Nuclear magnetic resonance sensing device and nuclear magnetic resonance sensing method

Abstract

To perform nuclear magnetic resonance sensing for accurately detecting a low-level NMR signal and having high resolution.SOLUTION: A nuclear magnetic resonance sensing unit 1 applies a high frequency magnetic field based on an RF signal to an object and generates an observation signal of a frequency obtained by shifting from RF signal frequency by NMR signal frequency. A mixer unit 6 generates an IF demodulation signal including the NMR signal. A lowpass filter 7 transmits low-frequency band components of the IF demodulation signal. A digitizing device 21 causes: a physical field generator to generate magnetic field and the like corresponding to the IF demodulation signal transmitting through the lowpass filter 7; an optical quantum sensor unit to generate light corresponding to the magnetic field and the like using a sensing member; a photoelectric element to convert the light into a sensor signal; and an analog / digital converter to digitize the sensor signal. The optical quantum sensor unit performs quantum operation to the above-mentioned sensing member to cause the sensing member to generate light corresponding to the above-mentioned magnetic field and the like.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a nuclear magnetic resonance sensing device and a nuclear magnetic resonance sensing method. [Background technology]

[0002] Fig. 10 is a block diagram showing an example of a measurement device using nuclear magnetic resonance. For example, as shown in Fig. 10, a measurement device using nuclear magnetic resonance generally (a) applies a high-frequency magnetic field based on an RF (Radio Frequency) signal having a frequency close to the frequency of precession to a measurement object 301 using a high-frequency coil 311 to resonate nuclear magnetization, (b) detects the resonated nuclear magnetization using a receiver coil 312 to generate an observation signal including a nuclear magnetic resonance (NMR) signal, (c) amplifies the observation signal using preamplifiers 313 and 314 such as low-noise amplifiers (LNA), and (d) detects the amplified observation signal using a detector to extract the NMR signal.

[0003] Generally, such observation signals and NMR signals are converted from analog signals to digital signals by an analog / digital converter 315, and are supplied as digital signals to a downstream processing device (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-039641 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-101776 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned devices require amplifier circuits such as preamplifiers to amplify the observed signals, which causes noise inherent in the amplifier circuits to be superimposed on the observed and NMR signals. As a result, NMR signals at levels equal to or lower than the noise floor of the amplifier circuits are buried in the noise, making it difficult to accurately detect such low-level NMR signals.

[0006] The present invention has been made in view of the above problems, and has as its object to provide a nuclear magnetic resonance sensing device and a nuclear magnetic resonance sensing method that can detect low-level NMR signals with high accuracy and have high resolution. [Means for solving the problem]

[0007] The nuclear magnetic resonance sensing device of the present invention comprises a nuclear magnetic resonance sensing unit that applies an RF signal to a target object and generates an observation signal having a frequency shifted from the frequency of the RF signal by the frequency of the nuclear magnetic resonance signal; a mixer unit that performs intermediate frequency demodulation of the observation signal to generate an intermediate frequency demodulated signal including the nuclear magnetic resonance signal; a low-pass filter that attenuates the high-frequency band component of the two band components obtained by intermediate frequency demodulation in the intermediate frequency demodulated signal and transmits the low-frequency band component of the two band components; and a digitizing device that digitizes the intermediate frequency demodulated signal that has passed through the low-pass filter. The digitizing device comprises a physical field generating device that generates a magnetic field or electric field corresponding to the intermediate frequency demodulated signal that has passed through a low-pass filter, an optical quantum sensor unit that generates light corresponding to the magnetic field or electric field using a sensing element and converts the light into an electrical signal as a sensor signal using a photoelectric element, and an analog / digital converter that digitizes the sensor signal, and the optical quantum sensor unit performs quantum operations on the above-mentioned sensing element to cause the sensing element to generate light corresponding to the above-mentioned magnetic field or electric field.

[0008] The nuclear magnetic resonance sensing device of the present invention comprises a nuclear magnetic resonance sensing unit that applies a high-frequency magnetic field based on an RF signal to a target object and generates an observation signal having a frequency shifted from the frequency of the RF signal by the frequency of the nuclear magnetic resonance signal; a mixer unit that performs intermediate frequency demodulation of the observation signal to generate an intermediate frequency demodulated signal including the nuclear magnetic resonance signal; a low-pass filter that attenuates frequency components of the intermediate frequency demodulated signal that are higher than the intermediate frequency of the intermediate frequency demodulation and passes the frequency components of the nuclear magnetic resonance signal; an analog quadrature phase detection circuit that performs quadrature phase detection on the intermediate frequency demodulated signal that has passed through the low-pass filter to generate a demodulated signal and a demodulated signal of the nuclear magnetic resonance signal; and a digitizing device that digitizes the demodulated signal and the demodulated signal. The digitizing device includes a first physical field generating device that generates a magnetic field or electric field corresponding to the demodulated signal, a second physical field generating device that generates a magnetic field or electric field corresponding to the demodulated signal, a first optical quantum sensor unit that generates light corresponding to the magnetic field or electric field generated by the first physical field generating device using a first sensing element and converts the light generated by the first sensing element into an electrical signal as a first sensor signal using a first photoelectric element, a second optical quantum sensor unit that generates light corresponding to the magnetic field or electric field generated by the second physical field generating device using a second sensing element and converts the light generated by the second sensing element into an electrical signal as a second sensor signal using a second photoelectric element, a first analog / digital converter that digitizes the first sensor signal, and a second analog / digital converter that digitizes the second sensor signal. The first optical quantum sensor unit and the second optical quantum sensor unit perform quantum operations on the first and second sensing elements, respectively, to generate light in the first and second sensing elements corresponding to the magnetic or electric fields described above.

[0009] A nuclear magnetic resonance sensing method according to the present invention includes the steps of applying an RF signal to a target object and generating an observation signal having a frequency shifted from the RF signal by the frequency of the nuclear magnetic resonance signal, performing intermediate frequency demodulation of the observation signal to generate an intermediate frequency demodulated signal containing the nuclear magnetic resonance signal, attenuating a high-frequency band component of two band components obtained by the intermediate frequency demodulation in the intermediate frequency demodulated signal using a low-pass filter and transmitting a low-frequency band component of the two band components, and digitizing the intermediate frequency demodulated signal that has passed through the low-pass filter using a digitizing device. The digitizing step includes (a) generating a magnetic field or electric field corresponding to the intermediate frequency demodulated signal that has passed through the low-pass filter, (b) generating light corresponding to the magnetic field or electric field using a sensing member, (c) converting the light into an electrical signal as a sensor signal using a photoelectric element, and (d) digitizing the sensor signal using an analog-to-digital converter. The digitizing step involves performing quantum operations on the sensing element to cause the sensing element to generate light corresponding to the magnetic or electric field.

