A molten dnp cross-polarization probe

Abstract

The application relates to a molten DNP cross-polarization probe which comprises a resonant cavity, an intracavity assembly, a flange, a double-resonance circuit and a radio frequency rod; the resonant cavity is a hollow cylindrical structure with an upper opening; the intracavity assembly is arranged in the interior of the resonant cavity and comprises a coil unit arranged in the middle of the resonant cavity and a mirror unit arranged outside the coil unit; the flange is buckled to the upper end of the resonant cavity, a first through hole is formed in the middle of the flange, a second through hole is formed outside the first through hole, and the double-resonance circuit is arranged at the upper end of the flange; and the radio frequency rod is connected with the coil unit in the interior of the resonant cavity through the second through hole. The application successfully realizes the application of the cross-polarization technology means in the molten dynamic nuclear polarization technology and solves the technical problems of low nuclear polarization degree and long polarization time.

Description

Technical Field

[0001] This invention relates to the field of dynamic nuclear polarization device technology, specifically to a fused DNP cross-polarization probe. Background Technology

[0002] Applying cross-polarization technology to improve the sensitivity of a probe for target nucleus detection is a technique employed in Dynamic Nuclear Polarization (DNP). Specifically, the DNP cross-polarized probe utilizes the principle of electron-proton-target nucleus triple resonance to achieve the transfer of electron polarization to the proton and then to the target nucleus, thereby increasing the polarizability of the target nucleus and shortening the polarization settling time. The realization of the electron-proton-target nucleus triple resonance requires the use of basic components such as a microwave resonant cavity and a radio frequency dual resonant circuit. Furthermore, to adapt to different application scenarios, the DNP cross-polarized probe also has different structural designs.

[0003] Meanwhile, dissolution dynamic nuclear polarization (dDNP) is a method that further improves detection sensitivity by applying the DNP principle. Unlike conventional DNP methods, dDNP requires polarizing frozen solid microbead samples in an environment of ultra-low temperature (<2K) and strong magnetic field (3-7T). After the sample polarization is completed, a high-temperature and high-pressure solvent is injected into the sample area to dissolve and obtain a target test solution with high polarizability.

[0004] Applying cross-polarization technology to dDNP can improve the polarizability of the detection nucleus, shorten the polarization time, and significantly reduce the liquid helium consumption per experiment. However, conventional DNP cross-polarization probes cannot meet the experimental requirements of dDNP: resonant cavities suitable for high-frequency microwaves required in strong magnetic fields; dual resonant circuits that can provide high radio frequency fields in ultra-low temperature environments; and spatial structures compatible with fusion devices. For these reasons, the design of cross-polarization probes for fusion DNP is particularly important for realizing the application of cross-polarization technology in fusion DNP. Summary of the Invention

[0005] To address the above problems, this invention provides a fusion DNP cross-polarized probe. The technical solution of this invention to solve the above-mentioned technical problems is as follows:

[0006] A fusion DNP cross-polarized probe includes a resonant cavity, an intracavity assembly, a flange, a dual resonant circuit, and an RF rod;

[0007] The resonant cavity is a hollow cylindrical structure with an opening at the top;

[0008] The cavity assembly is disposed inside the resonant cavity, and the cavity assembly includes a coil unit disposed in the middle of the resonant cavity and a reflector unit disposed outside the coil unit;

[0009] The flange is fastened to the upper end of the resonant cavity, a first through hole is formed in the middle of the flange, and a second through hole is formed on the outer side of the first through hole;

[0010] The dual resonant circuit is disposed at the upper end of the flange;

[0011] The radio frequency rod passes through the second through hole and connects to the coil unit inside the resonant cavity.

