JP2000065910A - Apparatus and method for magnetic resonance measuring and resonator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high-sensitivity magnetic resonance measurement which suppresses noise caused by vibration. SOLUTION: A frequency modulated wave outputted from an oscillator 1 is branched into a main modulated wave and a reference modulated wave by a distributor 12. The main modulated wave is supplied to a circulator (or hybrid) 8, and led to a resonator 2. A reflected wave from the resonator 2 enshrouding (or put in the vicinity of) a sample 15, passes through the circulator (or hybrid) 8, and is supplied to a mixer 4. The mixer 4 performs detection on the basis of the reflected wave and a reference wave supplied from a phase shifter 6. The modulated frequency component of the detected output is extracted by a lock-in amplifier 11. A DC magnetic field is swept by a DC magnetic field coil 5, and a measurement processing part 14 measures electron spin resonance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic resonance measuring apparatus, a measuring method, and a resonator, and more particularly, to a high sensitivity electron spin resonance using frequency modulation.
e: ESR or Nuclear Magnetic Reson
The present invention relates to a magnetic resonance measurement apparatus and a measurement method for measuring ance (NMR), and a resonator that can be mainly used for magnetic resonance measurement. Magnetic resonance includes ESR and NMR. E
SR is indicated by the spin of an electron, and mainly occurs at a high frequency such as a microwave (eg, 10 GHz) and a weak magnetic flux density (eg, about 0.3 T). In contrast, NM
R is indicated by the spin of the nucleus, and is mainly a low frequency (for example, 30 MHz or the like) and a strong magnetic flux density (for example, several T
Degree). In the following description, for example, ES
The following description will focus on R, but since ESR and NMR are similar in physical phenomena, the present invention can be applied to both.

[0002]

2. Description of the Related Art In general, the ESR method is a method for measuring atoms or molecules having unpaired electrons such as free radicals by using the motion of a magnetic moment of electrons. Usually, electrons are included in pairs in an atomic or molecular orbital, but in transition metal ions or radicals, for example, only one electron may exist in those orbitals. Such electrons are called unpaired electrons. The application fields of ESR are wide-ranging, such as chemistry, physics, biology, and medicine. Recently, it has been said that free radicals (molecules having unpaired electrons) naturally occurring in living organisms are related to cancer, aging, and the like, and have been attracting attention in fields such as medicine and biology. Free radicals have high chemical reactivity, so ES
R is currently the only valid way to measure this non-destructively.

The ESR apparatus mainly includes a pulse ESR method and a continuous wave ESR method (Continuous Wave-ESR method, CW-
ESR method). In the conventional CW-ESR method, the microwave frequency is kept constant and a magnetic field sweep is performed to obtain the EW.
Measure the SR signal. Further, in order to increase the sensitivity, the measurement is performed by applying a magnetic field modulation.

FIG. 10 shows a configuration diagram of a conventional CW-ESR apparatus. The CW-ESR apparatus includes an oscillator 101, a resonator 102, a modulation magnetic field coil 103, a mixer 104, a DC magnetic field coil 105, a phase shifter 106, and a power amplifier 10.
7, circulator 108, signal amplifier 109, modulation oscillator 110, lock-in amplifier 111, distributor 1
12, coupling degree possible one-turn coil 113, measurement processing unit 1
14 is provided.

[0005] The oscillator 101 generates a carrier wave for measurement such as a microwave. As the oscillation frequency, for example, an L band such as 700 MHz is used. The resonator 102 is brought into contact with or close to the sample in the surface coil type (disposed near), and the sample is disposed inside in the loop gap type. The detailed configuration of the resonator 102 will be described later. The modulation magnetic field coil 103 is for realizing high-sensitivity measurement by applying a modulation magnetic field. As the mixer 104, a double balanced mixer (DBM) or the like is used. The DC magnetic field coil 105 performs a magnetic field sweep by applying a DC magnetic field to the measurement site of the sample. The circulator 108 may be constituted by a directional coupler, a hybrid, or the like. The one-turn coil 113 has, for example, a coaxial cable and a one-turn coil.