[0010] The nuclear magnetic resonance sensing method according to the present invention comprises the steps of applying a high-frequency magnetic field based on an RF signal to a target object and generating an observation signal having a frequency shifted from the frequency of the RF signal by the frequency of the nuclear magnetic resonance signal; performing intermediate frequency demodulation of the observation signal to generate an intermediate frequency demodulated signal including the nuclear magnetic resonance signal; attenuating, using a low-pass filter, frequency components of the intermediate frequency demodulated signal that are higher than the intermediate frequency of the intermediate frequency demodulation and transmitting the frequency components of the nuclear magnetic resonance signal; performing quadrature phase detection on the intermediate frequency demodulated signal that has passed through the low-pass filter in an analog circuit to generate a demodulated signal and a demodulated signal of the nuclear magnetic resonance signal; and digitizing the demodulated signal and the demodulated signal. Then, in the digitizing step, (a1) a magnetic field or electric field corresponding to the demodulated signal is generated, (a2) a magnetic field or electric field corresponding to the demodulated signal is generated, (b1) light corresponding to the magnetic field or electric field corresponding to the demodulated signal is generated in a first sensing member, and the light generated by the first sensing member is converted by a photoelectric element into an electric signal as a first sensor signal, (b2) light corresponding to the magnetic field or electric field corresponding to the demodulated signal is generated in a second sensing member, and the light generated by the second sensing member is converted by a photoelectric element into an electric signal as a second sensor signal, (c1) digitizing the first sensor signal, and (c2) digitizing the second sensor signal. In the digitizing step, quantum operations are performed on the first and second sensing members, respectively, causing the first and second sensing members to generate light corresponding to the magnetic fields or electric fields corresponding to the demodulated signal and the demodulated signal, respectively. [Effects of the Invention]

[0011] According to the present invention, a nuclear magnetic resonance sensing device and a nuclear magnetic resonance sensing method are provided that can detect low-level NMR signals with high accuracy and have high resolution. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram showing the configuration of a nuclear magnetic resonance sensing device according to the first embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing the configuration of the digitizing device 21 in FIG. [Figure 3] FIG. 3 is a diagram showing the configuration of the sensor main body 51 in the digitizing device according to the first embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of a sensor signal in the digitizing device according to the first embodiment. [Figure 5] FIG. 5 is a diagram showing the configuration of a sensor main body 51 in a digitizing device according to the second embodiment. [Figure 6] FIG. 6 is a block diagram showing the configuration of a nuclear magnetic resonance sensing device according to the fourth embodiment of the present invention. [Figure 7] FIG. 7 is a block diagram showing the configuration of a digitizing device 221 in a nuclear magnetic resonance sensing apparatus according to the fourth embodiment. [Figure 8] FIG. 8 is a block diagram showing the configuration of the digitizing device 221 in the nuclear magnetic resonance sensing apparatus according to the fifth embodiment. [Figure 9] FIG. 9 is a diagram showing the configuration of the sensor main bodies 251 and 271 of the digitizing device 202 according to the fifth embodiment. [Figure 10] FIG. 10 is a block diagram showing an example of a measurement device that utilizes nuclear magnetic resonance. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] Embodiment 1

[0015] 1 is a block diagram showing the configuration of a nuclear magnetic resonance sensing device according to a first embodiment of the present invention. This nuclear magnetic resonance sensing device is used for molecular structure analysis, imaging, etc. of a target object.

[0016] The nuclear magnetic resonance sensing device shown in FIG. 1 includes a nuclear magnetic resonance sensing unit 1, a base signal generating device 2, a mixer unit 3, a switching unit 4, a matching and tuning circuit 5, a mixer unit 6, and a low-pass filter 7.

[0017] The nuclear magnetic resonance sensing unit 1 applies an RF signal, which will be described later, to the target object, and the RF signal has a frequency f RF to the frequency f of the nuclear magnetic resonance (NMR) signal NMR The frequency shifted by (f RF +f NMR ) observation signal (analog electrical signal).

[0018] Specifically, the nuclear magnetic resonance sensing unit 1 includes a coil 11 and a magnet unit 12. The coil 11 applies a high-frequency magnetic field based on an RF signal to the target object 101, senses magnetic field changes based on the movement of nuclear magnetization in the target object 101, and outputs an observation signal. The magnet unit 12 is a permanent magnet or an electromagnet, and applies a static magnetic field or a gradient magnetic field to the target object 101. This observation signal includes an NMR signal and has a frequency f NMR and RF signal frequency f RF The sum of the frequency (f RF +f NMR )

[0019] The base signal generator 2 generates a single intermediate frequency f IF an intermediate frequency (IF) base signal having a frequency f RF and intermediate frequency f IF and generates and outputs an RF-based signal having a single frequency that is the sum of

[0020] The mixer unit 3 mixes the RF base signal and the IF base signal to generate a signal at a frequency f RF The mixer unit 3 performs SSB (Single Side Band) modulation, and generates an RF signal having two frequency components (f RF +2f IF ),f RF Among them, the frequency (f RF +2f IF) component, and frequency f RF Only the RF signal is output.

[0021] For example, the mixer unit 3 is a DBM (Double Balanced Mixer) made up of a diode and a phase distributor.

[0022] The switching unit 4 switches the connection destination of the nuclear magnetic resonance sensing unit 1 side (nuclear magnetic resonance sensing unit via the matching and tuning circuit 5) from one of the RF signal transmission system (base signal generator 2 and mixer unit 3) and the observation signal reception system (base signal generator 2, mixer unit 6, and low-pass filter 7) to the other. Specifically, the switching unit 4 electrically connects the transmission system to the nuclear magnetic resonance sensing unit 1 side when transmitting an RF signal, and electrically connects the reception system to the nuclear magnetic resonance sensing unit 1 side when receiving an observation signal.

[0023] The matching and tuning circuit 5 is a circuit that performs impedance matching to suppress reflection of the RF signal at the nuclear magnetic resonance sensing unit 1, and also performs frequency tuning to improve the level of the NMR signal.

[0024] The mixer unit 6 mixes the observation signal and the RF base signal, performs intermediate frequency (IF) demodulation, and separates two frequency components (2f RF +f IF +f NMR ),(f IF -f NMR ) and outputs an intermediate frequency (IF) demodulated signal having a frequency of 1 / 2 kHz.

[0025] For example, the mixer unit 6 is a DBM made up of a diode and a phase distributor, and does not include active elements such as transistors.

[0026] The low-pass filter 7 separates the two band components (2f RF +f IF +f NMR ),(f IF -f NMR) of the high frequency band components (2f RF +f IF +f NMR ) and attenuates the low-frequency band component (f IF -f NMR ) The low-pass filter 7 is an analog filter that is made up of only passive elements such as capacitors, inductors, and resistors.

[0027] Furthermore, the nuclear magnetic resonance sensing device shown in FIG.

[0028] The digitizing device 21 converts the IF demodulated signal (frequency component (f IF -f NMR )) from an analog signal to a digital signal.

[0029] The control device 22 includes a computer that operates according to a control program, and the computer includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and performs the operation described below by loading the control program into the RAM and executing it on the CPU. Specifically, the control device 22 controls the nuclear magnetic resonance sensing unit 1 and the switching unit 4 to apply the above-mentioned high-frequency magnetic field to the nuclear magnetic resonance sensing unit 1 and output the above-mentioned observation signal. Furthermore, the control device 22 converts the IF demodulated signal (frequency component (f IF -f NMR )) is input from the digitizer 21 and subjected to predetermined signal processing (frequency component f NMR ) and extract the IF demodulated signal (frequency component (f IF -f NMR )) to the frequency f NMR The components (i.e., NMR signals) are extracted.

