WO2016095343A1 - 电子-核双共振谐振器 - Google Patents

电子-核双共振谐振器 Download PDF

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WO2016095343A1
WO2016095343A1 PCT/CN2015/073828 CN2015073828W WO2016095343A1 WO 2016095343 A1 WO2016095343 A1 WO 2016095343A1 CN 2015073828 W CN2015073828 W CN 2015073828W WO 2016095343 A1 WO2016095343 A1 WO 2016095343A1
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coil
radio frequency
curved guide
cavity
electron
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PCT/CN2015/073828
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English (en)
French (fr)
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刘朝阳
陶泉
贺玉贵
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中国科学院武汉物理与数学研究所
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Publication of WO2016095343A1 publication Critical patent/WO2016095343A1/zh
Priority to US15/621,987 priority Critical patent/US10340578B2/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P7/00—Resonators of the waveguide type
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
    • G01R33/34—Constructional details, e.g. resonators, specially adapted to MR
    • G01R33/34007—Manufacture of RF coils, e.g. using printed circuit board technology; additional hardware for providing mechanical support to the RF coil assembly or to part thereof, e.g. a support for moving the coil assembly relative to the remainder of the MR system
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
    • G01R33/34—Constructional details, e.g. resonators, specially adapted to MR
    • G01R33/34046—Volume type coils, e.g. bird-cage coils; Quadrature bird-cage coils; Circularly polarised coils
    • G01R33/34069—Saddle coils
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
    • G01R33/34—Constructional details, e.g. resonators, specially adapted to MR
    • G01R33/34092—RF coils specially adapted for NMR spectrometers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
    • G01R33/34—Constructional details, e.g. resonators, specially adapted to MR
    • G01R33/343—Constructional details, e.g. resonators, specially adapted to MR of slotted-tube or loop-gap type
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/32—Excitation or detection systems, e.g. using radio frequency signals
    • G01R33/36—Electrical details, e.g. matching or coupling of the coil to the receiver
    • G01R33/3628—Tuning/matching of the transmit/receive coil
    • G01R33/3635—Multi-frequency operation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/60—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using electron paramagnetic resonance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/62—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using double resonance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R33/00—Arrangements or instruments for measuring magnetic variables
    • G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
    • G01R33/28—Details of apparatus provided for in groups G01R33/44 - G01R33/64
    • G01R33/282—Means specially adapted for hyperpolarisation or for hyperpolarised contrast agents, e.g. for the generation of hyperpolarised gases using optical pumping cells, for storing hyperpolarised contrast agents or for the determination of the polarisation of a hyperpolarised contrast agent

Definitions

  • the present invention pertains to the field of magnetic resonance and, more particularly, to an electron-core dual resonant resonator.
  • Nuclear magnetic resonance is an important means to study the molecular structure of molecules, intermolecular interactions, etc., and has been widely used in materials, physics, chemistry, biology and medicine.
  • NMR sensitivity is very low
  • dynamic nuclear polarization (DNP) technology based on electron-nuclear polarization transfer provides an important way to enhance NMR signals.
  • Dynamic nuclear polarization is an electron-nuclear double resonance technique that transfers the high spin polarization of unpaired electrons (free radicals) to the nucleus by microwave-to-electron spin manipulation, thereby enhancing nuclear spin polarization.
  • the maximum DNP of protons is 660 times (13C). 2600 times).
  • the electron-core dual resonance system usually has three fields, one is the main magnetic field B0, and the other two are the RF field B1 generated by the RF coil and the microwave field B2 generated by the microwave resonator.
  • the B1 field is used to excite nuclear resonance and the B2 field is used to excite electron resonance.
  • the dual resonant resonator An important component of the dynamic nuclear polarization spectrometer is the dual resonant resonator.
  • the traditional metal resonator has been widely used due to its high Q value, but it is not suitable for the excitation of pulsed microwave because of its high Q value.
