Distributed compensation apparatus and method for stabilizing the magnetic field profile of a dDNP dissolution transfer pathway

Abstract

The application discloses a distributed compensation device and method for stabilizing a magnetic field of a dDNP fusion solution transfer path, which comprises a compensation control system, a magnetic field detection device, a magnetic field compensation device and a sample transfer channel. One magnetic field detection device and one magnetic field compensation device jointly constitute a compensation unit, multiple compensation units are distributedly arranged at the whole periphery of the sample transfer channel, the magnetic field detection device is located outside the magnetic field compensation device, the magnetic field detection device in each compensation unit is connected with the compensation control system through a corresponding transmitting circuit and a receiving circuit, and the magnetic field compensation device in each compensation unit is connected with the compensation control system through a corresponding compensation circuit. The magnetic field intensity value of the sample transfer path is acquired in real time, the magnetic field of the sample transfer path is dynamically and closed-loop compensated, the compensation range covers the whole link of the polarization magnet outlet, the transfer path and the test magnet inlet, and the uniformity and stability of the magnetic field distribution of the sample transfer path are ensured.

Description

Technical Field

[0001] This invention relates to the field of nuclear magnetic resonance technology, and more specifically to a distributed compensation device and method for stabilizing the magnetic field of the dDNP melting transfer path. Background Technology

[0002] dDNP achieves signal enhancement of up to four orders of magnitude by polarizing nuclear spins at ultra-low temperatures (≈1 K) and high magnetic fields (>3 T), followed by rapid dissolution in a high-temperature solvent and transfer to another NMR or MRI spectrometer for detection. However, the use of modern "super-shielded" magnets inevitably causes the sample transfer path to traverse regions with magnetic field strengths below 1 mT or even close to zero, leading to the following problems: 1) Low-field accelerated relaxation: The nuclear spin relaxation rate induced by paramagnetic substances is strongly negatively correlated with the magnetic field strength. Existing studies report that in regions with magnetic field strengths below 10 mT, especially below 1 mT, the relaxation rate induced by paramagnetic substances increases sharply, causing rapid attenuation of polarization in hyperpolarized nuclei (especially protons with high gyromagnetic ratios, ¹H); 2) The effect of residual paramagnetic agents: If paramagnetic reagents used for polarization (such as TEMPOL radicals) remain in the dissolved sample, their unpaired electrons will become strong relaxation sources, further exacerbating the attenuation of observed nuclear polarization in the aforementioned low-field environment. Existing studies report that in regions with magnetic field strengths below 10 mT, especially below 1 mT, the relaxation rate caused by paramagnetic substances increases sharply, resulting in rapid attenuation of polarization in hyperpolarized nuclei (especially protons with high gyromagnetic ratios, ¹H); 3) The effect of residual paramagnetic agents: If paramagnetic reagents used for polarization (such as TEMPOL radicals) remain in the dissolved sample, their unpaired electrons will become strong relaxation sources, further aggravating the attenuation of observed nuclear polarization in the aforementioned low-field environment. Below mT, the longitudinal proton relaxation rate caused by TEMPOL increases significantly; 3) Signal distortion caused by cross-relaxation: In the extremely weak stray field generated by the "super-shielded" magnet, the cross-correlation relaxation process between ¹H and ¹³C and other heteronuclei will be significantly changed or accelerated, which may lead to unpredictable phase reversal and multiple peak intensity distortion of the NMR signal of ¹³C and other observed nuclei, greatly increasing the difficulty of spectrum analysis.

[0003] To address the aforementioned problems, existing technologies have introduced magnetic field compensation devices (such as "magnetic tunnels" composed of electromagnetic coils or permanent magnet arrays) to provide a fixed magnetic field along the transmission path, thereby suppressing low-field relaxation. However, existing compensation schemes still have the following limitations:

[0004] 1. Incomplete spatial coverage: The compensating magnetic field is mainly concentrated in the middle horizontal section of the transmission pipeline, while the coverage of key vertical / bent path sections such as the polarization magnet outlet and the detection magnet inlet is insufficient, forming a magnetic field "blind spot".

[0005] 2. Insufficient uniformity: The magnetic field strength and distribution in the existing compensation scheme are preset fixed values, and no segmented compensation design is introduced, resulting in significant non-uniformity of magnetic field distribution at different locations along the transmission path.