[0030] For example, f IF is f NMR The frequency is 1000 times higher than f RFis f IF For example, f NMR = 1 kHz, f RF = 43MHz, f IF =1MHz.

[0031] Fig. 2 is a block diagram showing the configuration of the digitizing device 21 in Fig. 1. The digitizing device shown in Fig. 1 includes a physical field generating device 41, an optical quantum sensor unit 42, and an analog / digital converter (A / D converter, ADC) 43.

[0032] The physical field generator 41 generates a magnetic field corresponding to an input signal (i.e., an analog IF demodulated signal) input via an input terminal 41a of the physical field generator 41. For example, the physical field generator 41 generates the magnetic field using a conductive coil or wiring.

[0033] The optical quantum sensor unit 42 comprises a sensor body 51 and a photoelectric element 52. In the sensor body 51, a sensing member generates light (observation light) corresponding to the magnetic field generated by the physical field generating device 41, and the photoelectric element 52 converts the light into an electrical signal as a sensor signal. The photoelectric element 52 is a photodiode, phototransistor, or the like, and generates a sensor signal corresponding to the intensity of the incident observation light.

[0034] Specifically, the optical quantum sensor unit 42 (specifically, the sensor body 51) performs quantum operations (here, quantum operations using microwaves and laser light) on the sensing element, causing the sensing element to generate light corresponding to the magnetic field generated by the physical field generating device 41.

[0035] In the first embodiment, the optical quantum sensor unit 42 (specifically, the sensor body 51) performs quantum operations on the sensing element in accordance with optically detected magnetic resonance (ODMR) to cause the sensing element to generate the above-mentioned observation light.

[0036] Fig. 3 is a diagram showing the configuration of a sensor main body 51 in a digitizing device according to embodiment 1. In embodiment 1, for ODMR, as shown in Fig. 3, for example, the sensor main body 51 includes a magnetic resonance member 61 as a sensing member, a high-frequency magnetic field generator 62, a magnet 63, a high-frequency power supply 64, a light-emitting device 65, and a controller 66.

[0037] The magnetic resonance member 61 has a crystalline structure, and the electron spin quantum state changes in response to the magnetic field generated by the physical field generator 41. The magnetic resonance member 61 is a member that can perform electron spin quantum manipulation (based on Rabi oscillation) using microwaves with a frequency corresponding to the alignment direction of defects and impurities in the crystal lattice. In other words, the magnetic resonance member 61 is placed in the above-mentioned magnetic field.

[0038] In this embodiment, the magnetic resonance element 61 is a photodetecting magnetic resonance element having a plurality (i.e., an ensemble) of specific color centers, each of which has an energy level that can be Zeeman split and can assume a plurality of orientations with different energy level shift widths upon Zeeman splitting.

[0039] Here, the magnetic resonance member 61 is a member such as diamond that includes a plurality of NV (Nitrogen Vacancy) centers as a single type of specific color center. In the case of the NV center, the ground state is a triplet state of ms = 0, +1, -1, and the ms = +1 level and the ms = -1 level are Zeeman split. When the NV centers transition from the excited state of the ms = +1 and ms = -1 levels to the ground state, a certain proportion of them emit fluorescence, and the remaining proportion of the NV centers transition from the excited state (ms = +1 or ms = -1) to the ground state (ms = 0) without radiation.

[0040] The color center included in the magnetic resonance member 61 may be a color center other than the NV center.

[0041] The radio-frequency magnetic field generator 62 applies microwaves to the magnetic resonance member 61 to perform electron spin quantum manipulation of the magnetic resonance member 61. For example, the radio-frequency magnetic field generator 62 is a plate-shaped coil and includes a substantially circular coil portion that emits microwaves and terminal portions that extend from both ends of the coil portion and are fixed to a substrate. The radio-frequency power supply 64 generates a microwave current and conducts it to the radio-frequency magnetic field generator 62. The coil portion conducts two parallel currents at both end surfaces at a predetermined interval so as to sandwich the magnetic resonance member 61, thereby emitting the microwaves described above. In this example, although the coil portion is a plate-shaped coil, due to the skin effect, the microwave current flows through the end surfaces of the coil portion, forming two currents. As a result, microwaves of substantially uniform intensity are applied to the magnetic resonance member 61.

[0042] In the case of NV centers, color centers are formed in diamond crystals by defects (vacancies) (V) and nitrogen (N) as impurities. There are four possible positions of adjacent nitrogen (N) relative to the defects (vacancies) (V) in the diamond crystal (i.e., the arrangement direction of the vacancy-nitrogen pair), and the sublevels (i.e., the energy levels from the ground state) after Zeeman splitting corresponding to each of these arrangement directions are different. Therefore, in the characteristics of the fluorescence intensity after Zeeman splitting by a static magnetic field with respect to the microwave frequency, four different dip frequency pairs (fi+, fi-) appear corresponding to each direction i (i = 1, 2, 3, 4). Here, the frequency (wavelength) of the microwave mentioned above is set to correspond to one of these four dip frequency pairs.

[0043] The magnet 63 applies a static magnetic field (DC magnetic field) to the magnetic resonance member 61, and Zeeman-splits the energy levels of a plurality of specific color centers (here, a plurality of NV centers) in the magnetic resonance member 61. Here, the magnet 63 is a ring-shaped permanent magnet, such as a ferrite magnet, an alnico magnet, or a samarium-cobalt magnet. The magnet 63 may also be an electromagnet.

[0044] Furthermore, in the magnetic resonance member 61, the crystals of the magnetic resonance member 61 are formed and the orientation of the magnetic resonance member 61 is set so that the arrangement direction of the above-mentioned defects and impurities approximately coincides with the direction of the above-mentioned static magnetic field (and the direction of the applied magnetic field).

[0045] Furthermore, in this embodiment, an optical system (not shown) is provided from the light emitting device 65 to the magnetic resonance member 61 in order to irradiate the magnetic resonance member 41 with excitation light, and an optical system (not shown) is provided from the magnetic resonance member 61 to the photoelectric element 52 in order to detect fluorescence (observation light) from the magnetic resonance member 61.

[0046] The observation light is collected by an optical system such as a compound parabolic concentrator (CPC) toward the photoelectric element 52. For example, a magnetic resonance component 61 is placed on the CPC, and of the fluorescence emitted in all directions from the color center in the magnetic resonance component 61, the optical system collects the fluorescence that is emitted in a wide solid angle (for example, a predetermined percentage or more in all directions).

[0047] The light emitting device 65 includes a laser diode or the like as a light source, and emits laser light of a predetermined wavelength as excitation light to be irradiated onto the magnetic resonance member 61 from the light source.