  • the filling factor and the distribution of the microwave magnetic field are Very poor, not suitable for liquid samples with high dielectric constant.
  • the RF coil is generally placed outside the crack cavity, and adopts a solenoid form to shield the crack cavity.
  • the manufacturing method is generally formed by plating silver on the surface of quartz glass.
  • the diameter of the RF coil is required to be more than twice the diameter of the crack cavity, thereby greatly reducing the RF coil.
  • the fill factor and according to the theory, the system detection sensitivity is proportional to the coil fill factor, which will greatly reduce the detection sensitivity of the system.
  • the present invention proposes a method of combining a radio frequency coil and a microwave resonator into a multi-crack cavity.
  • the conductor is then connected as a radio frequency coil with an elongated wire.
  • the object of the present invention is to provide an electron-core dual resonance resonator, so that the RF coil and the microwave resonator are integrated, eliminating the shielding effect of the crack cavity on the RF field; more importantly, reducing the diameter of the RF coil to the crack The same size of the cavity increases the fill factor of the RF coil and improves the detection sensitivity of the system.
  • the structure of this resonator can greatly improve the microwave magnetic field distribution. Compared with the traditional metal resonator, this structure is more suitable for the excitation of pulsed microwave.
  • the electron-nuclear double resonance resonator proposed by the invention comprises a plurality of curved guide plates, and each of the curved guide plates is circumferentially distributed to form a cylindrical crack cavity, on the crack cavity Two opposite RF coil windows are opened, each RF coil window is formed by a concave portion of two adjacent curved guide plates, and each curved guide plate is connected to a radio frequency coil through a wire, and the radio frequency magnetic field generated by the radio frequency coil is sequentially Pass through two RF coil windows.
  • the two RF coil windows as described above are symmetrically distributed in the center of the axis of the fracture chamber.
  • the number of curved guide plates as described above is 2n, and n is a natural number greater than 1.
  • the radio frequency coil as described above is a saddle coil.
  • the electron-core dual resonance resonator further comprises a microwave coupling ring disposed in the crack cavity, wherein two terminals of the RF coil are connected in parallel with a tuning capacitor, one end of the tuning capacitor is connected with one end of the matching regulating capacitor, and the other end of the matching regulating capacitor forms a radio frequency interface. At one end, the other end of the tuning capacitor forms the other end of the RF interface.
  • the resonator of the invention combines the radio frequency coil and the microwave resonator into one, greatly reduces the structure size of the electron-core dual resonance coil resonator, improves the filling factor of the radio frequency coil, and increases the detection sensitivity of the system.
  • FIG. 2a is a magnetic line distribution diagram of a radio frequency field on a cross section of the resonator shown in FIG. 1, wherein a broken line indicates a magnetic line distribution
  • FIG. 2b is a magnetic line distribution diagram of a microwave field on a cross section of the resonator shown in FIG. 1, wherein a broken line indicates a magnetic line distribution.
  • FIG. 3 is a schematic diagram of a dynamic nuclear polarization (DNP) system for enhancing nuclear magnetic resonance signals using the resonator of the present invention.
  • DNP dynamic nuclear polarization
  • the electron-core dual resonance resonator comprises a plurality of curved guide plates, and each of the curved guide plates is circumferentially distributed to form a cylindrical crack cavity, and two opposite RF coil windows are opened on the crack cavity, and each RF coil window is opened.
  • the port is formed by a recess of the side of two adjacent arcuate guides, each of which is connected by a wire to a radio frequency coil, and the radio frequency magnetic field generated by the radio frequency coil sequentially passes through the two radio frequency coil windows.
  • the two RF coil windows are symmetrically distributed in the center of the axis of the fracture chamber.
  • the number of curved guides is 2n, n>1.
  • the saddle coil can be used for the RF coil.
  • the spacing between the sides of the curved guide is 0.02 to 0.2 times the diameter of the slit chamber.