FIG. 11 shows a configuration diagram of a resonator and a modulation magnetic field coil used in a conventional L-band CW-ESR device. A microwave having a constant frequency is applied to a sample 115 in the resonator 102 via a one-turn coil 113 having a coaxial cable and a one-turn coil. The reflected wave reflected from the resonator 102 in which the sample 115 is inserted is returned to the circulator 108 via the one-turn coil 113. During the measurement, the DC magnetic field coil 105 sweeps the magnetic field applied to the sample, and the modulation magnetic field coil 103 generates a temporal change in the magnetic field.

Next, an outline of the operation of the CW-ESR apparatus will be described. The modulation signal transmitted from the modulation oscillator 110 is
While being supplied to the modulation magnetic field coil 103, it is also supplied to the lock-in amplifier 111, and the phase, amplitude and DC component are adjusted. Since the modulation signal is usually weak, it is supplied to the modulation magnetic field coil via a power amplifier (omitted in the figure). The microwave output from the oscillator 101 is split by the distributor 112 into a main line microwave and a reference microwave. Main line microwave power amplifier 1
In step 07, the power is adjusted to the target power and supplied to the circulator 108. The main line microwave branched by the circulator 108 is guided to the resonator 102 via the one-turn coil 113, and the sample 115 in the resonator 102
Supplied to At this time, the distance between the one-turn coil 113 and the resonator 102 is adjusted so as to minimize the reflection. Resonator 102 in which sample 115 is included
The reflected wave reflected from is returned to the circulator 108 via the one-turn coil 113 again. The reflected wave is supplied to the mixer 104 after being amplified by the signal amplifier 109.

On the other hand, the reference microwave distributed by the distributor 112 is adjusted by the phase shifter 106 so that the phase of the reference microwave matches the phase of the reflected wave from the resonator 102, and is supplied to the mixer 104. The mixer 104 performs mixing and detection based on the reflected wave output from the circulator 108 and the reference microwave supplied from the phase shifter 106. Mixer 10
4 is output to the lock-in amplifier 111.
With this, the phase and amplitude are adjusted. The ESR signal output from the lock-in amplifier 111 is guided to the measurement processing unit 114. In the measurement processing unit 114, the DC magnetic field coil 1
05, the DC magnetic field is swept to find the E
Electron spin resonance is measured based on the SR signal.

[0009]

However, the CW-
In the ESR device, the current flowing through the modulation magnetic field coil receives a force due to the DC magnetic field generated by the DC magnetic field coil, and the modulation magnetic field coil causes mechanical vibration. An eddy current flows in a complicated manner in the resonator in the modulation magnetic field. In addition, the resonators also oscillate, as eddy currents are also subject to forces from DC magnetic fields. These mechanical vibrations cause electrical noise and hinder improvement in sensitivity of the ESR device.

[0010] Further, in the prior art, the sensitivity was insufficient, so that it was difficult to measure a dilute free radical that naturally occurs in a living body. In view of the above, an object of the present invention is to provide a highly sensitive magnetic resonance measuring apparatus and a measuring method which suppress noise due to vibration, and a resonator which can be mainly used for magnetic resonance measurement.

[0011]

According to a first aspect of the present invention, there is provided an oscillator for oscillating a modulated wave frequency-modulated by a modulation signal, and a sample provided inside or in the vicinity of the oscillator. A resonator that varies the resonance frequency by a modulation signal so as to change the resonance frequency so as to change the resonance frequency by applying a modulation wave from the oscillator to a sample in the resonator, and applying a modulated magnetic field or modulation applied to the sample. Provided is a magnetic resonance measurement apparatus that obtains a detection output based on a modulated wave from the oscillator and a reflected wave from the resonator by sweeping a wave frequency.