[0048] The controller 66 (a) controls the high-frequency power supply 64 and the light-emitting device 65 in accordance with a predetermined measurement sequence to perform quantum operations with the microwaves and laser light described above, causing the sensor main body 51 to generate observation light and the photoelectric element 52 to generate a sensor signal. For example, the controller 66 includes a computer that operates according to a control program, and the computer includes a CPU, ROM, RAM (Random Access Memory), etc., and performs the above-mentioned operations by loading the control program into the RAM and executing it on the CPU. Note that the controller 66 may be built into the control device 22, or the control device 22 may operate as the controller 66.

[0049] 4 is a diagram illustrating an example of a sensor signal in the digitizing device according to the first embodiment. This measurement sequence is set according to the frequency of the above-mentioned magnetic field, etc. For example, if the input signal (IF demodulated signal) is an AC signal with a relatively low frequency (for example, several tens of Hz), as shown in FIG. 4, the above-mentioned magnetic field corresponding to the input signal is measured multiple times (n times) in one period using a Ramsey pulse sequence (i.e., DC magnetic field measurement sequences SQ1 to SQn), and measurement values ​​BM1 to BMn are obtained as sensor signals. This generates sensor signals at levels corresponding to the magnetic field strength at each measurement sequence point.

[0050] Furthermore, for example, when the above-mentioned magnetic field is an AC magnetic field with a relatively high frequency (for example, several tens of kHz), a spin echo pulse sequence (such as a Hahn echo sequence) may be applied as the measurement sequence. However, the measurement sequence is not limited to these, and may be selected according to the frequency of the magnetic field to be measured. For example, when the period of the above-mentioned magnetic field is equal to or longer than the T2 relaxation time, magnetic field measurement is performed using a Ramsey pulse sequence multiple times as described above, and when the period of the above-mentioned magnetic field is shorter than the T2 relaxation time, a spin echo pulse sequence (such as a Hahn echo sequence) may be applied. Furthermore, when the period of the above-mentioned magnetic field is shorter than half the T2 relaxation time, magnetic field measurement may be performed according to the Qdyne method.

[0051] Returning to Figure 2, the A / D converter 43 digitizes the above-mentioned sensor signal (without digitizing the input signal), thereby generating a digital signal as an output signal corresponding to the input signal (IF demodulated signal), and outputs it via the output terminal 43a of the A / D converter 43.

[0052] In this embodiment, in particular, the optical quantum sensor unit 42 (specifically, the sensor body 51) generates the above-mentioned observation light in the sensing member so that the level of the sensor signal exceeds the noise floor of the A / D converter 43.

[0053] Here, the level (amplitude) of the sensor signal varies depending on factors such as the efficiency of the sensing element (in the first embodiment, the type and number of color centers in the magnetic resonance element 61), the light-gathering efficiency of the observation light (in the first embodiment, the amount of light incident on the photoelectric element 52 relative to the amount of light emitted by the color center), and the conversion efficiency of the photoelectric element 52 (the level of the sensor signal relative to the amount of incident light). Therefore, the values ​​of these factors are determined depending on the noise floor (known) of the A / D converter 43 so that the level of the sensor signal exceeds the noise floor of the A / D converter 43. As a result, for example, the sensitivity of the optical quantum sensor unit 42 can be set to 1.5 pT / Hz. 1 / 2 That is all.

[0054] Generally, noise from an A / D converter includes quantization noise and thermal noise, and in a high-resolution A / D converter, thermal noise is dominant compared to quantization noise. The A / D converter 43 in this embodiment is a high-resolution A / D converter, and the values ​​of the above factors are determined so that the level of the sensor signal exceeds the noise level of thermal noise.

[0055] The reference voltage of the A / D converter 43 is set according to the range (minimum and maximum levels) of the sensor signal. Note that lowering the reference voltage of the A / D converter reduces quantization noise, but does not reduce thermal noise.

[0056] The level (or range) of the input IF demodulated signal and the electromagnetic conversion efficiency of the physical field generator 41 are known.

[0057] In particular, in this embodiment, the digitizing device 21 does not include an amplifier circuit between the photoelectric element 52 and the A / D converter 43 that electrically amplifies the sensor signal. Furthermore, in this embodiment, no amplifier circuit that electrically amplifies the input signal is provided between the signal source of the input signal and the physical field generating device 41. In other words, in this embodiment, no electrical amplifier circuit that could be a noise source is provided upstream of the A / D converter 43. In such an amplifier circuit, thermal noise is generated and amplified, just like in the A / D converter 43, and the noise is superimposed on the signal input to the A / D converter 43. Therefore, it is preferable not to provide such an amplifier circuit.

[0058] The high frequency power supply 64 and the controller 66 are electrically separated from the A / D converter 43 so that electrical noise generated in the high frequency power supply 64 and the controller 66 does not enter the A / D converter 43 .

[0059] Furthermore, in this embodiment 1, the mixer unit 6 performs intermediate frequency demodulation of the observation signal with the RF base signal to generate an IF demodulated signal including the NMR signal, and the optical quantum sensor unit 42 (controller 66) uses the IF base signal as a synchronization signal and periodically and repeatedly performs quantum operations on the sensing element in accordance with the synchronization signal to cause the sensing element to generate light corresponding to the magnetic field, thereby causing the digitizing device 21 to output a digital IF demodulated signal in synchronization with the IF base signal. Then, the control device 22 accurately identifies the frequency fNMR of the NMR signal based on this digital IF demodulated signal in accordance with the Qdyne algorithm.

[0060] In this first embodiment, neither an amplifier circuit nor a buffer is provided between the nuclear magnetic resonance sensing unit 1 and the digitizing device 21. In other words, only passive elements are used in the circuit from the nuclear magnetic resonance sensing unit 1 to the digitizing device 21, thereby suppressing the generation of thermal noise.

[0061] Next, the operation of the nuclear magnetic resonance sensing device according to the first embodiment will be described.

[0062] The control device 22 controls the nuclear magnetic resonance sensing unit 1 and also controls the switching unit 4 to apply a high-frequency magnetic field based on an RF signal from the transmission system to the target object 101 in the nuclear magnetic resonance sensing unit 1, and controls the switching unit 4 to conduct the observation signal from the nuclear magnetic resonance sensing unit 1 to the receiving system.

[0063] As shown in FIG. 1, the observation signal is converted into an IF demodulated signal by a mixer unit 6, and the IF demodulated signal from which high frequency band components have been removed by a low-pass filter 7 is input to a digitizing device 21.

[0064] In the digitizing device 21, when the IF demodulated signal is applied to the physical field generator 41, a magnetic field of a strength corresponding to the level of the input signal is generated in the physical field generator 41 and applied to the sensor body 51 of the optical quantum sensor unit 42.

[0065] In the sensor main body 51, the measurement sequence is executed as described above, and the amount of light generated corresponds to the strength of the magnetic field. In the first embodiment, the magnetic resonance member 61 generates the amount of light corresponding to the strength of the magnetic field according to ODMR.

[0066] Then, the photoelectric element 52 receives the light, generates a sensor signal at a level corresponding to the amount of received light, and outputs the signal to the A / D converter 43 .

[0067] The A / D converter 43 digitizes the sensor signal to generate a digital IF demodulated signal corresponding to the analog IF demodulated signal, and outputs the digital IF demodulated signal to the control device 22 .

