CN109655773B - Pluggable roll-printing coil probe of nuclear magnetic resonance apparatus and design method thereof - Google Patents
Pluggable roll-printing coil probe of nuclear magnetic resonance apparatus and design method thereof Download PDFInfo
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- CN109655773B CN109655773B CN201910060767.6A CN201910060767A CN109655773B CN 109655773 B CN109655773 B CN 109655773B CN 201910060767 A CN201910060767 A CN 201910060767A CN 109655773 B CN109655773 B CN 109655773B
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- 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
- G01R33/34053—Solenoid coils; Toroidal coils
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- 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
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- 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
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- 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
- G01R33/34076—Birdcage 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
- G01R33/343—Constructional details, e.g. resonators, specially adapted to MR of slotted-tube or loop-gap type
Abstract
A pluggable roll-printing coil probe of a nuclear magnetic resonance instrument and a design method thereof relate to the nuclear magnetic resonance instrument. The probe is provided with a probe base, a tuning matching circuit, a fixing hole for additionally installing a shielding layer shimming coil, a sample tube, a supporting tube, a roll printing coil, a coil upper silver ring, a coil lower silver ring, an upper elastic metal contact, a lower elastic metal contact, a force column, a tuning capacitor, a matching capacitor and a lead. The conductive silver adhesive is printed on the surface of the sample tube by adopting a rolling printing method, so that the manufacturing of the rolling printing coil can be quickly finished, the complicated processing technology of printing and electroplating is omitted, and the manufacturing technology of the rolling printing coil is simplified. According to the design of requirements, printing models of different types of roll printing coils are designed on a photoetching substrate, conductive silver adhesive is attached to different types of sample tubes by using a roll printing method, the roll printing coils with various geometric shapes, such as saddle coils, AG coils, birdcage coils and the like, are manufactured, and the flexibility and the applicability of the design of the roll printing coils are expanded.
Description
Technical Field
The invention relates to a nuclear magnetic resonance instrument, in particular to a pluggable rolling coil probe of the nuclear magnetic resonance instrument and a design method thereof, wherein a coil is manufactured on a sample tube by a rolling printing method in the manufacturing of the coil of the nuclear magnetic resonance instrument, and the rolling printing coil probe is a pluggable probe device.
Background
In the design of a low-field miniaturized nuclear magnetic resonance instrument, a radio frequency coil is used as a front end for transmitting and receiving radio frequency signals, which is very important for acquiring the quality of nuclear magnetic signals, and the coil is usually manufactured by adopting a copper wire winding or copper sheet processing method. After the copper coil is designed and fixed, a sample tube with a size smaller than that of the coil can be accommodated, and according to the direct proportion relation between the signal-to-noise ratio of the nuclear magnetic signal and the coil filling factor, if the sample tube with the smaller size is placed into the coil with the fixed size, the signal-to-noise ratio is greatly reduced. Generally, if the signal-to-noise ratio needs to be ensured, in addition to the need to re-fabricate the coil and matching circuit to match the dimensions of the sample tube, the inner diameter of the coil needs to be reduced, the more easily the fabricated coil is deformed, and the re-design of the coil-stabilizing bracket is required. In 1997, the document "Using microcontact printing to surface microcoils on capillary for high resolution process on nano-device volumes" Applied Physics Letters 70(18): 2464-.
In addition, coils of a miniaturized nuclear magnetic resonance instrument are usually positioned in a probe base and a shimming coil, and as the roll printing coil is attached to the outer surface of a sample tube, if different samples or sample tubes need to be replaced, the probe base with the shimming coil and a shielding layer needs to be disassembled, copper wires welded at two ends of the roll printing coil are taken down, the coils and the sample tubes can be taken down, and more disassembly and assembly work and time are needed in an experiment. For example: U.S. Pat. No. 8847596B2, issued to Picospin series by Thermo Fisher Scientific in 2016, for the purpose of designing a miniature Nuclear Magnetic Resonance (NMR) device, describes a portable nuclear magnetic spectrometer that employs a pluggable probe to facilitate coil replacement. However, the probe design of the nuclear magnetic resonance instrument is a plug-in type probe specially designed for a specific micro planar coil and a capillary tube, and is not suitable for a rolling printing solenoid coil with a conventional size and a sample tube with a conventional size.
