant cavity through the microwave coupling structure, and the external high-frequency modulated magnetic field is coupled into the resonant cavity through the high-frequency modulated magnetic field coupling structure.

[0020] In order to adapt to the space limitation of the desktop continuous wave paramagnetic resonance spectrometer, the resonant cavity adopts a flat structure and a vertically arranged rectangular cavity. The vertical arrangement here means that the two narrowest opposite sides of the rectangular cavity are respectively connected to the microwave input side and the external signal source input side (refer to Figure 4 ), thereby reducing the thickness of the entire probe.

[0021] The microwave coupling structure is a first small hole 2 arranged at the waveguide access side of the rectangular cavity, and a second small hole 3 for accessing an external signal source is arranged on the side of the rectangular cavity opposite to the first small hole, and the high-frequency modulation magnetic field coupling structure includes two copper rods 4 vertically penetrating the rectangular cavity and arranged opposite to each other. The two copper rods form a Helmholtz coil, and an external modulation field driving circuit is connected to the modulation field, and the modulation field is driven by a large current to achieve high-efficiency high-frequency modulation magnetic field coupling and better distribution of the modulation field; on the other hand, the use of copper rods does not require coil winding, which is more conducive to mass production.

[0022] In order to save space, the first small hole 2 is a waist hole arranged parallel to the copper rod, and a tuning unit is arranged on the side of the first small hole of the rectangular cavity, and the tuning unit is composed of a tuning motor 5, a tuning screw 6 that moves back and forth under the drive of the tuning motor, and a tuning block 7 fixed to the top of the tuning screw. During the back and forth movement of the tuning screw 6, the tuning block 7 moves relative to the first small hole 2, thereby tuning the coupling state of the rectangular cavity. In this embodiment, the tuning block is a copper-plated silver metal head with a diameter of 5 mm and a thickness of 1 mm.

[0023] A sample tube 8 to be tested is vertically arranged in the middle of the rectangular cavity. Figure 2It can be seen that when other structures such as the copper rod are placed aside, the sample tube to be tested can be almost as thick as the rectangular cavity, which greatly expands the space of the sample detection area and makes it compatible with the variable temperature system, corner structure and lighting system. The sample tube to be tested is set through because the sample needs a low temperature system to provide a low temperature environment during the detection process.

[0024] The copper rod 4 is symmetrically arranged relative to the sample tube 8 to be tested; a standard sample tube 9 is arranged beside the sample tube 8 to facilitate real-time comparison during the sample detection process, and can more accurately test the g factor and spin number.

[0025] The first small hole side of the rectangular cavity is detachably connected to a waveguide access unit 10, and the second small hole side is detachably connected to an external signal source access unit 11. Figure 5 In this embodiment, the microwave application range is within the X-band, and the waveguide access unit is connected to the system through a coaxial interface, using a standard SMA interface.

[0026] The placement groove of the tuning unit, the sample tube to be tested and the rectangular cavity are integrally formed to form a probe main structure 12. The integrally formed probe main structure and its detachable connection structure with the waveguide access unit and the external signal source access unit can achieve convenient disassembly and assembly while ensuring the stability of the probe structure.

[0027] One side of the copper rod 4 is welded to the driving adapter plate 13, and the modulation field driving circuit is connected to the driving adapter plate 13. The other side is fixed to the probe main structure 12 through the copper rod base 14; the driving adapter plate 13 is detachably fixed to one side of the probe main structure 12. A large current is applied to one side of the two copper rods through the driving adapter plate, and the other sides of the two copper rods are connected through the copper rod base to form a loop. The driving adapter plate is fixedly connected to the probe main structure, ensuring the stability of the connection between it and the copper rod.

[0028] The desktop continuous wave paramagnetic resonance spectrometer probe disclosed by the present invention has a width of only 14 mm, which meets the space limitation requirements of the desktop continuous wave paramagnetic resonance spectrometer; the cavity resonance frequency is 9.82 GHz, the S11 is below -30 dB, and the Q value is greater than 3800 at critical coupling.

[0029] Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Those skilled in the art of the present invention may make various modifications or additions to the described specific embodiments or replace them in a similar manner, but they will not deviate from the spirit of the present invention or exceed the scope defined by the attached claims. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art and related fields without creative work shall fall within the scope of protection of the present invention.

Claims

1. A desktop continuous wave paramagnetic resonance spectrometer probe, comprising a resonant cavity and a microwave coupling structure and a high-frequency modulated magnetic field coupling structure arranged on the resonant cavity, characterized in that: The resonant cavity adopts a flat structure and a vertically arranged rectangular cavity, the microwave coupling structure is a first small hole arranged on the waveguide access side of the rectangular cavity; a second small hole for accessing an external signal source is arranged on the side of the rectangular cavity opposite to the first small hole, and the high-frequency modulation magnetic field coupling structure includes two copper rods vertically penetrating the rectangular cavity and arranged opposite to each other, and the copper rods are externally connected to a modulation field driving circuit; The first small hole is a waist hole arranged parallel to the copper rod. A tuning unit is provided on the side of the first small hole of the rectangular cavity. The tuning unit consists of a tuning motor, a tuning screw that moves back and forth driven by the tuning motor, and a tuning block fixed on the top of the tuning screw. During the back and forth movement of the tuning screw, the tuning block moves relative to the first small hole.

2. The desktop continuous wave paramagnetic resonance spectrometer probe according to claim 1, characterized in that: A sample tube to be tested is vertically arranged in the middle of the rectangular cavity.

3. The desktop continuous wave paramagnetic resonance spectrometer probe according to claim 2, characterized in that: The copper rod is symmetrically arranged relative to the sample tube to be tested.

4. The desktop continuous wave paramagnetic resonance spectrometer probe according to claim 2, characterized in that: A standard sample tube is arranged beside the sample tube to be tested.

5. The desktop continuous wave paramagnetic resonance spectrometer probe according to any one of claims 2 to 4, characterized in that: The first small hole side of the rectangular cavity is detachably connected with a waveguide access unit, and the second small hole side is detachably connected with an external signal source access unit; the placement groove of the tuning unit, the sample tube to be tested and the rectangular cavity are integrally formed to form a probe main body structure.

6. The desktop continuous wave paramagnetic resonance spectrometer probe according to claim 5, characterized in that: One side of the copper rod is welded to the driving adapter plate, and the modulation field driving circuit is externally connected through the driving adapter plate, and the other side is fixed to the probe main body structure through the copper rod base.

7. The desktop continuous wave paramagnetic resonance spectrometer probe according to claim 6, characterized in that: The driving adapter plate is detachably fixed to one side of the probe main body structure.

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