[0012] Compared with the prior art, the technical solution of this application has the following beneficial technical effects:

[0013] The fusion DNP cross-polarization probe provided in this application, through the design of a resonant cavity, ensures the transmission and focusing of microwave energy in the required frequency band during the dDNP experiment, ensuring that microwaves are effectively transmitted to the sample region, saturating electron EPR transitions, and enabling subsequent efficient electron-proton polarization transfer. With the cooperation of a dual-resonant circuit and related structures, a high radio frequency field is provided to achieve proton-target nucleus cross-polarization, while effectively avoiding the discharge and breakdown problems of the radio frequency circuit caused by ultra-low temperatures. The design of the overall mechanical structure of the probe meets the special requirements of the fusion stage in the dDNP experiment. Ultimately, the application of cross-polarization technology in fusion DNP is successfully realized, solving the technical problems of low detection nucleus polarization and long polarization time.

[0014] Based on the above technical solution, the present invention can be further improved as follows.

[0015] Furthermore, the coil unit includes a coil and a fixing member, the lower end face of the fixing member being fixed to the inner bottom surface of the resonant cavity, and the coil being fixed to the outside of the fixing member.

[0016] Furthermore, an annular groove is formed on the inner bottom surface of the resonant cavity, and an annular protrusion that mates with the annular groove is formed on the lower end of the fixing member.

[0017] The design of the annular protrusion and annular groove can isolate the resonant cavity and the coil, preventing them from short-circuiting.

[0018] Furthermore, the fastener includes a hollow cylinder and a disc, the disc being located outside the hollow cylinder and near the lower end of the hollow cylinder, the coil being disposed outside the hollow cylinder, and the upper end of the hollow cylinder being fixed to the bottom of the flange.

[0019] Furthermore, the coil is a single-layer radio frequency coil, and the coil uses a Hartmann-Hahn matched pulse sequence to achieve polarization transfer of protons to the target nucleus with high polarizability.

[0020] Furthermore, a boss is formed at the lower end of the flange, and the inner shape of the opening of the resonant cavity is adapted to the outer contour of the boss.

[0021] Furthermore, the reflector unit includes an upper thin plate and a microwave reflector. The upper end of the upper thin plate is fixed by the boss and the resonant cavity. The microwave reflector is directly opposite the gap of the coil and acts on the sample area at the center of the hollow cylinder.

[0022] By using a coil structure and a microwave reflector, the efficiency of microwave irradiation on the sample is improved, the focusing effect of the microwave magnetic field on the sample is enhanced, the intensity of the microwave magnetic field in the sample area is increased, the Q value of the resonant cavity is increased, the polarizability of the sample is improved, and the polarization time is further shortened.

[0023] Furthermore, a ground plane is vertically provided at the upper end of the flange. The ground plane is a conductor and is located near the outer side of the flange. The dual resonant circuit is located on the inner sidewall of the ground plane.

[0024] Furthermore, the outer curvature of the ground plane is consistent with the outer curvature of the resonant cavity, and the lower end of the ground plane is in close contact with the resonant cavity.

[0025] The ground plane provides a stable grounding loop for the radio frequency dual resonant circuit.

[0026] Furthermore, a third through hole is formed on the flange to fix the microwave waveguide, so that microwaves are fed into the resonant cavity along the third through hole, and there are two third through holes.

[0027] The RF rod passes through the first through hole and is connected to the coil inside the resonant cavity. The two third through holes can meet the requirements of single-ended input and dual-ended input. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of a fusion DNP cross-polarization probe provided in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of the external structure of the resonant cavity in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the internal structure of the resonant cavity in an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the intracavity component in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of the fixing member in the cavity assembly in an embodiment of the present invention.

[0033] Figure 6 This is a schematic diagram of the connection structure between the flange and the dual resonant circuit in an embodiment of the present invention;

[0034] Figure 7 for Figure 5 Another perspective illustration;

[0035] Figure 8 This is a circuit diagram of the dual resonant circuit in an embodiment of the present invention;

[0036] Figure 9 This is a schematic diagram illustrating the usage state of an embodiment of the present invention. Detailed Implementation

[0037] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0038] like Figures 1-4 As shown, this application discloses a fusion DNP cross-polarization probe, which includes a resonant cavity 10, an intracavity component 20, a flange 30, a dual resonant circuit 40, and a radio frequency rod 50.