According to a second aspect of the present invention, there is provided a loop gap resonance element having a loop portion and a gap portion for containing a sample, and a loop gap resonance element provided near the gap portion of the loop gap resonance element. A spacer, a plurality of electrodes provided on both sides of the gap on the opposite side of the loop gap resonance element with the spacer interposed therebetween, and a variable capacitance diode connected between the plurality of electrodes; A resonator having a choke coil provided on the electrode and applying a voltage to the electrode via the choke coil to vary a resonance frequency is provided.

According to a third solution of the present invention,
A magnetic resonance measuring apparatus using the above-described resonator is provided. Further, according to the fourth solution of the present invention, a sample is arranged inside or near the resonator, the resonance frequency of the resonator is made variable following the modulation signal, and the modulated wave frequency-modulated by the modulation signal is changed. Oscillate, apply a modulation wave to the sample, sweep the magnetic field or modulation wave frequency applied to the sample, and measure electron spin resonance or nuclear magnetic resonance based on the modulation wave and the reflected wave from the resonator. A method for measuring magnetic resonance is provided.

[0014]

FIG. 1 shows a configuration diagram of an ESR device according to the present invention. Here, as an example, the frequency modulation E
SR device (Frequency Modulation-ESR device, FM-
ESR device) is shown. The FM-ESR device includes an oscillator 1, a resonator 2, a modulation signal controller 3, a mixer 4, a DC magnetic field coil 5, a phase shifter 6, a power amplifier 7,
Circulator 8, signal amplifier 9, modulation oscillator 1
0, lock-in amplifier 11, distributor 12, coupling possibility 1
A turn coil 13 and a measurement processing unit 14 are provided.

The oscillator 1 generates a carrier wave for measurement such as a microwave. The oscillation frequency is (for example, 10M
From rf to quasi-optic and optical regions. Specific examples include, for example, 200 MHz, 300 MHz, and 700 MHz conventionally used for ESR.
z, 1-2 GHz, 10 GHz, and other frequencies in the millimeter wave band and the submillimeter wave band can be used. The oscillator 1 oscillates a modulated wave frequency-modulated by the supplied modulation signal. Here, as an example, a description will be given using a microwave as an oscillation source of the oscillator 1. The resonator 2 is brought into contact with or close to the sample in the surface coil type (disposed near), and the sample is disposed inside in the loop gap type.
The resonance frequency of the resonator 2 is made variable by a modulation signal. The detailed configuration of the resonator 2 will be described later. Here, the loop gap type resonator is mainly described, but the magnetic resonance apparatus of the present invention can be applied using a surface coil type resonator.

The modulation signal controller 3 supplies a modulation signal to the oscillator 1 and the resonator 2 so as to change the resonance frequency of the resonator following the modulation signal to the oscillator. The modulation signal controller 3 includes a lock-in amplifier 11
To supply the modulation signal to adjust the phase, amplitude and DC component. According to the present invention, unnecessary reflection can be suppressed by matching the frequency modulation wave oscillated from the oscillator 1 with the resonance frequency of the resonator 2 so as to match. Mixer 4
For example, a circuit using a diode or a double balanced mixer (DBM) having excellent detection efficiency is used. The DC magnetic field coil 5 performs a magnetic field sweep by applying a DC magnetic field to the resonator 2. The circulator 8 may be configured by a directional coupler, a hybrid, or the like. The lock-in amplifier 11 can include a bandpass filter that allows a component having a modulation frequency such as 100 kHz to pass. Such a band-pass filter may be provided separately in a stage preceding the lock-in amplifier 11. The one-turn coil 13 includes a coaxial cable, a one-turn coil, and the like. The circulator 8 has a function as a main modulation wave supply unit and a reflected wave detection unit.

