Nuclear magnetic resonance sensing device and nuclear magnetic resonance sensing method

Abstract

After an unnecessary band component is removed from an intermediate frequency (IF) demodulated signal obtained through IF demodulation of an observation signal of nuclear magnetic resonance, a digitization device (21) generates a magnetic field or the like corresponding to the IF demodulated signal, generates light corresponding to the magnetic field or the like by using a sensing member in an optical quantum sensor unit, converts the light to a sensor signal by using a photoelectric element, and digitizes the sensor signal by using an A / D converter to generate a digital IF demodulated signal. The optical quantum sensor unit has unstable output intensity characteristics in a prescribed frequency range. A correction processing unit (22b) corrects the IF demodulated signal in accordance with the frequency of the magnetic field or the like so that the frequency characteristics of the IF demodulated signal in the aforementioned frequency range are brought close to a constant value.

Description

Nuclear magnetic resonance sensing apparatus and nuclear magnetic resonance sensing method 【0001】 The present invention relates to a nuclear magnetic resonance sensing device and a nuclear magnetic resonance sensing method. 【0002】 Generally, a measurement device utilizing nuclear magnetic resonance applies a high-frequency magnetic field based on an RF (Radio Frequency) signal with a frequency close to the precession frequency to the object being measured using a high-frequency coil, causing the nuclear magnetization to resonate. This resonant nuclear magnetization is then detected by a receiving coil to generate an observation signal that includes a nuclear magnetic resonance (NMR) signal. 【0003】 A certain nuclear magnetic resonance sensing device (a) applies a high-frequency magnetic field based on an RF signal to a target object and generates an observation signal with a frequency shifted from the frequency of the RF signal by the frequency of the NMR signal, (b) generates an IF demodulated signal including the NMR signal in a mixer, (c) extracts the low-frequency band component of the IF demodulated signal in a low-pass filter, (d) further generates a magnetic field etc. corresponding to the IF demodulated signal that has passed through the low-pass filter in a digitizing device using a physical field generator, (e) generates light corresponding to the magnetic field etc. in an optical quantum sensor unit using a sensing member and converts that light into a sensor signal using a photoelectric element, and (f) digitizes the sensor signal in an analog / digital converter (see, for example, Patent Documents 1 and 2). This optical quantum sensor unit performs quantum operations on the sensing member described above to generate light corresponding to the magnetic field etc. in the sensing member. 【0004】 International Publication No. 2023 / 089883, International Publication No. 2024 / 224587 【0005】On the other hand, as an application of nuclear magnetic resonance sensing, the shift in the frequency of the NMR signal (Larmor frequency) depending on the molecular structure surrounding the atom containing the atomic nucleus being observed (i.e., chemical shift) is used to identify compounds and determine molecular structures. In this process, the amount of frequency shift and relative intensity (integral value of the peak waveform, etc.) of the peak corresponding to the chemical shift of a specific atomic nucleus within the molecular structure relative to a standard sample are identified in the NMR signal spectrum. Based on this amount of shift and relative intensity, a specific molecular structure (functional group, etc.) and its quantity contained in the target object are identified. The specific atomic nucleus mentioned above is, １ H １３ These include C, and tetramethylsilane (TMS) is used as a standard sample, for example. 【0006】 Therefore, when performing the aforementioned nuclear magnetic resonance sensing on an object having a chemical shift, if the aforementioned optical quantum sensor does not have a certain sensitivity to the frequency of the magnetic field applied to the aforementioned optical quantum sensor, it may not be possible to accurately evaluate specific molecules contained in the target substance quantitatively and stoichiometrically. 【0007】 The present invention has been made in view of the above problems, and aims to provide a nuclear magnetic resonance sensing device and a nuclear magnetic resonance sensing method that can accurately evaluate the abundance of specific molecules contained in a target object when performing nuclear magnetic resonance sensing on a target object having a chemical shift. 【0008】The nuclear magnetic resonance sensing device according to the present invention includes: 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 with 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 transmits a frequency component in the intermediate frequency demodulated signal that is shifted from the intermediate frequency of the intermediate frequency demodulation by the frequency of the nuclear magnetic resonance signal; a digitizing device that digitizes the intermediate frequency demodulated signal that has passed through the low-pass filter; and a correction processing unit that performs correction processing on the sensor signal after digitization. The digitizing device includes a physical field generator that generates a magnetic field or electric field corresponding to the intermediate frequency demodulated signal that has passed through the low-pass filter; an optical quantum sensor unit that generates light corresponding to the magnetic field or electric field using a sensing member 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 to generate a digital intermediate frequency demodulated signal. The optical quantum sensor unit (a) performs quantum operations on the sensing member to generate the aforementioned light corresponding to the aforementioned magnetic field or electric field on the sensing member, and (b) has inconsistent sensitivity characteristics and non-uniform output intensity characteristics in a predetermined frequency range. The correction processing unit, in the correction process, corrects the intermediate frequency demodulated signal in accordance with the frequency of the aforementioned magnetic field or electric field so that the frequency characteristics of the intermediate frequency demodulated signal in the aforementioned frequency range become closer to constant in accordance with the aforementioned output intensity characteristics. 【0009】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 with 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; using a low-pass filter to transmit frequency components in the intermediate frequency demodulated signal that are shifted from the intermediate frequency of the intermediate frequency demodulation by the frequency of the nuclear magnetic resonance signal; digitizing the intermediate frequency demodulated signal that has passed through the low-pass filter; and performing correction processing on the intermediate frequency demodulated signal after digitization. In the digitizing step, (a) a magnetic field or electric field corresponding to the intermediate frequency demodulated signal that has passed through the low-pass filter is generated; (b) an optical quantum sensor unit generates light corresponding to the above-mentioned magnetic field or electric field in a sensing member, and the light is converted into an electrical signal as a sensor signal by a photoelectric element; and (c) an analog / digital converter digitizes the sensor signal to generate a digital intermediate frequency demodulated signal. The optical quantum sensor unit (a) performs quantum operations on the sensing member to generate the aforementioned light corresponding to the aforementioned magnetic field or electric field on the sensing member, and (b) has inconsistent sensitivity characteristics and non-uniform output intensity characteristics in a predetermined frequency range. Then, in the correction process, the intermediate frequency demodulated signal is corrected in accordance with the frequency of the magnetic field or electric field so that the frequency characteristics of the intermediate frequency demodulated signal in the aforementioned frequency range become closer to constant in accordance with the aforementioned output intensity characteristics. 【0010】 According to the present invention, a nuclear magnetic resonance sensing apparatus and nuclear magnetic resonance sensing method are obtained that can quantitatively and accurately identify specific molecular structures contained in a target object when performing nuclear magnetic resonance sensing on a target object having a chemical shift. 