  • the window height of the RF coil window is 1 to 1.2 times the diameter of the crack cavity, and the window width is 0.25 to 0.3 times the diameter of the crack cavity.
  • the electron-core dual resonance resonator further comprises a microwave coupling ring disposed in the crack cavity, wherein two terminals of the RF coil are connected in parallel with a tuning capacitor, one end of the tuning capacitor is connected with one end of the matching regulating capacitor, and the other end of the matching regulating capacitor forms a radio frequency interface. At one end, the other end of the tuning capacitor forms the other end of the RF interface.
  • the four curved guide plates 101d, the first curved guide plates 101a and the second curved guide plates 101b constitute a first work guide, and the distance between the first curved guide 101a and the second curved guide 101b is a first straight line spacing 104a
  • the third curved guide plate 101c and the fourth curved guide plate 101d constitute a second work guide plate, and the distance between the third curved guide plate 101c and the fourth curved guide plate 101d is a second straight line spacing 104b, and the first work guide plate Forming a cylindrical crack cavity with the second work guide, and forming a workpiece spacing between the first work guide and the work shape convex portions on both sides of the second work guide, the first work guide and the second work form
  • the wires are sequentially connected in series with the fourth curved guide 101d, the first curved guide 101a, the third curved guide 101c, and the second curved guide 101b, that is, the fourth curved guide 101d and the first curved guide 101a are connected by the same end of the wire.
  • the first curved guide 101a and the third curved guide 101c are connected by the same end of the wire, and the third curved guide 101c and the second curved guide 101b are connected by the same end of the wire, the fourth curved guide 101d and the second curved shape
  • the guiding plates 101b are respectively connected to the resonance module through wires, and one end of the cylindrical cracking cavity is provided with a microwave coupling ring 107.
  • the first curved guide plates 101a to the fourth curved guide plates 101d and their connected wires constitute a saddle type radio frequency coil.
  • the fourth curved guide 101d and the first curved guide 101a connected by the wire are connected to the third curved guide 101d and the second curved guide connected by the wire.
  • the direction of the magnetic field generated by the loop formed by 101b is the same, that is, the first window 105a of the radio frequency coil is in the same direction as the magnetic field of the second window 105b of the radio frequency coil. In this way, a uniform magnetic field of a certain intensity is formed at the center of the coil to excite the sample placed at the center of the coil to undergo nuclear magnetic resonance.
  • the slit cavity composed of the first curved guide 101a, the second curved guide 101b, the third curved guide 101c, and the fourth curved guide 101d is limited
  • the microwave signal coupled into the cavity through the coupling ring will create a magnetic field in the fracture cavity along the axis of the fracture cavity and be evenly distributed throughout the central sample region. This stimulates the unparalleled electrons in the sample to undergo electron paramagnetic resonance.
  • the cylindrical crack cavity resonates at a higher frequency electronic resonance frequency, such as a magnetic field of 0.35 T, and the electron resonance frequency is about 9.8 GHz.
  • the elongated wire 102 connects the first arc-shaped guide 101a, the second curved guide 101b, the third curved guide 101c, and the fourth curved guide 101d to each other to resonate at a lower frequency nuclear resonance frequency, such as Under a magnetic field of 0.35 T, the hydrogen nuclear resonance frequency is about 14.9 MHz.
  • the arcuate guide spacing (103a, 103b, 104a, 104b) is 0.2 to 0.5 mm under a 0.35 T magnet to ensure uniformity and resonant mode of the microwave field.
  • the microwave signal of the fracture cavity can be excited by a coupling loop that is coaxial with the fracture cavity.
  • the window (105a, 105b) of the RF coil needs to take a reasonable size to take into account the uniformity of the RF field and the uniformity of the microwave field.
  • the window is 1 to 1.2 times the diameter of the crack cavity, and the width is 0.25 ⁇ . 0.3 times the diameter of the slit cavity.