Disclosure of Invention
Aiming at the limitations existing in the design and structure of the existing coil, the invention provides a pluggable roll-printing coil probe of a nuclear magnetic resonance instrument and a design method thereof in order to improve the signal-to-noise ratio of the coil and the convenience degree of replacing a sample tube coil.
The pluggable roll printing coil probe of the nuclear magnetic resonance apparatus is provided with a probe base, a tuning matching circuit, a fixing hole for additionally installing a shielding layer shimming coil, a sample tube, a supporting tube, a roll printing coil, a coil upper silver ring, a coil lower silver ring, an upper elastic metal contact, a lower elastic metal contact, a force column, a tuning capacitor, a matching capacitor and a lead;
the tuning matching circuit and the roll printing coil are fixed on the probe base, a fixing hole provided with a shielding layer shimming coil is formed in the probe base, a sample tube penetrates into the center of the probe base from a sample inlet hole of the probe base, the sample tube with the roll printing coil is inserted into the probe base, a support tube is arranged at the bottom of the probe base and is supported by the support tube, an upper elastic metal contact and a lower elastic metal contact are fixed on two sides of the sample tube and are connected and fixed through a force column, one end of each of the upper elastic metal contact and the lower elastic metal contact is connected and communicated with the roll printing coil, and the other end of each of the upper elastic metal contact and the other end of each of the lower elastic metal contacts are welded with a lead; the silver ring on the upper part of the coil, which is arranged on the upper part of the roll printing coil, is connected and conducted with the upper elastic metal contact; and the lower silver ring of the coil arranged at the bottom of the roll printing coil is connected and communicated with the lower elastic metal contact, and the upper elastic metal contact and the lower elastic metal contact are respectively connected with a tuning capacitor and a matching capacitor on the tuning matching circuit through leads to realize the conduction of the tuning matching circuit.
The sample tube is a glass sample tube.
The upper elastic metal contact and the lower elastic metal contact are nonmagnetic elastic metal contacts.
The force column adopts a nonconductive acrylic force column.
The copper beads at the front ends of the upper elastic metal contact and the lower elastic metal contact are embedded in the copper bead support and can roll at a free angle, the rear end of the copper bead support is provided with elastic force by a copper spiral spring, the rear section of the copper spiral spring is connected with the contact shell, the rear sections of the upper elastic metal contact and the lower elastic metal contact are threaded columns, and the purpose is to screw and fix the threaded columns of the force columns on the two sides of the sample tube access passage.
The roll printing coil adopts a saddle-shaped coil, an AG coil, a birdcage coil and the like.
The design method of the pluggable roll-printing coil probe of the nuclear magnetic resonance apparatus comprises the following steps:
1) adopting a laser engraving machine to engrave 12 coil parallel linear grooves with equal spacing and equal thickness on the surface of the substrate;
2) uniformly coating the prepared conductive silver adhesive on the parallel linear grooves of the coil on the substrate, placing the sample tube above the substrate and rolling for a circle, and attaching the conductive silver adhesive on the surface of the sample tube by utilizing the adhesiveness of the conductive silver adhesive to form a solenoid-shaped roll printing coil;
3) the method comprises the following steps that a laser engraving machine is used for engraving two silver circular ring linear grooves slightly thicker than the line width of a roll printing coil, the line width of each silver circular ring linear groove is 1.5mm, the length and the depth of each silver circular ring linear groove are consistent with those of a coil parallel linear groove of the roll printing coil, the distance between the two silver circular ring linear grooves is the distance between the front end and the rear end of the roll printing coil, and in order to ensure that the silver circular rings are in good contact conduction with the front end and the rear end of the roll printing coil, the two silver circular ring linear grooves are respectively contracted inwards by 0.2mm, and conductive silver adhesive is uniformly coated on the silver circular ring linear grooves;
4) the silver ring linear groove of the sample tube, which is vertical to the substrate, is respectively roll-printed with the upper silver ring and the lower silver ring of the coil, which are parallel to the plane of the tube opening of the sample tube, at the front end and the rear end of the roll-printed coil, and the silver rings are mutually communicated with the roll-printed coil, so that the sample tube can be kept in connection and communication with the upper elastic metal contact and the lower elastic metal contact no matter what axial rotation angle is inserted, and the roll-printed coil is prevented from being disconnected and communicated with the upper elastic metal contact and the lower elastic metal contact.