[0006] 3. Insufficient stability: The compensation mode is static and fixed, lacking the ability to provide real-time feedback and dynamic adjustment based on environmental changes. The compensation magnetic field is susceptible to external interference factors such as temperature drift, resulting in uncontrollable drift and making it difficult to guarantee a long-term stable and uniform compensation effect. Summary of the Invention

[0007] The purpose of this invention is to address the aforementioned deficiencies in the prior art by providing a distributed compensation device and method for stabilizing the magnetic field of the dDNP melting transfer path, thereby resolving the aforementioned technical problems in existing magnetic field compensation schemes.

[0008] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0009] A distributed compensation device for stabilizing the magnetic field of the dDNP melting transfer path includes a compensation control system, a magnetic field detection device, a magnetic field compensation device, and a sample transfer channel.

[0010] Multiple magnetic field detection devices and magnetic field compensation devices are provided, with one magnetic field detection device corresponding to one magnetic field compensation device, together forming a compensation unit;

[0011] The compensation units are distributed around the entire periphery of the sample transfer channel, and the compensation range covers the entire transmission path from the outlet of the polarized magnet to the inlet of the test magnet, with the magnetic field detection device located outside the magnetic field compensation device.

[0012] Each compensation unit is connected to the compensation control system via a corresponding transmitting circuit, receiving circuit, and compensation circuit.

[0013] The magnetic field detection device in each compensation unit is connected to the compensation control system through a corresponding transmitting circuit and receiving circuit.

[0014] The magnetic field compensation device in each compensation unit is connected to the compensation control system through a corresponding compensation circuit.

[0015] As described above, the compensation control system is connected to each compensation unit through a multi-channel parallel transmitting circuit, a multi-channel parallel receiving circuit, and a multi-channel parallel compensation circuit. It transmits and receives signals from the magnetic field detection devices in each compensation unit, and drives the magnetic field compensation devices in each compensation unit to generate a compensation magnetic field. The compensation control system is connected to the host computer through a communication interface.

[0016] The magnetic field detection device described above is either a radio frequency coil or a Hall sensor.

[0017] When the magnetic field detection device is an RF coil, the RF coil is a transceiver coil; the outer surface of the sample transfer channel is wrapped with a frequency calibration material, and the compensation control system calculates the real-time magnetic field strength value at the corresponding position based on the resonance signal of the frequency calibration material collected by the magnetic field detection device.

[0018] The radio frequency coil is a miniature surface coil or solenoid coil, the size of which matches the sample area being detected, and is arranged in a distributed manner along the sample transfer channel to monitor the magnetic field segmentally and independently throughout the transfer path.

[0019] When the magnetic field detection device is a Hall sensor, the Hall sensor is configured to measure the magnetic field strength at its location and output a corresponding electrical signal; the compensation control system is configured to receive the electrical signal to obtain the real-time magnetic field strength value and magnetic field direction offset at the corresponding location.

[0020] The magnetic field compensation device described above is an electromagnet or a combination of an electromagnet and a permanent magnet.

[0021] When the magnetic field compensation device is an electromagnet, the electromagnet includes a conductive coil; each electromagnet is connected to the compensation control system through a corresponding compensation circuit; the compensation control system is configured to control the current flowing into the conductive coil according to the magnetic field offset, so as to generate a compensation magnetic field with controllable intensity and direction.

[0022] When the magnetic field compensation device is a combination of an electromagnet and a permanent magnet, the permanent magnet is made of a permanent magnet material with high coercivity and high remanence. The permanent magnet is rectangular, cylindrical, or ring-shaped and is positioned in a specific section of the sample transfer channel to form a static magnetic field of the required strength and direction. The permanent magnet provides a stable bias magnetic field as a reference or operating point for magnetic field compensation. The electromagnet and the permanent magnet are arranged in combination in space and act together on the same sample area. The compensation control system finely adjusts the bias magnetic field established by the permanent magnet by controlling the current of the electromagnet.

[0023] A distributed compensation method for stabilizing the magnetic field of the dDNP melting transfer path includes the following steps:

[0024] Step 1: By using magnetic field detection devices distributed around the sample transfer channel, the magnetic field strength of each corresponding sample path segment is monitored synchronously or independently at different times to obtain real-time magnetic field data for each monitoring point.

[0025] Step 2: The compensation control system receives the real-time magnetic field data from all compensation units and compares the real-time magnetic field data with the preset target magnetic field strength value corresponding to each monitoring point, and calculates the magnetic field strength deviation at each monitoring point.

[0026] Step 3: The compensation control system generates independent control commands for driving the magnetic field compensation device at the corresponding position based on the calculated magnetic field strength deviation at each monitoring point and according to a predetermined control algorithm.

[0027] Step 4: The magnetic field compensation device in each compensation unit generates a compensation magnetic field of corresponding strength and direction according to the received independent control command, thereby locally and in real time correcting the magnetic field deviation of its section.