【0011】Figure 1 is a block diagram showing the configuration of a nuclear magnetic resonance sensing device according to Embodiment 1 of the present invention. Figure 2 is a block diagram showing the configuration of the digitizing device 21 in Figure 1. Figure 3 is a diagram showing the configuration of the sensor body 51 in the digitizing device according to Embodiment 1. Figure 4 is a diagram illustrating a specific phase in a pseudo-IF signal. Figure 5 is a diagram showing an example of a measurement sequence. Figure 6 shows the spinlock frequency f ＬＯＣＫ and the frequency f of the AC field under measurement ＡＣ This figure illustrates the relationship between the intensity S of the sensor signal and the maximum value of the derivative (dS / dB) of the intensity S of the sensor signal with respect to the magnetic flux density B of the AC field under measurement, max|dS / dB|. Figure 7 shows the frequency f of the AC field under measurement. ＡＣ This figure illustrates the distribution of sensor signal strength S (relative value) with respect to phase shift. Figure 8 shows the frequency f of the AC field under measurement in Embodiment 1. ＡＣ This figure illustrates the maximum slope value max |dS / dB|. Figure 9 illustrates the sampling of the sensor signal. Figure 10 illustrates the sensor signal appearing in the observable band. Figure 11 illustrates the case where the above-described filtering process attenuates the band corresponding to the range from half the sampling frequency fs (fs / 2) to the sampling frequency fs. Figure 12 illustrates the case where the above-described filtering process attenuates the band corresponding to the range from 0 to half the sampling frequency (fs / 2). Figure 13 illustrates the correction process based on calibration data and the derivation of the NMR spectrum. Figure 14 is １ This figure shows the NMR spectrum of ethylbenzene with respect to H. Figure 15 is a diagram illustrating the identification of calibration data in Embodiment 2. Figure 16 is a diagram illustrating the setting of the intermediate frequency in Embodiment 3. Figure 17 is a diagram illustrating the setting of the intermediate frequency in Embodiment 4. Figure 18 is a diagram illustrating the setting of the spinlock frequency in Embodiment 5. Figure 19 is a diagram illustrating the measurement sequence (dynamic decoupling) in Embodiment 6. Figure 20 shows the frequency f of the AC field under measurement in Embodiment 6. ＡＣThis is a diagram for explaining the maximum value of the slope \(max|\frac{dS}{dB}|\) with respect to 【0012】 Hereinafter, embodiments of the present invention will be described based on the drawings. 【0013】 Embodiment 1. 【0014】 FIG. 1 is a block diagram showing the configuration of a nuclear magnetic resonance sensing apparatus according to Embodiment 1 of the present invention. This nuclear magnetic resonance sensing apparatus is used for analyzing the molecular structure of an object using chemical shift. 【0015】 The nuclear magnetic resonance sensing apparatus shown in FIG. 1 includes a nuclear magnetic resonance sensing unit 1, reference signal generation devices 2 and 3, a switching unit 4, a matching and tuning circuit 5, a mixer unit 6, and a low-pass filter 7. 【0016】 The nuclear magnetic resonance sensing unit 1 applies an RF signal described later to the object, and generates an observation signal (analog electrical signal) having a frequency (f ＲＦ + f ＮＭＲ ) that is shifted from the frequency f of the RF signal by the frequency of the nuclear magnetic resonance (NMR) signal. ＲＦ + f ＮＭＲ ). 【0017】 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 the RF signal to the object 101, and outputs an observation signal by sensing a magnetic field change based on the movement of nuclear magnetization in the object 101. The magnet unit 12 is a permanent magnet or an electromagnet, and applies a static magnetic field or an inclined magnetic field to the object 101. This observation signal includes an NMR signal and has a frequency that is the sum of the frequency f ＮＭＲ and the RF signal frequency f ＲＦ (f ＲＦ + f ＮＭＲ ). 【0018】 The reference signal generation device 2 generates and outputs an RF signal. The reference signal generation device 3 generates and outputs a local oscillation (LO) signal. The LO signal is a single intermediate frequency f ＲＦ shifted from the RF signal frequency f ＩＦIt has a lower frequency. The RF signal is split by coupler 2a, and the LO signal is split by splitter 3a so that they are at the same level after splitting. 【0019】 The switching unit 4 switches the connection destination of the nuclear magnetic resonance sensing unit 1 (nuclear magnetic resonance sensing unit via the matching and tuning circuit 5) from one of the RF signal transmission system (reference signal generator 2) and the observation signal reception system (reference signal generators 2 and 3, mixer unit 6, and low-pass filter 7) to the other. Specifically, when transmitting an RF signal, the switching unit 4 electrically connects the transmission system to the nuclear magnetic resonance sensing unit 1, and when receiving an observation signal, it electrically connects the reception system to the nuclear magnetic resonance sensing unit 1. 【0020】 The matching and tuning circuit 5 is a circuit that performs impedance matching to suppress reflection of the RF signal in the nuclear magnetic resonance sensing unit 1, as well as frequency tuning to improve the level of the NMR signal. 【0021】 The mixer unit 6 performs intermediate frequency demodulation of the observed signal based on the LO signal to generate an intermediate frequency demodulated signal (IF demodulated signal) that includes the nuclear magnetic resonance signal. Specifically, the mixer unit 6 mixes the observed signal and the LO signal and performs intermediate frequency (IF) demodulation to obtain two frequency components (2f ＲＦ -f ＩＦ -f ＮＭＲ ), (f ＩＦ +f ＮＭＲ It generates and outputs an IF demodulated signal having ). For example, the mixer section 6 is a DBM (Double Balanced Mixer) consisting of a diode and a phase divider, and does not include active elements such as transistors. 【0022】 The low-pass filter 7 attenuates unwanted band components in the IF demodulated signal described above, and modulates the intermediate frequency f of the intermediate frequency demodulation. ＩＦ From the frequency f of the nuclear magnetic resonance signal ＮＭＲ It allows the frequency components that have been shifted by only a certain amount to pass through. Specifically, the low-pass filter 7 allows the two bandwidth components (2f) obtained from the IF demodulation signal of the IF demodulation signal of the mixer section 6 to pass through. ＲＦ -f ＩＦ -fＮＭＲ ), (f ＩＦ +f ＮＭＲ ) the high-frequency band component (2f ＲＦ -f ＩＦ -f ＮＭＲ ) is attenuated, and the lower frequency band component (f) of the two band components is attenuated. ＩＦ +f ＮＭＲ This is a filter that allows the signal to pass through. The low-pass filter 7 is an analog filter composed solely of passive elements such as capacitors, inductors, and resistors. 【0023】 Furthermore, the nuclear magnetic resonance sensing device shown in Figure 1 includes a mixer unit 8 and a phase detection unit 9. 【0024】 The mixer section 8 generates a pseudo-intermediate frequency signal (frequency f) from the LO signal and the RF signal. ＩＦ This generates a pseudo-IF signal. Here, in order to suppress the delay between the IF demodulated signal and the pseudo-IF signal, it is preferable to use the same mixer unit 8 as the mixer unit 6. 【0025】 The phase detection unit 9 detects a specific phase in the waveform of the pseudo-IF signal and generates and outputs a synchronization signal indicating the specific phase. The phase detection unit 9 may detect the specific phase using a comparator (such as a zero-crossing comparator), or it may convert the pseudo-IF signal into a digital signal using an analog-to-digital converter and perform signal processing on the digital signal using a DSP (Digital Signal Processor) or the like to detect the specific phase. 【0026】 Furthermore, the nuclear magnetic resonance sensing device shown in Figure 1 includes a digitizing device 21 and a control device 22. 【0027】 The digitizing device 21 outputs the IF demodulated signal (frequency component (f)) from the low-pass filter 7. ＩＦ +f ＮＭＲ Converts an analog signal to a digital signal. 【0028】The control device 22 includes a non-volatile storage device 22a such as flash memory, and a computer that operates according to a control program. This computer includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. It loads the control program from the ROM or storage device 22a into the RAM and executes it with the CPU to perform the operations described later, and also operates as a correction processing unit 22b and an identification processing unit 22c. The storage device 22a stores the calibration data described later. 【0029】 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 outputs the IF demodulated signal (frequency component (f) as a digital signal. ＩＦ +f ＮＭＲ The signal is input from the digitizing device 21 and undergoes predetermined signal processing (frequency component f ＮＭＲ (For example, extraction of the IF demodulated signal (frequency components (f))) is performed, and the IF demodulated signal (frequency components (f) ＩＦ +f ＮＭＲ )) from frequency f ＮＭＲ Extract the component (i.e., the NMR signal). ＩＦ is, f ＮＭＲ It is a sufficiently high frequency compared to f ＲＦ is, f ＩＦ This is a significantly higher frequency compared to [another frequency]. 【0030】 The correction processing unit 22b performs correction processing on the digitized IF demodulated signal (specifically, the digitized sensor signal described later). 