US-12625205-B2 - Nuclear magnetic resonance sensing device and nuclear magnetic resonance sensing method

US12625205B2US 12625205 B2US12625205 B2US 12625205B2US-12625205-B2

Abstract

A nuclear magnetic resonance sensor applies a high frequency magnetic field based on an RF signal to a target and generates an observation signal with a frequency shifted from that of the RF signal by a frequency of an NMR signal. A mixer generates an IF demodulation signal including the NMR signal. A low-pass filter passes a low frequency component of the IF demodulation signal. In a digitizing device, a physical field generator generates a magnetic field corresponding to the IF demodulation signal passed through the low-pass filter, an optical quantum sensor generates light corresponding to the magnetic field by a sensing member and converts the light into a sensor signal by a photoelectric element, and an analog/digital converter digitizes the sensor signal. The optical quantum sensor performs a quantum operation on the sensing member and causes the sensing member to generate the light corresponding to the magnetic field.

Inventors

Izuru Ohki
Norikazu MIZUOCHI
Yoshiharu Yoshii
Tsunaki KANEKO
Akifumi Sako

Assignees

SUMIDA CORPORATION
KYOTO UNIVERSITY

Dates

Publication Date: 20260512
Application Date: 20220812
Priority Date: 20211119

Claims (11)

1 . A nuclear magnetic resonance sensing device comprising: a nuclear magnetic resonance sensing part that applies a high frequency magnetic field based on an RF signal to a target object and generates an observation signal with a frequency that is shifted from a frequency of the RF signal by a frequency of a nuclear magnetic resonance signal; a mixer part that performs intermediate frequency demodulation of the observation signal and generates an intermediate frequency demodulation signal including the nuclear magnetic resonance signal; a low-pass filter that attenuates a high frequency component higher than an intermediate frequency of the intermediate frequency demodulation of the intermediate frequency demodulation signal and passes a frequency component of the nuclear magnetic resonance signal; and a digitizing device that digitizes the intermediate frequency demodulation signal that has passed through the low-pass filter, wherein the digitizing device includes: a physical field generator that generates a magnetic field or an electric field corresponding to the intermediate frequency demodulation signal that has passed through the low-pass filter; an optical quantum sensor part that generates light corresponding to the magnetic field or the electric field by a sensing member and converts the light into an electrical signal as a sensor signal by a photoelectric element; and an analog/digital converter that digitizes the sensor signal, and the optical quantum sensor part performs a quantum operation with respect to the sensing member and causes the sensing member to generate the light corresponding to the magnetic field or the electric field.
2 . The nuclear magnetic resonance sensing device according to claim 1 , further comprising: a base signal generation device that generates a RF base signal and an intermediate frequency base signal; and a transmission system mixer part that mixes the RF base signal and the intermediate frequency base signal to generate the RF signal, wherein the mixer part performs the intermediate frequency demodulation of the observation signal by the RF base signal to generate the intermediate frequency demodulation signal including the nuclear magnetic resonance signal, and the optical quantum sensor part uses the intermediate frequency base signal as a synchronizing signal, performs the quantum operation with respect to the sensing member according to the synchronizing signal periodically and repeatedly, and causes the sensing member to generate the light corresponding to the magnetic field or the electric field.
3 . The nuclear magnetic resonance sensing device according to claim 1 , wherein neither an amplifier circuit nor a buffer is provided between the nuclear magnetic resonance sensing part and the digitizing device.
4 . The nuclear magnetic resonance sensing device according to claim 1 , wherein the optical quantum sensor part causes the sensing member to generate the light so that a level of the sensor signal exceeds a noise floor of the analog/digital converter.
5 . The nuclear magnetic resonance sensing device according to claim 1 , Wherein an amplifier circuit in which the sensor signal is increased is not provided between the photoelectric element and the analog/digital converter.
6 . The nuclear magnetic resonance sensing device according to claim 1 , wherein the optical quantum sensor part performs the quantum operation with respect to the sensing member according to an optically detected magnetic resonance measuring method or an optically pumped atomic magnetic force measurement method, and causes the sensing member to generate the light corresponding to the magnetic field or the electric field.