[0028] Step 5: Repeat steps 1 to 4 to form a closed-loop feedback control until the magnetic field strength at each monitoring point along the entire sample transfer path reaches and stabilizes within the allowable error range of the preset target magnetic field strength value.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] 1) This invention achieves distributed compensation of the magnetic field of the dDNP polarization transfer path through multiple magnetic field detection and magnetic field compensation devices, and performs targeted dynamic compensation of the magnetic field in the sample channel to ensure the uniformity and stability of the magnetic field distribution throughout the sample channel.

[0031] 2) The number, length and diameter of the assembly units of the magnetic field detection and magnetic field compensation device of the present invention can be flexibly configured according to actual needs.

[0032] 3) The parallel processing and real-time feedback mechanism of this invention ensures the system's rapid response capability, can dynamically track and counteract magnetic field drift caused by factors such as temperature changes, and ensures the long-term stability of the magnetic field.

[0033] 4) This invention provides multiple detection methods for RF / Hall sensors and various electromagnetic / hybrid compensation combinations, offering flexible configuration options. The innovative coil time-division multiplexing technology further simplifies the structure, reduces cost, and minimizes interference while ensuring performance. Attached Figure Description

[0034] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are intended to explain the invention, but do not constitute an undue limitation thereof. In the drawings:

[0035] Figure 1 This is an overall schematic diagram of the distributed compensation device of the present invention;

[0036] Figure 2 This is the axial section of the magnetic field compensation unit structure of the present invention;

[0037] Figure 3 This is a block diagram of the compensation control system of the present invention;

[0038] Figure 4 This is a schematic diagram of the structure of the electromagnet-only compensation method of the present invention;

[0039] Figure 5 This is a schematic diagram of the structure of the electromagnet and permanent magnet combined compensation method of the present invention.

[0040] Among them, 1. Polarized magnet; 2. Test magnet; 3. Polarized sample; 4. Sample transfer channel; 5. Compensation unit; 6. Compensation channel outer tube; 7. Signal transmission link; 8. Compensation control system; 9. Host computer; 10. Internal area of ​​sample transfer channel; 11. Area where magnetic field detection device is located; 12. Area where magnetic field compensation device is located; 13. Radio frequency coil; 14. Electromagnet; 15. Permanent magnet. Detailed Implementation

[0041] To facilitate understanding and implementation of the present invention by those skilled in the art, the present invention will be further described in detail below with reference to embodiments. It should be understood that the embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0042] like Figure 1 As shown, a distributed compensation device for stabilizing the magnetic field of the dDNP melting transfer path includes a compensation control system 8, a magnetic field detection device, a magnetic field compensation device, and a sample transfer channel 4 for transporting polarized sample 3.

[0043] Multiple magnetic field detection devices and magnetic field compensation devices are provided, and one magnetic field detection device corresponds to one magnetic field compensation device, which together constitute a compensation unit 5;

[0044] Compensation units 5 are distributed around the entire periphery of the sample transfer channel 4, and the compensation range covers the entire transmission path from the outlet of the polarized magnet 1 to the inlet of the test magnet 2. The spatial distribution of each device within the compensation unit is as follows: Figure 2 As shown, the sample transfer channel internal area 10 is the inside of the sample transfer channel 4, the magnetic field detection device area 11 is located outside the sample transfer channel 4, the magnetic field compensation device area 12 is located outside the magnetic field detection device area 11, and the compensation channel outer tube 6 is the outermost layer of the compensation unit.

[0045] Each compensation unit 5 is connected to the compensation control system 8 through a corresponding transmitting circuit, receiving circuit and compensation circuit;

[0046] The magnetic field detection device in each compensation unit 5 is connected to the compensation control system 8 through a corresponding transmitting circuit and receiving circuit.

[0047] The magnetic field compensation device in each compensation unit 5 is connected to the compensation control system 8 through a corresponding compensation circuit.

[0048] The compensation control system 8 achieves synchronous control of multi-channel parallel transmission and reception, and multi-channel drive compensation feedback, and transmits signals through the signal transmission link 7. Specifically, the compensation control system 8 controls the orderly operation of the transmitting circuit, receiving circuit, and compensation circuit according to the magnetic field compensation workflow (e.g., Figure 3 As shown in the figure, it realizes real-time magnetic field detection, magnetic field status feedback to the host computer 9, and magnetic field compensation functions.

[0049] The compensation control system 8 is used to transmit and receive signals from each magnetic field detection device, and after signal processing, obtain the corresponding magnetic field strength value, and then calculate the control electrical signals required by each magnetic field compensation device.

