CN109298454A - A kind of effective nuclear quadrupole resonance probe for inhibiting hangover ring - Google Patents
A kind of effective nuclear quadrupole resonance probe for inhibiting hangover ring Download PDFInfo
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- CN109298454A CN109298454A CN201811095399.0A CN201811095399A CN109298454A CN 109298454 A CN109298454 A CN 109298454A CN 201811095399 A CN201811095399 A CN 201811095399A CN 109298454 A CN109298454 A CN 109298454A
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- circuit
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/14—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with electron or nuclear magnetic resonance
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/38—Processing data, e.g. for analysis, for interpretation, for correction
Abstract
The invention belongs to the solid matter detection device technical fields of the core containing quadrupole moment, more particularly to a kind of nuclear quadrupole resonance probe for effectively inhibiting hangover ring, including resonance matching circuit, Q value switching circuit and filter circuit, the resonance matching circuit, Q value switching circuit and filter circuit are electrically connected；Equipped with resonance matching circuit, Q value switching circuit and filter circuit, resonance matching circuit can make probe coil obtain maximum power after RF excited arriving, and under test substance characteristic frequency resonance to motivate sample to generate NQR signal；Q value switching circuit can switch Q value according to the working condition of probe, and to obtain optimal NQR signal and detection signal-to-noise ratio, filter circuit can filter out the noise generated in excitation and other environment.Circuit improves signal acquisition efficiency, improves the signal-to-noise ratio of output signal, which has symmetry Q value switching circuit, and the ring recovery time of probe can be made to be reduced to 12.127 μ s from 390 μ s, and ring hangover signal can be effectively suppressed.
Description
Technical field
The invention belongs to the solid matter detection device technical fields of the core containing quadrupole moment, and in particular to a kind of effectively to inhibit to drag
The nuclear quadrupole resonance of tail ring is popped one's head in.
Background technique
Today's society is faced with many anti-terrorism safety problems, mainly related with explosive, explosive show concealment and
Each opposite sex, detects it and brings huge challenge.The usual existing defects of traditional bomb object detection method, for example, metal detector
In magnetic soil, the mine of low-metal content, clay, humidity and electric conductivity soil and the mine very close with earth's surface all
There are problems that high false alarm rate；For another example metal detector and the false alarm rate of Ground Penetrating Radar (GPR) are higher, this is because their inspection
Survey is all based on secondary feature, rather than the essential ingredient based on explosive；NQR is a kind of Nuclear Physics phenomenon, refers to atomic nucleus
Non-cyanide leaching part because with core dispatch from foreign news agency field gradient interaction cause energy level splitting, outside plus radiofrequency field effect under, generate energy
The process of order transition.Since NQR technology only detects the material molecule of explosive itself, not by metal material, shell, shape etc. its
The influence of its factor has in terms of identifying substance and is widely applied, be one so NQR technology has uniqueness to material identification
The ideal solid matter Detection Techniques of kind.
However when carrying out explosive detection using NQR method, there are various interference signals, to the shadow of NQR detectable signal
Sound is larger, is interfered caused by the hangover signal that wherein driving pulse generates on probe the most seriously, due to driving pulse itself
Signal is stronger, and after driving pulse, the energy storage in system inductive probe cannot be discharged at once, so that driving pulse terminates
There are still the ring of a period of time hangover signals in inductive probe afterwards, and the NQR signal that tested sample is excited and is generated is decayed
Rate is very fast and itself is again very faint, trails signal during reduction, NQR signal has been decayed most, this to adopt
The NQR signal collected is very faint, and signal-to-noise ratio is extremely low, needs to be repeated several times acquisition, therefore improve probe antenna sensitivity and letter
Make an uproar than be NQR detection system main direction of studying.
Summary of the invention
To solve the problems mentioned above in the background art.The present invention provides a kind of cores four for effectively inhibiting hangover ring
Polar moment resonance probe has and ring hangover signal characteristic can be effectively suppressed.