【0031】 The identification processing unit 22c derives the NMR spectrum of the target object 101 based on the IF demodulated signal corrected by the correction processing unit 22b, and identifies the molecular structure (functional groups, etc.) and the quantity (number) of that molecular structure (functional groups, etc.) from the NMR spectrum. 【0032】Figure 2 is a block diagram showing the configuration of the digitizing device 21 in Figure 1. As shown in Figure 2, the digitizing device 21 comprises a physical field generator 41, an optical quantum sensor unit 42, and an analog-to-digital converter (A / D converter, ADC) 43. 【0033】 The physical field generator 41 generates a magnetic field corresponding to the input signal (i.e., the analog IF demodulated signal that has passed through the low-pass filter 7) input via the input terminal 41a of the physical field generator 41. For example, the physical field generator 41 generates this magnetic field using conductive coils or wiring. This generated magnetic field corresponds to the frequency of the IF demodulated signal (here, f ＩＦ +f ＮＭＲ ) has the same frequency f ＡＣ It has. 【0034】 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 generator 41, and the photoelectric element 52 converts this light into an electrical signal as a sensor signal. The photoelectric element 52 is a photodiode or phototransistor, and generates a sensor signal corresponding to the intensity of the incident observation light. 【0035】 Specifically, the optical quantum sensor unit 42 (specifically the sensor body 51) performs quantum operations (in this case, quantum operations using microwaves and laser light) on the sensing member at a specific phase timing specified by the synchronization signal, causing light corresponding to the magnetic field generated by the physical field generator 41 to be generated on the sensing member. 【0036】 In Embodiment 1, the optical quantum sensor unit 42 (specifically the sensor body 51) performs quantum operations on the sensing member according to optical magnetic resonance measurement (ODMR) to generate the aforementioned observation light on the sensing member. 【0037】 Preferably, the phase detection unit 9 detects a specific phase in the waveform of the pseudo-IF signal immediately after the start of free induction decay, and the optical quantum sensor unit 42 performs the above-mentioned quantum operation on the sensing member 1 by applying microwaves to the sensing member 1 at the timing of that specific phase. 【0038】 Figure 3 shows the configuration of the sensor body 51 in the digitizing device according to Embodiment 1. In Embodiment 1, for ODMR, as shown in Figure 3, for example, the sensor body 51 includes a magnetic resonance member 61 as a sensing member, a high-frequency magnetic field generator 62, and a magnet 63, a high-frequency power supply 64, a light-emitting device 65, and a controller 66. 【0039】 The magnetic resonance member 61 has a crystalline structure, and its electron spin quantum state changes in response to the magnetic field generated by the physical field generator 41. It is also a member capable of electron spin quantum manipulation (based on Rabi oscillations) using microwaves of 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 within the aforementioned magnetic field. 【0040】 In this embodiment, the magnetic resonance member 61 is a photodetector magnetic resonance member having a plurality (i.e., an ensemble) of specific color centers. These specific color centers have energy levels that can be Zeeman split, and can take on multiple orientations in which the shift width of the energy levels during Zeeman splitting is different from that of the others. 【0041】 Here, the magnetic resonance member 61 is a material such as diamond containing multiple NV (Nitrogen Vacancy) centers as a single type of specific color center. In the case of NV centers, the ground state is a triplet state with ms = 0, +1, -1, and the ms = +1 and ms = -1 levels undergo Zeeman splitting. When the NV centers transition from the excited state of the ms = +1 and ms = -1 levels to the ground state, a predetermined proportion fluoresce, while the remaining proportion of NV centers transition non-radiatively from the excited state (ms = +1 or ms = -1) to the ground state (ms = 0). Note that the color centers included in the magnetic resonance member 61 may be color centers other than NV centers. 【0042】The high-frequency magnetic field generator 62 applies microwaves to the magnetic resonance member 61 to perform quantum manipulation of the electron spin of the magnetic resonance member 61. For example, the high-frequency magnetic field generator 62 comprises a substantially circular coil section that emits microwaves and terminal sections that extend from both ends of the coil section and are fixed to a substrate. The high-frequency power supply 64 generates its microwave current and conducts it to the high-frequency magnetic field generator 62. The coil section conducts two parallel currents at a predetermined interval so as to sandwich the magnetic resonance member 61, and emits the microwaves described above. The coil section is, for example, a plate-shaped coil, and due to the skin effect, the microwave current flows through the end face of the coil section, thus forming the two currents described above. The coil section may also be formed of two conductors corresponding to the two currents described above. As a result, microwaves of substantially uniform intensity are applied to the magnetic resonance member 61. 【0043】 In the case of NV centers, color centers are formed in the diamond crystal by defects (vacancies) (V) and nitrogen (N) as impurities. There are four possible positions for adjacent nitrogen (N) atoms relative to defects (vacancies) (V) in the diamond crystal (i.e., the alignment direction of pairs of vacancies and nitrogen atoms), and the sub-levels after Zeeman splitting (i.e., energy levels from the ground) corresponding to each of these alignment directions are all different. Therefore, in the characteristics of fluorescence intensity after Zeeman splitting due to a static magnetic field with respect to microwave frequency, four distinct dip frequency pairs (fi+, fi-) appear, corresponding to each direction i (i = 1, 2, 3, 4). Here, the microwave frequency (wavelength) is set corresponding to one of these four dip frequency pairs. 【0044】 Furthermore, the magnet 63 applies a static magnetic field (DC magnetic field) to the magnetic resonance member 61, causing Zeeman splitting of the energy levels of multiple specific color centers (in this case, multiple NV centers) within the magnetic resonance member 61. Here, the magnet 63 is a ring-shaped permanent magnet, such as a ferrite magnet, alnico magnet, or samarium-cobalt magnet. Note that the magnet 63 may also be an electromagnet. 【0045】Furthermore, in the magnetic resonance member 61, the crystal of the magnetic resonance member 61 is formed and the orientation of the magnetic resonance member 61 is set such that the arrangement direction of the defects and impurities described above substantially coincides with the direction of the static magnetic field (and the direction of the applied magnetic field) described above. 【0046】 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. 【0047】 The observed light is focused toward the photoelectric element 52 by an optical system, such as a composite parabolic focuser (CPC). For example, a magnetic resonance member 61 is placed on the CPC, and of the fluorescence emitted in all directions from the color center within the magnetic resonance member 61, the fluorescence emitted over a wide solid angle (for example, a predetermined proportion or more of all directions) is focused by this optical system. 【0048】 The light-emitting device 65 is equipped with 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. 【0049】 The controller 66 controls (a) the high-frequency power supply 64 and the light-emitting device 65 according to a predetermined measurement sequence (e.g., Hahn echo sequence) to perform quantum operations with the microwave and laser light described above, generating observation light in the sensor body 51 and generating a sensor signal in the photoelectric element 52. 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 operations by loading the control program into RAM and executing it with the CPU. The controller 66 may be built into the control device 22, or the control device 22 may be configured to operate as the controller 66. 【0050】Figure 4 illustrates specific phases in a pseudo-IF signal. In this embodiment, for example, as shown in Figure 4, the phase detection unit 9 detects consecutive 0 degrees, 180 degrees, and 360 degrees as specific phases in the waveform of the pseudo-IF signal, and the optical quantum sensor unit 42 performs the above-mentioned quantum operation on the sensing member 1 by applying microwaves to the sensing member 1 at timings T1, T2, and T3 of the detected specific phases according to the Hahn echo sequence. According to the Hahn echo sequence, π / 2 pulse microwaves are applied at timings T1 and T3, and π pulse microwaves are applied at timing T2. 【0051】 Note that the frequency f of the pseudo-IF signal ＩＦ and the frequency (f) of the IF demodulated signal ＩＦ +f ＮＭＲ The difference between (=f) and ) ＮＭＲ ) has, f ＮＭＲ ga f ＩＦ Because it is sufficiently small, the pseudo-IF signal is almost synchronized with the IF demodulated signal (especially in the initial stages of observation), as shown in Figure 4, for example. Therefore, based on the synchronization signal described above, the quantum operations described above are performed at the appropriate timing in the IF demodulated signal. 