Double-helmet magnetoencephalogram measuring device

Abstract

A dual helmet magnetoencephalography measuring device includes: an inner container for storing a liquid refrigerant; an outer container surrounding the inner container and including first and second outer helmets; a first sensor-mounted helmet surrounding the first outer helmet between the outer container and the inner container; a second sensor-mounted helmet surrounding a second outer helmet between the outer container and the inner container; a plurality of first and second SQUID sensor modules disposed on the first and second sensor-mounted helmets, respectively, the inner container including: a neck portion into which a baffle insert is inserted and a main body portion having an increased diameter compared to the neck portion, the device further including: a refrigerant discharge pipe at the baffle insert and discharging vaporized refrigerant; the refrigerant injection pipe is arranged at the baffle plate inserting part and injects a refrigerant; and a condenser connected to the refrigerant discharge pipe and the injection pipe and condensing the refrigerant discharged through the refrigerant discharge pipe, and the refrigerant injection pipe has a coaxial structure inserted in the refrigerant discharge pipe.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 202180010493.5, the patent application of No. 202180010493.5 has an application date of February 26, 2021, and the invention title is "Dual-helmet magnetoencephalogram device". Technical Field

[0002] The present disclosure relates to a magnetoencephalogram device, and more particularly, to a magnetoencephalogram device provided with a dual-helmet. Background Art

[0003] A magnetoencephalogram device is a device for measuring magnetic signals generated by microcurrents of cranial nerve circuits, and is used for studying brain functions and diagnosing functional brain diseases.

[0004] Generally, magnetoencephalogram signals have an amplitude of 10 fT to 1 pT and a frequency of 0.1 kHz to 1 kHz. Therefore, there is a need for magnetic sensors with improved sensitivity and techniques for eliminating environmental magnetic noise. Currently, the most practically advantageous magnetic sensor is a superconducting quantum interference device (SQUID) based on low-temperature superconductor niobium (Nb).

[0005] Since the critical temperature of Nb for low-temperature superconducting SQUID is 9 K, cooling using liquid helium or a cryocooler is required. Conventional magnetoencephalogram devices need to replenish liquid helium. Optimization of the structure, thickness, and installation method of materials is required to reduce the evaporation rate of the Dewar while reducing the thermomagnetic noise caused by superadiabatic and heat-insulating plates installed in the vacuum part of the Dewar. In addition, since helium gas easily passes through small gaps, high-density glass fiber-reinforced plastic is required as the material of the Dewar.

[0006] Since the intensity of the magnetic signal from the magnetic signal source decreases in inverse proportion to the square of the distance, it is necessary to significantly reduce the distance between the signal source and the pickup coil to improve the signal-to-noise ratio (SNR). Research has been conducted on this method to develop and use a coil-in-vacuum (CIV) SQUID in which the pickup coil is arranged in a vacuum container.

[0007] In a CIV SQUID device, the pickup coil and the SQUID sensor are arranged to be maintained in a vacuum state. Therefore, only the cryogenic refrigerant exists in the internal helium storage container for storing the cryogenic refrigerant. Therefore, there is only a path for filling the refrigerant. Therefore, the diameter of the neck of the internal helium storage container can be significantly reduced. Therefore, the evaporation rate of the cryogenic refrigerant can be reduced. Summary of the Invention

[0008]

Technical Problem

[0009] One aspect of the present disclosure is to provide a single magnetoencephalogram device measuring apparatus capable of measuring a vacuum coil and a double helmet structure for both adults and children.

[0010] Another aspect of the present disclosure is to provide a cooling device having a double-wall structure capable of blocking radiant heat.

[0011] Another aspect of the present disclosure is to provide a coolant pipe structure having a coaxial double-tube structure capable of providing a rotational movement of a Dewar flask.

[0012] Another aspect of the present disclosure is to provide a cooling device capable of recycling a refrigerant.

[0013] Another aspect of the present disclosure is to provide a magnetoencephalogram measuring apparatus including two helmets.

[0014]

Technical Solution

[0015] A double-helmet magnetoencephalogram measuring apparatus according to an exemplary embodiment includes: an inner container storing a liquid refrigerant; an outer container disposed to surround the inner container and including a first outer helmet and a second outer helmet disposed to be spaced apart from each other; a first sensor-mounted helmet disposed to surround the first outer helmet between the outer container and the inner container; a second sensor-mounted helmet disposed to surround the second outer helmet between the outer container and the inner container; a plurality of first SQUID sensor modules disposed on the first sensor-mounted helmet; and a plurality of second SQUID sensor modules disposed on the second sensor-mounted helmet. A space between the outer container and the inner container is in a vacuum state.

[0016] In an exemplary embodiment, the outer container may branch in a T shape. The outer container may include a first branch and a second branch branching in a T shape from a cylindrical outer container body portion. Each of the first outer helmet and the second outer helmet may be respectively connected to the first branch and the second branch. The first outer helmet and the second outer helmet may face each other and may have different sizes.

[0017] In an exemplary embodiment, the double-helmet magnetoencephalogram measuring apparatus may further include: a rotational movement unit that rotates the inner container and the outer container about a central axis of the rotational movement unit.

[0018] In an exemplary embodiment, the inner container may include: a neck into which a baffle plug is inserted; and an inner body portion having a diameter larger than that of the neck. The neck may have a double-wall structure including an inner cylinder and an outer cylinder surrounding the inner cylinder.

[0019] In an exemplary embodiment, the neck may further include a heat insulation layer disposed between the inner cylinder and the outer cylinder.

[0020] In an exemplary embodiment, the inner cylinder may further include a plurality of annular protrusions protruding outward from the inner cylinder. Thermal anchors may be respectively connected to the annular protrusions. The annular protrusions may be arranged to be spaced apart from each other. The outer cylinder may be separate, with the annular protrusions sandwiched therebetween.

[0021] In an exemplary embodiment, the outer circumferential surface of the annular protrusion and the inner circumferential surface of the thermal anchor may be threadedly connected to each other.

[0022] In an exemplary embodiment, the thermal anchor may include a cylindrical thermal anchor connection portion and a disc-shaped thermal anchor main body portion disposed on the outer circumferential surface of the thermal anchor connection portion. The inner circumferential surface of the thermal anchor connection portion may be threadedly connected to the outer circumferential surface of the annular protrusion.

[0023] In an exemplary embodiment, the inner container may include: a neck into which a baffle plug is inserted; and a main body portion having a diameter larger than that of the neck. The dual-helmet magnetoencephalogram measuring device may further include: a refrigerant discharge pipe disposed at the baffle plug and discharging vaporized refrigerant; a refrigerant injection pipe disposed at the baffle plug and injecting refrigerant; and a condenser connected to the refrigerant discharge pipe and the refrigerant injection pipe and condensing the vaporized refrigerant discharged through the refrigerant injection pipe. The refrigerant injection pipe may have a coaxial structure inserted in the refrigerant discharge pipe.

[0024] In an exemplary embodiment, each of the refrigerant discharge pipe and the refrigerant injection pipe may be a double pipe including an inner pipe and an outer pipe.