To achieve the above object, the invention provides the following technical scheme: a kind of nuclear quadrupole moment for effectively inhibiting hangover ring
Resonance probe, including resonance matching circuit, Q value switching circuit and filter circuit, the resonance matching circuit, Q value switching circuit
It is electrically connected with filter circuit；The resonance matching circuit includes the branch one and branch two being connected in parallel, and the branch one wraps
Concatenated probe coil inductance Lo, equivalent resistance Ro and tuning capacitance Co are included, the branch two includes equivalent inductance L1；The Q
Value switching circuit includes two transistor switching circuits being arranged symmetrically and the signal circuit by transformer connection；The filter
The input and output side of wave circuit is connected with amplitude limiter circuit, and the filter circuit further includes three filter branch in parallel.
Effectively inhibit the nuclear quadrupole resonance probe optimal technical scheme of hangover ring, the spy as one kind of the invention
Head coil inductance Lo is 3 μ H, and equivalent resistance Ro is 0.3 Ω, and tuning capacitance Co is 382pF, and equivalent inductance L1 is 134.4nH.
The nuclear quadrupole resonance of hangover ring is effectively inhibited to pop one's head in optimal technical scheme as one kind of the invention, described three
Pole pipe switching circuit includes triode, and the pole the B concatenation 1k Ω resistance of the pole the E ground connection of the triode, the triode is connected to TTL
End, the pole E and the pole B of triode are also parallel with 2k Ω resistance, and the pole C of the triode is connected with transformer and parallel with one another in turn
Capacitor, resistance, be then attached to the end VCC.
Effectively inhibit the nuclear quadrupole resonance probe optimal technical scheme of hangover ring, the phase as one kind of the invention
Mutually capacitor in parallel, resistance, resistance value is 120 Ω, capacitance is 0.1 μ F.
The nuclear quadrupole resonance of hangover ring is effectively inhibited to pop one's head in optimal technical scheme as one kind of the invention, described three
Transformation ratio between pole pipe switching circuit and the signal circuit is 1:8.
The nuclear quadrupole resonance of hangover ring is effectively inhibited to pop one's head in optimal technical scheme as one kind of the invention, described three
The filter branch of a parallel connection is respectively filter branch one, filter branch two and filter branch three, and the filter branch one includes one
The inductance of a 134.3nH, the filter branch two include inductance, the resistance of 0.3 Ω and the capacitor of 382pF of 3 μ H of concatenation,
The filter branch three includes the capacitor of a 692pF, is also connected with 1.73 μ between the filter branch two and filter branch three
The inductance of H is connected with 1.73 μ H inductance between the filter branch three and amplitude limiter circuit.
Effectively inhibit the nuclear quadrupole resonance probe optimal technical scheme of hangover ring, the limit as one kind of the invention
Width circuit is the diode of two reverse parallel connections.
Compared with prior art, the beneficial effects of the present invention are: being equipped with resonance matching circuit, Q value switching circuit and filtering
Circuit, resonance matching circuit can make probe coil obtain maximum RF excited power, and the resonance under characteristic frequency,
To motivate sample to generate NQR signal；Q value switching circuit can switch Q value according to the working condition of probe, optimal to obtain
NQR signal and detection signal-to-noise ratio, filter circuit can filter out the noise generated in excitation and other environment, which, which has, improves
The advantage of the signal-to-noise ratio of signal acquisition efficiency and raising output signal, the circuit have symmetry Q value switching circuit, can make to pop one's head in
Ring recovery time be reduced to 12.127 μ s from 390 μ s, can be effectively suppressed ring hangover signal.
Detailed description of the invention
Attached drawing is used to provide further understanding of the present invention, and constitutes part of specification, with reality of the invention
It applies example to be used to explain the present invention together, not be construed as limiting the invention.In the accompanying drawings:
Fig. 1 is the structural diagram of the present invention；
Fig. 2 is the resonance matching circuit diagram in the present invention；
Fig. 3 is the Q value switching circuit figure in the present invention；
Fig. 4 is the filter circuit figure in the present invention；
Fig. 5 is the detection system schematic diagram in the present invention；
Fig. 6 is the probe antenna equivalent schematic in the present invention；
Fig. 7 is the normalization third-order low-pass prototype schematic diagram in the present invention；
Fig. 8 is the transformed filter schematic in the present invention；
Fig. 9 is that the Multisim software in the present invention carries out analogous diagram；
In figure: 1, resonance matching circuit；2, Q value switching circuit；3, filter circuit.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
Embodiment
Fig. 1-4 is please referred to, the present invention provides a kind of technical solution: a kind of nuclear quadrupole resonance effectively inhibiting hangover ring
Probe, including resonance matching circuit, Q value switching circuit and filter circuit, resonance matching circuit, Q value switching circuit and filtered electrical
Road is electrically connected；Resonance matching circuit includes the branch one and branch two being connected in parallel, and branch one includes concatenated probe coil
Inductance Lo, equivalent resistance Ro and tuning capacitance Co, branch two include equivalent inductance L1；Q value switching circuit includes two symmetrical cloth
The transistor switching circuit set and the signal circuit connected by transformer；The input and output side connection of filter circuit is limited
Width circuit, filter circuit further include three filter branch in parallel.