[0068] The control device 22 continuously and repeatedly acquires the value of the digital IF demodulated signal, and as described above, processes the signal to generate an NMR signal (specifically, f NMR Based on the NMR signal, molecular structure analysis, imaging, etc. of the target object 101 are performed.

[0069] As described above, according to the first embodiment, the nuclear magnetic resonance sensing unit 1 applies an RF signal to the object of interest 101 and generates an observation signal having a frequency equal to the sum of the frequency of the RF signal and the frequency of the nuclear magnetic resonance signal. The mixer unit 6 performs IF demodulation on the observation signal to generate an IF demodulated signal containing the nuclear magnetic resonance signal. The low-pass filter 7 attenuates the high-frequency component of the two band components obtained by IF demodulation in the IF demodulated signal and transmits the low-frequency component of the two band components. The digitizing unit 21 digitizes the IF demodulated signal that has passed through the low-pass filter 7. In the digitizing unit 21, the physical field generator 41 generates a magnetic field or electric field corresponding to the intermediate frequency demodulated signal that has passed through the low-pass filter 7. The optical quantum sensor unit 42 generates light corresponding to the magnetic field or electric field using a sensing element and converts the light into an electrical signal as a sensor signal using a photoelectric element. The analog-to-digital converter 43 digitizes the sensor signal. The optical quantum sensor unit 42 performs quantum operations on the sensing element, causing the sensing element to generate light corresponding to the magnetic or electric field.

[0070] As a result, a relatively high-level sensor signal corresponding to a weak IF demodulation signal is obtained and digitized using the physical field generator 41 and the optical magnetic sensor unit 42, and an IF demodulation signal (digital signal) including an NMR signal is obtained with high accuracy. Therefore, a weak IF demodulation signal at a level similar to or lower than the noise level of the A / D converter 43 can be digitized with high accuracy. Consequently, it becomes possible to accurately detect low-level NMR signals and perform high-resolution nuclear magnetic resonance sensing.

[0071] Embodiment 2

[0072] In the second embodiment, the optical quantum sensor unit 42 performs quantum operations on the sensing element in accordance with optically pumped atomic magnetometry (OPAM) instead of ODMR, causing the sensing element to generate light corresponding to a magnetic field.

[0073] 5 is a diagram showing the configuration of a sensor main body 51 in a digitizing device according to embodiment 2. In embodiment 2, sensor main body 51 includes a cell 71, a magnet 72, and light-emitting devices 73 and 74 for OPAM.

[0074] The cell 71 is a transparent glass cell or the like, and alkali metal atoms (K, Rb, Cs, etc.) as the sensing member 71a are sealed together with a buffer gas in the cell 71. The magnet 72 is a magnet that applies a static magnetic field to the sensing member, and may be a permanent magnet as described above or an electromagnet.

[0075] The light emitting device 73 generates pump light and irradiates it onto the sensing element 71a. The light emitting device 74 generates probe light and irradiates it onto the sensing element 71a. In the OPAM measurement sequence, spin polarization occurs in the sensing element due to optical pumping by the pump light, and the rotation of the spin polarization in response to the magnetic field is measured by the magneto-optical rotation of the probe light. Specifically, the deflection rotation angle of the observation light (i.e., the probe light after magneto-optical rotation) is detected. The deflection rotation angle of the observation light is detected by multiple photoelectric elements 52 using a four-detector method or the like. When detection is performed by multiple photoelectric elements 52, the sensor signals may be digitized by multiple A / D converters 43, converted into multiple digital signals, and then subjected to arithmetic processing (such as difference calculation).

[0076] The other configurations and operations of the nuclear magnetic resonance sensing device according to the second embodiment are the same as those of the first embodiment, and therefore the description thereof will be omitted.

[0077] Embodiment 3

[0078] In embodiment 3, the physical field generating device 41 generates an electric field corresponding to an input signal (i.e., an analog IF demodulated signal) input via the input terminal 41a of the physical field generating device 41, and the optical quantum sensor unit 42 generates light (observation light) corresponding to the electric field generated by the physical field generating device 41 in the sensing member in the sensor main body 51, and converts the light into an electrical signal as a sensor signal using the photoelectric element 52.

[0079] For example, the physical field generator 41 generates the electric field using a pair of electrode plates. Note that this input signal may be a single-frequency AC signal, an AC signal with a predetermined cycle having multiple frequency components, or a DC signal. In other words, the electric field described above may be a single-frequency AC field, an AC field with a predetermined cycle having multiple frequency components, a DC electric field, or the like, depending on the input signal.

[0080] Other configurations and operations of the nuclear magnetic resonance sensing device according to embodiment 3 are the same as those of embodiment 1 or 2, and therefore will not be described here. However, the sensing member used in ODMR or OPAM is one whose quantum state changes depending on the electric field and can measure the electric field using a similar measurement sequence.

[0081] Embodiment 4

[0082] FIG. 6 is a block diagram showing the configuration of a nuclear magnetic resonance sensing device according to the fourth embodiment of the present invention.

[0083] As shown in FIG. 6, the nuclear magnetic resonance sensing device of the fourth embodiment includes the same components as those of the first embodiment, such as a nuclear magnetic resonance sensing unit 1, a base signal generating unit 2, a mixer unit 3, a switching unit 4, a matching and tuning circuit 5, a mixer unit 6, and a low-pass filter 7, as well as an analog quadrature phase detection circuit 201, a digitizing unit 202, and a control unit 203.

[0084] The analog quadrature phase detection circuit 201 performs quadrature phase detection on the intermediate frequency demodulated signal that has passed through the low pass filter 7, and generates a demodulated signal I and a demodulated signal Q of the nuclear magnetic resonance signal.

[0085] Specifically, the analog quadrature phase detection circuit 201 includes a 90-degree phase shifter 211, mixer units 212 and 213, and low-pass filters 214 and 215. The 90-degree phase shifter 211 shifts the phase of the IF base signal by 90 degrees. Note that the 90-degree phase shifter 211 is an analog circuit and may not include any active elements. The mixer unit 212 mixes and demodulates the IF demodulated signal and the IF base signal, and extracts two frequency components (2f IF -f NMR ),f NMR The low-pass filter 214 generates and outputs a demodulated signal having two band components (2f IF -f NMR ),f NMR The high frequency band component (2f IF -f NMR ) and attenuates the low-frequency band component (f NMR The mixer unit 213 mixes and demodulates the IF demodulated signal and the IF base signal after a 90-degree phase shift, and generates two frequency components (2f IF -f NMR ),f NMR The low-pass filter 215 generates and outputs a demodulated signal having two band components (2f IF -f NMR ),f NMR The high frequency band component (2f IF -f NMR ) and attenuates the low-frequency band component (f NMR ) is a filter that transmits the low-pass filters 214 and 215. The low-pass filters 214 and 215 are analog filters that are made up of only passive elements such as capacitors, inductors, and resistors. For example, the mixer units 212 and 213 are DBMs made up of diodes and phase distributors.

[0086] The digitizing device 202 converts the demodulated signal I and the demodulated signal Q (frequency components f NMR ) are digitized and converted from analog to digital signals.