[0025] In an exemplary embodiment, the dual-helmet magnetoencephalogram measuring device may further include: a C-shaped outer container support portion supporting the lower surfaces of the first branch and the second branch; and a rotational movement unit connected to the outer container support portion to provide a rotational movement to the outer container.

[0026] In an exemplary embodiment, the dual-helmet magnetoencephalogram measurement device may further include: a vacuum sealing portion that is inserted into through holes formed in the lower surfaces of each of the first branch and the second branch to seal signal lines and is disposed inside the outer container support portion; and a signal line junction box that is disposed below the outer container support portion and connects the signal lines sealed by the vacuum sealing portion to each other. The rotational movement unit may further include: an upper base box that is disposed to surround the signal line junction box; a lower base box that is disposed below the upper base box; and a bearing portion that is disposed between the upper base box and the lower base box to provide a rotational movement to the upper base box.

[0027] In an exemplary embodiment, the dual-helmet magnetoencephalogram measurement device may further include: a handle that is connected to the outer side of the upper base box.

[0028] In an exemplary embodiment, the first outer helmet may include a connecting portion provided with a long groove. The first outer helmet may be connected to one end of the first branch while rotating in an aligned state along the long groove. The second outer helmet may include a connecting portion provided with a long groove. The second outer helmet may be connected to one end of the second branch while rotating in an aligned state along the long groove.

[0029] In an exemplary embodiment, the inner container may include: a neck into which a baffle plug is inserted; a first main body portion having a diameter larger than that of the neck; a second main body portion having a diameter larger than that of the first main body portion; and a third main body portion having a diameter smaller than that of the second main body portion.

[0030] In an exemplary implementation, the dual-helmet magnetoencephalogram measurement device may further include: a pair of first support parts, which are connected to the interface between the neck and the first main body part and extend respectively along the directions of the first external helmet and the second external helmet; a pair of second support parts, which are connected to the interface between the first main body part and the second main body part and extend respectively along the directions of the first external helmet and the second external helmet; a pair of third support parts, which are connected to the interface between the second main body part and the third main body part and extend respectively along the directions of the first external helmet and the second external helmet; a first fixing ring, which is connected to the first support part, the second support part and the third support part along the direction of the first external helmet; a second fixing ring, which is connected to the first support part, the second support part and the third support part along the direction of the second external helmet; a first auxiliary fixing part, which connects the first fixing ring and the first helmet equipped with sensors; and a second auxiliary fixing part, which connects the second fixing ring and the second helmet equipped with sensors.

[0031] In an exemplary implementation, each of the first support part, the second support part and the third support part may include a plurality of arc-shaped long grooves. A connecting member may be inserted into each of the arc-shaped long grooves to connect to the inner container.

[0032] In an exemplary implementation, the first helmet equipped with sensors may include: a helmet main body having an opening area for ensuring the field of view, a lower brim arranged along the edge of the lower surface of the helmet main body, an upper brim provided with a brim at the opening of the helmet main body, a helmet fixing ring having an annular shape connected continuously from the lower edge at a predetermined interval to the upper brim, and a plurality of connecting columns vertically connecting the lower brim and the upper brim to each other.

[0033] In an exemplary implementation, the dual-helmet magnetoencephalogram measurement device may further include: a first auxiliary thermal anchor, which is arranged on the lower surface of each of the upper brim and the lower brim of the first helmet equipped with sensors; a first internal 4K heat insulation part, which is in thermal contact with the first auxiliary thermal anchor and is arranged on the inner surface of the first helmet equipped with sensors; and a first external 4K heat insulation part, which is in thermal contact with the first auxiliary thermal anchor and is arranged on the outer surface of the first helmet equipped with sensors. The first auxiliary thermal anchor, the first internal 4K heat insulation part and the first external 4K heat insulation part may be in thermal contact with the main thermal anchor through litz wire.

[0034] In an exemplary embodiment, each of the plurality of first SQUID sensor modules may be in thermal contact with a main thermal anchor disposed on the lower surface of the inner container via a Litz wire. Each of the plurality of second SQUID sensor modules may be in thermal contact with a main thermal anchor disposed on the lower surface of the inner container via a Litz wire.

[0035] In an exemplary embodiment, the first SQUID sensor module may be cooled by a plurality of Litz wires. A portion of the plurality of Litz wires disposed around the first SQUID sensor module may be connected to the first SQUID sensor module, and the remaining portions of the plurality of Litz wires may be in thermal contact with the main thermal anchor.

[0036] In an exemplary embodiment, the first SQUID sensor module may be cooled by six Litz wires. Among the six Litz wires, two Litz wires may be in thermal contact with the main thermal anchor, and four Litz wires disposed around the first SQUID sensor module may be connected to the first SQUID sensor module.

[0037] In an exemplary embodiment, the inner container may include a neck in which a baffle plug is inserted. The neck may have a double-wall structure. First to third thermal anchors in the shape of washer disposed perpendicular to each other with a space therebetween may be provided on the outer side of the neck. The first thermal anchor may be connected to a 120K thermal insulation layer. The second thermal anchor may be connected to an 80K thermal insulation layer. The third thermal anchor may be connected to a 40K thermal insulation layer.

[0038] In an exemplary embodiment, the 40K thermal insulation layer may be disposed to surround the first sensor-mounted helmet and the second sensor-mounted helmet.

[0039] In an exemplary embodiment, the first SQUID sensor module may be inserted into a through hole formed in the first sensor-mounted helmet to be fixed. The first SQUID sensor module may include a plurality of holes. Litz wires may be respectively inserted into the holes to cool the SQUID sensors.

[0040] In an exemplary embodiment, the main thermal anchor may include: a first heat transfer unit formed of oxygen-free copper and including a first disk, a first upper protrusion protruding from a central axis of the first disk to an upper surface of the first disk, and a first lower protrusion protruding from the central axis of the first disk to a lower surface of the first disk; a second heat transfer unit formed of oxygen-free copper and including a second disk, a second upper protrusion protruding from a central axis of the second disk to an upper surface of the second disk, and a second lower protrusion protruding from the central axis of the second disk to a lower surface of the second disk; a third heat transfer unit formed of oxygen-free copper and including a third disk, a third upper protrusion protruding from a central axis of the third disk to an upper surface of the third disk, and a third lower protrusion protruding from the central axis of the third disk to a lower surface of the third disk; a fourth heat transfer unit formed of oxygen-free copper and including a fourth disk, a fourth upper protrusion protruding from a central axis of the fourth disk to an upper surface of the fourth disk, and a fourth lower protrusion protruding from the central axis of the fourth disk to a lower surface of the fourth disk; a fifth heat transfer unit formed of oxygen-free copper, connected to the fourth heat transfer unit, and having a plate shape; a first thermal expansion control unit formed of an insulating material and inserted between the first disk of the first heat transfer unit and the second disk of the second heat transfer unit; and a second thermal expansion control unit formed of an insulating material and inserted between the third disk of the third heat transfer unit and the fourth disk of the fourth heat transfer unit. A groove for connecting to the first lower protrusion of the first heat transfer unit may be provided on the second upper protrusion of the second heat transfer unit. A groove for connecting to the third upper protrusion of the third heat transfer unit may be provided on the second lower protrusion of the second heat transfer unit. A groove for connecting to the fourth upper protrusion of the fourth heat transfer unit may be provided on the third lower protrusion of the third heat transfer unit.