In the present embodiment, first part is resonance matching circuit, and the effect of this partial circuit is exactly to come in RF excited
So that probe coil is obtained maximum power after facing, and under characteristic frequency resonance to motivate sample to generate NQR signal；Second
It is divided into Q value switching circuit, the effect of this partial circuit is exactly to switch Q value according to the working condition of probe, to obtain optimal NQR
Signal and detection signal-to-noise ratio (SNR)；Part III is filter segment, and the effect of this part is filtered out in excitation and other environment
The noise of generation, main purpose are to improve signal acquisition efficiency, improve the signal-to-noise ratio of output signal.
Specifically, probe coil inductance Lo is 3 μ H, equivalent resistance Ro is 0.3 Ω, and tuning capacitance Co is 382pF, equivalent electricity
Sense L1 is 134.4nH.
In the present embodiment, this time the matching network of NQR probe circuit actual design uses Π type network, in order to simplify design
Step is easy to implement optimization impedance matching, is designed the improvement of process using following thought in calculating process:
(1) it imbibes ideas: stray reactance being included in impedance matching calculating, it is total to replace to obtain an equivalent reactance
Reactance.
(2) resonance thought: resonance circuit is constituted with the opposite element of reactance characteristic, under resonant state, pure resistance is presented in circuit
Property, impedance matching, that is, resistors match, this is resonance matching.
Circuit parameter and design are as follows: probe coil uses cored screw pipeline circle, and equivalent circuit is as shown in Figure 6:
Capacitor C can indicate insertion loss, due to its value very little, can not consider.If the frequency of detecting material is f0, adjust
Humorous match circuit is as shown in Figure 2, wherein the input admittance at the both ends mn are as follows:
Enable GmnReal part is 1/Z0, it is available:
It is known that Z0For 50 Ω, the impedance of transmitter and output machine is pure resistance, probe coil inductance L0It is equivalent for 3 μ H
Resistance R0For 0.3 Ω, C can be obtained by formula (1,2), (1,3)0For 382pF, L1For 134.4nH.
Specifically, transistor switching circuit includes triode, the pole the E ground connection of the triode, the pole B of the triode concatenates 1k
Ω resistance is connected to the end TTL, and the pole E and the pole B of triode are also parallel with 2k Ω resistance, and the pole C of triode is connected with transformation in turn
Device and capacitor parallel with one another, resistance, are then attached to the end VCC.
Specifically, the resistance value of capacitor parallel with one another, resistance is 120 Ω, capacitance is 0.1 μ F.
Specifically, the transformation ratio between transistor switching circuit and signal circuit is 1:8.
In the present embodiment, Fig. 3: Q value switching circuit 2 is please referred to using symmetric form double-triode valve as switching circuit, two
The transformation ratio of primary to secondary is all 1:8, it is assumed that transformer is ideal, then left side Q value circuit and right side tuning
Q value with circuit is equal, if resistance (R in figure) is not added on collector, the Q value of probe can be by being applied to the door of the pole transistor B
Control signal control:
Wherein rCEIt is the effective resistance between C grades and E grades of triode.When gate-control signal accesses high level (5V), three-level
Pipe conducting, rCEVery little, low reactance-resistance ratio is presented in circuit at this time, so that probe fast quick-recovery after strong radio-frequency pulse；When gate-control signal accesses
When low level (0V), triode is in off state, rCEVery big, high q-factor is presented in circuit.If resistance R is added on collector,
R can be replaced with the value of RCE, it may be assumed that
Q value, but also available introducing resistance and ring response recovery time can be not only obtained by changing R value in this way
Relationship, in addition, from the formula can be seen that using two triode parallel connections constitute symmetric circuit can further decrease R value, from
And reduce the Q value of probe circuit.