【0052】 The measurement sequence is not limited to the Hahn echo sequence, but can be selected according to the frequency of the magnetic field being measured. For example, if the period of the magnetic field is greater than or equal to the T2 relaxation time, the magnetic field measurement is performed using multiple Ramsey pulse sequences as described above. If the period of the magnetic field is shorter than the T2 relaxation time, a spin echo pulse sequence (such as the Hahn echo sequence) may be applied. Furthermore, if the period of the magnetic field is shorter than half of the T2 relaxation time, the magnetic field measurement may be performed according to the Qdyne method. 【0053】 Returning to Figure 2, the A / D converter 43 digitizes the aforementioned sensor signal (without directly digitizing the input signal from the low-pass filter 7), thereby generating a digital IF demodulated signal corresponding to the input signal (analog IF demodulated signal), which is output via the output terminal 43a of the A / D converter 43. 【0054】In this embodiment, the optical quantum sensor unit 42 (specifically the sensor body 51) generates the aforementioned observation light on the sensing member (magnetic resonance member 61) such that the level of the sensor signal exceeds the noise floor of the A / D converter 43. 【0055】 Here, the level (amplitude) of the sensor signal changes depending on factors such as the efficiency of the sensing member (in Embodiment 1, the type and number of color centers in the magnetic resonance member 61, etc.), the light collection efficiency of the observed light (in Embodiment 1, the amount of incident light to 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 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 unit 42 is 1.5 pT / Hz. 1 / 2 That is considered to be the case. 【0056】 Furthermore, generally speaking, the noise of an A / D converter includes quantization noise and thermal noise, and in high-resolution A / D converters, thermal noise is dominant over quantization noise. In this embodiment, the A / D converter 43 is a high-resolution A / D converter, and the values ​​of the above-mentioned factors are determined so that the level of the sensor signal exceeds the noise level of the thermal noise. 【0057】 Furthermore, the reference voltage of the A / D converter 43 is set according to the range of the sensor signal (minimum level and maximum level). Note that lowering the reference voltage of the A / D converter reduces quantization noise, but does not reduce thermal noise. 【0058】 The level (or range) of the input IF demodulated signal and the electromagnetic conversion efficiency of the physical field generator 41 are known. 【0059】Furthermore, in this embodiment, the digitizing device 21 does not have an amplification circuit between the photoelectric element 52 and the A / D converter 43 to electrically increase the sensor signal. Moreover, in this embodiment, there is no amplification circuit between the input signal source and the physical field generator 41 to electrically increase the input signal. In other words, in this embodiment, there is no electrical amplification circuit upstream of the A / D converter 43 that would be a source of noise. In such an amplification circuit, thermal noise is generated and amplified, similar to the A / D converter 43, so noise is superimposed on the signal input to the A / D converter 43. Therefore, it is preferable that such an amplification circuit is not provided. 【0060】 Furthermore, the high-frequency power supply 64 and controller 66 are electrically isolated from the A / D converter 43, so that electrical noise generated by the high-frequency power supply 64 and controller 66 does not enter the A / D converter 43. 【0061】 Furthermore, in this embodiment 1, the optical quantum sensor unit 42 (controller 66) periodically and repeatedly performs quantum operations on the sensing member according to the synchronization signal to generate light corresponding to the magnetic field on the sensing member, thereby causing the digitizing device 21 to output a digital IF demodulated signal synchronized with the synchronization signal. Then, the control device 22, based on this digital IF demodulated signal, accurately determines the frequency f of the NMR signal according to the Qdyne method. ＮＭＲ Identify it. 【0062】 In this embodiment 1, neither an amplification 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. 【0063】 Furthermore, when controlling the high-frequency power supply 64 and the light-emitting device 65 to apply microwaves and excitation light to the magnetic resonance member 1 in a predetermined measurement sequence, in a normal Hahn echo pulse sequence (spin echo pulse sequence) or a normal dynamic decoupling, the reciprocal of the spin lock frequency of the microwave pulse sequence is 1 / f. ＬＯＣＫ) is the period of the measured AC field (1 / f ＡＣ ) is matched, but the controller 66 sets the reciprocal of the spinlock frequency of the microwave pulse sequence in the measurement sequence (1 / f ＬＯＣＫ ) is the period of the measured AC field (1 / f ＡＣ Microwaves and excitation light are applied to the magnetic resonance member 1 in a manner different from that described above. Here, f ＬＯＣＫ f is the spin lock frequency, ＡＣ f is the frequency of the AC field under measurement, and the AC field under measurement is the AC magnetic field or AC electric field applied to the sensing member (magnetic resonance member 61), and here, as described above, it is the frequency f generated by the physical field generator 41. ＡＣ It is the magnetic field. 【0064】 Figure 5 shows an example of a measurement sequence. Figure 5 shows the timing of the microwave pulse relative to the AC magnetic field under measurement, and the timing of the excitation light irradiation (twice, for initialization and measurement) in the measurement sequence of Embodiment 1. As shown in Figure 5, fluorescence is detected during the excitation light irradiation period for each measurement. 【0065】 In particular, the controller 66 applies a microwave pulse sequence based on a Hahn echo pulse sequence or dynamic decoupling to the magnetic resonance member 1. At that time, the reciprocal of the spinlock frequency of the microwave pulse sequence (1 / f) is applied. ＬＯＣＫ ) is the period of the measured AC field (1 / f ＡＣ This is different from the previous example. In Embodiment 1, a microwave pulse sequence based on a Hahn echo sequence (spin echo pulse sequence) is applied to the magnetic resonance member 1. 【0066】 The reciprocal of the spinlock frequency (1 / f) in the case of a Hahn echo pulse sequence. ＬＯＣＫ ) is the time length from the end of the first π / 2 pulse to the tip of the second π / 2 pulse, as shown in Figure 5, for example. In Embodiment 1, the controller 66 applies a microwave pulse sequence based on the Hahn echo pulse sequence to the magnetic resonance member 1 in the measurement sequence. However, the reciprocal of the spinlock frequency of the microwave pulse sequence (1 / f)ＬＯＣＫ ) is the period of the measured AC field (1 / f ＡＣ It is shorter than ). 【0067】 Figure 6 shows the spin lock frequency f ＬＯＣＫ and the frequency f of the AC field under measurement ＡＣ This figure illustrates the relationship between the intensity S of the sensor signal and the maximum value of the derivative (dS / dB) of the intensity S of the sensor signal with respect to the magnetic flux density B of the AC field being measured, max|dS / dB|. 【0068】 As shown in Figure 6, the intensity S of the sensor signal is B, f ＡＣ , and f ＬＯＣＫ It is a function, and max|dS / dB| is f ＡＣ and f ＬＯＣＫ It is a function of . In the equation shown in Figure 6, γ is the gyromagnetic ratio (constant), and φ ０ This is the phase difference between the microwave pulse sequence and the AC field being measured. 【0069】 Here, as shown in Figure 6 for example, dS / dB represents the slope, and the larger dS / dB, the higher the sensitivity. Therefore, under the condition that max|dS / dB| is maximized, f ＡＣ and f ＬＯＣＫ It is preferable that this is set. 【0070】 Figure 7 shows the frequency f of the AC field under measurement. ＡＣ This figure illustrates the distribution of sensor signal strength S (relative value) with respect to phase shift. In Figure 7, the sensor signal strength S (relative value) is represented by contour lines. Figure 8 shows the frequency f of the AC field under measurement in Embodiment 1. ＡＣ This figure illustrates the maximum value of the slope with respect to θ, max|dS / dB|. 【0071】 For example, as shown in Figure 7, the sensor signal strength S changes depending on the magnitude of the phase shift between the AC field under measurement and the measurement sequence, but for example, as shown in Figures 7 and 8, the maximum value of the sensor signal strength S is f ＡＣ ga f ＬＯＣＫ If it is the same as f ＡＣ ga f ＬＯＣＫ The value becomes larger when the value is lower. Note that Figure 8 shows f without considering phase shift. ＡＣIt shows the maximum slope value max|dS / dB| at each value of 【0072】 That is, the maximum value (max|dS / dB|) of the differential (dS / dB) of the intensity S of the sensor signal with respect to the magnetic flux density B of the measured AC field is the spin-lock frequency f of the microwave pulse sequence ＬＯＣＫ is the frequency f of the measured AC field ＡＣ is set to be greater than when it coincides with the frequency f of the measured AC field ＬＯＣＫ and the frequency f of the measured AC field ＡＣ are set. Note that the frequency f of the measured AC field ＡＣ is preferably set to the peak frequency (or its vicinity) of the characteristic curve in FIG. 8. 