[0041] In an exemplary embodiment, the first thermal expansion control unit may include: a first insulating main body having a diameter equal to a first diameter of the first disk; a second insulating main body embedded in a lower surface of the inner main body and having a second diameter larger than the first diameter; and a third insulating main body having a third diameter smaller than the second diameter. The third insulating main body may be arranged to surround an outer circumferential surface of the second disk.

[0042] A magnetic field measuring device according to an exemplary embodiment includes: an outer container; and a cylindrical inner container that stores a liquid refrigerant and is inserted in the outer container. The inner container includes: a neck into which a baffle plug is inserted; and a main body portion having a diameter larger than that of the neck. The neck may have a double-wall structure including an inner cylinder and an outer cylinder surrounding the inner cylinder.

[0043] In an exemplary embodiment, the inner cylinder may further include a plurality of annular protrusions protruding outward from the cylinder body. The thermal anchors may be respectively connected to the annular protrusions. The annular protrusions may be arranged to be spaced apart from each other. The outer cylinder may be separate, and the annular protrusions are sandwiched therebetween.

[0044] In an exemplary embodiment, the neck may further include a heat-insulating layer disposed between the inner cylinder and the outer cylinder.

[0045] In an exemplary embodiment, the outer circumferential surface of the annular protrusion and the inner circumferential surface of the thermal anchor may be threadedly connected to each other.

[0046] In an exemplary embodiment, each thermal anchor may include a disk-shaped thermal anchor main body portion disposed on the outer circumferential surface of the cylindrical thermal anchor connecting portion and the thermal anchor connecting portion. The inner circumferential surface of the thermal anchor connecting portion may be threadedly connected to the outer circumferential surface of the annular protrusion.

[0047] In an exemplary embodiment, the thermal anchors may include a first thermal anchor to a third thermal anchor. The first thermal anchor may be connected to the 120K heat-insulating layer, the second thermal anchor may be connected to the 80K heat-insulating layer, and the third thermal anchor may be connected to the 40K heat-insulating layer.

[0048] In an exemplary embodiment, the magnetic field measuring device may further include: a refrigerant discharge pipe disposed at the baffle plug and discharging vaporized refrigerant; a refrigerant injection pipe disposed at the baffle plug and injecting refrigerant; and a condenser connected to the refrigerant discharge pipe and the refrigerant injection pipe and condensing the vaporized refrigerant discharged through the refrigerant injection pipe. The refrigerant injection pipe is provided with a coaxial structure to be inserted into the refrigerant discharge pipe. Each of the refrigerant discharge pipe and the refrigerant injection pipe may be a double pipe including an inner pipe and an outer pipe.

[0049] The magnetic field measuring device according to an exemplary embodiment includes: an outer container; a cylindrical inner container storing liquid refrigerant and inserted into the outer container; a baffle plug inserted into the inner container; a refrigerant discharge pipe disposed at the baffle plug and discharging vaporized refrigerant; a refrigerant injection pipe disposed at the baffle plug and injecting refrigerant; and a condenser connected to the refrigerant discharge pipe and the refrigerant injection pipe and condensing the vaporized refrigerant discharged through the refrigerant injection pipe. The refrigerant injection pipe may have a coaxial structure inserted into the refrigerant discharge pipe. Each of the refrigerant discharge pipe and the refrigerant injection pipe may be a double pipe including an inner pipe and an outer pipe.

[0050] In an exemplary embodiment, the inner container may include: a neck into which a baffle plug is inserted; and a body portion having a diameter larger than that of the neck. The neck may have a double-wall structure including an inner cylinder and an outer cylinder surrounding the inner cylinder.

[0051] A magnetic field measuring device according to an exemplary embodiment includes: an outer container; a cylindrical inner container for storing a liquid refrigerant and inserted in the outer container; a main heat anchor disposed on a lower surface of the inner container; and a plurality of first SQUID sensor modules disposed outside the inner container. Each of the plurality of first SQUID sensor modules may be in thermal contact with the main heat anchor disposed on the lower surface of the inner container through a Litz wire.

[0052] In an exemplary embodiment, the main heat anchor may include: a first heat transfer unit formed of oxygen-free copper and including a first disk and a first lower protrusion protruding from a central axis of the first disk to a lower surface of the first disk; a second heat transfer unit formed of oxygen-free copper and including a second disk, a second upper protrusion protruding from a central axis of the second disk to an upper surface of the second disk, and a second lower protrusion protruding from a central axis of the second disk to a lower surface of the second disk; a third heat transfer unit formed of oxygen-free copper and including a third disk, a third upper protrusion protruding from a central axis of the third disk to an upper surface of the third disk, and a third lower protrusion protruding from a central axis of the third disk to a lower surface of the third disk; a fourth heat transfer unit formed of oxygen-free copper and including a fourth disk and a fourth upper protrusion protruding from a central axis of the fourth disk to an upper surface of the fourth disk; a first thermal expansion control unit formed of an insulating material and inserted between the first disk of the first heat transfer unit and the second disk of the second heat transfer unit; and a second thermal expansion control unit formed of an insulating material and inserted between the third disk of the third heat transfer unit and the fourth disk of the fourth heat transfer unit. A groove for connecting to the first lower protrusion of the first heat transfer unit may be provided on the second upper protrusion of the second heat transfer unit. A groove for connecting to the third upper protrusion of the third heat transfer unit may be provided on the second lower protrusion of the second heat transfer unit. A groove for connecting to the fourth upper protrusion of the fourth heat transfer unit may be provided on the third lower protrusion of the third heat transfer unit.

[0053] In an exemplary implementation, the first thermal expansion control unit may include: a first insulating main body having a diameter equal to the first diameter of the first disk; a second insulating main body embedded in the lower surface of the inner body and having a second diameter larger than the first diameter; and a third insulating main body having a third diameter smaller than the second diameter. The third insulating main body may be arranged to surround the outer circumferential surface of the second disk.

[0054]

Beneficial Effects

[0055] As described above, the magnetoencephalogram (MEG) measuring device according to the exemplary implementation may use a child helmet and an adult helmet respectively arranged at both ends of a barrel-shaped Dewar flask horizontally placed in a narrow magnetic shielding room, and measure child MEG or adult MEG according to the rotation state.

[0056] The magnetoencephalogram (MEG) measuring device according to the exemplary implementation may use the neck with a double-wall structure of a horizontally placed barrel-shaped Dewar flask to effectively block radiant heat.

[0057] The magnetoencephalogram (MEG) measuring device according to the exemplary implementation may measure child MEG or adult MEG according to the rotation state by arranging a rotational motion unit on the ground of a horizontally arranged barrel-shaped Dewar flask and setting the rotational motion.

[0058] The magnetoencephalogram (MEG) measuring device according to the exemplary implementation may improve the efficiency of the condenser or cooler by transmitting cryogenic refrigerant to the condenser while providing rotational motion using a coaxial double-tube structure connecting the condenser and the Dewar flask to each other.