In step 1), the substrate may be an acrylic substrate; the length, the width and the depth of the parallel linear grooves of the coils can be respectively 20mm, 0.7mm and 0.5mm, and the interval between the parallel linear grooves of the adjacent coils can be 0.7 mm.
In the step 2), the sample tube is placed above the base plate, the included angle between the sample tube and the coil parallel straight line groove is 60 degrees, and the sample tube is pushed to roll for a circle from back to front.
In the step 4), the length of the roll printing coil is 16.8mm, and the total length of the silver rings which are added with the roll printing at the front end and the rear end of the roll printing coil is 19.5 mm.
The roll printing coil is printed on the surface of the sample tube, and according to a theoretical formula and a formula of a signal-to-noise ratio:
where ω is Larmor precession frequency, B⊥Is a transverse electromagnetic field, TcoilTemperature at data acquisition, Δ f bandwidth of the receiving stage, R noise, M⊥K is the boltzmann constant, which is the magnetization vector of the imaging nuclei. From the formula, the roll printing coil can be closer to an imaging area to increase a transverse electromagnetic field to increase the signal to noise ratio, so that the roll printing coil adopted by the invention can effectively ensure the signal to noise ratio theoretically. In practice, the signal-to-noise ratio of nuclear magnetic signals is influenced by many factors such as the impedance of the roll-printing coil, the volume and concentration of the sample, the magnetic field strength of the instrument, and the circuit noise of the instrument, and other influences are not explored only from the roll-printing coil filling factor.
The connection design strategy of the roll printing coil and the matching circuit is as follows: the copper balls of the two pairs of nonmagnetic metal contacts are in point-contact connection with the silver rings at the front end and the rear end of the roll printing coil, so that when the roll printing coil and the sample tube need to be replaced, the probe structures of the roll printing coil and the sample tube can be replaced in a pluggable mode, and the sample tube cannot be broken due to extrusion. The metal contact shells on the two sides are connected through arc-shaped wires and connected with the tuning matching circuit, so that the phenomenon that the metal contact on one side is not connected with the coil to generate open circuit is prevented, and the conduction of the contact and the coil is ensured.
The structure of the elastic metal contact is as follows: the copper metal bead at the front end of the elastic metal contact is embedded in the metal bracket and can roll at a free angle, the back end of the metal bracket is provided with elastic force by a copper spring, the back section of the spring is connected with the metal shell, and the back section of the elastic metal contact is a stud, so that the elastic metal contact is screwed and fixed at the screw holes of the acryl posts at the two sides of the sample tube access passage.
When the roll printing coil and the sample tube need to be replaced, the sample tube attached with the roll printing coil is only required to be inserted into and pulled out of the sample inlet hole of the probe base. The process of replacing the roll printing coil in a plug-in mode comprises the following steps: before inserting the sample tube, the distance between the two coaxial copper beads of the elastic metal contacts at the two sides of the inlet and outlet channel of the sample tube is smaller than the diameter of the sample tube; after the sample tube is inserted, the copper bead bracket is extruded by the inserted sample tube to shrink towards the left side and the right side, and the copper beads always roll along the glass surface of the sample tube due to the elasticity of the spring in the process of inserting and pulling the sample tube out, so that the smooth inserting and pulling-out process is provided. Until the contact points of the elastic metal contact are respectively butted with the silver circular rings at the front end and the rear end of the roll printing coil, and the sample tube is inserted into the bottom of the sample tube bracket of the base. The shells of the upper and lower pairs of elastic metal contacts are connected by a wire and are connected with two matching capacitors of the tuning matching circuit to realize the conduction of the tuning matching circuit.
In order to meet the requirements of sample tubes with different sizes, the distance of the coaxial upper elastic metal contact and the elasticity of the built-in spring can be adjusted through the threaded column, and the sample tubes with different sizes can be ensured to be well inserted and conducted without breaking.
