CN113030820A

CN113030820A - Table type continuous wave paramagnetic resonance spectrometer probe

Info

Publication number: CN113030820A
Application number: CN202110449980.3A
Authority: CN
Inventors: 胡江波; 石致富; 苏陶
Original assignee: Chinainstru and Quantumtech Hefei Co Ltd
Current assignee: Chinainstru and Quantumtech Hefei Co Ltd
Priority date: 2021-04-25
Filing date: 2021-04-25
Publication date: 2021-06-25

Abstract

The invention discloses a table type continuous wave paramagnetic resonance spectrometer probe, which comprises a resonant cavity, and a microwave coupling structure and a high-frequency modulation magnetic field coupling structure which are arranged on the resonant cavity, wherein the resonant cavity adopts a rectangular cavity which is of a flat structure and is vertically arranged, and the microwave coupling structure is a first small hole arranged at the waveguide access side of the rectangular cavity; the high-frequency modulation magnetic field coupling structure comprises two copper rods which vertically penetrate through the rectangular cavity and are oppositely arranged, and the copper rods are externally connected with a modulation field driving circuit. The two copper rods form a Helmholtz coil, are externally connected with a modulation field driving circuit, and drive a modulation field through large current, so that high-efficiency high-frequency modulation magnetic field coupling is realized, and the modulation field is well distributed; the copper rod is used as a Helmholtz coil, and the coil winding is not needed, so that the coil is more beneficial to mass production.

Description

Table type continuous wave paramagnetic resonance spectrometer probe

Technical Field

The invention relates to the technical field of electron paramagnetic resonance, in particular to a table type continuous wave paramagnetic resonance spectrometer probe.

Background

Electron Paramagnetic Resonance (EPR) is a magnetic resonance technique that is derived from the magnetic moment of unpaired electrons, and can be used to qualitatively and quantitatively detect the unpaired electrons contained in substance atoms or molecules and to explore the structural characteristics of their surroundings. Electron paramagnetic resonance spectrometers are mainly classified into two types, pulse-type and continuous-wave-type. The continuous wave paramagnetic resonance spectrometer obtains a continuous wave EPR spectral line by putting a sample to be measured into a microwave field with constant frequency and changing the frequency of an external magnetic field.

In electron paramagnetic resonance experiments, resonant cavities play an important role. According to different experimental requirements, different forms of resonant cavities are developed. Rectangular cavities, cylindrical cavities, medium cavities, crack cavities and the like are commonly used. In a continuous wave electron paramagnetic resonance experiment, the design requirements of a resonant cavity are as follows: 1. ensuring that the direction of the magnetic field B1 is vertical to the direction of the external static magnetic field; 2. ensuring that the magnetic field B1 of the sample placement area is as large as possible; 3. the device has high-frequency modulation field coupling capacity so as to meet the requirement of a continuous wave paramagnetic resonance spectrometer on a high-frequency modulation field number detection mode; 4. the device has a standard sample comparison measurement function so as to accurately measure the g factor and the spin number of a sample to be measured.

The existing continuous wave paramagnetic resonance spectrometer in the market has a larger volume, and in order to meet the market demand for a light and portable continuous wave paramagnetic resonance spectrometer, a miniaturized desktop continuous wave paramagnetic resonance spectrometer becomes the development direction of the continuous wave paramagnetic resonance spectrometer, and the reduction of the occupied space of a probe plays a crucial role.

Disclosure of Invention

The invention provides a table type continuous wave paramagnetic resonance spectrometer probe based on the design requirements of a continuous wave paramagnetic resonance spectrometer on a resonance cavity and combined with the development direction of table type miniaturization.

A table type continuous wave paramagnetic resonance spectrometer probe comprises a resonant cavity, and a microwave coupling structure and a high-frequency modulation magnetic field coupling structure which are arranged on the resonant cavity, wherein the resonant cavity adopts a rectangular cavity which is of a flat structure and is vertically arranged, and the microwave coupling structure is a first small hole arranged on the waveguide access side of the rectangular cavity; the high-frequency modulation magnetic field coupling structure comprises two copper rods which vertically penetrate through the rectangular cavity and are oppositely arranged, and the copper rods are externally connected with a modulation field driving circuit.