[0050] Among them, each magnetic field detection device is used to detect the magnetic field strength at each position along the transfer path in real time, as a basis for compensation.

[0051] One optional solution for the various magnetic field detection devices is a transceiver integrated radio frequency coil 13. The radio frequency coil 13 can be a miniature surface coil or a solenoid coil, its size matching the sample area being detected, and arranged in a distributed manner along the sample transfer channel 4. The compensation control system 8 transmits the resonant frequency of the calibrator under the target magnetic field. The radio frequency signal is collected, and then the resonance signal of the frequency calibrator wrapped on the outer surface of the sample transfer channel 4 is acquired. The resonance frequency of the frequency calibrator under the current magnetic field is then quickly calculated. And calculate the error frequency. Based on the one-to-one correspondence between magnetic field strength and the frequency information of the resonance signal: The system calculates the current magnetic field condition and uploads it to the host computer 9 via the communication interface through the compensation control system 8, displaying the magnetic field of the entire sample transfer path in real time. The compensation control system 8 sends appropriate compensation drive voltages based on the magnetic field deviation and relevant parameters of the magnetic field compensation device. This enables segmented and independent monitoring and real-time compensation of magnetic field deviations throughout the entire transfer path.

[0052] Another option for each magnetic field detection device is a triaxial Hall sensor. The Hall sensor measures the magnetic field strength at its location and outputs a corresponding voltage signal. The compensation control system 8 acquires this voltage signal to obtain the real-time magnetic field strength value and magnetic field direction offset at the corresponding location for subsequent real-time magnetic field compensation.

[0053] One option for various magnetic field compensation devices is an electromagnet 14, which can be selected from conductive coils (such as...). Figure 4 As shown), the electromagnet 14 in each compensation unit 5 is connected to the compensation control system 8 through an independent compensation circuit. The compensation control system 8 is configured to control the current flowing into the conductive coil according to the magnetic field offset, so as to generate a compensation magnetic field with controllable intensity and direction.

[0054] Another alternative for each magnetic field compensation device is a combined structure of electromagnet 14 and permanent magnet 15 (e.g.) Figure 5 As shown, the permanent magnet 15 provides a stable bias magnetic field as a reference or operating point for magnetic field compensation; the electromagnet 14 and the permanent magnet 15 are arranged in space to act together on the same sample area; the compensation control system 8 adjusts the bias magnetic field established by the permanent magnet 15 quickly and with small amplitude by controlling the current of the electromagnet 14.

[0055] The permanent magnet 15 can be made of high coercivity and high remanence permanent magnet materials such as neodymium iron boron, samarium cobalt or alnico. Its shape can be rectangular, cylindrical or ring-shaped, and it is positioned to form a static magnetic field of the required strength and direction in a specific section of the sample transfer channel 4.

[0056] This embodiment provides a distributed compensation method for stabilizing the magnetic field of the dDNP melting transfer path, comprising the following steps:

[0057] Step 1: By using the magnetic field detection devices distributed around the sample transfer channel 4, the magnetic field strength of each corresponding sample path segment is monitored synchronously or independently at different times to obtain real-time magnetic field data for each monitoring point.

[0058] Step 2: The compensation control system 8 receives the real-time magnetic field data from all compensation units 5, compares the real-time magnetic field data with the preset target magnetic field strength value corresponding to each monitoring point, and calculates the magnetic field strength deviation at each monitoring point.

[0059] Step 3: The compensation control system 8 generates independent control commands for driving the magnetic field compensation device at the corresponding position based on the calculated magnetic field strength deviation at each monitoring point and according to a predetermined control algorithm.

[0060] Step 4: The magnetic field compensation device in each compensation unit 5 generates a compensation magnetic field of corresponding strength and direction according to the received independent control command, thereby locally and in real time correcting the magnetic field deviation of its section.

[0061] Step 5: Repeat steps 1 to 4 to form a closed-loop feedback control until the magnetic field strength at each monitoring point along the entire sample transfer path reaches and stabilizes within the allowable error range of the preset target magnetic field strength value.