[0059] The magnetoencephalogram (MEG) measuring device according to the exemplary implementation may adopt a vacuum coil structure, so the distance between the SQUID sensor and the current source can be reduced to increase the signal-to-noise ratio (SNR).

[0060] The magnetoencephalogram measuring device according to the exemplary implementation of the present disclosure may include a main thermal anchor for cooling the SQUID sensor on the lower surface of an inner container storing refrigerant. The main thermal anchor may include multiple components to increase the thermal contact area while suppressing damage to the inner container caused by thermal expansion. Therefore, the litz wire and the SQUID sensor can be effectively cooled. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In view of the drawings and the accompanying detailed description, the present disclosure will become more clear. The implementations described herein are provided by way of example and not by way of limitation, where like reference numerals refer to the same or similar elements. The drawings are not necessarily drawn to scale, but focus on illustrating the various aspects of the present disclosure.

[0062] Figure 1 is a conceptual diagram showing a magnetoencephalogram measurement device according to an exemplary embodiment of the present disclosure.

[0063] Figure 2 is a perspective view showing the magnetoencephalogram measurement device.

[0064] Figure 3 is taken along Figure 2 sectional view taken along line A-A'.

[0065] Figure 4 is a perspective view showing the inner container and the helmet equipped with sensors.

[0066] Figure 5 is an exploded perspective view showing the rotary motion unit that supports the outer container and provides rotary motion.

[0067] Figure 6 is an enlarged sectional view of the inner container of the magnetoencephalogram measurement device.

[0068] Figure 7 is a perspective view showing the support part of the helmet equipped with sensors of the magnetoencephalogram measurement device.

[0069] Figure 8 is a view observed from the lower surface of the inner container of the magnetoencephalogram measurement device.

[0070] Figure 9 is a perspective view showing the helmet equipped with sensors according to an exemplary embodiment of the present disclosure.

[0071] Figure 10 is Figure 9 sectional view of the helmet equipped with sensors.

[0072] Figure 11 is a conceptual diagram showing the connection relationship between the main thermal anchor and the SQUID sensor module according to an exemplary embodiment of the present disclosure.

[0073] Figure 12 is a sectional view of the main thermal anchor.

[0074] Figure 13A is a perspective view showing the SQUID sensor module according to an exemplary embodiment of the present disclosure.

[0075] Figure 13B is showing Figure 13A exploded perspective view of the SQUID sensor module.

[0076] Figure 13C is a sectional view showing the SQUID sensor module according to an exemplary embodiment of the present disclosure.

[0077] Figure 14 is a perspective view showing a SQUID sensor module according to another exemplary embodiment of the present disclosure. Detailed Description

[0078] According to the exemplary embodiment, a technique of directly re - condensing helium gas using a refrigerator and re - sending the re - condensed helium gas to a Dewar is applied. Since the magnetic noise and vibration noise caused by the refrigerator and the refrigerant delivery pipe are very large, a special Dewar structure and a special SQUID arrangement method are required to prevent the SQUID from reacting to vibrations. In particular, a stable structure for supporting the helmet on which the SQUID is mounted is needed.

[0079] With the recent increase in the price of helium gas, a technique of directly re - condensing helium gas using a refrigerant and re - sending the re - condensed helium gas to a magnetoencephalogram Dewar is required. The vaporized helium is supplied to the refrigerator through a refrigerant discharge pipe, and the liquefied refrigerant is supplied to the Dewar through a refrigerant injection pipe. When the refrigerant discharge pipe and the refrigerant injection pipe include a single pipe, ice condenses on the baffle plug cover. This ice hinders the best sealing and causes a large amount of external heat to flow in.

[0080] The CIV SQUID according to the exemplary embodiment solves the problem of ice condensation on the baffle plug cover using a coaxial double - pipe structure. The refrigerant discharge pipe and the refrigerant injection pipe have a coaxial structure, and both the refrigerant discharge pipe and the refrigerant injection pipe have a double - pipe structure. The double - pipe structure can prevent the condensation of water vapor occurring on the upper plate surface of the Dewar. Therefore, a sealing member such as an O - ring can be used to provide the rotation of the Dewar. In addition, the double - pipe structure can transfer the temperature of the evaporated helium gas to the cooler in the cold state, thereby improving the efficiency of the cooler.

[0081] In the CIV SQUID, the Dewar includes an inner container and an outer container surrounding the inner container. However, the inner container absorbs radiant heat from the outside, thereby increasing the consumption of the refrigerant.

[0082] In the CIV SQUID, the Dewar uses a double - wall structure in the neck of the inner container in which a baffle plug is inserted. This double - wall structure improves the mechanical stability caused by thermal expansion. In addition, the heat insulation layer arranged between the double walls reduces the inflow of radiant heat. In addition, the heat anchor arranged outside the double - wall structure uses a threaded connection to thermally contact the inner wall of the inner container having a double - wall structure with a large contact area while reducing the damage caused by thermal expansion. The double - wall structure can reduce the evaporation rate of the refrigerant and can stably support the internal structure with a high load, thereby reducing the internal vibration caused by the evaporation of the refrigerant.

[0083] The magnetoencephalogram (MEG) signal depends on the distance between the SQUID sensor and the brain. Therefore, the MEG helmet for adults is not suitable for measuring the MEG of children. Therefore, there is a need for a dual helmet in which a single MEG device can measure both adults and children.

[0084] The helmet for children can provide 144 channels, and the helmet for adults can provide 192 channels. Therefore, as a structure most suitable for the head size, it is desirable to improve the quality of the MEG signal, especially for children. It is beneficial to measure the development process of the brain function of children to that of adults.

[0085] The magnetoencephalogram device according to an exemplary embodiment has a structure in which two helmets are arranged on a single dewar. The helmet for children and the helmet for adults with different sizes are mounted to face each other.

[0086] In the magnetoencephalogram device according to an exemplary embodiment, both the helmet for children and the helmet for adults can measure the magnetoencephalogram in a lying state according to the rotation state of the dewar. To provide the rotational movement of the dewar, the rotational movement unit can use a non-metallic bearing to provide the rotational movement of the dewar. The rotational movement unit can include a signal line junction box to which the signal lines are connected.

[0087] The magnetoencephalogram device according to an exemplary embodiment includes a main thermal anchor provided on the lower surface of the inner container. The main thermal anchor includes a plurality of heat transfer portions threadedly connected to each other, and a thermal expansion control portion formed of an insulating material and controlling the sealing failure caused by thermal expansion between the heat transfer portion and the inner container. When the plurality of heat transfer portions are connected to each other, a pair of thermal expansion control portions arranged to be embedded in the outer surface and the inner surface of the inner container are pressed to prevent damage to the components caused by sealing and thermal expansion.

[0088] Hereinafter, embodiments of the present disclosure will be described more fully with reference to the accompanying drawings. However, the present disclosure can be implemented in different forms and should not be construed as limited to the embodiments set forth herein. Instead, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0089] Figure 1 is a conceptual diagram showing a magnetoencephalogram measuring device according to an exemplary embodiment of the present disclosure.

[0090] Figure 2 is a perspective view showing the magnetoencephalogram measuring device.

[0091] Figure 3 is along Figure 2 a cross-sectional view taken along line A-A'.