【0073】 Also, when there is a possibility that the frequency f of the measured AC field ＡＣ has a variation or deviation of a predetermined width, by setting the spin-lock frequency so that a measurement band of a predetermined width including the peak frequency of the characteristic curve in FIG. 8 becomes the frequency band of interest, the maximum slope value (max|dS / dB|) (that is, the sensitivity) can be measured under good conditions. 【0074】 As described above, the optical quantum sensor unit 42 has uncertain sensitivity characteristics and non-uniform output intensity characteristics in a predetermined frequency range (the range of the frequency f of the applied AC field ＡＣ ). Here, the sensitivity characteristics and output intensity characteristics are uncertain in the above frequency range because, as described above, the reciprocal of the spin-lock frequency is different from the period (1 / f ＡＣ ) of the magnetic field or electric field applied to the sensing member. The above correction processing unit 22b performs correction of the IF demodulation signal corresponding to the frequency f ＡＣ of the magnetic field or electric field applied to the sensing member so as to make the frequency characteristics of the IF demodulation signal in that frequency range closer to constant (that is, the gain of each frequency becomes constant). That is, the value of the IF demodulation signal is corrected by the correction coefficient corresponding to the frequency f ＡＣ . 【0075】In this embodiment, calibration data corresponding to the output intensity characteristics is stored in the storage device 22a, and the correction processing unit 22b performs the above-mentioned correction processing by referring to the calibration data. For example, the calibration data is for each frequency f ＡＣ Regarding its frequency f ＡＣ The calibration data includes the signal strength and a correction coefficient obtained from that signal strength. The correction processing unit 22b refers to the calibration data and performs the correction process by multiplying the sensor signal value by the correction coefficient corresponding to the frequency of the magnetic field or electric field. 【0076】 Furthermore, the frequency range described above is set according to the chemical shift of one or more specific molecular structures. Here, the frequency range described above is defined as the range that includes the appearance range of one or more specific molecular structure chemical shifts. 【0077】 Note that the chemical shift (ppm) and the frequency f of the NMR signal are different. ＮＭＲ The relationship is as follows: 【0078】 f ＮＭＲ = f ＲＦ × Chemical shift (ppm) 【0079】 Furthermore, the frequency f of the alternating current field (magnetic field or electric field) applied to the magnetic resonance member 61 ＡＣ is, f ＡＣ = f ＩＦ +f ＮＭＲ Because they have the relationship described below, f ＩＦ When f is kept constant, the above frequency range corresponds to the chemical shift of one or more specific molecular structures. ＡＣ It is set to include all of the above. 【0080】 For example, the target nucleus of NMR １ H (proton) and the frequency f of the RF signal ＲＦ When the NMR resonance frequency is 43 MHz, and the range of chemical shifts to be detected is set to -2 ppm to 18 ppm, the frequency of the NMR signal f ＮＭＲ The range is -86Hz to 774Hz, and the above f ＡＣ The frequency range (i.e., the frequency range in which the IF demodulated signal should be corrected) is the intermediate frequency f ＩＦBased on this, the frequency f of the NMR signal ＮＭＲ It is set according to the range. 【0081】 Furthermore, if the molecular structure of the target is unknown, the above-mentioned frequency range may be set by the user as appropriate. 【0082】 Figure 9 illustrates the sampling of a sensor signal. For example, as shown in Figure 9, when the A / D converter 43 samples and digitizes the sensor signal at a predetermined sampling frequency fs under undersampling conditions, the observable bandwidth of the digitized sensor signal will be from 0 to fs / 2. 【0083】 Figure 10 illustrates the sensor signal appearing in the observable bandwidth. For example, as shown in Figure 10, if the sensor signal contains unwanted components in addition to the components of the AC field being measured, aliasing may cause these unwanted components to enter the observable bandwidth. Therefore, in order to attenuate such unwanted components, filtering is performed on the sensor signal to attenuate bandwidths other than the predetermined measurement bandwidth. This measurement bandwidth is set corresponding to the sampling frequency fs. This filtering may be performed by an analog circuit for the sensor signal as an analog signal, or by a digital signal processor or the control device 22 described above for the sensor signal as a digital signal. 【0084】 Figure 11 illustrates the case where the above-described filtering process attenuates the bandwidth corresponding to the range from half the sampling frequency fs (fs / 2) to the sampling frequency fs. For example, the above-described measurement bandwidth corresponds to the range from 0 to half the sampling frequency fs, and includes the peak frequency which is the maximum value (max |dS / dB|) of the derivative of the intensity of the sensor signal with respect to the magnetic flux density of the AC field under measurement, by setting the spinlock frequency f ＬＯＣＫThis is set. In this case, aliasing is suppressed, and as shown in Figure 11, for example, the measurement bandwidth is set to a range between a frequency that is an integer (n-1) multiple of the sampling frequency fs ((n-1)fs) and a frequency that is an integer (n-1) multiple of the sampling frequency fs plus half of the sampling frequency fs ((n-1)fs + fs / 2), thereby enabling the detection of the sensor signal with good sensitivity in the observable bandwidth. 【0085】 Figure 12 illustrates the case where the filtering process described above attenuates the bandwidth corresponding to the range from 0 to half the sampling frequency (fs / 2). For example, the spinlock frequency f is set such that the measurement bandwidth corresponds to the range from half the sampling frequency fs to the sampling frequency fs, and includes the peak frequency which is the maximum value of the derivative of the intensity of the sensor signal with respect to the magnetic flux density of the AC field under measurement. ＬＯＣＫ This is set. In this case, assuming aliasing is used, for example as shown in Figure 12, the measurement bandwidth is set to the range between the frequency obtained by adding half of the sampling frequency fs to an integer (n-1) multiple of the sampling frequency fs ((n-1)fs + fs / 2) and the frequency which is an integer n multiple of the sampling frequency fs (nfs), thereby enabling the detection of the sensor signal with good sensitivity in the observable bandwidth. In this case, due to aliasing, the sensor signal is detected at a frequency symmetric to (n-1 / 2) × fs. 【0086】 Next, the operation of the nuclear magnetic resonance sensing device according to Embodiment 1 will be described. 【0087】 The control device 22 controls the nuclear magnetic resonance sensing unit 1 and the switching unit 4 to apply a high-frequency magnetic field based on the RF signal from the transmitting 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. 【0088】As shown in Figure 1, the observed signal is converted into an IF demodulated signal based on the LO signal by the mixer unit 6, and the IF demodulated signal, from which the high-frequency band components have been removed by the low-pass filter 7, is input to the digitizer 21. 【0089】 Furthermore, the mixer unit 8 generates a pseudo-IF signal from the RF signal and the LO signal, and the phase detection unit 9 generates a synchronization signal indicating a specific phase from the pseudo-IF signal. 【0090】 In the digitizing device 21, when the IF demodulated signal is applied to the physical field generator 41, the physical field generator 41 generates a magnetic field of an intensity corresponding to the level of the input signal, which is applied to the sensor body 51 of the optical quantum sensor unit 42. 【0091】 In the sensor body 51, the measurement sequence is executed in synchronization with the synchronization signal as described above, and light is generated with an intensity corresponding to the strength of the magnetic field. In Embodiment 1, according to the ODMR, the magnetic resonance member 61 generates light with an intensity corresponding to the strength of the magnetic field. 【0092】 Specifically, the controller 66 executes a measurement sequence continuously, as shown in Figure 5, for example, and each measurement sequence (in Embodiment 1, f ＡＣ higher f ＬＯＣＫ In the Hahn echo sequence, the light-emitting device 12 emits excitation light, and the high-frequency magnetic field generator 62 emits microwaves. 