Next, an outline of the operation of the FM-ESR apparatus will be described. The modulation signal transmitted from the modulation oscillator 10 is supplied to the modulation signal controller 3. The modulation signal controller 3 supplies a modulation signal to the oscillator 1 and the resonator 2. The frequency-modulated wave output from the oscillator 1
By 2, the signal is split into a main modulation wave and a reference modulation wave. The main modulation wave is adjusted to a target power by the power amplifier 7 and supplied to the circulator 8. Circulator 8
Is guided to the resonator 2 via the one-turn coil 13 and supplied to the sample 15 in the resonator 2. At this time, by adjusting the distance between the one-turn coil 13 and the resonator 2, the reflection can be adjusted to be minimized. The reflected wave reflected from the resonator 2 in which the sample 15 is included or placed in the vicinity is returned to the circulator 8 via the one-turn coil 13 again. The reflected wave output from the circulator 8 is supplied to the mixer 4 after being amplified by the signal amplifier 9.

On the other hand, the reference modulated wave distributed by the distributor 12 is adjusted by the phase shifter 6 so that the phase of the reference modulated wave matches the phase of the reflected wave from the resonator 2, and is supplied to the mixer 4. Mixer 4
Performs mixing and detection based on the reflected wave output from the circulator 8 and the reference modulation wave supplied from the phase shifter 6. From the detection output output from the mixer 4, a modulation frequency component is extracted and amplified by the lock-in amplifier 11. The ESR signal output from the lock-in amplifier 11 is guided to the measurement processing unit 14. In the measurement processing unit 14,
The DC magnetic field coil 5 measures the differential curve of the electron spin resonance absorption based on the detection output obtained by sweeping the DC magnetic field.

FIG. 2 shows a configuration diagram and an equivalent circuit diagram of a resonator according to the present invention. As shown in FIG. 2A, the variable resonance frequency resonator includes a loop gap resonance element 21;
It includes a spacer 22, an electrode 23, a variable capacitance diode 24, a choke coil 25, an internal spacer 26, and an internal electrode 27.

The resonator includes a loop gap resonance element 2
An electrode 23 is provided on one gap via a spacer 22 made of Teflon or the like. The loop gap resonance element 21 can be made of, for example, a material in which copper is plated with gold. The size is, for example, height 2
8mm, inner diameter 28mm, outer diameter 30mm and gap width 1
mm. Such spacers 22 and electrodes 23 are provided on both sides of the gap of the loop gap resonance element. The variable capacitance diode 24 is connected between the plurality of electrodes 23. Further, a choke coil 25 is connected to each electrode 23. One choke coil 25 can be omitted as appropriate.

Note that an internal spacer 26 and an internal electrode 27 may be provided inside the loop gap resonance element 21 (these may be omitted as appropriate).
The internal spacer 26 is formed of an appropriate dielectric such as Teflon. The size of the internal spacer 26 and the internal electrode 27 is, for example, about 1/3 the width of the loop inner circumference (about 10 m).
m), the vertical length can be about the same as the loop gap resonance element 21 (about 28 mm). In general, the loop gap gap element
The microwave electric field leaks into the gap resonance element 21. When this electric field leaks, part of the energy stored in the resonator is consumed due to the dielectric loss of the sample,
The Q value of the resonator decreases. The internal spacer 26 and the internal electrode 27 can prevent leakage to the inside and prevent the Q of the resonator from being reduced.

FIG. 2B shows an equivalent circuit of the resonator according to the present invention. In the FM-ESR method, a frequency-modulated microwave is supplied to the resonator, so that it is necessary to change the resonance frequency of the resonator in order to match the supplied modulated wave. Thus, in the present invention, the resonance frequency can be made variable by attaching the variable capacitance diode 24 and the like to the loop gap resonance element 21 as described above. That is, a voltage such as a modulation voltage is applied to the electrode 23 via the choke coil 25, and the reverse bias of the variable capacitance diode 24 is changed to change the capacitance. The variable capacitance diode 2
For 4, it is preferable to use a material having a high Q as much as possible to prevent a decrease in the Q of the resonator.