[0092] Figure 4is a perspective view showing an inner container and a helmet equipped with a sensor.

[0093] Figure 5 is an exploded perspective view showing a rotary motion unit that supports an outer container and provides a rotary motion.

[0094] Figure 6 is an enlarged cross-sectional view of an inner container of a magnetoencephalogram measuring device.

[0095] Refer to Figures 1 to 6 , the magnetoencephalogram measuring device 300 includes: an inner container 360 that stores a liquid refrigerant; an outer container 310 that is arranged to surround the inner container 360 and includes a first outer helmet 320 and a second outer helmet 330 that are arranged to be spaced apart from each other; a first sensor-equipped helmet 322 that is arranged to surround the first outer helmet 320 between the outer container 310 and the inner container 360; a second sensor-equipped helmet 332 that is arranged to surround the second outer helmet 330 between the outer container 310 and the inner container 360; a plurality of first SQUID sensor modules 103a that are arranged on the first sensor-equipped helmet 322; and a plurality of second SQUID sensor modules 103b that are arranged on the second sensor-equipped helmet 332. The space between the outer container 310 and the inner container 360 is in a vacuum state.

[0096] Each of the plurality of first SQUID sensor modules 103a is in thermal contact with a main thermal anchor 170 arranged on the lower surface of the inner container 360 through a litz wire 12. Each of the plurality of second SQUID sensor modules 103b is in thermal contact with a main thermal anchor 170 arranged on the lower surface of the inner container 360 through a litz wire 12. The space between the outer container 310 and the inner container 360 is in a vacuum state. The SQUID sensors of the first sensor-equipped helmet 322 and the second sensor-equipped helmet 332 can be effectively cooled through the litz wire 12.

[0097] The magnetoencephalogram measuring device 300 can be arranged inside the magnetic shielding room 11.

[0098] The outer container 310 may branch in a T shape. The outer container 310 may include a first branch 312 and a second branch 314 that branch from a cylindrical outer container body portion 316 in a T shape. Each of the first outer helmet 320 and the second outer helmet 330 may be connected to the first branch 312 and the second branch 314, respectively. The first outer helmet 320 and the second outer helmet 330 may face each other and may have different sizes. The diameter of each of the first branch 312 and the second branch 314 may be greater than the diameter of the outer container body portion 316. The first outer helmet 320 may include an opening 321 for ensuring a field of view. The outer container body portion 316 may be vertically arranged, and the first branch 312 and the second branch 314 may be horizontally arranged. The outer container 310 may be a fiberglass-reinforced plastic such as G10 epoxy resin.

[0099] The outer container body portion 316 may have a cylindrical shape and may rotate about its central axis. The first outer helmet 320 or the second outer helmet 330 may measure the magnetoencephalogram signals of a child or an adult according to the rotation state of the outer container 310.

[0100] The rotational motion unit 340 may be connected to the lower surfaces of the first branch 312 and the second branch 314. The rotational motion unit 340 may include a bearing formed of a non-conductive material. The rotational motion unit 340 may be mounted on the bottom surface of the magnetic shielding chamber 11.

[0101] The first outer helmet 320 may be provided with a long groove 320a in a portion connected to the first branch 312. The first outer helmet 320 may rotate along the long groove 320a to be connected to one end of the first branch 312 in an aligned state therewith. The long groove 320a may provide alignment between the first outer helmet 320 and the first sensor-mounted helmet 322. The first outer helmet 320 may include an opening 321 for ensuring a field of view.

[0102] The second outer helmet 330 may be provided with a long groove in a portion connected to the second branch 314. The second outer helmet 330 may rotate along the long groove to be connected to one end of the second branch 314 in an aligned state therewith.

[0103] The inner container 360 may store a liquid refrigerant and may cool the SQUID sensor modules 103a and 103b through the main thermal anchor 170 and the litz wire 12. The material of the inner container 360 may be a fiberglass-reinforced plastic such as G10 epoxy resin.

[0104] The inner container 360 may include: a neck portion 362 into which the baffle plug 150 is inserted; a first main body portion 364 having a diameter larger than that of the neck portion 362; a second main body portion 366 having a diameter larger than that of the first main body portion 364; and a third main body portion 368 having a diameter smaller than that of the second main body portion. The inner container 360 may include a main body portion and the neck portion 362 into which the baffle plug 150 is inserted. The main body portion may include: a first main body portion 364 having a diameter larger than that of the neck portion 362; a second main body portion 366 having a diameter larger than that of the first main body portion 364; and a third main body portion 368 having a diameter smaller than that of the second main body portion.

[0105] The neck portion 362 may have a double-wall structure including an inner cylinder and an outer cylinder surrounding the inner cylinder. The first main body portion 364 may be continuously connected to the neck portion 362. The second main body portion 366 may be continuously connected to the first main body portion 364. The second main body portion 366 may have a diameter larger than that of the first main body portion 364. The third main body portion 368 may be continuously connected to the second main body portion 366. The third main body portion 368 may have a diameter smaller than that of the second main body portion 366. The first main body portion 364 and the third main body portion 368 may have equal diameters.

[0106] The first sensor-equipped helmet 322 and the second sensor-equipped helmet 332 are symmetrically arranged with respect to the first main body portion 364, the second main body portion 366, and the third main body portion 368 to provide cooling mechanical stability and symmetry.

[0107] The lower surface 368a of the third main body portion 368 may include a plurality of getter grooves 368b having a fan shape in a direction toward the lower surface or the vacuum side. A getter for collecting residual gas in a vacuum state may be disposed in the getter grooves 368b.

[0108] The neck portion 362 may include an inner cylinder 162a and an outer cylinder 162b surrounding the inner cylinder 162a. A heat insulating layer 162c may be disposed between the inner cylinder 162a and the outer cylinder 162b. The heat insulating layer 162c may have a multi-layer structure in which a metal thin film having a high reflectivity and a low emissivity and a very thin non-woven fabric having a low thermal conductivity are sequentially stacked.

[0109] The inner cylinder 162a may further include a plurality of annular protrusions 162a' protruding outward from the cylinder body. The annular protrusions 162a' may have a cylindrical ring shape and may be formed integrally with the inner cylinder 162a. Screws for threaded connection may be formed on the outer circumferential surface of the annular protrusions 162a'.

[0110] The annular protrusions 162a' can be arranged to be spaced apart from each other. The outer cylinder 162b can be separate, with the annular protrusions 162a' sandwiched therebetween. That is, the outer cylinder 162b can include a plurality of cylindrical members that are separate from each other. The distance between the outer cylinder 162b and the inner cylinder 162a can be within a few millimeters (mm). Each of the outer cylinders 162a can have raised points to surround the thermal anchor connection portion 106a” and the annular protrusions 162a'. The outer cylinder 162b can be connected to surround the annular protrusions 162a', and the connection portion can be fixed and sealed with an adhesive such as epoxy resin.

[0111] The thermal anchors 106a, 106b, and 106c can be respectively connected to the annular protrusions 162a'. The outer circumferential surface of the annular protrusions 162a' and the inner circumferential surfaces of the thermal anchors 106a, 106b, and 106c can be threadedly connected to each other. Each of the thermal anchors 106a, 106b, and 106c can have a circular washer shape. Each of the thermal anchors 106a, 106b, and 106c can include copper (Cu) or aluminum (Al).