【0093】 Then, the photoelectric element 52 receives the light generated by the sensor body 51, generates a sensor signal with a level corresponding to the amount of light received, and outputs it to the A / D converter 43. 【0094】 The A / D converter 43 digitizes the sensor signal, generates a digital IF demodulated signal corresponding to the analog IF demodulated signal, and outputs it to the control device 22. 【0095】In the control device 22, the correction processing unit 22b continuously and repeatedly acquires the value of the digital IF demodulated signal and corrects the value of the digital IF demodulated signal based on the calibration data as described above. The identification processing unit 22c then derives an NMR signal and an NMR spectrum from the corrected IF demodulated signal through signal processing and performs molecular structure analysis of the target object 101 based on the NMR spectrum. 【0096】 Figure 13 illustrates the correction process based on calibration data and the derivation of the NMR spectrum. For example, as shown in Figure 13, the output intensity characteristics are specified as calibration data within the calibration range (the frequency range described above), and the intensity of the IF demodulated signal (i.e., the sensor signal described above) is corrected based on the calibration data. Specifically, for each frequency in the output intensity characteristics, the ratio of the signal intensity S at that frequency to the signal intensity So at the reference frequency (S / So) is used as the correction coefficient, and the intensity of the IF demodulated signal obtained at that frequency is multiplied by this coefficient to correct the intensity of the IF demodulated signal. The reference frequency is the frequency f of the IF demodulated signal obtained for a standard sample (here, TMS). ＡＣ Therefore, as shown in Figure 13, for example, the NMR spectrum is obtained as the frequency shift and relative intensity relative to the frequency (reference frequency) and intensity of the standard sample. 【0097】 Here, the identification processing unit 22c derives an NMR spectrum based on the corrected IF demodulated signal, and identifies the molecular structure (such as a functional group) and its quantity contained in the target object based on the peak position and peak shape in the NMR spectrum. 【0098】 The NMR spectrum shows the relative frequency (ppm) and relative intensity relative to the frequency and intensity of the standard sample (in this case, TMS). 【0099】 Figure 14 shows １This figure shows the NMR spectrum of ethylbenzene with respect to H. For example, as shown in Figure 14, in the case of ethylbenzene, peaks for methyl, methylene, and phenyl groups appear in the NMR spectrum. In other words, if the identification processing unit 22c detects peaks like those shown in Figure 14 in the NMR spectrum, it determines that the target object contains methyl, methylene, and phenyl groups, and determines that it contains ethylbenzene based on the ratio of the number of methyl, methylene, and phenyl groups. 【0100】 As described above, according to Embodiment 1, the nuclear magnetic resonance sensing unit 1 applies a high-frequency magnetic field based on an RF signal to the target object, and the frequency f of the RF signal ＲＦ From the frequency f of the nuclear magnetic resonance signal ＮＭＲ The system generates an observation signal with a frequency shifted by a certain amount. The mixer section 6 performs intermediate frequency demodulation of the observation signal to generate an intermediate frequency demodulated signal that includes the nuclear magnetic resonance signal. The low-pass filter 7 attenuates unwanted band components in the intermediate frequency demodulated signal, and the intermediate frequency f of the intermediate frequency demodulation is reduced. ＩＦ From the frequency f of the nuclear magnetic resonance signal ＮＭＲ The frequency components shifted by only a certain amount are transmitted. The digitizing device 21 digitizes the intermediate frequency demodulated signal that has passed through the low-pass filter 7. The correction processing unit 22b performs correction processing on the sensor signal after digitization. The digitizing device 21 includes a physical field generator 41 that generates a magnetic field or electric field corresponding to the intermediate frequency demodulated signal that has passed through the low-pass filter 7, an optical quantum sensor unit 42 that generates light corresponding to the magnetic field or electric field with a sensing member and converts the light into an electrical signal as a sensor signal with a photoelectric element, and an A / D converter 43 that digitizes the sensor signal and generates a digital intermediate frequency demodulated signal. The optical quantum sensor unit 42 (a) performs quantum operations on the sensing member to generate the light corresponding to the magnetic field or electric field with the sensing member, and (b) has non-uniform output intensity characteristics in a predetermined frequency range. Then, in the correction processing, the correction processing unit 22b adjusts the frequency f of the magnetic field or electric field to bring the frequency characteristics of the intermediate frequency demodulated signal in the above frequency range closer to a constant value, corresponding to its output intensity characteristics. ＡＣThe intermediate frequency demodulated signal is corrected accordingly. 【0101】 As a result, the intensity of the intermediate frequency demodulated signal, which fluctuates due to sensitivity variations in the optical quantum sensor unit 42 that depend on the frequency of the applied magnetic field, is compensated for. Therefore, when performing nuclear magnetic resonance sensing on an object that has a chemical shift, specific molecular structures contained in the object can be quantitatively and accurately identified. 【0102】 Embodiment 2. 【0103】 Figure 15 is a diagram illustrating the identification of calibration data in Embodiment 2. In Embodiment 2, the above-mentioned calibration data is the intermediate frequency f of intermediate frequency demodulation for a specific target object. ＩＦ By changing the frequency f of multiple magnetic or electric fields in the above frequency range, for example, as shown in Figure 15, ＡＣ This is set based on the intensity distribution of the sensor signal obtained. The specific target object may be the standard sample mentioned above or other substances. The calibration data may be its intensity distribution or the distribution of the ratio S / So (correction coefficient) mentioned above. If the calibration data is an intensity distribution, the correction coefficient is derived from the intensity values ​​in the calibration data during the correction process. 【0104】 The other configurations and operations of the nuclear magnetic resonance sensing device according to Embodiment 2 are the same as those of any of the other embodiments, so their description will be omitted. 【0105】 Embodiment 3. 【0106】 In Embodiment 3, the above-mentioned calibration data is obtained in a predetermined frequency range (i.e., the range in which calibration should be performed), and includes the spin lock frequency and the magnetic field frequency f. ＡＣ It is calculated based on the following. Specifically, for example, the signal strength S shown in Figure 6 is used for each frequency f. ＡＣ Calibration data is derived by deriving the following. The calibration data may be the intensity distribution or the distribution of the ratio S / So described above. In Embodiment 3, the calibration data may be calculated in advance and stored in the storage device 22a, or it may be calculated during the correction process. 【0107】Figure 16 is a diagram illustrating the setting of the intermediate frequency in Embodiment 3. In Embodiment 3, the intermediate frequency f described above is ＩＦ As shown in Figure 16, for example, the frequency f corresponds to the median of the range of chemical shifts (chemical shift range) for multiple specific molecular structures. ＡＣ This is set to match the peak frequency of the sensitivity characteristic (i.e., the frequency at which sensitivity is maximum). 【0108】 For example, the spinlock frequency f ＬＯＣＫ When f is 20 kHz and the peak frequency of the sensitivity characteristic is 15 kHz, ＲＦ When the frequency is 43 MHz and the target range for chemical shift is -2 to 18 ppm, f ＮＭＲ The range is -86 Hz to 774 Hz. 【0109】 In this case, f ＮＭＲ Since the median of the range is 344 Hz, f ＮＭＲ = f at 344 Hz ＡＣ The intermediate frequency f is set so that the peak frequency matches 15 kHz. ＩＦ It is said to be 14.656 kHz (= 15 kHz - 344 Hz). Therefore, in this case, f ＡＣ The frequency range is 14.57 kHz to 15.43 kHz. 【0110】 Furthermore, as shown above, f ＡＣ When the frequency range is 14.57 kHz to 15.43 kHz, and digitization is performed with a sampling frequency fs of 13 kHz, an undersampling condition is met. As described above, in the observable bandwidth of 0 to 6.5 kHz, the peak of the IF demodulated signal is observed at a frequency between 1.57 kHz and 2.43 kHz. In the case of an undersampling condition, the original f is obtained from the frequency of the peak observed in the observable range. ＡＣ The frequency, and therefore f ＮＭＲ The frequency and chemical shift are derived. 