[0087] The control device 203 includes a computer that operates according to a control program, and the computer includes a CPU, a ROM, a RAM, etc., and performs the operations described below by loading the control program into the RAM and executing it on the CPU. Specifically, the control device 203, like the control device 22, controls the nuclear magnetic resonance sensing unit 1 and the switching unit 4 to apply the above-mentioned high-frequency magnetic field to the nuclear magnetic resonance sensing unit 1 and output the above-mentioned observation signal. Furthermore, the control device 203 converts the demodulated signal I and the demodulated signal Q (frequency component f) as digital signals into a signal to be demodulated. NMR ) is input from the digitizer 202 and subjected to predetermined signal processing to generate an NMR signal (frequency component f NMR ) is extracted. Here, in this predetermined signal processing, a Fourier transform such as FFT (Fast Fourier Transform) is performed on each of the demodulated signal I and the demodulated signal Q to identify the frequency components of each of the demodulated signal I and the demodulated signal Q, thereby extracting the NMR signal (frequency component f NMR ) and detect chemical shifts.

[0088] Fig. 7 is a block diagram showing the configuration of a digitizing device 221 in a nuclear magnetic resonance sensing apparatus according to embodiment 4. The digitizing device 202 shown in Fig. 7 includes a digitizing unit 202a that digitizes a demodulated signal I and a digitizing unit 202b that digitizes a demodulated signal Q.

[0089] The digitizing unit 202a includes a physical field generator 241 similar to the physical field generator 41, an optical quantum sensor unit 242 similar to the optical quantum sensor unit 42, and an A / D converter 243 similar to the A / D converter 43. The digitizing unit 202b includes a physical field generator 261 similar to the physical field generator 41, an optical quantum sensor unit 262 similar to the optical quantum sensor unit 42, and an A / D converter 263 similar to the A / D converter 43.

[0090] The physical field generators 241 and 261 respectively generate magnetic fields corresponding to input signals (i.e., analog IF demodulated signals) input via input terminals 241a and 261a of the physical field generators 241 and 261. For example, the physical field generators 241 and 261 generate the magnetic fields using conductive coils or wiring.

[0091] The optical quantum sensor units 242, 262 each include a sensor body 251, 271 similar to the sensor body 51 and a photoelectric element 252, 272 similar to the photoelectric element 52, and in the sensor body 251, 271, a sensing member generates light (observation light) corresponding to the magnetic field generated by the physical field generator 241, 261, and the photoelectric element 252, 272 converts the light into an electrical signal as a sensor signal. The photoelectric element 252, 272 is a photodiode, a phototransistor, or the like, and generates a sensor signal corresponding to the intensity of the incident observation light.

[0092] In the fourth embodiment, the optical quantum sensor units 242, 262 (specifically, the sensor bodies 251, 271) each perform quantum operations on the sensing element in accordance with optically detected magnetic resonance (ODMR) to cause the sensing element to generate the above-mentioned observation light.

[0093] In this embodiment, as in embodiment 1, in the optical quantum sensor units 242, 262, an optical system is provided from the light emitting device to the magnetic resonance member in order to irradiate excitation light onto the magnetic resonance member, and an optical system is provided from the magnetic resonance member to the photoelectric element in order to detect fluorescence (observation light) from the magnetic resonance member.

[0094] Similarly to optical quantum sensor unit 42, optical quantum sensor units 242 and 262 each (a) control a high-frequency power supply and a light-emitting device to perform quantum operations with microwaves and laser light in accordance with a predetermined measurement sequence, causing sensor bodies 251 and 271 to generate observation light and photoelectric elements 252 and 272 to generate sensor signals. Similar to embodiment 1, this measurement sequence is set according to the frequency of the magnetic field described above, etc.

[0095] The A / D converters 243, 263 digitize the sensor signals output from the optical magnetic sensor unit 242 (without directly digitizing the analog demodulated signal I and demodulated signal Q), thereby generating digital signals as output signals corresponding to the demodulated signal I and demodulated signal Q, and output them via the output terminals 243a, 263a of the A / D converters 243, 263.

[0096] In this embodiment, in particular, the optical quantum sensor units 242, 262 (specifically, the sensor bodies 251, 271) generate the above-mentioned observation light in the sensing member so that the level of the sensor signal exceeds the noise floor of the A / D converters 243, 263.

[0097] Here, as in the first embodiment, factors such as the efficiency of the sensing member, the light collection efficiency of the observation light, and the conversion efficiency of the photoelectric elements 252 and 272 are determined so that the level of the sensor signal exceeds the noise floor of the A / D converter 43 according to the noise floor (known) of the A / D converter 43. As a result, for example, the sensitivity of the optical quantum sensor units 242 and 262 is set to 1.5 pT / Hz. 1 / 2 The above is the case. Furthermore, the A / D converters 243, 263 in this embodiment are high-resolution A / D converters, and the values ​​of the above factors are determined so that the level of the sensor signal exceeds the noise level of thermal noise. Furthermore, the reference voltages of the A / D converters 243, 263 are set according to the range (minimum level and maximum level) of the sensor signal. Note that the levels (or ranges) of the input demodulated signal and demodulated signal and the electromagnetic conversion efficiency of the physical field generators 241, 261 are known.

[0098] In particular, in this embodiment, the digitizing device 202 does not include an amplifier circuit for electrically amplifying the sensor signal between the photoelectric elements 252, 272 and the A / D converters 243, 263. Furthermore, in this embodiment, no amplifier circuit for electrically amplifying the input signal is provided between the signal source of the input signal and the physical field generators 241, 261. In other words, in this embodiment, no electrical amplifier circuit that could be a noise source is provided upstream of the A / D converters 243, 263.

[0099] The optical quantum sensor units 242 and 262 are electrically separated from the A / D converters 243 and 263 so that electrical noise generated in the optical quantum sensor units 242 and 262 does not enter the A / D converters 243 and 263 .

[0100] In the fourth embodiment, neither an amplifier circuit nor a buffer is provided between the nuclear magnetic resonance sensing unit 1 and the digitizing device 202. In other words, only passive elements are used in the circuit from the nuclear magnetic resonance sensing unit 1 to the digitizing device 202, thereby suppressing the generation of thermal noise.

[0101] Next, the operation of the nuclear magnetic resonance sensing device according to the fourth embodiment will be described.

[0102] The control device 203 controls the nuclear magnetic resonance sensing unit 1 and also controls the switching unit 4 to apply a high-frequency magnetic field based on the RF signal from the transmission system to the target object 101 in the nuclear magnetic resonance sensing unit 1, and controls the switching unit 4 to conduct the observation signal from the nuclear magnetic resonance sensing unit 1 to the reception system. As shown in Fig. 6, the observation signal is converted into an IF demodulated signal by the mixer unit 6, and further, the IF demodulated signal from which high-frequency band components have been removed by the low-pass filter 7 is input to the analog quadrature phase detection circuit 201.

[0103] The quadrature detection circuit 201 performs quadrature detection on the IF demodulated signal with the IF base signal to detect the frequency component f NMRThe demodulated signal I and the demodulated signal Q are generated and input to the digitizing device 202 .