[0039] Among them, combined Figure 2 and Figure 3 As shown, the resonant cavity 10 is a hollow cylindrical structure with an opening at the top; the upper part of the resonant cavity 10 has a screw hole for fixing to the upper flange 30.

[0040] In the embodiments of this application, a cylinder 101 extending outward is formed on the bottom end face of the resonant cavity 10. A threaded hole is formed inside the cylinder 101 for fixing the lower end of the resonant cavity 10. Specifically, the limiting plastic plate can be connected to the bottom of the resonant cavity with screws. Preferably, the resonant cavity 10 is made of copper to ensure a certain wall thickness, and the surface is gold-plated to be suitable for the ultra-low temperature environment during the melting DNP experiment.

[0041] Combination Figure 4 As shown, the cavity assembly 20 is disposed inside the resonant cavity 10. The cavity assembly 20 includes a coil unit 11 disposed in the middle of the resonant cavity 10 and a reflector unit 12 disposed outside the coil unit 11.

[0042] Specifically, the coil unit 11 includes a coil Ls and a fixing member 112. The lower end face of the fixing member 112 is fixed to the inner bottom surface of the resonant cavity 10, and the coil Ls is fixed to the outside of the fixing member 112.

[0043] In an optional embodiment of this application, the inner bottom surface of the resonant cavity 10 has a limiting structure that matches the lower end surface of the fixing member 112, which can isolate the resonant cavity and the coil Ls and prevent them from short-circuiting.

[0044] In some embodiments, an annular groove 10a is formed on the inner bottom surface of the resonant cavity 10, and an annular protrusion 1123 that mates with the annular groove 10a is formed at the lower end of the fixing member 112. In other embodiments, the inner bottom surface of the resonant cavity 10 may form a protrusion and the lower end of the fixing member 112 may form a groove. Furthermore, the groove and protrusion are not limited to annular shapes, but may be any other optional shapes, such as squares or triangles.

[0045] The coil Ls is a single-layer radio frequency coil. Different types of coils can be used according to actual needs. It has a hollow cylindrical shape.

[0046] For conventional NMR detection radio frequency coils, the main function is to excite the target nucleus spin and receive nuclear magnetic resonance signals. Specifically, the coil acts as an excitation coil combined with a single-port single resonant circuit to generate a radio frequency field perpendicular to the main magnetic field to excite the target nucleus, and then acts as a receiving coil to capture the change in magnetization vector during the nuclear spin relaxation process.

[0047] The coil Ls in this design serves as the radio frequency (RF) coil responsible for cross-polarization. Unlike conventional NMR coils, in the CP experiment, the RF coil is connected to a specially designed single-port / dual-port RF dual-resonant circuit to excite the two resonant frequencies of the proton and the target nucleus. Specifically, during the experiment, the coil uses a Hartmann-Hahn matched pulse sequence to achieve polarization transfer from the highly polarizable proton to the target nucleus.

[0048] The Hartmann-Hahn matching condition is expressed as follows:

[0049] γ I B 1I =γ S B 1S

[0050] Where, γ I and γ S These are two different nuclei (e.g.) 1 H and 13 C) gyromagnetic ratio; B 1I and B 1SThese are the intensities of the radio frequency fields applied to these two nuclei, respectively.

[0051] It describes how, in a cross-polarization experiment, a radio frequency field is used to polarize two different nuclei (such as...) 1 H and 13 C) The condition for spin-locked frequency matching. To achieve polarization transfer, the ratio of the radio frequency fields of the two nuclei must be equal to the ratio of their gyromagnetic ratios; this is known as spin-locked frequency matching. This matching condition can effectively transfer polarization from high-abundance, high-sensitivity nuclei (e.g., nuclei with high polarization density and high sensitivity). 1 H) is transferred to low-abundance, low-sensitivity nuclei (e.g., H) 13 C), thereby enhancing the signal of low-sensitivity nuclei.