[0112] The thermal anchor 106a can include a cylindrical thermal anchor connection portion 106a” and a disc-shaped thermal anchor main body portion 106a' arranged on the outer circumferential surface of the connection portion. The inner circumferential surface of the thermal anchor connection portion 106a” can be threadedly connected to the outer circumferential surface of the annular protrusions 162a'. Therefore, the thermal anchors 106a, 106b, and 106c can be stably fixed to the inner container and can be cooled while being in thermal contact with each other over a large area.

[0113] The threaded connection between the annular protrusions 162a' and the thermal anchor 106a can improve mechanical stability while providing effective thermal contact caused by thermal expansion.

[0114] The double-wall structure can prevent radiant heat from flowing into the inner container 360 from an external entity. When the inner container is cooled by a refrigerant, the space between the inner cylinder and the outer cylinder can be maintained in a vacuum state. Therefore, heat inflow caused by heat transfer can be blocked, and the heat insulation layer 162c can additionally block the inflow of radiant heat. Therefore, compared with the neck of a single-wall structure, the neck of the double-wall structure can provide high mechanical stability and high heat insulation performance.

[0115] The thermal anchors 106a, 106b, and 106c may include a first thermal anchor 106a, a second thermal anchor 106b, and a third thermal anchor 106c arranged in sequence. The first thermal anchor 106a may be disposed at the uppermost side of the neck portion 362 and may be connected to the 120K thermal insulation layer 107a. The second thermal anchor 106b may be disposed below the first thermal anchor 106a and connected to the 80K thermal insulation layer 107b. The third thermal anchor 106c may be disposed on the lower side of the second thermal anchor 106b and may be connected to the 40K thermal insulation layer 107b. The outer diameter of the first thermal anchor 106a may be greater than the outer diameter of the second thermal anchor 106b.

[0116] The first thermal anchor 106a may be spaced farthest from the refrigerant to maintain the highest temperature, and the third thermal anchor 106c may be closest to the refrigerant to maintain the lowest temperature. The first thermal anchor 106a, the second thermal anchor 106b, and the third thermal anchor 106c may be in thermal contact with the vaporized refrigerant to be cooled. The 40K thermal insulation layer 107c may be connected to the outer circumferential surface of the third thermal anchor 106c and may be arranged to surround the inner container 360 to block the inflow of radiant heat. The 40K thermal insulation layer 107c may include a heat-insulating layer and a wire mesh woven from wires insulated from each other. The 40K thermal insulation layer 107c may branch in a T-shape to surround the first sensor-mounted helmet 322 and the second sensor-mounted helmet 332, and then may surround the first sensor-mounted helmet 322 and the second sensor-mounted helmet 332.

[0117] The 80K thermal insulation layer 107b may be connected to the outer circumferential surface of the second thermal anchor 106b and may be arranged to surround the 40K thermal insulation layer 107c and block the inflow of radiant heat. The 80K thermal insulation layer 107b may include a heat-insulating layer and a wire mesh woven from wires insulated from each other. The 80K thermal insulation layer 107b may branch in a T-shape to surround the first sensor-mounted helmet 322 and the second sensor-mounted helmet 332. The 80K thermal insulation layer 107b may extend along the edge direction of the first sensor-mounted helmet 322 and may extend along the edge direction of the second sensor-mounted helmet 332.

[0118] The 120K thermal insulation layer 107a may be connected to the outer circumferential surface of the first thermal anchor 106a and may be arranged to surround the 80K thermal insulation layer 107b and block the inflow of radiant heat. The 120K thermal insulation layer 107a may include a heat-insulating layer and a wire mesh woven from wires insulated from each other. The 120K thermal insulation layer 107a may branch in a T-shape to surround the first sensor-mounted helmet 322 and the second sensor-mounted helmet 332.

[0119] Each of the first heat anchor 106a, the second heat anchor 106b, and the third heat anchor 106c may have an opening in a direction toward the outer container support portion 341. These openings may be arranged so as not to overlap each other. Accordingly, the signal line may pass through the openings of the first heat anchor 106a, the second heat anchor 106b, and the third heat anchor 106c in a zigzag shape to pass through the vacuum seal portion 344.

[0120] The space between the inner container 360 and the outer container 310 may be maintained in a vacuum state. The outer container lid 311 may include a discharge port 311a connected to a vacuum pump. The discharge port 311a may be formed of a G-10 epoxy resin tube.

[0121] The baffle plug 150 may be arranged to be inserted into the neck 362 of the inner container 360. The baffle plug 150 may include a plug upper plate 151, a baffle 156 disposed below the plug upper plate, and a plurality of guide rods 154 that support the baffle 156 and are fixed to the plug upper plate 151.

[0122] The plug upper plate 151 may have a disk shape and may be formed of G-10 epoxy resin. The plug upper plate 151 may be fixed to the outer container lid 311. The guide rods 154 are formed of G-10 epoxy resin and may have a rod shape or a tube shape. The guide rods 154 may support the baffle 156. The baffle 156 may include polystyrene foam having enhanced heat retention and a conductive plate. The conductive plate may include an aluminum-plated polyester film layer and a copper layer stacked in sequence to block radiant heat.

[0123] The refrigerant discharge pipe 153 may be arranged on the plug upper plate of the baffle plug 150 and may discharge the vaporized refrigerant. The refrigerant injection pipe 152 may be arranged on the plug upper plate 151 of the baffle plug 150 and may inject the refrigerant. Each of the refrigerant discharge pipe 153 and the refrigerant injection pipe 152 may be a double pipe including an inner pipe and an outer pipe. In the double pipe, the space between the inner pipe and the outer pipe may be maintained in a vacuum state during cooling. The refrigerant injection pipe 152 may have a coaxial structure inserted into the refrigerant discharge pipe 153. The refrigerant discharge pipe 153 and the refrigerant injection pipe 152 may be formed of G-10 epoxy resin.

[0124] The coaxial double tubes 152 and 153 can reduce the thermal contact with the plug upper plate 151 to reduce the icing of the plug upper plate 151. When the refrigerant discharge pipe and the refrigerant injection pipe are single tubes, the plug upper plate 151 and the refrigerant discharge pipe will ice up, thus hindering the sealing between the outer container lid 111 and the plug upper plate 151 and increasing the inflow of external heat. The coaxial double tubes 152 and 153 can be arranged on the central axis of the plug upper plate 151. One end of the refrigerant discharge pipe 153 can be arranged at a position higher than the first thermal anchor 106a. When the outer container 310 and the inner container 360 rotate, the coaxial double tubes 152 and 153 can remain sealed while not rotating by using a sealing device such as an O-ring.

[0125] The condenser 159 can be connected to the refrigerant discharge pipe 153 and the refrigerant injection pipe 152, and can condense the vaporized refrigerant discharged through the refrigerant injection pipe 153. The condenser 159 can be arranged outside the magnetic shielding chamber 11.

[0126] The rotary motion unit 340 can be connected to the lower surfaces of the first branch 312 and the second branch 314. The rotary motion unit 340 can provide the rotary motion of the outer container 310.