Specifically, three filter branch in parallel are respectively filter branch one, filter branch two and filter branch three, filtering
The inductance of branch one an including 134.3nH, filter branch two include the inductance of 3 μ H of concatenation, the resistance of 0.3 Ω and
The capacitor of 382pF, filter branch three include the capacitor of a 692pF, are also connected between filter branch two and filter branch three
The inductance of 1.73 μ H is connected with 1.73 μ H inductance between filter branch three and amplitude limiter circuit.
Specifically, amplitude limiter circuit is the diode of two reverse parallel connections.
In the present embodiment, definitionThen have:
Characteristic impedance transformation is carried out again, is had:
Wherein, low-pass prototype parameter is normalized are as follows: Z0For 1 Ω, L0=1H, C0=1F, f0=1/2 π Hz.As shown in Figure 7.
This secondary design resonance frequency f=4.6MHz, then the formula of bringing into can calculate L2Theoretical value be 1.73 μ H, C0For 692pF, new
Low-pass filter section is as shown in Figure 8 (transformed).
After Butterworth LPF is added in probe circuit, circuit is as shown in Figure 4.Because NQR signal must be
When typical multipulse sequence occurs, every millisecond of acquisition is primary, and typical PC software addition operation usually requires the more time,
It is therefore desirable to add hardware to acquire NQR signal.
The working principle of the invention and process for using: referring to FIG. 5, after the present invention installs, step 1, computer is sent
Pulse control sequence generates radio-frequency pulse identical with sample to be tested characteristic frequency to signal generator, signal generator, this is penetrated
Frequency pulse is loaded on probe coil after high-power transmitter amplifies, the outside radiation field of probe coil, explosion to be measured
Nitrogen-atoms that nuclear quadrupole moment in object is not zero (14N) generated after absorbing the energy that gives off of aerial coil energy level transition (it is assumed that
Contain test substance in sample)；Step 2, when computer control radio-frequency pulse stops working, in subsequent test substance14N by
Upper state is restored to equilibrium state, releases the energy comprising characteristic frequency, i.e. NQR signal in the process；Step 3, NQR signal
After preamplifier amplifies, after carrying out the relevant treatments such as analog-to-digital conversion by reception device, and result is given to master control meter
Calculation machine is handled, and differentiates in sample whether contain explosive to be measured accordingly.It is emulated using Multisim software, Fig. 9 (a)
The waveform diagram of radio-frequency pulse when being no bell signal suppression circuit, radio-frequency pulse when Fig. 9 (b) has bell signal suppression circuit
Waveform diagram.The 1 position time of scale is 526.505 μ s, waveform voltage in Fig. 9 (a) it can be seen from Fig. 9 (a) and Fig. 9 (b)
Value is 862.409V, and the 2 position time of scale is 891.244 μ s, and waveform voltage value is 3.269 μ V, so Fig. 9 (a) gets the bid
Time used in ruler 1 to scale 2 is 364.739 μ s；The 1 position time of scale is 224.788 μ s, waveform voltage value in Fig. 9 (b)
For 841.533V, the 2 position time of scale is 236.915 μ s, and waveform voltage value is -2.054 μ V, so scale in Fig. 9 (b)
1 to time used in scale 2 is 12.127 μ s, it can be seen that there is ring hangover suppression circuit to eliminate antenna smear effects very
Obviously.
Finally, it should be noted that the foregoing is only a preferred embodiment of the present invention, it is not intended to restrict the invention,
Although the present invention is described in detail referring to the foregoing embodiments, for those skilled in the art, still may be used
To modify the technical solutions described in the foregoing embodiments or equivalent replacement of some of the technical features.
All within the spirits and principles of the present invention, any modification, equivalent replacement, improvement and so on should be included in of the invention
Within protection scope.
Claims (7)
1. a kind of nuclear quadrupole resonance probe for effectively inhibiting hangover ring, it is characterised in that: including resonance matching circuit (1), Q
Value switching circuit (2) and filter circuit (3), the resonance matching circuit (1), Q value switching circuit (2) and filter circuit (3) electricity
Property connection；The resonance matching circuit (1) includes the branch one and branch two being connected in parallel, and the branch one includes concatenated spy
Head coil inductance Lo, equivalent resistance Ro and tuning capacitance Co, the branch two include equivalent inductance L1；The Q value switching circuit
(2) signal circuit for including two transistor switching circuits being arranged symmetrically and being connected by transformer；The filter circuit
(3) input and output side is connected with amplitude limiter circuit, and the filter circuit (3) further includes three filter branch in parallel.