  • the electron-core dual resonance resonator further includes a radio frequency interface 106, a matching adjustment capacitor 109, a tuning capacitor 110, a microwave coupling loop 107, and a microwave transmission coaxial line 108; the tuning capacitor 110 tunes the radio frequency coil to At the nuclear resonance frequency, the matching adjustment capacitor 109 matches the RF coil to an optimum state. The distance between the microwave coupling ring 107 and the crack cavity is adjusted to achieve an optimal coupling effect with the crack cavity.
  • the electron-core dual resonance resonator is applied to a magnet with a magnetic field strength of 0.35 T.
  • the resonance frequency of the hydrogen nucleus is 14.9 MHz, and the electron resonance frequency is 9.8 GHz.
  • Similar structures can be used on magnets of other magnetic field strengths.
  • the microwave resonant frequency can be changed by simply adjusting the arc guide spacing (103a, 103b, 104a, 104b) and the diameter of the crack cavity.
  • the resonant frequency of the RF coil can be Adjusted by tuning capacitor 110.
  • a high-power RF signal is transmitted to the RF coil through the RF interface 106 for exciting the nuclear magnetic resonance signal in the sample, and the resulting free-sensing attenuation signal (FID) is transmitted to the receiver through the RF interface 106.
  • a high power microwave signal is applied to the crack cavity through the coaxial line 108 for exciting the electronic paramagnetic working signal.
  • FIGS. 2a and b are schematic diagrams showing the distribution of the magnetic field lines of the resonator and the magnetic field lines of the microwave when the resonator is tuned to the nuclear resonance frequency and the electronic resonance frequency, respectively.
  • the RF coil is fixed in the shielding cavity by the cross-linked polystyrene support, and the coaxial line connecting the microwave coupling ring 107 can move up and down along the axial direction of the resonator within a certain range, thereby adjusting the microwave coupling ring 107 and the crack cavity. Coupling state.
  • Figure 3 shows a schematic diagram of a system for an electron-core dual resonant resonator used in a dynamic nuclear polarization system.
  • the control part of the whole system is undertaken by a service computer 211, which includes a host, a display, a keyboard, and a mouse. Standard.
  • the control of the entire system is completed by the service computer 211, and the service computer 211 performs data interaction with each module through the network switch 210, including a radio frequency transmitter module 205, a microwave transmitter module 208, a receiver module 206, and a main control board module 209.
  • the RF transmitter module 205 primarily generates amplitude, phase, and frequency adjustable RF pulses for exciting nuclear magnetic resonance.
  • the microwave transmitter module 208 primarily generates amplitude, phase, and frequency adjustable microwave pulses for exciting electron spin resonance.
  • the receiver module 206 is mainly used for receiving a free induction attenuation signal generated by nuclear magnetic resonance, and performing processing such as amplification, sampling, and down-conversion.
  • the main control board module 209 is responsible for starting and synchronizing the entire system.
  • the user sends corresponding pulse sequence data through the service computer 211 to the RF transmitter module 205, the receiver module 206, the microwave transmitter module 208, and the main control board module 209, and the main control board module 209 analyzes the pulse sequence.
  • Control signals are obtained for the microwave transmitter module 208, the radio frequency transmitter module 205, and the receiver module 206.
  • the RF transmitter module 205 parses the corresponding RF signal and sends it to the RF power amplifier 204 for power amplification.
  • the amplified RF signal is sent to the RF input terminal of the dual resonant coil resonator 200 through the RF transceiver switch 202. Used to excite nuclear magnetic resonance signals.
  • the microwave transmitter module 208 parses the corresponding microwave signal and sends it to the microwave power amplifier 207 for power amplification.
  • the amplified microwave signal is sent to the microwave input end of the dual resonant coil resonator 200 for exciting the electron spin resonance signal.
  • the RF transceiver switch 202 sends the obtained FID signal to the RF preamplifier module 203, performs amplification on the preamplifier, downconverts it, and sends it to the receiver module 206, and the receiver module performs digital sampling.