Furthermore, the first small hole is a waist hole parallel to the copper bar, a tuning unit is arranged on the side of the first small hole of the rectangular cavity, the tuning unit is composed of a tuning motor, a tuning screw rod driven by the tuning motor to move back and forth, and a tuning block fixed at the top of the tuning screw rod, and in the back and forth movement process of the tuning screw rod, the tuning block moves relative to the first small hole.

Furthermore, a sample tube to be detected vertically penetrates through the middle of the rectangular cavity; the copper rods are symmetrically arranged relative to the sample tube to be detected; and a standard sample tube is arranged beside the sample tube to be detected.

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 of the rectangular cavity; the placing 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.

Furthermore, one side of the copper bar is welded on the driving adapter plate, the driving adapter plate is externally connected with a modulation field driving circuit, and the other side of the copper bar is fixed on the probe main body structure through the copper bar base; the drive adapter plate is detachably fixed on one side of the probe main body structure.

The invention has the beneficial effects that: 1. the two copper rods form a Helmholtz coil, are externally connected with a modulation field driving circuit, and drive a modulation field through large current, so that high-efficiency high-frequency modulation magnetic field coupling is realized, and the modulation field is well distributed; 2. the copper rod is used as a Helmholtz coil, and the coil winding is not needed, so that the mass production is facilitated; 3. the rectangular cavity with the flat structure and the penetrating sample tube to be detected which are vertically arranged are adopted, so that the thickness of the probe is reduced, and meanwhile, the sufficient space of a sample area is ensured; 4. the width of the probe is only 14mm, and the space limit of 15mm of the magnet gap of the table type continuous wave paramagnetic resonance spectrometer is met; 5. the standard sample tube is additionally arranged, so that real-time comparison can be conveniently carried out in the sample detection process, and the g factor and the spin number can be more accurately tested.

Drawings

FIG. 1 is a side perspective view of the probe body structure;

FIG. 2 is a perspective view of the other side of the probe body structure;

FIG. 3 is a side view of a bench-top CW paramagnetic resonance spectrometer probe;

FIG. 4 is a cross-sectional view taken along the line A-A in FIG. 3;

FIG. 5 is a schematic diagram of a probe of a bench-top continuous wave paramagnetic resonance spectrometer.

Detailed Description

The present invention will be described in further detail with reference to the following drawings and specific examples. The embodiments of the present invention have been presented for purposes of illustration and description, and are not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.

Example 1

A table type continuous wave paramagnetic resonance spectrometer probe is shown in figures 1-4 and comprises a resonant cavity 1, and a microwave coupling structure and a high-frequency modulation magnetic field coupling structure which are arranged on the resonant cavity. Microwave signals are coupled into the resonant cavity through the microwave coupling structure, and an external high-frequency modulation magnetic field is coupled into the resonant cavity through the high-frequency modulation magnetic field coupling structure.

In order to adapt to the space limitation problem of the desk-top continuous wave paramagnetic resonance spectrometer, the resonant cavity adopts a rectangular cavity which is of a flat structure and is vertically arranged. The standing arrangement here means that the microwave input side and the external signal source input side are connected with two narrowest opposite faces of a rectangular cavity, respectively (refer to fig. 4), thereby reducing the thickness of the whole probe.

The microwave coupling structure is a first small hole 2 arranged at the waveguide access side of the rectangular cavity, a second small hole 3 used for accessing an external signal source is arranged at the opposite side of the rectangular cavity and the first small hole, and the high-frequency modulation magnetic field coupling structure comprises two copper rods 4 vertically penetrating through the rectangular cavity and oppositely arranged. The two copper rods form a Helmholtz coil, are externally connected with a modulation field driving circuit, and drive a modulation field through large current, so that high-efficiency high-frequency modulation magnetic field coupling is realized, and the modulation field is well distributed; on the other hand, the copper bar is adopted, so that the coil winding is not needed, and the mass production is facilitated.

In order to save space, the first small hole 2 is parallel to a waist hole formed in the copper rod, a tuning unit is arranged on the side of the first small hole in the rectangular cavity and consists of a tuning motor 5, a tuning screw 6 and a tuning block 7, wherein the tuning screw 6 is driven by the tuning motor to move back and forth, the tuning block 7 is fixed at the top of the tuning screw, and in the back and forth movement process of the tuning screw 6, the tuning block 7 moves relative to the first small hole 2, so that the coupling state of the rectangular cavity is tuned. In this embodiment, the tuning block is a copper silver-plated metal head with a diameter of 5mm and a thickness of 1 mm.