By the method of roll printing, the shaped conductive silver paste is printed on the sample tube to be tested, so that different types of roll printing coils are attached to the glass on the outer surface of the sample tube with different sizes, and the structure of the probe base, in which the tuning matching circuit is communicated with the roll printing coils, is designed, so that the common sample tube and the roll printing coils can be replaced simultaneously.
The invention comprises the improvement of the roll printing coil structure and the connecting structure of the roll printing coil and the probe.
The invention has the following beneficial effects:
according to the invention, the conductive silver adhesive is printed on the surface of the sample tube by adopting a rolling printing method, so that the manufacturing of the rolling printing coil can be rapidly completed, the complex processing technology of printing and electroplating is avoided, and the manufacturing technology of the rolling printing coil is simplified. The method can be designed according to requirements, printing models of different types of roll printing coils are designed on the photoetching substrate, conductive silver adhesive is attached to different types of sample tubes by using a roll printing method, and the roll printing coils with various geometric shapes, such as saddle coils, AG coils, birdcage coils and the like, can be manufactured, so that the flexibility and the applicability of the design of the roll printing coils are expanded.
The roll-printing coil can be tightly attached to the surfaces of different sample tubes and is closer to a sample collection area, so that the filling factor is improved, the signal-to-noise ratio of the roll-printing coil is improved, the signal-to-noise ratio of a nuclear magnetic experiment is ensured, and the work of designing coil support tubes for the sample tubes with different sizes is omitted.
The method for the point-contact connection of the roll printing coil and the matching circuit is convenient for the insertion and the extraction of the roll printing coil and the sample tube, when the roll printing coil and the sample tube need to be replaced, only the sample tube attached with the roll printing coil needs to be inserted and extracted from the sample inlet hole of the probe base under the condition of not dismounting the probe, and the work and the time for dismounting the probe and replacing the roll printing coil and the sample tube are saved; and the elastic metal contact connecting spring has elasticity, can accommodate sample tubes of different sizes, and has strong adaptability to the sizes of the sample tubes.
Drawings
FIG. 1 is a schematic structural diagram of an embodiment of a pluggable roll-printing coil probe of an NMR spectrometer according to the invention.
FIG. 2 is a diagram showing the process of replacing the coil and the sample tube in the embodiment of the pluggable rolling coil probe of the NMR spectrometer according to the present invention.
Fig. 3 is a schematic view of a method for manufacturing the sample tube roll printing conductive silver paste according to the present invention.
FIG. 4 is a schematic diagram of a second method for manufacturing the sample tube roll printing conductive silver paste according to the present invention.
FIG. 5 is a schematic diagram of a sample tube roll-printed coil according to the present invention.
Fig. 6 is a schematic structural view of the upper and lower elastic metal contacts according to the present invention.
Fig. 7 is one of sectional structural views a-a of fig. 6.
FIG. 8 is a second sectional view of the structure of section A-A of FIG. 6.
Fig. 9 is a schematic connection diagram of the sample tube, the upper elastic metal contact and the lower elastic metal contact of the roll printing conductive silver paste.
In FIGS. 1 to 9, the symbols are: 1 is a probe base, 2 is a tuning matching circuit, 3 is a fixing hole for additionally installing a shielding layer shim coil, 3, 4 is a sample tube, 5 is a support tube, 6 is a roll printing coil, 71 is a coil upper silver ring, 72 is a coil lower silver ring, 81 is an upper elastic metal contact, 82 is a lower elastic metal contact, 9 is a force column, 10 is a tuning capacitor, 11 is a matching capacitor, 12 is a lead, 201 is a substrate, 202 is a coil parallel linear groove, 203 is a silver ring linear groove, 401 is a copper bead, 402 is a copper bead bracket, 403 is a copper coil spring, 404 is a contact shell, 405 is a threaded column and 501 is a force column screw hole.
Detailed Description
The following describes the embodiments and methods of the present invention with reference to the drawings.