  • the orthogonal down-conversion is performed, and the accumulation function is completed in a predetermined manner, and uploaded to the service computer 211 through the network switch 210, and is supplied to the experimenter for observation and further processing.
  • Magnet system 201 provides a stable, uniform static magnetic field throughout the system.

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  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)

Abstract

电子-核双共振谐振器，包括裂隙腔和细长导线（102）；裂隙腔由若干个弧形导板（101a、101b、101c、101d）构成，细长导线（102）将弧形导体（101a、101b、101c、101d）连接成射频线圈；裂隙腔谐振于电子共振频率，射频线圈谐振于原子核共振频率；使用裂隙腔结构能够促使电磁场的分离，保证谐振腔内部磁场与电场的比值最大化；使用细长导线（102）是为了尽量使其不会影响裂隙腔的谐振频率及模式，同时又可利用裂隙腔的导体将其连接成射频线圈。本电子-核双共振谐振器利用细长导线（102）巧妙的将裂隙腔和射频线圈合二为一，在保证两个谐振模式效率的同时，简化了电子-核双共振谐振器的结构。

Description

电子-核双共振谐振器 技术领域
本发明属于磁共振领域，更具体地，涉及电子-核双共振谐振器。
背景技术
核磁共振(NMR)是研究物质分子结构，分子间相互作用等的重要手段，已广泛应用于材料、物理、化学、生物和医学中。然而，核磁共振灵敏度很低，基于电子-核极化转移的动态核极化(DNP)技术提供了一条增强NMR信号的重要途径。动态核极化是电子-核双共振技术，通过微波对电子自旋操控把未配对电子(自由基)的高自旋极化度转移到核上，从而增强核自旋极化。由于电子的旋磁比γ(或极化)是质子的660倍(13C的2600倍)，如果把电子的极化度完全转移到对应的核上，则质子的最大DNP增强为660倍(13C为2600倍)。
电子-核双共振系统通常有三个场，一个是主磁场B0，另外两个分别是由射频线圈产生的射频场B1和由微波谐振器产生的微波场B2。B1场用于激发核共振，B2场用于激发电子共振。
动态核极化谱仪一个重要的部件就是双共振谐振器。传统的金属谐振腔由于其高Q值得到了较大的应用，但是正是因为其高Q值导致其并不适用于脉冲微波的激发，同时由于其尺寸较大，填充因子以及微波磁场的分布都很差，不适合于高介电常数的液体样品。虽然新发展的裂隙腔能够解决一定的问题，但是其射频线圈一般放置于裂隙腔外，采用螺线管形式，同时对裂隙腔起屏蔽作用，为了减小裂隙腔对射频场的屏蔽作用，其制作方法一般是在石英玻璃表面镀银形成。由于射频线圈需要对裂隙腔起屏蔽作用，为了得到所需的微波谐振模式，即较好的场分布，这就要求射频线圈的直径要大于裂隙腔直径的两倍以上，从而将大大降低射频线圈的填充因子，而根据理论推导，系统检测灵敏度正比于线圈填充因子，这样做将大大减小系统的检测灵敏度。
为了解决现有技术方案中存在的缺点，增大系统的检测灵敏度，本发明提出了一种将射频线圈与微波谐振器合二为一的方案，将传统的双裂隙腔变为多裂隙腔，然后用细长导线将其导体连接为一射频线圈。