[0052] Since the coil Ls needs to be located in the center of the internal sample tube to achieve better detection results while avoiding contact with the resonant cavity 10, the fixing member 112 needs to use an insulating material as the fixing device for the coil Ls.

[0053] Among them, combined Figure 5 As shown, the fastener 112 includes a hollow cylinder 1121 and a disc 1122. The disc 1122 is located outside the hollow cylinder 1121 and near the lower end of the hollow cylinder 1121. The coil Ls is located outside the hollow cylinder 1121. The upper end of the hollow cylinder 1121 is fixed to the bottom of the flange 30.

[0054] The upper and lower ends of the hollow cylinder 1121 are respectively secured to the lower end of the flange 30 and the bottom of the resonant cavity 10.

[0055] In a preferred embodiment, the coil Ls is a saddle-shaped coil made of gold-plated copper. The coil's shape resembles a saddle-shaped bend, with its inner diameter matching the outer diameter of the coil mounting post. All corners are chamfered to reduce RF loss. In practical implementation, a capacitor is connected directly in parallel across the coil, functioning as a near-end tuning capacitor.

[0056] like Figure 1 , Figure 6 and Figure 7 As shown, the flange 30 is fastened to the upper end of the resonant cavity 10, serving to fix the resonant cavity 10 and other components of the probe.

[0057] Preferably, a boss 31 is formed at the lower end of the flange 30, and the inner shape of the opening of the resonant cavity 10 is adapted to the outer contour of the boss 31.

[0058] A first through hole 30a is formed in the middle of the flange 30. Considering that this design needs to be used in the melting DNP experiment, the first through hole 30a is used to insert the melting rod.

[0059] The flange 30 has two second through holes 30b for radio frequency rods. The radio frequency rod 50 passes through the second through holes 30b and is connected to the coil Ls in the resonant cavity 10, which can meet the requirements of single-ended input and dual-ended input.

[0060] The flange 30 has a third through hole 30c for fixing the microwave waveguide, and microwaves are fed into the resonant cavity 10 along the third through hole 30c.

[0061] The dual resonant circuit 40 is disposed at the upper end of the flange 30. The dual resonant circuit 40 needs to be placed close to the resonant cavity to reduce the loss of the high-frequency circuit, and also needs to be stably grounded to ensure the stability of the circuit. Therefore, a fixing position for the grounding plate 60 is reserved on the flange 30.

[0062] The ground plane 60 is a conductor structure, preferably a good conductor, used to provide a stable grounding loop for the dual resonant circuit 40. Preferably, the bottom copper layer of the circuit board of the dual resonant circuit 40 is in close contact with the platform of the ground plane 60 by screws, providing a stable grounding point for the circuit.

[0063] Preferably, both the flange 30 and the grounding plate 60 are made of gold-plated copper, which is suitable for the ultra-low temperature environment of fusion DNP experiments, while also meeting the non-magnetic requirement of NMR experiments.

[0064] Considering that this design needs to be used in experiments involving fused DNP, the ground plane also needs to meet the experimental requirements of fused DNP. Specifically, since the entire polarization process of fused DNP needs to be completed at ultra-low temperatures, a cryostat is required. This limits the maximum outer diameter of the probe, and at the same time, it is necessary to reduce the sharp protrusions of the probe to avoid scratching the inner wall of the cryostat when the probe is inserted into or removed from the cryostat.

[0065] Secondly, for the fusion DNP experiment, after polarization, a melting rod needs to be inserted from top to bottom at the center of the probe to achieve the melting process. Therefore, sufficient space is required around the probe axis for subsequent rod insertion. Thus, the design of the ground plane 60 needs to consider space utilization. Therefore, the ground plane 60 has two herringbone-shaped platforms inside, similar to tiles, fitted onto the side near the flange 30. Preferably, the outer curvature of the ground plane 60 matches the outer wall curvature of the resonant cavity 10, and its lower end is in close contact with the resonant cavity 10.