Referring to fig. 1 to 9, the embodiment of the pluggable roll-printing coil probe of the nuclear magnetic resonance apparatus is provided with a probe base 1, a tuning matching circuit 2, a fixing hole 3 for installing a shielding layer shim coil, a sample tube 4, a support tube 5, a roll-printing coil 6, a coil upper silver ring 71, a coil lower silver ring 72, an upper elastic metal contact 81, a lower elastic metal contact 82, a force column 9, a tuning capacitor 10, a matching capacitor 11 and a lead 12;
the tuning matching circuit 2 and the roll printing coil 6 are fixed on the probe base 1, a fixing hole 3 additionally provided with a shielding layer shimming coil is formed in the probe base 1, a sample tube 4 penetrates into the center of the probe base 1 from a sample inlet of the probe base 1, the sample tube 4 with the roll printing coil 6 is inserted into the probe base 1, a support tube 5 is arranged at the bottom of the probe base 1, the sample tube 4 is supported by the support tube 5, an upper elastic metal contact 81 and a lower elastic metal contact 82 are fixed on two sides of the sample tube 4, the upper elastic metal contact 81 and the lower elastic metal contact 82 are connected and fixed through a force column 9, one ends of the upper elastic metal contact 81 and the lower elastic metal contact 82 are connected and communicated with the roll printing coil 6, and the other ends of the upper elastic metal contact 81 and the lower elastic metal contact 82 are welded with a lead 12; the upper silver ring 71 of the coil arranged at the upper part of the roll printing coil 6 is connected and communicated with the upper elastic metal contact 81; the lower silver ring 72 of the coil arranged at the bottom of the roll printing coil 6 is connected and conducted with the lower elastic metal contact 82, and the upper elastic metal contact 81 and the lower elastic metal contact 82 are respectively connected with the tuning capacitor 10 and the matching capacitor 11 on the tuning matching circuit 2 through the lead 12, so that the tuning matching circuit is conducted.
The sample tube 4 is a glass sample tube.
The upper elastic metal contact 81 and the lower elastic metal contact 82 are nonmagnetic elastic metal contacts.
The force column 9 is a nonconductive acrylic column.
The copper beads 401 at the front ends of the upper elastic metal contact 81 and the lower elastic metal contact 82 are embedded in the copper bead bracket 402 and can roll at a free angle, the back end of the copper bead bracket 402 is provided with elastic force by a copper spiral spring 403, the back section of the copper spiral spring 403 is connected with the contact shell 404, the back sections of the upper elastic metal contact 81 and the lower elastic metal contact 82 are threaded columns 405, and the purpose is to screw and fix the force column screw holes 501 of the force columns 9 at the two sides of the access passage of the sample tube 4.
The roll printing coil 6 adopts a saddle coil, an AG coil, a birdcage coil and the like.
The design method of the pluggable roll-printing coil probe of the nuclear magnetic resonance apparatus comprises the following steps:
1) etching 12 coil parallel linear grooves 202 with equal spacing and equal thickness on the surface of a substrate 201 by using a laser engraving machine;
2) uniformly smearing the prepared conductive silver adhesive on the coil parallel linear grooves 202 on the base plate 201, placing the sample tube 4 above the base plate 201 to roll for a circle, and adhering the conductive silver adhesive on the surface of the sample tube 4 by utilizing the adhesiveness of the conductive silver adhesive to form a solenoid-shaped roll-printing coil 6;
3) the method comprises the following steps of (1) engraving two silver ring linear grooves 203 slightly thicker than the line width of a roll printing coil 6 by using a laser engraving machine, wherein the line width of each silver ring linear groove 203 is 1.5mm, the length and the depth of each silver ring linear groove 203 are consistent with those of a coil parallel linear groove 202 of the roll printing coil 6, the distance between the two silver ring linear grooves 203 is the distance between the front end and the rear end of the roll printing coil, and for good contact conduction of the silver rings and the front end and the rear end of the roll printing coil 6, the two silver ring linear grooves 203 are respectively inwards contracted by 0.2mm, and conductive silver adhesive is uniformly coated on the silver ring linear grooves 203;
4) the sample tube 4 is perpendicular to the silver ring linear groove 203 of the base plate 201, the upper coil silver ring 71 and the lower coil silver ring 72 which are parallel to the tube opening plane of the sample tube 4 are respectively roll-printed at the front end and the rear end of the roll-printing coil 6 and are mutually communicated with the roll-printing coil 6, so that the sample tube 4 can be kept connected and communicated with the upper elastic metal contact 81 and the lower elastic metal contact 82 no matter what axial rotation angle is inserted, and the roll-printing coil 6 is prevented from being disconnected and communicated with the upper elastic metal contact 81 and the lower elastic metal contact 82.