[0104] In the digitizing device 202, when the demodulated signal I is applied to the physical field generator 241, the physical field generator 241 generates a magnetic field of an intensity corresponding to the level of the input signal, and the magnetic field is applied to the sensor body 251 of the optical quantum sensor unit 242. The sensor body 251 executes the measurement sequence as described above, and generates light of an amount corresponding to the intensity of the magnetic field. In the fourth embodiment, in accordance with ODMR, the magnetic resonance element generates light of an amount corresponding to the intensity of the magnetic field. Then, the photoelectric element 252 receives the light, generates a sensor signal of a level corresponding to the amount of received light, and outputs the sensor signal to the A / D converter 243. The A / D converter 243 digitizes the sensor signal to generate a digital demodulated signal I corresponding to the analog demodulated signal I, and outputs the digital demodulated signal I to the control device 203.

[0105] In parallel with this, in the digitizing device 202, when the demodulated signal Q is applied to the physical field generating device 261, the physical field generating device 261 generates a magnetic field of an intensity corresponding to the level of the input signal, and the magnetic field is applied to the sensor body 271 of the optical quantum sensor unit 262. The sensor body 271 executes the measurement sequence as described above, and generates light of an amount corresponding to the intensity of the magnetic field. In the fourth embodiment, in accordance with ODMR, the magnetic resonance element generates light of an amount corresponding to the intensity of the magnetic field. Then, the photoelectric element 272 receives the light, generates a sensor signal of a level corresponding to the amount of received light, and outputs the sensor signal to the A / D converter 263. The A / D converter 263 digitizes the sensor signal to generate a digital demodulated signal Q corresponding to the analog demodulated signal Q, and outputs the digital demodulated signal Q to the control device 203.

[0106] The control device 203 continuously and repeatedly acquires the values ​​of the digital demodulated signal I and the demodulated signal Q at each point in time, and as described above, performs signal processing to generate an NMR signal (specifically, f NMR The NMR signal and chemical shift are derived, and the molecular structure of the target object 101 is analyzed, imaged, and so on, based on the NMR signal and chemical shift.

[0107] The other configurations and operations of the nuclear magnetic resonance sensing device according to the fourth embodiment are the same as those of any of the first to third embodiments, and therefore, description thereof will be omitted.

[0108] As described above, according to the fourth embodiment, the analog quadrature phase detection circuit 201 performs quadrature phase detection on the intermediate frequency demodulated signal that has passed through the low-pass filter 7, generating a demodulated signal I and a demodulated signal Q of the nuclear magnetic resonance signal. The digitizing device 202 digitizes the demodulated signal I and the demodulated signal Q. In the digitizing device 202, the physical field generators 241 and 261 generate magnetic fields or electric fields corresponding to the demodulated signal and the demodulated signal, respectively, and the optical quantum sensor units 242 and 262 generate light corresponding to the magnetic fields or electric fields generated by the physical field generators 241 and 261 using their sensing elements, respectively. The light generated by these sensing elements is converted by the photoelectric elements 252 and 272 into electrical signals as first and second sensor signals, and the A / D converters 243 and 263 digitize the first and second sensor signals, respectively. Here, the optical quantum sensor units 242 and 262 each perform quantum operations on the sensing element to generate light corresponding to the magnetic field or electric field described above in the sensing element.

[0109] As a result, the target nuclear magnetic resonance signal and the chemical shift are detected by being distinguished from each other through analysis in the control device 203 based on the demodulated signal I and the demodulated signal Q. Consequently, it becomes possible to accurately detect low-level nuclear magnetic resonance signals and perform high-resolution nuclear magnetic resonance sensing.

[0110] Embodiment 5.

[0111] FIG. 8 is a block diagram showing the configuration of the digitizing device 221 in the nuclear magnetic resonance sensing apparatus according to the fifth embodiment.

[0112] In embodiment 5, as shown in Figure 8, the optical quantum sensor units 242, 262 irradiate their respective sensing elements with a common laser light (the above-mentioned excitation light) to perform the above-mentioned quantum operations, causing their respective sensing elements to generate light corresponding to the magnetic field or electric field generated by the physical field generating devices 241, 261.

[0113] FIG. 9 is a diagram showing the configuration of the sensor main bodies 251 and 271 of the digitizing device 202 according to the fifth embodiment.

[0114] 9, in the fifth embodiment, for ODMR, the sensor main bodies 251 and 271 each include magnetic resonance members 291a and 291b, high-frequency magnetic field generators 292a and 292b, and magnets 293a and 293b as sensing members, and the sensor main body 251 further includes a high-frequency power supply 294, a light-emitting device 295, and a controller 296. The high-frequency power supply 294, the light-emitting device 295, and the controller 296 are a single high-frequency power supply, light-emitting device, and controller common to the two systems of magnetic resonance members 291a and 291b and high-frequency magnetic field generators 292a and 292b. The laser light emitted from the light-emitting device 295 is branched by an optical system (not shown) into a laser light incident on the magnetic resonance member 291a, a laser light incident on the magnetic resonance member 291b, and a laser light used as a reference light (described later).

[0115] The magnetic resonance members 291a, 291b, the high-frequency magnetic field generators 292a, 292b, the magnets 293a, 293b, the high-frequency power supply 294, the light-emitting device 295, and the controller 296 are similar to the magnetic resonance member 61, the high-frequency magnetic field generator 62, the magnet 63, the high-frequency power supply 64, the light-emitting device 65, and the controller 66.

[0116] Also, here, the sensor body 251 is equipped with a high-frequency power supply 294, a light-emitting device 295, and a controller 296, but instead, the sensor body 271 may be equipped with a high-frequency power supply 294, a light-emitting device 295, and a controller 296.

[0117] Furthermore, in the fifth embodiment, as shown in FIGS. 8 and 9, the digitizing device 202 includes a photoelectric element 281 and differential circuits 282 and 283 as analog circuits.

[0118] The photoelectric element 281 converts the reference light branched from the common laser light into an electrical signal as a third sensor signal. The photoelectric element 281 is a photodiode, a phototransistor, or the like.

[0119] The difference circuit 282 performs common mode rejection on the sensor signals (first sensor signals) of the optical quantum sensor unit 242 based on the third sensor signal. Specifically, the difference circuit 282 subtracts the third sensor signal from the first sensor signal, and inputs the first sensor signal after the subtraction to the A / D converter 243. Furthermore, the difference circuit 283 performs common mode rejection on the sensor signals (second sensor signals) of the optical quantum sensor unit 262 based on the third sensor signal. Specifically, the difference circuit 283 subtracts the third sensor signal from the second sensor signal, and inputs the second sensor signal after the subtraction to the A / D converter 263.

[0120] The photoelectric element 281 and the difference circuits 282 and 283 may be provided as needed, or may not be provided.

[0121] Next, the operation of the nuclear magnetic resonance sensing device according to the fifth embodiment will be described.

[0122] In the digitizing device 202 of embodiment 5, the optical quantum sensor units 242, 262 use a single light emitting device 295 to irradiate common excitation light onto the magnetic resonance members 291a, 291b of the sensor bodies 251, 271, and generate and output a first sensor signal corresponding to the demodulated signal I and a second sensor signal corresponding to the demodulated signal Q, as well as generate and output a third sensor signal corresponding to the reference light.