7 . A nuclear magnetic resonance sensing device comprising: a nuclear magnetic resonance sensing part that applies a high frequency magnetic field based on an RF signal to a target object and generates an observation signal with a frequency that is shifted from a frequency of the RF signal by a frequency of a nuclear magnetic resonance signal; a mixer part that performs intermediate frequency demodulation of the observation signal and generates an intermediate frequency demodulation signal including the nuclear magnetic resonance signal; a low-pass filter that attenuates a high frequency component higher than an intermediate frequency of the intermediate frequency demodulation of the intermediate frequency demodulation signal and passes a frequency component of the nuclear magnetic resonance signal; an analog quadrature phase detection circuit that performs quadrature phase detection with respect to the intermediate frequency demodulation signal that has passed through the low-pass filter and generates a demodulation signal and a demodulated signal of the nuclear magnetic resonance signal; and a digitizing device that digitizes the demodulation signal and the demodulated signal, wherein the digitizing device includes: a first physical field generator that generates a magnetic field or an electric field corresponding to the demodulation signal; a second physical field generator that generates a magnetic field or an electric field corresponding to the demodulated signal; a first optical quantum sensor part that generates light, by a first sensing member, corresponding to the magnetic field or the electric field generated by the first physical field generator and converts, by a first photoelectric element, the light generated by the first sensing member into an electrical signal as a first sensor signal; a second optical quantum sensor part that generates light, by a second sensing member, corresponding to the magnetic field or the electric field generated by the second physical field generator and converts, by a second photoelectric element, the light generated by the second sensing member into an electrical signal as a second sensor signal; a first analog/digital converter that digitizes the first sensor signal; and a second analog/digital converter that digitizes the second sensor signal, and the first and second optical quantum sensor parts respectively perform quantum operations with respect to the first and second sensing members and respectively cause the first and second sensing members to generate the lights corresponding to the magnetic fields or the electric fields.
8 . The nuclear magnetic resonance sensing device according to claim 7 , wherein the first and second optical quantum sensor parts respectively perform the quantum operations with respect to the first and second sensing members by irradiating common laser light thereto and respectively cause the first and second sensing members to generate the lights corresponding to the magnetic fields or the electric fields.
9 . The nuclear magnetic resonance sensing device according to claim 8 , further comprising: a third photoelectric element that converts reference light that is branched from the common laser light into an electrical signal as a third sensor signal; a first difference circuit that respectively performs common mode rejection on the first sensor signal based on the third sensor signal; and a second difference circuit that respectively performs common mode rejection on the second sensor signal based on the third sensor signal.
10 . A nuclear magnetic resonance sensing method comprising: a step of applying a high frequency magnetic field based on an RF signal to a target object and generating an observation signal with a frequency that is shifted from a frequency of the RF signal by a frequency of a nuclear magnetic resonance signal; a step of performing intermediate frequency demodulation of the observation signal and generating an intermediate frequency demodulation signal including the nuclear magnetic resonance signal; a step of attenuating, by a low-pass filter, a high frequency component higher than an intermediate frequency of the intermediate frequency demodulation of the intermediate frequency demodulation signal and passing a frequency component of the nuclear magnetic resonance signal; and a digitizing step of digitizing, by a digitizing device, the intermediate frequency demodulation signal that has passed through the low-pass filter, wherein the digitizing step includes: (a) generating a magnetic field or an electric field corresponding to the intermediate frequency demodulation signal that has passed through the low-pass filter; (b) generating light corresponding to the magnetic field or the electric field by a sensing member; (c) converting the light into an electrical signal as a sensor signal by a photoelectric element; and (d) digitizing the sensor signal by an analog/digital converter, and in the digitizing step, a quantum operation with respect to the sensing member is performed, and the sensing member is caused to generate the light corresponding to the magnetic field or the electric field.
11 . A nuclear magnetic resonance sensing method comprising: a step of applying a high frequency magnetic field based on an RF signal to a target object and generating an observation signal with a frequency that is shifted from a frequency of the RF signal by a frequency of a nuclear magnetic resonance signal; a step of performing intermediate frequency demodulation of the observation signal and generating an intermediate frequency demodulation signal including the nuclear magnetic resonance signal; a step of attenuating, by a low-pass filter, a high frequency component higher than an intermediate frequency of the intermediate frequency demodulation of the intermediate frequency demodulation signal and passing a frequency component of the nuclear magnetic resonance signal; a step of performing, by an analog circuit, quadrature phase detection with respect to the intermediate frequency demodulation signal that has passed through the low-pass filter and generating a demodulation signal and a demodulated signal of the nuclear magnetic resonance signal; and a digitizing step of digitizing the demodulation signal and the demodulated signal, wherein the digitizing step includes: (a1) generating a magnetic field or an electric field corresponding to the demodulation signal; (a2) generating a magnetic field or an electric field corresponding to the demodulated signal; (b1) generating light, by a first sensing member, corresponding to the magnetic field or the electric field corresponding to the demodulation signal and converting, by a photoelectric element, the light generated by the first sensing member into an electrical signal as a first sensor signal; (b2) generating light, by a second sensing member, corresponding to the magnetic field or the electric field corresponding to the demodulated signal and converting, by a photoelectric element, the light generated by the second sensing member into an electrical 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 with respect to the first and second sensing members are respectively performed, and the first and second sensing members are respectively caused to generate the lights corresponding to the magnetic fields or the electric fields corresponding to the demodulation signal and the demodulated signal.