In step 1), the substrate 201 is an acrylic substrate; the length, width and depth of the coil parallel linear grooves 202 are respectively 20mm, 0.7mm and 0.5mm, and the interval between adjacent coil parallel linear grooves 202 can be 0.7 mm.
In the step 2), the sample tube 4 is placed above the base plate 201, and the included angle between the sample tube and the coil parallel linear groove 202 is 60 degrees, so that the sample tube is pushed to roll for a circle from back to front.
In the step 43), the length of the roll printing coil 6 is 16.8mm, and the total length of the roll printing silver rings added at the front end and the rear end of the roll printing coil 6 is 19.5 mm.
The roll printing coil is printed on the surface of the sample tube, and according to a theoretical formula and a formula of a signal-to-noise ratio:
where ω is Larmor precession frequency, B⊥Is a transverse electromagnetic field, TcoilTemperature at data acquisition, Δ f bandwidth of the receiving stage, R noise, M⊥K is the boltzmann constant, which is the magnetization vector of the imaging nuclei. From the formula, the roll printing coil can be closer to an imaging area to increase a transverse electromagnetic field to increase the signal to noise ratio, so that the roll printing coil adopted by the invention can effectively ensure the signal to noise ratio theoretically. In practice, the signal-to-noise ratio of nuclear magnetic signals is influenced by many factors such as the impedance of the roll-printing coil, the volume and concentration of the sample, the magnetic field strength of the instrument, and the circuit noise of the instrument, and other influences are not explored only from the roll-printing coil filling factor.
The process of replacing the roll-printing coil 6 and the sample tube 4 is as shown in fig. 2, only the sample tube 4 attached with the roll-printing coil 6 needs to be directly inserted into and pulled out of the sample hole of the probe base 1, and the upper elastic metal contact 81 and the lower elastic metal contact 82 are elastically contracted inwards to ensure that the contacts are smoothly inserted and pulled out close to the outer wall of the sample tube 4.
The sample tube with the attached roll-printed coil is illustrated with reference to fig. 5. In this embodiment, a silver colloid solenoid coil 6 is roll-printed at a position 3cm from the bottom of a sample tube 4 with an outer diameter of 5mm, and the line width and the line pitch of the printed silver colloid solenoid are determined by the grooving process of the photolithographic substrate 201. A circle of silver rings 204 parallel to the plane of the sample port are respectively printed at the head end and the tail end of the coil and are connected and conducted with the roll printing coil 6, and the width is 1.5 mm. The design of the coil with the wider silver ring ensures that the coil can be well connected and conducted with the metal contact no matter the sample tube is inserted in any axial direction, and prevents the phenomenon that the tuning matching circuit is not conducted with the coil because the solenoid shape of the coil cannot be well touched with the metal contact.
The sectional structure a-a of the upper elastic metal contact 81 and the lower elastic metal contact 82 is shown in fig. 7 and 8, the inner spring is connected to the copper bead holder 402 and the contact housing 404, the copper coil spring 403 is in a free state when the syringe 4 is not inserted, and the copper bead 401 and the copper bead holder 402 are pressed to compress the copper coil spring 403 when the syringe is inserted, as shown in fig. 7.