发明内容
本发明的目的是：提供电子-核双共振谐振器，使射频线圈与微波谐振器为一整体结构，消除裂隙腔对射频场的屏蔽作用；更重要的是，将射频线圈直径缩小到与裂隙腔同一尺寸，从而增大了射频线圈的填充因子，提高系统检测灵敏度。同时，这种谐振器的结构能够极大的改善微波磁场分布，相对于传统的金属谐振器，这种结构更适合于脉冲微波的激发。本发明提出的电子-核双共振谐振器，包括若干个弧形导板，各个弧形导板沿周向分布构成圆筒状的裂隙腔，裂隙腔上 开设有两个相对的射频线圈窗口，每个射频线圈窗口由其中两个相邻的弧形导板的侧边的凹部构成，各个弧形导板通过导线连接为射频线圈，射频线圈产生的射频磁场依次穿过两个射频线圈窗口。
如上所述的两个射频线圈窗口以裂隙腔的轴线中心对称分布。
如上所述的弧形导板的个数为2n个，n为大于1的自然数。
如上所述的射频线圈为马鞍形线圈。
电子-核双共振谐振器，还包括设置在裂隙腔内的微波耦合环，射频线圈的两个的端子并联有调谐电容，调谐电容一端与匹配调节电容一端连接，匹配调节电容另一端构成射频接口的一端，调谐电容的另一端构成射频接口的另一端。
本发明的优点是：
本发明的谐振器将射频线圈和微波谐振器合二为一，大大缩减了电子-核双共振线圈谐振器的结构尺寸，提高了射频线圈的填充因子，增大了系统的检测灵敏度。
附图说明
下面结合附图及实施例对本发明作进一步描述：
图1为本发明谐振器(以n＝2为例)的结构图；
其中，101a-第一弧形导板；101b-第二弧形导板；101c-第三弧形导板；101d-第四弧形导板；102-细长的导线；103a-第一工部间距；103b-第二工部间距；104a-第一直线间距；104b-第二直线间距；105a-射频线圈第一窗口；105b-射频线圈第二窗口；106-射频接口；107-微波耦合环；108-同轴线；109-匹配调节电容；110-调谐电容。
图2a为图1所示谐振器横截面上射频场的磁力线分布图，其中虚线表示磁力线分布，图2b为图1所示谐振器轴截面上微波场的磁力线分布图，其中虚线表示磁力线分布。
图3为使用本发明谐振器用于增强核磁共振信号的动态核极化(DNP)系统示意图。
其中，200-上述双共振谐振器；201-磁体系统；202-射频收发切换开关；203-射频前置放大器模块；204-射频功率放大器；205-射频发射机模块；206-接收机模块；207-微波功率放大器；208-微波发射机模块；209-主控板模块；210-网络交换机；211-服务计算机。
具体实施方式
实施例1：
电子-核双共振谐振器，包括若干个弧形导板，各个弧形导板沿周向分布构成圆筒状的裂隙腔，裂隙腔上开设有两个相对的射频线圈窗口，每个射频线圈窗 口由其中两个相邻的弧形导板的侧边的凹部构成，各个弧形导板通过导线连接为射频线圈，射频线圈产生的射频磁场依次穿过两个射频线圈窗口。两个射频线圈窗口以裂隙腔的轴线中心对称分布。弧形导板的个数为2n个，n>1。射频线圈可选用马鞍形线圈。
作为一种优选方案，弧形导板的侧边之间的间距为0.02～0.2倍的裂隙腔的直径。射频线圈窗口的窗口高为1～1.2倍裂隙腔的直径，窗口宽为0.25～0.3倍裂隙腔的直径。
电子-核双共振谐振器，还包括设置在裂隙腔内的微波耦合环，射频线圈的两个的端子并联有调谐电容，调谐电容一端与匹配调节电容一端连接，匹配调节电容另一端构成射频接口的一端，调谐电容的另一端构成射频接口的另一端。
实施例2(n＝2的情况)：