[0123] The difference circuits 282 and 283 subtract the third sensor signal from the first sensor signal and the second sensor signal, respectively, and input the first sensor signal and the second sensor signal after subtraction to the A / D converters 243 and 263, respectively.

[0124] The other configurations and operations of the nuclear magnetic resonance sensing device according to the fifth embodiment are the same as those of the fourth embodiment, and therefore, description thereof will be omitted.

[0125] As described above, according to the fifth embodiment, a single laser beam is used as excitation light common to the magnetic resonance members 291a and 291b, thereby suppressing deviation in output characteristics between the optical quantum sensor units 242 and 262. Furthermore, noise components contained in the first sensor signal and the second sensor signal due to noise components contained in the laser beam generated by the light emitting device 295 are suppressed.

[0126] It should be noted that various changes and modifications to the above-described embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing its intended advantages. In other words, it is intended that such changes and modifications be included within the scope of the claims.

[0127] For example, in embodiments 1 to 5, the measurement method in the sensor body 51, 251, 271 is not limited to the above-mentioned ODMR and OPAM, and any other measurement method may be used as long as it uses a sensing element corresponding to a physical field and performs quantum operations on the sensing element to detect observation light corresponding to the physical field intensity.

[0128] In the first to fifth embodiments, the control device 22 may perform predetermined arithmetic processing on the output signals of the digitizing devices 21 and 202 so that the values ​​(digital values) of the output signals match the levels of the analog IF demodulated signals.

[0129] In addition, in the first to fifth embodiments, a low-noise buffer (voltage amplification degree=1) that satisfies the noise level requirement may be provided between the low-pass filter 7 and the digitizing devices 21 and 202, if necessary. [Industrial Applicability]

[0130] The present invention is applicable to, for example, various measurements and imaging that utilize nuclear magnetic resonance. [Explanation of symbols]

[0131] 1. Nuclear magnetic resonance sensing unit 2. Bass signal generator 3 Mixer section (example of a transmitter mixer section) 6 Mixer section 7 Low-pass filter 21,202 Digitizing Device 41 Physical Field Generator 42 Optical Quantum Sensor Section 43 Analog / Digital Converter 52,252,272 Photoelectric element 101 Target Object 201 Quadrature phase detection circuit 241 Physical Field Generator (an example of the first physical field generator) 242 Optical quantum sensor unit (an example of the first optical quantum sensor unit) 243 Analog / Digital Converter (Example of First Analog / Digital Converter) 261 Physical Field Generator (an example of a second physical field generator) 262 Optical quantum sensor unit (an example of the second optical quantum sensor unit) 263 Analog / Digital Converter (an example of a second analog / digital converter) 281 Photoelectric element (an example of a third photoelectric element) 282 Differential circuit (an example of a first differential circuit) 283 Differential circuit (an example of a second differential circuit)

Claims

1. a nuclear magnetic resonance sensing unit that applies a high frequency magnetic field based on an RF signal to a target object and generates an observation signal having a frequency that is shifted from the frequency of the RF signal by the frequency of the nuclear magnetic resonance signal; a mixer unit that performs intermediate frequency demodulation of the observation signal to generate an intermediate frequency demodulated signal including the nuclear magnetic resonance signal; a low-pass filter that attenuates frequency components of the intermediate frequency demodulation signal that are higher than the intermediate frequency of the intermediate frequency demodulation and transmits frequency components of the nuclear magnetic resonance signal; an analog quadrature phase detection circuit that performs quadrature phase detection on the intermediate frequency demodulated signal that has passed through the low-pass filter to generate a demodulated signal and a demodulated signal of the nuclear magnetic resonance signal; a digitizing device for digitizing the demodulated signal and the demodulated signal; the digitizing device comprises: a first physical field generating device that generates a magnetic field or an electric field corresponding to the demodulated signal; a second physical field generating device that generates a magnetic field or an electric field corresponding to the demodulated signal; a first optical quantum sensor unit that generates light corresponding to the magnetic field or the electric field generated by the first physical field generating device using a first sensing member and converts the light generated by the first sensing member into an electric signal as a first sensor signal using a first photoelectric element; a second optical quantum sensor unit that generates light corresponding to the magnetic field or the electric field generated by the second physical field generating device using a second sensing member and converts the light generated by the second sensing member into an electric signal as a second sensor signal using a second photoelectric element; a first analog / digital converter that digitizes the first sensor signal; and a second analog / digital converter that digitizes the second sensor signal. the first optical quantum sensor unit and the second optical quantum sensor unit perform quantum operations on the first and second sensing elements, respectively, to generate the light corresponding to the magnetic field or the electric field in the first and second sensing elements; A nuclear magnetic resonance sensing device characterized by:

2. The nuclear magnetic resonance sensing device of claim 1, wherein the first optical quantum sensor unit and the second optical quantum sensor unit each perform the quantum operation by irradiating a common laser light onto the first and second sensing elements, thereby generating the light corresponding to the magnetic field or the electric field in the first and second sensing elements.

3. a third photoelectric element that converts a reference light branched from the common laser light into an electrical signal as a third sensor signal; a first differential circuit that performs common mode rejection on the first sensor signal based on the third sensor signal; a second differential circuit that performs common mode rejection on the second sensor signal based on the third sensor signal; 3. The nuclear magnetic resonance sensing device according to claim 2, further comprising:

4. applying a radio frequency magnetic field based on an RF signal to a target object, and generating an observation signal having a frequency shifted from the frequency of the RF signal by the frequency of a nuclear magnetic resonance signal; performing intermediate frequency demodulation of the observation signal to generate an intermediate frequency demodulated signal including the nuclear magnetic resonance signal; a step of attenuating, by a low-pass filter, frequency components of the intermediate frequency demodulation signal that are higher than the intermediate frequency of the intermediate frequency demodulation and transmitting frequency components of the nuclear magnetic resonance signal; a step of performing quadrature phase detection on the intermediate frequency demodulated signal transmitted through the low pass filter in an analog circuit to generate a demodulated signal and a demodulated signal of the nuclear magnetic resonance signal; a digitizing step of digitizing the demodulated signal and the demodulated signal, In the digitizing step, (a1) a magnetic field or an electric field corresponding to the demodulated signal is generated, (a2) a magnetic field or an electric field corresponding to the demodulated signal is generated, (b1) light corresponding to the magnetic field or the electric field corresponding to the demodulated signal is generated by a first sensing member, and the light generated by the first sensing member is converted by a photoelectric element into an electric signal as a first sensor signal, (b2) light corresponding to the magnetic field or the electric field corresponding to the demodulated signal is generated by a second sensing member, and the light generated by the second sensing member is converted by a photoelectric element into an electric signal as a second sensor signal, (c1) digitizing the first sensor signal, and (c2) digitizing the second sensor signal, In the digitizing step, quantum operations are performed on the first and second sensing elements, respectively, to generate the light corresponding to the magnetic field or the electric field corresponding to the demodulated signal and the demodulated signal in the first and second sensing elements, respectively; A nuclear magnetic resonance sensing method comprising:

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