FIG. 3 is a block diagram showing the second and third embodiments of the resonator according to the present invention. The resonator shown in FIG. 3A is a modification of the spacer 22 shown in FIG. That is, in this case, the spacer 33 is constituted by one common to both the electrodes 32.
Further, the resonator shown in FIG. 3B further includes another electrode 34 on the spacer 35. Thereby, the coupling of the variable capacitance diode is reduced, and the Q of the resonator is reduced.
Can be raised. Further, FIG.
(B) is a modification of the electrode 34, and has another electrode 36 having a tapered shape. Electrode 36
Is moved in a direction in which the width in the vicinity of the cap changes (the direction of the arrow shown in the figure), so that the resonance frequency can be finely adjusted. Note that the internal spacer 26 and the internal electrode 27 can be added or omitted as appropriate.

Next, the detection operation by the mixer 4 will be described. FIG. 4 shows an example of a circuit diagram of the mixer. In this embodiment, as an example, the mixer 4 having good detection efficiency is provided with a DBM.
Is used. The input (a) is a reflected wave from the sample, and the input (b) is a reference modulated wave. Further, a value proportional to the product of the inputs (a) and (b) is output as a detection output to the output (c).

Next, for the sake of simplicity, the explanation will be made on the assumption that amplitude modulation of a sine wave is applied to amplitude modulation of a reflected wave. FIG. 5 is a schematic waveform diagram illustrating the detection operation of the mixer. The microwave (main modulation wave) traveling from the oscillator to the resonator is a frequency modulation wave, which is represented by the following equation, and has a waveform as shown in FIG.

[0026]

(Equation 1) In addition, microwaves (reflected waves) reflected by a resonator containing or near a sample in which electron spin resonance occurs.
Is represented by the following equation, and has a waveform as shown in FIG.

[0027]

(Equation 2) Next, the waveform after detection of the DBM, that is, the output (c) becomes a signal proportional to the product of the inputs (a) and (b), and is expressed by the following equation, and as shown in FIG. Waveform.

[0028]

(Equation 3) As described above, the spectrum after DBM detection is obtained.

FIG. 6 shows an example of a spectrum diagram of the DBM output. This figure shows a carrier 700 MHz of the oscillator 1,
The result is a modulation frequency of 100 kHz and a frequency shift of 1 MHz. The modulation degree of the amplitude modulation is 0.2 in FIG. 6A and 0.3 in FIG. 6B. ES
When microwave energy is absorbed by R (hereinafter referred to as absorption), amplitude modulation is applied to the frequency-modulated wave of the reflected wave. At this time, as shown in the figure, it can be seen that when the degree of modulation increases, the frequency component at the modulation frequency of 100 kHz increases in proportion to the degree of modulation.

Based on the narrow band frequency selection characteristic of the lock-in amplifier based on the detection output, 100 k
The spectrum other than Hz is removed, and this 100 kHz
By extracting only the component, a DC output proportional to this amplitude is obtained.

Here, a spectrum obtained when DBM detection is performed will be described. FIG. 7 is an explanatory diagram of an ESR signal measured by frequency modulation. It is assumed that a frequency-modulated microwave is applied to a sample in a resonator, causing an electron spin resonance phenomenon. FIG. 7 (A)
As shown in the figure, the frequency of the main modulation wave applied to the sample is frequency-modulated, so that the amount of absorption by the electron spin resonance of the sample is modulated. It varies along a curve. That is, the input impedance of the resonator containing (or placed near) the sample is modulated, and the FM-ESR
In the electron spin resonance state of the method, a reflected wave in which the frequency modulation wave is amplitude-modulated from the resonator is generated. Therefore, an absorption-type ESR signal as shown in FIG. 7B is converted into a first-order differential ESR signal as shown in FIG. 7C by frequency modulation. That is, the electron spin resonance magnetic field H can be obtained with high sensitivity by measuring the position of the zero crossing using the first derivative type ESR signal.