电子-核双共振谐振器，包括裂隙腔和连接裂隙腔的细长导线，对于n＝2的裂隙腔包括第一弧形导板101a、第二弧形导板101b、第三弧形导板101c、第四弧形导板101d，第一弧形导板101a与第二弧形导板101b构成第一工形导板，第一弧形导板101a与第二弧形导板101b之间的间距为第一直线间距104a，第三弧形导板101c与第四弧形导板101d构成第二工形导板，第三弧形导板101c与第四弧形导板101d之间的间距为第二直线间距104b，第一工形导板与第二工形导板构成筒形的裂隙腔，第一工形导板和第二工形导板的两侧的工形的凸部之间构成工部间距，第一工形导板和第二工形导板的两侧的工形的凹部构成射频线圈第一窗口105a和射频线圈第二窗口105b，即第一弧形导板101a与第四弧形导板101d的工形凹部之间构成射频线圈第一窗口105a，第二弧形导板101b与第三弧形导板101c的工形凹部之间构成射频线圈第二窗口105b。导线依次串联第四弧形导板101d、第一弧形导板101a、第三弧形导板101c、第二弧形导板101b，即第四弧形导板101d和第一弧形导板101a通过导线同端连接，第一弧形导板101a和第三弧形导板101c通过导线同端连接，第三弧形导板101c和第二弧形导板101b通过导线同端连接，第四弧形导板101d和第二弧形导板101b分别通过导线与谐振模块连接，筒形的裂隙腔一端设置有微波耦合环107。第一弧形导板101a～第四弧形导板101d及其相连的导线构成马鞍型射频线圈。
当射频端口106通入射频信号时，通过导线连接后的第四弧形导板101d、第一弧形导板101a组成的环路与通过导线连接后的第三弧形导板101d、第二弧形导板101b组成的环路所产生的磁场方向相同，即射频线圈第一窗口105a与射频线圈第二窗口105b磁场方向同向。如此便可在线圈中心形成一定强度的均匀磁场来激发放置在线圈中心的样品发生核磁共振。由第一弧形导板101a、第二弧形导板101b、第三弧形导板101c、第四弧形导板101d组成的裂隙腔，在所限 定的尺寸下，通过耦合环耦合进腔内的微波信号将在裂隙腔内形成沿裂隙腔轴线方向的磁场，并在中心样品区域内均匀分布。如此便可激励样品中的未配对电子发生电子顺磁共振。
筒形的裂隙腔谐振于频率较高的电子共振频率上，如在0.35T的磁场下，电子共振频率约9.8GHz。
细长的导线102将第一弧形导板101a、第二弧形导板101b、第三弧形导板101c、第四弧形导板101d连接而成的射频线圈谐振于频率较低的原子核共振频率，如在0.35T磁场下，氢核共振频率约14.9MHz。
弧形导板间距(103a、103b、104a、104b)在0.35T磁体下为0.2～0.5mm，以保证其微波场的均匀性和谐振模式。
裂隙腔的微波信号可通过耦合环来激励，所述耦合环与裂隙腔同轴。
射频线圈的窗口(105a、105b)需取一个合理的尺寸以同时兼顾射频场的均匀性和微波场的均匀性，在0.35T磁体下，窗口高1～1.2倍裂隙腔的直径，宽0.25～0.3倍裂隙腔的直径。
如图1所示，电子-核双共振谐振器还包括射频接口106、匹配调节电容109、调谐电容110、微波耦合环107、微波传输同轴线108；所述调谐电容110使射频线圈调谐到核共振频率上，匹配调节电容109使射频线圈匹配在最佳状态。调节微波耦合环107与裂隙腔的距离使其与裂隙腔之间到达最佳耦合效果。
电子-核双共振谐振器应用在0.35T磁场强度的磁体上，在0.35T磁场强度下，氢核共振频率14.9MHz，电子共振频率9.8GHz。类似的结构还可使用在其它磁场强度的磁体上，只需调节弧形导板间距(103a、103b、104a、104b)和裂隙腔的直径便可改变其微波谐振频率，而射频线圈的谐振频率可通过调谐电容110调节。