The specific connection of the roll-printing coil, the upper elastic metal contact 81 and the lower elastic metal contact 82 is shown in fig. 9, which illustrates the connection of the roll-printing coil and the probe base in partial detail. In this embodiment, the force columns 9 for fixing the upper elastic metal contact 81 and the lower elastic metal contact 82 are additionally installed at the positions at equal intervals at the two ends of the sample tube 4, and the force column screw holes 501 on the fixing columns are matched and connected with the threaded columns 405 of the upper elastic metal contact 81 and the lower elastic metal contact 82, so that the upper elastic metal contact 81 and the lower elastic metal contact 82 are fixed at the positions at equal intervals at the two sides of the sample tube 4, the stress balance of the upper elastic metal contact 81 and the lower elastic metal contact 82 on the sample tube 4 is ensured, the contact shells 404 at the two sides are connected by the independent arc-shaped lead 12, and the conduction of the two copper balls 401 of each pair of the upper elastic metal contact 81 and the lower elastic metal contact 82 with the roll printing coil 6 is. Before the sample tube 4 is inserted, the distance between the upper elastic metal contact 81 and the lower elastic metal contact 82 on the two sides is smaller than the diameter of the sample tube 4, after the sample tube 4 is inserted, as can be seen from fig. 9, the upper elastic metal contact 81 and the lower elastic metal contact 82 on the two sides are acted by the insertion force of the sample tube 4, the copper helical spring 403 contracts, and the copper ball always clings to the surface glass of the sample tube to roll until the upper silver ring 71 and the lower silver ring 72 of the coil at the front end and the rear end of the roll-printing coil 6 are respectively butted with the upper elastic metal contact 81 and the lower elastic metal contact 82. The copper coil spring 403 is elastically adjusted so that the glass sample tube 4 can be smoothly inserted into the bottom of the base support tube 5 without being crushed and deformed by the upper elastic metal contact 81 and the lower elastic metal contact 82.
In this embodiment, the distance between each pair of metal contacts and the elastic force of the spring can be adjusted according to the outer diameter of the sample tube, so that the sample tubes with different sizes can be inserted and conducted well without being crushed too much to cause the sample tube to break, and the stable connection can be maintained, for example, the sample tubes with the outer diameter of 10mm, 3mm or less than 1mm, etc.
The invention utilizes the rolling printing method to attach the silver colloid on the surface of the sample tube to manufacture the radio frequency receiving and transmitting solenoid coil with a specific shape, and designs the point contact connection mode of the coil and the tuning matching circuit, thereby realizing the pluggable probe connection interface of the rolling printing coil. The roll printing coil is formed by coating prepared conductive silver adhesive on a substrate carved with parallel linear grooves, so that a sample tube rolls on the substrate according to a certain direction, and the conductive silver adhesive is firmly attached to the sample tube to form a solenoid coil; the coil and contact connection structure adopts an upper pair of non-magnetic elastic contact structures and a lower pair of non-magnetic elastic contact structures, and copper ball contacts in the contacts are connected with the front silver circular ring part and the rear silver circular ring part of the roll printing silver coil, so that the copper ball contacts are conducted with a tuning matching circuit, and the roll printing coil can be plugged. The coil manufacturing method is simple, the structure is exquisite and easy to use, on one hand, the roll printing coil is adopted to facilitate the batch processing of the coil, the coil processing method is greatly simplified, the wires with different geometric shapes can be flexibly manufactured, the sample acquisition area is more attached, and the signal-to-noise ratio of the coil is ensured; on the other hand, the replacement mode of the sample tube printed with the roll printing coil is greatly simplified, the work and time for replacing the sample tube and the coil are reduced, and the experiment efficiency is improved.
Claims (10)
1. A pluggable roll printing coil probe of a nuclear magnetic resonance apparatus is characterized by being provided with a probe base, a tuning matching circuit, a fixing hole for additionally installing a shimming coil of a shielding layer, a sample tube, a supporting tube, a roll printing coil, an upper silver ring of the coil, a lower silver ring of the coil, an upper elastic metal contact, a lower elastic metal contact, a force column, a tuning capacitor, a matching capacitor and a lead;
the tuning matching circuit and the roll printing coil are fixed on the probe base, a fixing hole provided with a shielding layer shimming coil is formed in the probe base, a sample tube penetrates into the center of the probe base from a sample inlet hole of the probe base, the sample tube with the roll printing coil is inserted into the probe base, a support tube is arranged at the bottom of the probe base and is supported by the support tube, an upper elastic metal contact and a lower elastic metal contact are fixed on two sides of the sample tube and are connected and fixed through a force column, one end of each of the upper elastic metal contact and the lower elastic metal contact is connected and communicated with the roll printing coil, and the other end of each of the upper elastic metal contact and the other end of each of the lower elastic metal contacts are welded with a lead; the silver ring on the upper part of the coil, which is arranged on the upper part of the roll printing coil, is connected and conducted with the upper elastic metal contact; and the lower silver ring of the coil arranged at the bottom of the roll printing coil is connected and communicated with the lower elastic metal contact, and the upper elastic metal contact and the lower elastic metal contact are respectively connected with a tuning capacitor and a matching capacitor on the tuning matching circuit through leads to realize the conduction of the tuning matching circuit.