2. a kind of nuclear quadrupole resonance probe for effectively inhibiting hangover ring according to claim 1, it is characterised in that: institute
Stating probe coil inductance Lo is 3 μ H, and equivalent resistance Ro is 0.3 Ω, and tuning capacitance Co is 382pF, and equivalent inductance L1 is
134.4nH。。
3. a kind of nuclear quadrupole resonance probe for effectively inhibiting hangover ring according to claim 1, it is characterised in that: institute
Stating transistor switching circuit includes triode, and the pole the B concatenation 1k Ω resistance of the pole the E ground connection of the triode, the triode is connected to
The end TTL, the pole E and the pole B of triode are also parallel with 2k Ω resistance, and the pole C of the triode is connected with transformer and mutually in turn
Capacitor, the resistance of parallel connection, are then attached to the end VCC.
4. a kind of nuclear quadrupole resonance probe for effectively inhibiting hangover ring according to claim 3, it is characterised in that: institute
Capacitor parallel with one another, resistance are stated, resistance value is 120 Ω, capacitance is 0.1 μ F.
5. a kind of nuclear quadrupole resonance probe for effectively inhibiting hangover ring according to claim 1, it is characterised in that: institute
Stating the transformation ratio between transistor switching circuit and the signal circuit is 1:8.
6. a kind of nuclear quadrupole resonance probe for effectively inhibiting hangover ring according to claim 1, it is characterised in that: institute
Stating three filter branch in parallel is respectively filter branch one, filter branch two and filter branch three, and the filter branch one wraps
The inductance of a 134.3nH is included, the filter branch two includes the inductance of 3 μ H, the resistance of 0.3 Ω and 382pF of concatenation
Capacitor, the filter branch three include the capacitor of a 692pF, are also connected between the filter branch two and filter branch three
The inductance of 1.73 μ H is connected with 1.73 μ H inductance between the filter branch three and amplitude limiter circuit.
7. a kind of nuclear quadrupole resonance probe for effectively inhibiting hangover ring according to claim 1, it is characterised in that: institute
State the diode that amplitude limiter circuit is two reverse parallel connections.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811095399.0A CN109298454A (en) | 2018-09-19 | 2018-09-19 | A kind of effective nuclear quadrupole resonance probe for inhibiting hangover ring |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201811095399.0A CN109298454A (en) | 2018-09-19 | 2018-09-19 | A kind of effective nuclear quadrupole resonance probe for inhibiting hangover ring |
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| WO2012151282A1 (en) * | 2011-05-02 | 2012-11-08 | The Penn State Research Foundation | Isotropic metamaterial lens for magnetic imaging applications |
| CN204129220U (en) * | 2014-07-18 | 2015-01-28 | 同致电子科技（厦门）有限公司 | A kind of radar for backing car transless radiating circuit reduces remained shock circuit |
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2018
- 2018-09-19 CN CN201811095399.0A patent/CN109298454A/en active Pending
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|---|---|---|---|---|
| CN1672059A (en) * | 2002-06-13 | 2005-09-21 | Qr科学有限公司 | A receive system for high Q antennas in nqr and a method of detecting substances |
| WO2005017565A1 (en) * | 2003-08-08 | 2005-02-24 | The Government Of The United States Of America, As Represented By The Secretary Of The Navy | Cancellation of ringing in magnetic resonance utilizing a composite pulse |
| WO2012151282A1 (en) * | 2011-05-02 | 2012-11-08 | The Penn State Research Foundation | Isotropic metamaterial lens for magnetic imaging applications |
| CN102624411A (en) * | 2012-02-28 | 2012-08-01 | 西安电子科技大学 | Low frequency tuning antenna applicable to explosive detection |
| CN204129220U (en) * | 2014-07-18 | 2015-01-28 | 同致电子科技（厦门）有限公司 | A kind of radar for backing car transless radiating circuit reduces remained shock circuit |
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Application publication date: 20190201 |