正常工作时，大功率射频信号通过射频接口106传输到射频线圈上，用于激发样品内的核磁共振信号，得到的自由感应衰减信号(FID)通过射频接口106传输到接收机端。同时，大功率的微波信号通过同轴线108作用到裂隙腔内，用于激发电子顺磁工作信号。
图2a、b分别是上述谐振器调谐到核共振频率和电子共振频率时，谐振器的射频场磁力线和微波场磁力线分布示意图。
射频线圈通过交联聚苯乙烯支座固定在屏蔽腔中，连接微波耦合环107的同轴线可在一定范围内沿着谐振器轴向上下移动，以此调节微波耦合环107与裂隙腔的耦合状态。
图3所示为电子-核双共振谐振器用于动态核极化系统中的系统示意图。整个系统的控制部分由一台服务计算机211承担，它包括主机、显示器、键盘、鼠 标。
整个系统的控制由服务计算机211完成，服务计算机211通过网络交换机210与各个模块进行数据交互，包括射频发射机模块205，微波发射机模块208，接收机模块206，主控板模块209。射频发射机模块205主要产生幅度、相位、频率可调节的射频脉冲用于激发核磁共振。微波发射机模块208主要产生幅度、相位、频率可调节的微波脉冲用于激发电子自旋共振。接收机模块206主要用于接收核磁共振产生的自由感应衰减信号，并进行放大、采样、下变频等处理。主控板模块209负责整个系统的启动与同步。在一次具体实验中，用户通过服务计算机211发送相应的脉冲序列数据到射频发射机模块205、接收机模块206、微波发射机模块208和主控板模块209，主控板模块209通过解析脉冲序列得到对微波发射机模块208、射频发射机模块205、接收机模块206的控制信号。在发射阶段，射频发射机模块205解析出相应的射频信号后送给射频功率放大器204进行功率放大，放大的射频信号经过射频收发切换开关202选择送给双共振线圈谐振器200的射频输入端，用于激发核磁共振信号。微波发射机模块208解析出相应的微波信号后送给微波功率放大器207进行功率放大，放大的微波信号送给双共振线圈谐振器200的微波输入端，用于激发电子自旋共振信号。在接收阶段，射频收发切换开关202将得到的FID信号送到射频前置放大器模块203上，在前置放大器上进行放大、下变频后送入给接收机模块206，接收机模块进行数字采样，正交下变频，按预定方式完成累加功能，并通过网络交换机210上传到服务计算机211上，供给实验人员观察与进一步处理。磁体系统201为整个系统提供稳定均匀的静态磁场。
本文中所描述的具体实施例仅仅是对本发明精神作举例说明。本发明所属技术领域的技术人员可以对所描述的具体实施例做各种各样的修改或补充或采用类似的方式替代，但并不会偏离本发明的精神或者超越所附权利要求书所定义的范围。

Claims (5)

  1. 电子-核双共振谐振器，包括若干个弧形导板，各个弧形导板沿周向分布构成圆筒状的裂隙腔，裂隙腔上开设有两个相对的射频线圈窗口，每个射频线圈窗口由其中两个相邻的弧形导板的侧边的凹部构成，各个弧形导板通过导线连接为射频线圈，射频线圈产生的射频磁场依次穿过两个射频线圈窗口。
  2. 根据权利要求1所述的电子-核双共振谐振器，其特征在于，所述的两个射频线圈窗口以裂隙腔的轴线中心对称分布。
  3. 根据权利要求1所述的电子-核双共振谐振器，其特征在于，所述的弧形导板的个数为2n个，n为大于1的自然数。
  4. 根据权利要求1所述的电子-核双共振谐振器，其特征在于，所述的射频线圈为马鞍形线圈。
  5. 根据权利要求1所述的电子-核双共振谐振器，其特征在于，还包括设置在裂隙腔内的微波耦合环，射频线圈的两个的端子并联有调谐电容，调谐电容一端与匹配调节电容一端连接，匹配调节电容另一端构成射频接口的一端，调谐电容的另一端构成射频接口的另一端。
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