[0066] This design saves considerable space, allowing the ground plane 60 to accommodate the specific dual-resonant circuits required for the experiment. Specifically, electrical components can be soldered onto the ground plane 60 to form the resonant circuit needed for the experiment. For specific cross-polarization experiments, a dual-resonant circuit providing both the proton's resonant frequency and the target nucleus's resonant frequency is required. Experience shows that soldering and tuning electrical components is time-consuming and tedious. Therefore, this design incorporates a circuit board mounting mechanism on the ground plane 60 platform. In experiments, pre-packaged circuit boards can be directly mounted, replacing the traditional probe soldering process, thus simplifying the experimental workload.

[0067] The reflector unit 12 includes an upper thin plate 121 and a microwave reflector 122. The upper end of the upper thin plate 121 is fixed by the boss 31 and the resonant cavity 10. The microwave reflector 122 is directly opposite the gap of the coil Ls and acts on the sample area at the center of the hollow cylinder. In order to ensure the fixation of the microwave reflector 122, a through-hole threaded hole is left in the middle of the inner wall of the resonant cavity 10 for the installation and fixation of the reflector.

[0068] The upper thin plate 121 serves to fix the sample and limit its movement in conjunction with the resonant cavity 10 and flange 30. The inclined mirror surface of the microwave reflector 122 reflects the microwaves introduced by the waveguide. It is important to note that during the experiment, the sample tube / sample cup containing the sample needs to be placed at the exact center of the coil Ls. Therefore, the interior of the support device also serves to fix the sample, ensuring that the sample does not move during polarization and subsequent processes and remains centered on the coil.

[0069] By setting the coil Ls, in conjunction with the microwave reflector 122, the irradiation efficiency of microwaves on the sample is improved, the focusing effect of the microwave magnetic field on the sample is enhanced, the intensity of the microwave magnetic field in the sample area is increased, the Q value of the resonant cavity is increased, the polarizability of the sample is increased, and the polarization time is further shortened.

[0070] This example uses a dual-input dual-resonance circuit, with two platforms connected to the ground plane 60. 1 H / 13 The circuit board for the C-type dual resonant circuit. While achieving dual resonance, the design of the isolation circuit avoids mutual interference between the two frequencies.

[0071] Specifically, RF rods are connected to the ports of the two circuit boards near the resonant cavity, passing through flange 30 and connecting to the two ends of the saddle-shaped coil Ls inside the resonant cavity; simultaneously, RF rods are connected to the upper ends of the two circuit boards respectively. 1 H / 13 The C-frequency transmission control is connected. Simultaneously, the upper part of the ground plane 60 is fitted with a circular fixing plate, which is fixedly connected through screw holes on the side of the support plate to ensure the stability of the overall device.

[0072] As an optional embodiment, the dual resonant circuit of this application is as follows: Figure 8 As shown, in this circuit, a double resonant circuit is formed by two inductors (L2, Ls) and their corresponding capacitors.