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a 371 U.S. National Phase of International Application No. PCT/JP2022/030783, filed on Aug. 12, 2022, which claims priority to Japanese Patent Application No. 2021-188930, filed Nov. 19, 2021. The entire disclosures of the above applications are incorporated herein by reference. BACKGROUND Technical Field The present invention relates to a nuclear magnetic resonance sensing device and a nuclear magnetic resonance sensing method. Related Art FIG. 10 is a block diagram that shows an example of a measurement device using nuclear magnetic resonance. For instance, as shown in FIG. 10, in general, the measurement device using nuclear magnetic resonance: (a) makes nuclear magnetization resonate by applying a high frequency magnetic field based on an RF (Radio Frequency) signal having a frequency close to a precession frequency with a high frequency coil 311 with respect to a measuring object 301; (b) detects the resonated nuclear magnetization with a receiving coil 312 and generates an observation signal including a nuclear magnetic resonance (NMR) signal; (c) amplifies the observation signal by preamplifiers 313 and 314 such as a low noise amplifier (LNA), and (d) detects the amplified observation signal by a detector so as to extract the NMR signal. Further, in general, such observation signals and NMR signals are converted from analog signals to digital signals by an analog/digital conversion circuit 315 and are supplied to a post-stage arithmetic processing device as digital signals (for instance, refer to Patent Documents 1 and 2). PRIOR ART DOCUMENTS Patent Documents Patent Document 1: Japanese Patent Publication Number 2008-039641.Patent Document 2: Japanese Patent Publication Number 2011-101776. However, in the above-mentioned device, because an amplifier circuit such as a preamplifier is provided in order to amplify the observation signal, noise being peculiar to the amplifier circuit is superposed on the observation signal and the NMR signal. For this reason, the NMR signals with a level similar to or lower than the noise floor of the amplifier circuit are buried in noise, and it is difficult to accurately detect such the low-level NMR signals. The present invention has an object that is to obtain a nuclear magnetic resonance sensing device and a nuclear magnetic resonance sensing method that can accurately detect a low-level NMR signal and have high resolution in view of the above-described problems. SUMMARY A nuclear magnetic resonance sensing device according to the present invention includes a nuclear magnetic resonance sensing part that applies a high frequency magnetic field based on an RF signal to a target object and generates an observation signal with a frequency that is shifted from a frequency of the RF signal by a frequency of a nuclear magnetic resonance signal, a mixer part that performs intermediate frequency demodulation of the observation signal and generates an intermediate frequency demodulation signal including the nuclear magnetic resonance signal, a low-pass filter that attenuates a high frequency band component among two band components obtained by the intermediate frequency demodulation of the intermediate frequency demodulation signal and passes a low frequency band component among two band components, and a digitizing device that digitizes the intermediate frequency demodulation signal that has passed through the low-pass filter. The digitizing device includes a physical field generator that generates a magnetic field or an electric field corresponding to the intermediate frequency demodulation signal that has passed through the low-pass filter, an optical quantum sensor part that generates light corresponding to the magnetic field or the electric field by a sensing member and converts the light into an electrical signal as a sensor signal by a photoelectric element, and an analog/digital converter that digitizes the sensor signal. The optical quantum sensor part performs a quantum operation with respect to the sensing member and causes the sensing member to generate the light corresponding to the magnetic field or the electric field. A nuclear magnetic resonance sensing device includes a nuclear magnetic resonance sensing part that applies a high frequency magnetic field based on an RF signal to a target object and generates an observation signal with a frequency that is shifted from a frequency of the RF signal by a frequency of a nuclear magnetic resonance signal, a mixer part that performs intermediate frequency demodulation of the observation signal and generates an intermediate frequency demodulation signal including the nuclear magnetic resonance signal, a low-pass filter that attenuates a high frequency component higher than an intermediate frequency of the intermediate frequency demodulation of the intermediate frequency demodulation signal and passes a frequency component of the nuclear magnetic resonance sig