[0127] The rotary motion unit 340 can include an outer container support portion 341, an upper support box 342, a lower support box 347, and a bearing portion 346.

[0128] The outer container support portion 341 can be in the form of a C, and can support the lower surfaces of the first branch 312 and the second branch 314. The outer container support portion 341 can have a through hole in its center.

[0129] The vacuum sealing portion 344 can be inserted into the through holes formed in the lower surfaces of the first branch 312 and the second branch 314 to seal the signal lines, and is arranged inside the outer container support portion 341. The vacuum sealing portion 344 can seal the outer container 310 in a vacuum state and the outside in an atmospheric pressure state from each other.

[0130] The signal line junction box 345 can be arranged below the outer container support portion 341, and can connect the sealed signal lines 15 to each other through the vacuum sealing portion 344. The signal line junction box 345 can be arranged inside the upper support box 342.

[0131] The upper support box 342 can be arranged to surround the signal line junction box 345, and can have a cylindrical shape. The upper support box 342 can support the outer container support portion 341. The handle 343 can be connected to the outside of the upper support box 342. The user can rotate the handle 343 to select the rotation state of the magnetoencephalogram measuring device.

[0132] The lower support box 347 can be arranged below the upper support box 342.

[0133] The bearing portion 346 can be arranged between the upper support box 342 and the lower support box 347 to provide rotational movement of the upper support box 342.

[0134] Figure 7 is a perspective view of a support portion of a sensor - mounted helmet of a magnetoencephalogram measuring device.

[0135] Figure 8 is a view observed from the lower surface of an inner container of a magnetoencephalogram measuring device.

[0136] Figure 9 is a perspective view of a sensor - mounted helmet according to an exemplary embodiment of the present disclosure.

[0137] Figure 10 is Figure 9 a cross - sectional view of a sensor - mounted helmet.

[0138] Referring to Figures 7 to 10 , the first sensor - mounted helmet 322 can be configured to cover the head and can include an opening to ensure the field of view of the subject. The first sensor - mounted helmet 322 can include brims 322a' and 322a” on its edge. The brims 322a' and 322a” can be connected to a fixing device for fixing the first sensor - mounted helmet 322.

[0139] The second sensor - mounted helmet 332 can be configured to cover the head and includes an opening to ensure the field of view of the subject. The second sensor - mounted helmet 332 can include a brim on its edge. The brim can be connected to a fixing device for fixing the second sensor - mounted helmet 332.

[0140] A pair of first support portions 382 can be connected to the interface between the neck 362 and the first main body portion 364 and can extend respectively along the direction of the first outer helmet 320 and the direction of the second outer helmet 330. The first support portion 382 can include a C - shaped portion 382c connected to the interface between the neck 362 and the first main body portion 364, and a pair of struts 382b extending parallel to the direction of the corresponding outer helmet. The C - shaped portion 382c can have a plurality of arcuate long grooves 382a. The fixing device can be connected to each arcuate long groove 382a to provide alignment with the corresponding sensor - mounted helmet.

[0141] A pair of second support portions 384 may be connected to the interface between the first main body portion 364 and the second main body portion 366, and extend respectively along the direction of the first outer helmet 320 and the direction of the second outer helmet 330. The second support portion 384 may include a C-shaped portion connected to the interface between the first main body portion 364 and the second main body portion 366, and a pair of struts extending parallel to the direction of the corresponding outer helmet. The C-shaped portion may include a plurality of arcuate long grooves 384a. Fixing means may be connected to each of the arcuate long grooves 384a to provide alignment with the corresponding sensor-equipped helmet.

[0142] A pair of third support portions 386 may be connected to the interface between the second main body portion 366 and the third main body portion 368, and may extend respectively along the direction of the first outer helmet 320 and the direction of the second outer helmet 330. The second support portion 384 may include a C-shaped portion connected to the interface between the second main body portion 366 and the third main body portion 368, and a pair of struts extending parallel to the direction of the corresponding outer helmet. The C-shaped portion may include a plurality of arcuate long grooves 386a. Fixing means may be connected to the arcuate long grooves to provide alignment with the corresponding sensor-equipped helmet.

[0143] The first fixing ring 387 may be connected to the first support portion 382, the second support portion 384, and the third support portion 386 along the direction of the first outer helmet 320.

[0144] The second fixing ring 388 may be connected to the first support portion 382, the second support portion 384, and the third support portion 386 along the direction of the second outer helmet 330.

[0145] The first auxiliary fixing portion 323 may connect the first fixing ring 387 and the first sensor-equipped helmet 322 to each other. The first auxiliary fixing portion 323 may include an upper ring 323a, a lower ring 323c spaced apart from the upper ring 323a, and a plurality of support rods 323b connecting the upper ring 323a and the lower ring 323c to each other.

[0146] The second auxiliary fixing portion 333 may connect the second fixing ring 388 and the second sensor-equipped helmet 332 to each other. The second auxiliary fixing portion 333 may include an upper ring, a lower ring spaced apart from the upper ring, and a plurality of support rods connecting the upper ring and the lower ring to each other.

[0147] The first sensor-equipped helmet 322 may include brims 322a' and 322a'' on its edge. The first sensor-equipped helmet 322 may have the same structure as the second sensor-equipped helmet 332, but the first sensor-equipped helmet 322 may differ from the second sensor-equipped helmet 332 in terms of size and the number of SQUID sensor modules. The first sensor-equipped helmet 322 may have a first through-hole 322b for mounting the SQUID sensor module, a second through-hole 322c for placing signal lines, and a third through-hole for mounting a fixing member for fixing the SQUID sensor module 103a.

[0148] The first sensor-equipped helmet 322 may include a helmet body 322' having an opening area for ensuring a field of view, a lower brim 322a' disposed along the edge of the lower surface of the helmet body, an upper brim 322a'' provided with a brim at the opening of the helmet body, a helmet fixing ring 322f having an annular shape that is connected to the upper brim 322a'' continuously at a predetermined interval from the lower brim 322a', and a plurality of connecting columns 322e that perpendicularly connect the lower brim 322a' and the upper brim 322a'' to each other. The brims of the first sensor-equipped helmet 322 may include an upper brim disposed in the opening to ensure a field of view and a lower brim that surrounds the occipital region of the subject.

[0149] The first auxiliary thermal anchor 185 may be disposed on the lower surface of the brim 322a of the first sensor-equipped helmet 322. The first auxiliary thermal anchor 185 may be divided into a plurality of components 185a to 185d. The first auxiliary thermal anchor 185 may be made of an oxygen-free copper tape. The separate first auxiliary thermal anchor 185 may be divided into four parts to reduce eddy current noise caused by high-frequency magnetic noise and thermal noise caused by free electrons of the metal, and may provide a uniform position-dependent temperature gradient. The first auxiliary thermal anchor 185 may be thermally contacted with the main thermal anchor 170 through a Litz wire 12.

[0150] The first internal 4K thermal insulation part 124 may be thermally contacted with the first auxiliary thermal anchor 185 and may be disposed on the inner surface of the first sensor-equipped helmet 322. The first internal 4K thermal insulation part 124 may be disposed to surround the SQUID sensor module 103a and may include an insulating coated metal mesh.