[0062] It should be noted that the specific embodiments described in this invention are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains can make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A distributed compensation device for stabilizing the magnetic field of the dDNP melting transfer path, characterized in that, It includes a compensation control system, a magnetic field detection device, a magnetic field compensation device, and a sample transfer channel; Multiple magnetic field detection devices and magnetic field compensation devices are provided, and one magnetic field detection device corresponds to one magnetic field compensation device, which together constitute a compensation unit. The magnetic field detection device is a radio frequency coil or a Hall sensor, and the magnetic field compensation device is an electromagnet or a combination of an electromagnet and a permanent magnet. The compensation units are distributed around the entire periphery of the sample transfer channel, and the compensation range covers the entire transmission path from the outlet of the polarized magnet to the inlet of the test magnet, with the magnetic field detection device located outside the magnetic field compensation device. Each compensation unit is connected to the compensation control system via a corresponding transmitting circuit, receiving circuit, and compensation circuit. The magnetic field detection device in each compensation unit is connected to the compensation control system through a corresponding transmitting circuit and receiving circuit. The magnetic field compensation device in each compensation unit is connected to the compensation control system through a corresponding compensation circuit. The compensation control system is connected to each compensation unit through a multi-channel parallel transmitting circuit, a multi-channel parallel receiving circuit, and a multi-channel parallel compensation circuit. It transmits and receives signals from the magnetic field detection devices in each compensation unit, drives the magnetic field compensation devices in each compensation unit to generate a compensation magnetic field, and controls the orderly operation of the transmitting circuit, receiving circuit and compensation circuit according to the magnetic field compensation workflow to realize real-time magnetic field detection, magnetic field status feedback to the host computer and magnetic field compensation functions.

2. The distributed compensation device for stabilizing the magnetic field of the dDNP melting transfer path according to claim 1, characterized in that, When the magnetic field detection device is an RF coil, the RF coil is a transceiver coil; the outer surface of the sample transfer channel is wrapped with a frequency calibration material, and the compensation control system calculates the real-time magnetic field strength value at the corresponding position based on the resonance signal of the frequency calibration material collected by the magnetic field detection device.

3. The distributed compensation device for stabilizing the magnetic field of the dDNP melting transfer path according to claim 2, characterized in that, The radio frequency coil is a miniature surface coil or solenoid coil, the size of which matches the sample area being detected, and is arranged in a distributed manner along the sample transfer channel to monitor the magnetic field segmentally and independently throughout the entire transfer path.

4. The distributed compensation device for stabilizing the magnetic field of the dDNP melting transfer path according to claim 1, characterized in that, When the magnetic field detection device is a Hall sensor, the Hall sensor is configured to measure the magnetic field strength at its location and output a corresponding electrical signal; the magnetic field control system is configured to acquire the electrical signal to obtain the real-time magnetic field strength value and magnetic field direction offset at the corresponding location.

5. The distributed compensation device for stabilizing the magnetic field of the dDNP melting transfer path according to claim 1, characterized in that, When the magnetic field compensation device is an electromagnet, the electromagnet includes a conductive coil; each electromagnet is connected to the compensation control system through an independent compensation circuit; the compensation control system is configured to control the current flowing into the conductive coil according to the magnetic field offset, so as to generate a compensation magnetic field with controllable intensity and direction.

6. The distributed compensation device for stabilizing the magnetic field of the dDNP melting transfer path according to claim 1, characterized in that, When the magnetic field compensation device is a combination of an electromagnet and a permanent magnet, the permanent magnet is made of a permanent magnet material with high coercivity and high remanence. The permanent magnet is rectangular, cylindrical, or ring-shaped and is positioned in a specific section of the sample transfer channel to form a static magnetic field of the required strength and direction. The permanent magnet provides a stable bias magnetic field as a reference or operating point for magnetic field compensation. The electromagnet and the permanent magnet are arranged in space and act together on the same sample area. The compensation control system finely adjusts the bias magnetic field established by the permanent magnet by controlling the current of the electromagnet.

7. A distributed compensation method for stabilizing the magnetic field of the dDNP melting transfer path, applied to the distributed compensation device as described in any one of claims 1-6, characterized in that, The method includes the following steps: Step 1: By using magnetic field detection devices distributed around the sample transfer channel, the magnetic field strength of each corresponding sample path segment is monitored synchronously or independently at different times to obtain real-time magnetic field data for each monitoring point. Step 2: The compensation control system receives the real-time magnetic field data from all compensation units and compares the real-time magnetic field data with the preset target magnetic field strength value corresponding to each monitoring point, and calculates the magnetic field strength deviation at each monitoring point. Step 3: The compensation control system generates independent control commands for driving the magnetic field compensation device at the corresponding position based on the calculated magnetic field strength deviation at each monitoring point and according to a predetermined control algorithm. Step 4: The magnetic field compensation device in each compensation unit generates a compensation magnetic field of corresponding strength and direction according to the received independent control command, thereby locally and in real time correcting the magnetic field deviation of its section. Step 5: Repeat steps 1 to 4 to form a closed-loop feedback control until the magnetic field strength at each monitoring point along the entire sample transfer path reaches and stabilizes within the allowable error range of the preset target magnetic field strength value.

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