【0111】 Furthermore, the other configurations and operations of the nuclear magnetic resonance sensing device according to Embodiment 3 are the same as those of any of the other embodiments, so their description will be omitted. 【0112】 Embodiment 4. 【0113】 Figure 17 is a diagram illustrating the setting of the intermediate frequency in Embodiment 4. In Embodiment 4, if the molecular structure to be detected in the target object is specified, the intermediate frequency f ＩＦ This is the frequency f corresponding to the frequency of the chemical shift of that particular molecular structure. ＡＣ This is set to match the peak frequency of the sensitivity characteristics. 【0114】 For example, the spinlock frequency f ＬＯＣＫ When f is 20 kHz and the peak frequency of the sensitivity characteristic is 15 kHz, ＲＦ When the frequency is 43 MHz and the chemical shift of the target molecular structure is 10 ppm, f ＮＭＲ This becomes 430 Hz. In this case, f ＡＣ The intermediate frequency f is set so that the peak frequency matches 15 kHz. ＩＦ It is said to be 14.57 kHz (= 15 kHz - 430 Hz). 【0115】 Furthermore, the frequency f of the IF demodulated signal is as described above. ＡＣ When the frequency is 15 kHz, and digitization is performed with a sampling frequency fs of 12 kHz, an undersampling condition is met. As described above, in the observable bandwidth of 0-6 kHz, the peak of the digital IF demodulated signal is observed at 3 kHz (= 15 kHz - 12 kHz). In the case of undersampling, the original f is obtained from the frequency of the peak observed within the observable range. ＡＣ The frequency, and therefore f ＮＭＲ The frequency and chemical shift are derived. 【0116】 Furthermore, the other configurations and operations of the nuclear magnetic resonance sensing device according to Embodiment 4 are the same as those of any of the other embodiments, so their description will be omitted. 【0117】 Embodiment 5. 【0118】Figure 18 is a diagram illustrating the setting of the spinlock frequency in Embodiment 5. In Embodiment 5, if the molecular structure to be detected in the target object is specified, the spinlock frequency f ＬＯＣＫ This is the frequency f corresponding to the frequency of the chemical shift of that particular molecular structure. ＡＣ This is set to match the peak frequency of the sensitivity characteristic. In other words, the spin lock frequency f ＬＯＣＫ When this changes, the sensitivity characteristics change, and the peak frequency of the sensitivity characteristics also changes. Therefore, the peak frequency of the sensitivity characteristics corresponds to the frequency f of the chemical shift of that particular molecular structure. ＡＣ It will be adjusted to match. 【0119】 For example, f ＲＦ If the frequency is 43 MHz and the chemical shift of the target molecular structure is 5 ppm, then f ＮＭＲ This becomes 215 Hz, and the intermediate frequency f ＩＦ If it is set to 13 kHz, the frequency of the IF demodulated signal f ＡＣ This corresponds to 13.215 kHz. 【0120】 Therefore, to ensure that the peak frequency of the sensitivity characteristic is 13.215 kHz, the spin lock frequency f is determined based on the relationship shown in Figure 6, for example. ＬＯＣＫ The following is set. Here, the spinlock frequency f ＬＯＣＫ It is set to 17.62 kHz. 【0121】 Furthermore, f ＡＣ When the frequency is 13.215 kHz, and digitization is performed with a sampling frequency fs of 12 kHz, an undersampling condition is met. As described above, in the observable bandwidth of 0-6 kHz, the peak of the digital IF demodulated signal is observed at 1.215 kHz (= 13.215 kHz - 12 kHz). In the case of undersampling, the original f is obtained from the frequency of the peak observed in the observable range. ＡＣ The frequency, and therefore f ＮＭＲ The frequency and chemical shift are derived. 【0122】The other configurations and operations of the nuclear magnetic resonance sensing device according to Embodiment 5 are the same as those of any of the other embodiments, so their description will be omitted. 【0123】 Embodiment 6. 【0124】 Figure 19 is a diagram illustrating the measurement sequence (dynamic decoupling) in Embodiment 6. In Embodiment 6, dynamic decoupling is used as the measurement sequence, for example, as shown in Figure 19. Examples of dynamic decoupling include XY8-k and CPMG (Carr-Purcell-Meiboom-Gill). 【0125】 In the optical quantum sensor unit 42, the controller 66 applies a microwave pulse sequence based on dynamic decoupling to the magnetic resonance member 1 during this measurement sequence. However, the reciprocal of the spinlock frequency of the microwave pulse sequence (1 / f) is used. ＬＯＣＫ ) is the period of the measured AC field (1 / f ＡＣ It is longer than ). Note that in the case of dynamic decoupling, the reciprocal of the spin lock frequency (1 / f) ＬＯＣＫ ) is the time length from the center of the first π pulse to the center of the last π pulse in a sequence of N π pulses, as shown in Figure 19, for example. 【0126】 Figure 20 shows the frequency f of the AC field under measurement in Embodiment 6. ＡＣ This figure illustrates the maximum value of the slope with respect to θ, max|dS / dB|. 【0127】 In the case of dynamic decoupling, for example, as shown in Figure 20, the frequency f of the AC field under measurement ＡＣ The characteristic of the maximum slope value max|dS / dB| with respect to changes depending on the number of π pulses N, but the peak frequency is the spinlock frequency f ＬＯＣＫ It is higher. Therefore, the frequency f of the AC field being measured ＡＣ However, the spin lock frequency f ＬＯＣＫ It is set higher. In other words, the reciprocal of the spinlock frequency of the microwave pulse sequence (1 / fＬＯＣＫ ) is the period of the measured AC field (1 / f ＡＣ It will be set to be longer than ). 【0128】 The other configurations and operations of the nuclear magnetic resonance sensing device according to Embodiment 6 are the same as those of any of the other embodiments, so their description will be omitted. 【0129】 Furthermore, various changes and modifications to the embodiments described above will be obvious to those skilled in the art. Such changes and modifications may be made without deviating from the spirit and scope of the subject matter and without diminishing the intended advantages. In other words, such changes and modifications are intended to be included in the claims. 【0130】 For example, in the above embodiment, quadrature phase detection may be performed. In that case, specifically, the above-described LO signal and the LO signal after a 90-degree phase shift are used, and the above-described signal processing is performed on each to demodulate each IF demodulated signal to obtain the demodulated signal I and the demodulated signal Q (frequency component f). ＮＭＲ ) are generated and predetermined signal processing is performed to obtain an NMR signal (frequency component f ＮＭＲ Extract the following: 【0131】 Furthermore, in the above embodiment, the measurement method in the sensor body 51 is not limited to the ODMR described above, and any other measurement method is acceptable as long as it uses a sensing member corresponding to a physical field such as an electric field, performs quantum operations on the sensing member, and can detect observed light corresponding to the physical field intensity. 【0132】 Furthermore, in the above embodiment, the control device 22 may perform predetermined calculation processing on the output signal of the digitizing device 21 so that the value of the output signal (digital value) matches the level of the analog IF demodulated signal. 【0133】 Furthermore, in the above embodiment, a low-noise buffer (voltage amplification = 1) that satisfies the noise level requirement may be provided between the low-pass filter 7 and the digitizing device 21, if necessary. 【0134】Furthermore, although digitization is performed under undersampling conditions in the above embodiment, the sampling conditions are not limited to undersampling conditions. 【0135】 Furthermore, in the above embodiment, for the identification of molecular structure based on chemical shift １ The NMR spectrum of H has been derived, but instead, １３ The NMR spectra of other atomic nuclei, such as carbon (C), may also be derived. 【0136】 Furthermore, in the above embodiment, the spin lock frequency f ＬＯＣＫ and the frequency f of the IF demodulated signal ＡＣ Although the sensitivity characteristics and output intensity characteristics are inconsistent due to this, even if the output intensity characteristics are inconsistent due to other factors (e.g., frequency (wavelength) characteristics of the optical system), the same correction as described above compensates for the intensity of the IF demodulated signal that has fluctuated due to the inconsistency of the output intensity characteristics. 【0137】 Furthermore, the part that generates the analog IF demodulated signal in the above embodiment is not limited to what has been described above, but may also be the one described in International Publication No. 2023 / 089883, International Publication No. 2024 / 224587, etc. In other words, unwanted frequency band components are removed and the intermediate frequency f ＩＦ From the frequency f of the NMR signal ＮＭＲ All that is needed is an IF demodulated signal with a frequency shifted by that amount. 【0138】 The present invention can be applied, for example, to various measurements and imaging using nuclear magnetic resonance.