2. The pluggable rolling coil probe of claim 1, wherein the sample tube is a glass sample tube.
3. The pluggable roll-printing coil probe of claim 1, wherein the upper elastic metal contact and the lower elastic metal contact are nonmagnetic elastic metal contacts.
4. The pluggable rolling coil probe of claim 1, wherein the force column is a nonconductive acrylic force column.
5. The pluggable rolling-printing coil probe of claim 1, wherein the copper balls at the front ends of the upper and lower elastic metal contacts are embedded in a copper ball holder and can roll at a free angle, the rear ends of the copper ball holder are provided with elastic force by a copper helical spring, the rear section of the copper helical spring is connected with the contact housing, and the rear sections of the upper and lower elastic metal contacts are threaded columns for screwing and fixing the force column screw holes of the force columns at the two sides of the sample tube access passage.
6. The pluggable rolling coil probe of claim 1, wherein the rolling coil is a saddle coil, an AG coil or a birdcage coil.
7. The design method of the pluggable rolling-printing coil probe of the nuclear magnetic resonance instrument is characterized by comprising the following steps of:
1) adopting a laser engraving machine to engrave 12 coil parallel linear grooves with equal spacing and equal thickness on the surface of the substrate;
2) uniformly coating the prepared conductive silver adhesive on the parallel linear grooves of the coil on the substrate, placing the sample tube above the substrate and rolling for a circle, and attaching the conductive silver adhesive on the surface of the sample tube by utilizing the adhesiveness of the conductive silver adhesive to form a solenoid-shaped roll printing coil;
3) the method comprises the following steps that a laser engraving machine is used for engraving two silver circular ring linear grooves thicker than the width of a roll printing coil, the width of each silver circular ring linear groove is 1.5mm, the length and the depth of each silver circular ring linear groove are consistent with those of a coil parallel linear groove of the roll printing coil, the distance between the two silver circular ring linear grooves is the distance between the front end and the rear end of the roll printing coil, and in order to ensure that the silver circular rings are in good contact conduction with the front end and the rear end of the roll printing coil, the two silver circular ring linear grooves are respectively contracted inwards by 0.2mm, and conductive silver adhesive is uniformly coated on the silver circular ring linear grooves;
4) the silver ring linear groove of the sample tube, which is vertical to the substrate, is respectively roll-printed with the upper silver ring and the lower silver ring of the coil, which are parallel to the plane of the tube opening of the sample tube, at the front end and the rear end of the roll-printed coil, and the silver rings are mutually communicated with the roll-printed coil, so that the sample tube can be kept in connection and communication with the upper elastic metal contact and the lower elastic metal contact no matter what axial rotation angle is inserted, and the roll-printed coil is prevented from being disconnected and communicated with the upper elastic metal contact and the lower elastic metal contact.
8. The design method of the pluggable roll-printing coil probe of the nuclear magnetic resonance apparatus according to claim 7, wherein in the step 1), the substrate is an acrylic substrate; the length, the width and the depth of the parallel linear grooves of the coils are respectively 20mm, 0.7mm and 0.5mm, and the interval between the parallel linear grooves of the adjacent coils is 0.7 mm.
9. The design method of the pluggable rolling coil probe of claim 7, wherein in step 2), the sample tube is placed above the substrate and forms an included angle of 60 degrees with the parallel linear grooves of the coil, the sample tube is pushed to roll for one circle from back to front, and then the rolling coil is rolled for one circle perpendicular to the linear grooves of the silver ring.
10. The design method of the pluggable rolling coil probe of the nuclear magnetic resonance apparatus according to claim 7, wherein in the step 3), the length of the rolling coil is 16.8mm, and the total length of the rolling silver rings at the front end and the rear end of the rolling coil is 19.4 mm.
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| CN114235531B (en) * | 2021-12-17 | 2024-01-23 | 中国核动力研究设计院 | Electrochemical etching sample table in hot chamber |
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