The middle part of the rectangular cavity is vertically provided with a sample tube 8 to be detected in a penetrating mode, and as can be seen from figure 2, under the condition that other structures such as copper bars are arranged beside the sample tube, the thickness of the sample tube to be detected can be almost equal to that of the rectangular cavity, the space of a sample detection area is greatly expanded, and the sample detection area can be compatible with a temperature changing system, a corner structure and an illumination system. The sample tube to be tested is arranged in a penetrating mode, and a low-temperature system is needed to provide a low-temperature environment for the sample tube in the detection process.

The copper rods 4 are symmetrically arranged relative to the sample tube 8 to be detected; the standard sample tube 9 is arranged beside the sample tube 8 to be tested, so that real-time comparison can be conveniently carried out in the sample detection process, and the g factor and the spin number can be more accurately tested.

The first small hole side of the rectangular cavity is detachably connected with a waveguide access unit 10, and the second small hole side is detachably connected with an external signal source access unit 11, as shown in fig. 5. In this embodiment, the microwave application range is within the X band, the waveguide access unit is connected to the system through a coaxial interface, and a standard SMA interface is used.

The placing 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 12. Integrated into one piece's probe major structure and with waveguide access unit, external signal source access unit detachable connection structure, can realize convenient dismouting under the prerequisite of guaranteeing probe structure stability.

One side of the copper rod 4 is welded on a driving adapter plate 13, a modulation field driving circuit is externally connected through the driving adapter plate 13, and the other side of the copper rod 4 is fixed on the probe main body structure 12 through a copper rod base 14; the drive adapter plate 13 is detachably fixed on one side of the probe main body structure 12. Heavy current is applied to one side of the two copper rods through the driving adapter plate respectively, 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 with the probe main body structure, so that the stability of connection between the driving adapter plate and the copper bar is ensured.

The width of the table type continuous wave paramagnetic resonance spectrometer probe disclosed by the invention is only 14mm, so that the space limitation requirement of the table type continuous wave paramagnetic resonance spectrometer is met; the resonant frequency of the cavity is 9.82GHz, the S11 bit is below 30dB, and the Q value is more than 3800 when the coupling is critical.

It is to be understood that the described embodiments are merely exemplary of the invention and that various modifications or additions may be made to the described embodiments by those skilled in the art or those skilled in the art which are similar thereto without departing from the spirit of the invention or exceeding the scope of the appended claims. All other embodiments, which can be derived by one of ordinary skill in the art and related arts based on the embodiments of the present invention without any creative effort, shall fall within the protection scope of the present invention.

Claims

1. A desk-top continuous wave paramagnetic resonance spectrometer probe comprises a resonant cavity, and a microwave coupling structure and a high-frequency modulation magnetic field coupling structure which are arranged on the resonant cavity, and is characterized in that the resonant cavity adopts a rectangular cavity which is of a flat structure and is vertically arranged, and the microwave coupling structure is a first small hole arranged on the waveguide access side of the rectangular cavity; the high-frequency modulation magnetic field coupling structure comprises two copper rods which vertically penetrate through the rectangular cavity and are oppositely arranged, and the copper rods are externally connected with a modulation field driving circuit.

2. The probe of claim 1, wherein the first small hole is a waist hole parallel to the copper rod, a tuning unit is disposed on a side of the first small hole of the rectangular cavity, the tuning unit is composed of a tuning motor, a tuning screw driven by the tuning motor to move back and forth, and a tuning block fixed on a top of the tuning screw, and the tuning block moves relative to the first small hole during the back and forth movement of the tuning screw.

3. The probe of claim 1, wherein a sample tube to be tested is vertically disposed through the middle of the rectangular cavity.

4. The probe of claim 3, wherein the copper rods are symmetrically disposed with respect to the sample tube to be tested.

5. The probe of claim 3, wherein a standard sample tube is disposed beside the sample tube to be measured.

6. The probe of any one of claims 1 to 5, wherein the rectangular cavity has a waveguide access unit detachably connected to a first small hole side and an external signal source access unit detachably connected to a second small hole side; the placing 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.

7. The probe of claim 6, wherein one side of the copper rod is welded to a driving adapter plate, the driving adapter plate is externally connected with a modulation field driving circuit, and the other side of the copper rod is fixed on the probe main body structure through a copper rod base.

8. The probe of claim 7, wherein the drive adapter plate is removably attached to one side of the probe body structure.