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 with 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 and generates an intermediate frequency demodulated signal including the nuclear magnetic resonance signal; a low-pass filter that transmits a frequency component in the intermediate frequency demodulated signal that is shifted from the intermediate frequency of the intermediate frequency demodulation by the frequency of the nuclear magnetic resonance signal; a digitizing device that digitizes the intermediate frequency demodulated signal that has passed through the low-pass filter; and a correction processing unit that performs correction processing on the intermediate frequency demodulated signal after digitization. The digitizing device comprises a physical field generator that generates a magnetic field or electric field corresponding to the intermediate frequency demodulated signal transmitted through the low-pass filter; an optical quantum sensor unit that generates light corresponding to the magnetic field or electric field using a sensing member and converts the light into an electrical signal as a sensor signal using a photoelectric element; and an analog-to-digital converter that digitizes the sensor signal to generate a digital intermediate frequency demodulated signal, wherein the optical quantum sensor unit (a) performs quantum operations on the sensing member to generate light corresponding to the magnetic field or electric field on the sensing member, and (b) has an inconsistent output intensity characteristic in a predetermined frequency range, and the correction processing unit, in the correction processing, corrects the intermediate frequency demodulated signal in accordance with the frequency of the magnetic field or electric field so that the frequency characteristics of the intermediate frequency demodulated signal in the frequency range corresponding to the output intensity characteristic become closer to constant.

2. The sensing member is a magnetic resonance member whose electron spin quantum state changes in response to the magnetic field and which is capable of electron spin quantum manipulation with microwaves, and the optical quantum sensor unit comprises the sensing member, a high-frequency magnetic field generator that performs electron spin quantum manipulation of the magnetic resonance member with microwaves, a high-frequency power supply that generates microwaves in the high-frequency magnetic field generator, a light-emitting device that emits excitation light to be irradiated onto the magnetic resonance member, a light-receiving device that receives fluorescence emitted by the magnetic resonance member in response to the excitation light and generates a sensor signal corresponding to the intensity of the fluorescence, and a controller that controls the high-frequency power supply and the light-emitting device to apply the microwaves and the excitation light to the magnetic resonance member in a predetermined measurement sequence, the controller applies a microwave pulse sequence based on a Hahn echo pulse sequence or dynamic decoupling to the magnetic resonance member, the reciprocal of the spin lock frequency of the microwave pulse sequence is different from the period of the magnetic field, and the output intensity characteristics are inconsistent in the frequency range due to the reciprocal of the spin lock frequency being different from the period of the magnetic field. A nuclear magnetic resonance sensing device according to claim 1, characterized by the following:

3. A nuclear magnetic resonance sensing device according to claim 1 or 2, further comprising a storage device for storing calibration data corresponding to the output intensity characteristics, wherein the correction processing unit performs the correction processing by referring to the calibration data, and the calibration data is set for a specific target object based on the distribution of the intensity of the sensor signal obtained at multiple magnetic field frequencies in the frequency range by changing the intermediate frequency of the intermediate frequency demodulation.

4. The nuclear magnetic resonance sensing device according to claim 2, characterized in that the correction processing unit performs the correction processing by referring to the calibration data, and the calibration data is calculated based on the spin lock frequency and the frequency of the magnetic field or electric field.

5. The nuclear magnetic resonance sensing device according to claim 1, characterized in that the intermediate frequency of the intermediate frequency demodulation is set such that the frequency of the magnetic field or electric field corresponding to the median of the appearance range of chemical shifts of a plurality of specific molecular structures matches the peak frequency of the sensitivity characteristics of the optical quantum sensor unit.

6. The nuclear magnetic resonance sensing device according to claim 1, characterized in that the intermediate frequency of the intermediate frequency demodulation is set such that the frequency of the magnetic field or electric field corresponding to the frequency of the chemical shift of one specific molecular structure matches the peak frequency of the sensitivity characteristics of the optical quantum sensor unit.

7. The nuclear magnetic resonance sensing device according to claim 2, characterized in that the spin lock frequency is set such that the frequency of the magnetic field or electric field corresponding to the frequency of the chemical shift of one specific molecular structure matches the peak frequency of the sensitivity characteristics of the optical quantum sensor.

8. The nuclear magnetic resonance sensing device according to claim 1, characterized in that the frequency range is set according to the range of appearance of chemical shifts of one or more specific molecular structures.

9. The method comprises the steps of: applying a high-frequency magnetic field based on an RF signal to a target object and generating an observation signal with 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; using a low-pass filter to transmit frequency components in the intermediate frequency demodulated signal that are shifted from the intermediate frequency of the intermediate frequency demodulation by the frequency of the nuclear magnetic resonance signal; digitizing the intermediate frequency demodulated signal that has passed through the low-pass filter; and performing correction processing on the intermediate frequency demodulated signal after digitization. A nuclear magnetic resonance sensing method characterized by the following steps: (a) generating a magnetic field or electric field corresponding to the intermediate frequency demodulated signal transmitted through the low-pass filter; (b) generating light corresponding to the magnetic field or electric field in a sensing member using an optical quantum sensor unit, and converting the light into an electrical signal as a sensor signal using a photoelectric element; (c) digitizing the sensor signal with an analog-to-digital converter to generate a digital intermediate frequency demodulated signal; the optical quantum sensor unit (a) performing quantum operations on the sensing member to generate light corresponding to the magnetic field or electric field in the sensing member; and (b) having an inconsistent output intensity characteristic in a predetermined frequency range; and the correction process correcting the intermediate frequency demodulated signal in accordance with the frequency of the magnetic field or electric field so that the frequency characteristics of the intermediate frequency demodulated signal in the frequency range become closer to constant in accordance with the output intensity characteristic.

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