[0073] In the embodiments of this application, the dual-resonant circuit is an out-of-line dual-resonant circuit, capable of achieving resonance at two frequency points (specifically for the 5T polarization system in the embodiments and...). 1 H / 13 For the C-core, the dual resonant frequencies are 211.7MHz and 53.4MHz respectively: Port 1 and Port 2 in the figure are two RF input terminals, providing RF signals of 211.7MHz and 53.4MHz respectively; the components appearing on the left side of the part from Port 1 to coil Ls in the figure are fixed on an inner plane of the ground plane 60 using a PCB board in this embodiment (hereinafter referred to as the left-end circuit). Similarly, the components appearing on the right side of the part from Port 2 to coil Ls are fixed on another inner plane of the ground plane 60 using a PCB board in this embodiment (hereinafter referred to as the right-end circuit); the coil Ls in the center of the figure is the saddle-shaped RF coil mentioned above, which can be regarded as an inductor in the circuit. A near-end tuning capacitor, namely capacitor C9, is connected in parallel on the saddle-shaped coil. It shares part of the resonance function at the near end (the part closest to the sample is the near end), thereby reducing the power loss caused by the transmission line; capacitor C9, capacitor C5 in the left-end circuit, capacitor C7 in the right-end circuit, together with coil Ls, form a resonant circuit, which can generate 1 The resonance occurs at the resonant frequency of H, 211.7MHz. The capacitor C3, connected in series in the left-hand circuit, functions as a matching capacitor in this loop, adjusting the circuit... 1 Impedance matching at the H frequency; capacitor C9 (number 9), capacitor C6 (number 6) in the right-hand circuit, and coil Ls form a resonant circuit that can generate... 13 The resonance frequency of C is 53.4MHz. The capacitor C4, connected in series in the right-hand circuit, acts as a matching capacitor in this loop, adjusting the circuit. 13 Impedance matching at frequency C; the inductor L3 (number 3) and capacitor C2 (number 2) on the left end are connected in series to form the first notch filter circuit, resonating at... 13 At the resonant frequency of C, 53.4MHz, it is allowed 13 The C resonant frequency passes; correspondingly, the inductor L2 on the right and the capacitor C1 on the right are connected in parallel to form a second notch circuit, which resonates at the C resonant frequency. 1 At the resonant frequency of H, 211.7MHz, it is allowed 1 H resonant frequency by simultaneously preventing 13 Frequency C passes through; with the cooperation of two notch filter circuits, signal interference is avoided and signal transmission stability is ensured. The above circuit components work together to achieve dual resonance.

[0074] It is understood that dual resonant circuits are a common technical means. Therefore, those skilled in the art can design dual resonant circuits different from the above embodiments based on the design concept of this application. Therefore, this application does not limit the specific structure of dual resonant circuits. However, as long as the design concept of using resonant cavity and dual resonant circuit to achieve cross-polarization is consistent with this application, it should be included in the protection scope of this application.

[0075] Combination Figure 9 As shown, in use, the resonant cavity 10 of the fusion DNP cross-polarization probe provided in this application is placed inside the cavity of the cryostat 90. The cryostat 90 is placed inside the polarization magnet, which provides the main magnetic field, and the cryostat provides the ultra-low temperature environment required for the fusion DNP experiment. An external microwave source 100 generates microwaves, which are introduced into the resonant cavity along the waveguide and focused by the reflector onto the sample area at the center of the coil. Under the combined action of the main magnetic field and the microwaves, the sample achieves electron paramagnetic resonance and the transfer of electron polarization to protons, thereby achieving hyperpolarization of the protons. An external radio frequency source 200 is connected to the probe to provide the required frequency signal for the dual resonant circuit, thereby driving the dual resonant circuit to resonate at the frequency points of the protons and the target nucleus, achieving cross-polarization of the protons and the target nucleus, and thus achieving hyperpolarization of the target nucleus.

[0076] The fusion DNP experiment relies on a high-intensity radio frequency (RF) field to excite nuclear spin. This embodiment employs a low-loss near-end resonant circuit design, placing the dual resonant circuit on the resonant cavity flange 30 near the coil Ls using a ground plane 60. This reduces cable loss and meets the requirement for high efficiency and high RF field strength. Simultaneously, the low-pressure gaseous helium environment in the experiment can easily lead to discharge and breakdown of the RF circuit. In this design, the near-end resonant circuit is placed as close as possible to the detection coil to reduce the voltage amplitude of the resonant circuit, effectively avoiding discharge and breakdown phenomena in the RF circuit. Furthermore, the design of the ground plane 60 provides a stable grounding point for the overall circuit, further reducing circuit losses and ensuring the achievement of a high RF field.