Further, when measuring an ESR signal as described above, a similar ESR signal absorption curve can be obtained by using a frequency sweep instead of a magnetic field sweep. That is, hf = gβH (where h: Planck's constant, f: frequency, g: constant,
This is because the magnetic field H is proportional to the frequency f from the relationship of β: constant, H: DC magnetic field. According to the frequency sweep, the sweep time can be shortened, and a large amount of signals can be measured. Therefore, the S / N ratio can be improved, and the sensitivity can be further increased. The present invention can be similarly applied to a magnetic resonance measurement apparatus using frequency sweep instead of magnetic field sweep.

Next, FIG. 8 is an explanatory diagram showing measured values of the ESR signal. In this figure, as an example, the sample is DPP
The change in the ESR signal with respect to the DC magnetic field when H (diphenylpicrylhydrazyl) powder is 20 mg is shown.

FIG. 9 shows a conventional magnetic field modulation CW-ES.
FIG. 3 shows a comparative explanatory diagram of the R method and the FM-ESR method of the present invention.
FIG. 9A shows a conventional magnetic field modulation CW-ESR method.
(B) shows an ESR signal by the FM-ESR method according to the present invention, respectively. These were the same as the center frequency of 700 MHz and the modulation frequency of 100 kHz, and the same resonator with a variable capacitance diode was used to make the conditions the same. The modulation magnetic field of CW-ESR is FM-
0.0714mTpp equivalent to 1MHz ESR frequency transfer
(Millitesla peak-to-peak). At this time, the S / N was about 10.5 in the measurement by CW-ESR.
On the other hand, it was about 12.4 in FM-ESR, and the result that the sensitivity of the present invention was slightly higher was obtained.

The following can be considered to further increase the sensitivity of the ESR device. For example, in order to obtain a large ESR signal, it is preferable to increase the frequency shift of the oscillator so that the waveform of the ESR signal is not distorted. At this time, it is preferable that unnecessary reflection at the resonator is suppressed, and the matching of the resonator with respect to the frequency modulation wave is firm.

[0036]

As described above, according to the present invention, it is possible to provide a highly sensitive magnetic resonance measuring apparatus and a measuring method which suppress noise due to vibration, and a resonator which can be used mainly for magnetic resonance measurement. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an ESR device according to the present invention.

FIG. 2 is a configuration diagram and an equivalent circuit diagram according to a first embodiment of the resonator according to the present invention.

FIG. 3 is a configuration diagram according to second and third embodiments of the resonator according to the present invention.

FIG. 4 is a circuit diagram of a mixer.

FIG. 5 is a schematic waveform diagram illustrating a detection operation of the mixer.

FIG. 6 is a spectrum diagram of a DBM output.

FIG. 7 is an explanatory diagram of an ESR signal measured by frequency modulation.

FIG. 8 is an explanatory diagram showing a measured value of an ESR signal.

FIG. 9 shows a conventional magnetic field modulation CW-ESR method and the FM of the present invention.
-Comparison explanatory drawing with ESR method.

FIG. 10 is a configuration diagram of a conventional CW-ESR apparatus.

FIG. 11 is a configuration diagram showing a resonator and a modulation magnetic field coil used in a conventional L-band CW-ESR device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oscillator 2 Resonator 3 Modulation signal controller 4 Mixer 5 DC magnetic field coil 6 Phase shifter 7 Power amplifier 8 Circulator 9 Signal amplifier 10 Modulation oscillator 11 Lock-in amplifier 12 Distributor 13 Coupling degree possible one-turn coil 14 Measurement processing unit

Claims (13)

[Claims] An oscillator for oscillating a modulated wave frequency-modulated by a modulation signal, and a sample in or near the oscillator, wherein a modulation signal is applied so as to change a resonance frequency following a modulation wave from the oscillator. Comprising a resonator that varies the resonance frequency, applying a modulated wave from the oscillator to a sample in the resonator,
A magnetic resonance measuring apparatus wherein a detection output is obtained based on a modulated wave from the oscillator and a reflected wave from the resonator by sweeping a magnetic field or a modulated wave frequency applied to a sample. 2. An oscillator for oscillating a modulated wave frequency-modulated by a modulation signal, a resonator having a sample in or near the interior thereof, the resonance frequency being variable by the modulation signal, and following a modulation wave from the oscillator. A modulation signal controller that supplies a modulation signal to the oscillator and the resonator so as to change the resonance frequency of the resonator; a DC magnetic field coil that applies a DC magnetic field to the sample; and an output from the oscillator. A splitter that splits the modulated wave into a main modulation wave and a reference modulation wave, a main modulation wave supply unit that supplies the main modulation wave split by the splitter to the resonator, and a reflection reflected from the resonator. A reflected wave detection unit that detects a wave; and a mixer that performs detection based on the reflected wave detected by the reflected wave detection unit and the reference modulation wave. Given the harmonics,
A magnetic resonance measuring apparatus wherein a detection output is obtained based on a modulated wave from the oscillator and a reflected wave from the resonator by sweeping a magnetic field or a modulated wave frequency applied to a sample. 3. The lock-in amplifier according to claim 1, further comprising a lock-in amplifier that receives the modulation signal and extracts a modulation frequency component based on a detection output to output an electron spin resonance signal or a nuclear magnetic resonance signal. The magnetic resonance measurement apparatus according to claim 1. 4. A measurement processing unit for measuring electron spin resonance or nuclear magnetic resonance based on an electron spin resonance signal output from the lock-in amplifier by sweeping a DC magnetic field applied to a sample. The magnetic resonance measurement apparatus according to claim 1. 5. The magnetic resonance measuring apparatus according to claim 1, further comprising an amplifier for amplifying a modulation signal input to said resonator. 6. The magnetic resonance apparatus according to claim 1, wherein the modulated wave from the oscillator uses any one of frequencies from a radio wave to a quasi-optic and an optical region. measuring device. 7. A loop gap resonance element having a loop portion and a gap portion for containing a sample, a spacer provided near a gap portion of the loop gap resonance element, and A plurality of electrodes provided on the opposite side of the loop-gap resonance element on both sides of the gap, a variable capacitance diode connected between the plurality of electrodes, and a choke coil provided on one or each of the electrodes. A resonator that varies a resonance frequency by applying a voltage to the electrode via the choke coil. 8. The resonator according to claim 7, wherein one of said spacers is provided in common for a plurality of said electrodes, or provided for each of said electrodes. 9. The resonator according to claim 8, further comprising another electrode provided near the gap on the opposite side of the loop gap resonance element with the spacer interposed therebetween. 10. A magnetic resonance measurement apparatus according to claim 1, wherein the resonator according to any one of claims 7 to 9 is used. 11. A sample is arranged inside or near a resonator, a resonance frequency of the resonator is made variable by following a modulation signal, a modulation wave frequency-modulated by the modulation signal is oscillated, and the modulation wave is applied to the sample. A magnetic resonance measuring method for sweeping a magnetic field or a modulated wave frequency applied to a sample, and measuring electron spin resonance or nuclear magnetic resonance based on the modulated wave and a reflected wave from the resonator. 12. A modulated wave frequency-modulated by a modulated signal is oscillated, the modulated wave is branched into a main modulated wave and a reference modulated wave, and the resonance frequency is made variable by following the oscillated modulated wave or the main modulated wave. The sample is placed inside or near the resonator, and the magnetic field or modulated wave frequency applied to the sample is swept, the branched main modulated wave is guided to the sample, and the reflected wave reflected from the resonator and the reference wave A magnetic resonance measurement method comprising: obtaining a detection output based on the detection output; and measuring electron spin resonance or nuclear magnetic resonance based on the detection output. 13. An electronic spin resonance signal or nuclear magnetic resonance is output by receiving a modulation signal and extracting a modulation frequency component based on a detection output.
4. The magnetic resonance measurement method according to 1.