[0077] Furthermore, the realization of proton-low gyromagnetic ratio nuclei dual resonance at low temperatures requires a stable dual-resonant circuit. In conjunction with the above, the dual-resonant circuit in this embodiment includes multiple capacitors and inductors. Due to the limitations of the cryogenic experimental conditions in this case, the location of the dual-resonant circuit is restricted to the vicinity of the resonant cavity 10. Therefore, this design incorporates a herringbone-shaped tile-like ground plane 60, increasing the space utilization near the resonant cavity 10.

[0078] In summary, the fusion-modulated DNP cross-polarization probe provided in this application, through the design of the resonant cavity, ensures the transmission and focusing of microwave energy during dynamic polarization experiments, achieving control over the microwave mode and selection of the reflection path. This ensures that microwave energy is effectively transmitted to the sample region during the experiment, acting on electrons in the free radicals and causing saturated electrons to undergo EPR transitions, facilitating subsequent efficient electron-nuclear polarization transfer. Then, under the action of the dual resonant circuit and coil, cross-polarization of electrons, protons, and the target nucleus is achieved, increasing the polarizability and shortening the polarization time. Simultaneously, the cross-polarization method makes it possible to select samples to be polarized where the target nucleus does not directly contact the free electrons. Therefore, it avoids the influence of the electron paramagnetic environment on the hyperpolarized solution obtained after melting, thereby extending the polarization retention time of the sample and meeting the needs of long-distance inspection.

[0079] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fused DNP cross-polarization probe, characterized in that, The resonant cavity, the cavity component, the flange plate, the double resonance circuit and the radio frequency rod; the resonant cavity is a hollow cylindrical structure with an open upper part; the cavity component is arranged inside the resonant cavity, and the cavity component includes a coil unit arranged in the middle of the resonant cavity and a mirror unit arranged outside the coil unit; the flange plate is buckled at the upper end of the resonant cavity, and the middle of the flange plate is formed with a first through hole, and the outside of the first through hole is formed with a second through hole; the double resonance circuit is arranged at the upper end of the flange plate; the radio frequency rod passes through the second through hole and is connected with the coil unit inside the resonant cavity; The upper end of the flange plate is vertically provided with a grounding plate, the grounding plate is a conductor, the grounding plate is arranged close to the outside of the flange plate, and the double resonance circuit is arranged on the inner side wall of the grounding plate; the outer side curvature of the grounding plate is consistent with the outer side wall curvature of the resonant cavity, and the lower end of the grounding plate is in close contact with the resonant cavity; the third through hole for fixing the microwave waveguide is formed on the flange plate, so that the microwave is fed into the resonant cavity along the third through hole, and the number of the second through holes is two.

2. The fused DNP cross-polarization probe of claim 1, wherein, The coil unit includes a coil and a fixing part, the lower end surface of the fixing part is limited and fixed with the inner bottom surface of the resonant cavity, and the coil is fixed on the outside of the fixing part.

3. The fused DNP cross-polarization probe of claim 2, wherein, The inner bottom surface of the resonant cavity is formed with an annular groove, and the lower end of the fixing part is formed with an annular protrusion matched with the annular groove.

4. The fused DNP cross-polarization probe of claim 3, wherein, The fixing part includes a hollow cylinder and a disc, the disc is located outside the hollow cylinder and is arranged close to the lower end of the hollow cylinder, the coil is arranged outside the hollow cylinder, and the upper end of the hollow cylinder is fixed on the bottom of the flange plate.

5. The fused DNP cross-polarization probe of claim 4, wherein, The coil is a single-layer radio frequency coil, the coil applies Hartmann-Hahn matching condition pulse sequence to realize polarization transfer of high polarization degree protons to target nuclei.

6. The fused DNP cross-polarization probe of claim 4, wherein, The lower end of the flange plate is formed with a boss, and the inside shape of the opening of the resonant cavity is matched with the outer contour of the boss.

7. The fused DNP cross-polarization probe of claim 6, wherein, The mirror unit includes an upper sheet and a mirror, the upper end of the upper sheet is limited and fixed by the boss and the resonant cavity, the mirror is opposite to the gap of the coil, and acts on the sample area in the center of the hollow cylinder.

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