[0151] The first external 4K thermal insulation part 126 can be in thermal contact with the first auxiliary thermal anchor 185 and can be disposed on the outer surface of the first sensor-mounted helmet 322. The first external 4K thermal insulation part 126 can be arranged to surround the outer surface of the first sensor-mounted helmet 322. The first external 4K thermal insulation part 126 can include an insulated coated metal mesh. Thus, the first auxiliary thermal anchor 185, the first internal 4K thermal insulation part 124, and the first external 4K thermal insulation part 126 can be in thermal contact with the main thermal anchor 170 through the litz wire 12.

[0152] The second auxiliary thermal anchor can be disposed on the lower surface of the brim of the second sensor-mounted helmet 332. The second internal 4K thermal insulation part can be in thermal contact with the second auxiliary thermal anchor and can be disposed on the inner surface of the second sensor-mounted helmet 332. The second external 4K thermal insulation part can be in thermal contact with the second auxiliary thermal anchor and can be disposed on the outer surface of the second sensor-mounted helmet. The second auxiliary thermal anchor, the second internal 4K thermal insulation part, and the second external 4K thermal insulation part can be in thermal contact with the main thermal anchor 170 through the litz wire 12.

[0153] Figure 11 is a conceptual diagram showing the connection relationship between the main thermal anchor and the SQUID sensor module according to an exemplary embodiment of the present disclosure.

[0154] Figure 12 is a cross-sectional view of the main thermal anchor.

[0155] Refer to Figure 11 and Figure 12 , each of the plurality of first SQUID sensor modules 103a can be in thermal contact with the main thermal anchor 170 disposed on the lower surface of the inner container 360 through the litz wire 12. Each of the plurality of second SQUID sensor modules 103b can be in thermal contact with the main thermal anchor 170 disposed on the lower surface of the inner container 360 through the litz wire 12.

[0156] The main thermal anchor 170 can include a first heat transfer unit 171, a second heat transfer unit 172, a third heat transfer unit 173, a fourth heat transfer unit 174, a fifth heat transfer unit 175, a first thermal expansion control unit 176, and a second thermal expansion control unit 177. The main thermal anchor 170 can include a plurality of components to increase the thermal contact area while preventing damage to the inner container caused by thermal expansion, and thus can effectively cool the litz wire 12 and the SQUID sensor.

[0157] The first thermal expansion control unit 176 can be connected to a double groove having two radii formed on the inner side of the lower surface of the inner container, and the second thermal expansion control unit 177 can be connected to a double groove having two radii formed on the outer side of the lower surface of the inner container.

[0158] The first heat transfer unit 171 may be formed of oxygen-free copper and may include a first disk 171a and a first lower protrusion 171b protruding from the central axis of the first disk 171a to the lower surface of the first disk 171a. The first heat transfer unit 171 may further include a first upper protrusion 171c protruding from the central axis of the first disk 171a to the upper surface of the first disk 171a.

[0159] The second heat transfer unit 172 may be formed of oxygen-free copper and may include a second disk 172a, a second upper protrusion 172b protruding from the central axis of the second disk 172a to the upper surface of the second disk 172a, and a second lower protrusion 172c protruding from the central axis of the second disk 172a to the lower surface of the second disk 172a. The second upper protrusion 172b of the second heat transfer unit 172 may include a threaded groove 172d for connecting to the first lower protrusion 171b of the first heat transfer unit 171. The second lower protrusion 172c of the second heat transfer unit 172 may have a threaded groove 172e for connecting to the third upper protrusion 173b of the third heat transfer unit 173.

[0160] The third heat transfer unit 173 may be formed of oxygen-free copper and may include a third disk 173a, a third upper protrusion 173b protruding from the central axis of the third disk 173a to the upper surface of the third disk 173a, and a third lower protrusion 173c protruding from the central axis of the third disk 173a to the lower surface of the third disk 173a. The third lower protrusion 173c of the third heat transfer unit 173 may have a threaded groove 173d for connecting to the fourth upper protrusion 174b of the fourth heat transfer unit 174.

[0161] The fourth heat transfer unit 174 may be formed of oxygen-free copper and may include a fourth disk, a fourth upper protrusion 174b protruding from the central axis of the fourth disk to the upper surface of the fourth disk, and a fourth lower protrusion 174c protruding from the central axis of the fourth disk to the lower surface of the fourth disk.

[0162] The fifth heat transfer unit 175 may be formed of oxygen-free copper and may include a C-shaped plate. The fifth heat transfer unit 175 may be connected to the fourth lower protrusion 174c of the fourth heat transfer portion 174. The lower surface of the fifth heat transfer unit 175 may be connected to a fixing device 178. The fixing device 178 may fix and cool the litz wire 12 connected to the SQUID sensor module 103a.

[0163] The first thermal expansion control unit 176 may be formed of a heat-insulating material or may be inserted between the first disk 171a of the first heat transfer unit 171 and the second disk 172b of the second heat transfer unit 172. The first thermal expansion control unit 176 may include the same material as the inner container.

[0164] The second thermal expansion control unit 177 may be formed of a heat-insulating material and may be inserted between the third disk 173a of the third heat transfer unit 173 and the fourth disk 174a of the fourth heat transfer unit 174. The second thermal expansion control unit 177 may include the same material as the inner container.

[0165] The first thermal expansion control unit 176 may include: a first insulating main body portion 176a having a diameter equal to the first diameter D1 of the first disk 171a; a second insulating main body portion 176b embedded in the lower surface of the inner main body and having a second diameter D2 larger than the first diameter D1; and a third insulating main body portion 176c having a third diameter D3 smaller than the second diameter D2. The third insulating main body portion 176c may be arranged to surround the outer circumferential surface of the second disk 172a. Threaded grooves may be provided on the outer circumferential surface of the third insulating main body portion 176c.

[0166] The second thermal expansion control unit 177 may have the same structure as the first thermal expansion control unit 176.

[0167] When the first heat transfer unit 171 to the fourth heat transfer unit 174 are connected to each other, the first thermal expansion control unit 176 and the second thermal expansion control unit 177 may be pressed to seal with the inner container. In addition, the first disk 171a and the fourth disk 174a may be sealed by pressing the first thermal expansion control unit 176 and the second thermal expansion control unit 177.

[0168] The main thermal anchor 170 may cool the first SQUID sensor module 103a and the second SQUID sensor module 103b through Litz wires.

[0169] Each of the first SQUID sensor modules 103a may be cooled by a plurality of Litz wires 12. A part of the plurality of Litz wires 12 may be supplied to adjacent first SQUID sensor modules 103a. The remaining part of the plurality of Litz wires 12 may be in thermal contact with the main thermal anchor 170.

[0170] Each of the first SQUID sensor modules 103a may be cooled by six Litz wires 12. Two Litz wires 12 may be in thermal contact with the main thermal anchor 170, and the remaining four Litz wires 12 may be connected to adjacent first SQUID sensor modules 103a.

[0171] Each of the first SQUID sensor modules 103a may be inserted into a through hole formed in the first sensor-mounted helmet 322 to be fixed.

[0172] The first SQUID sensor module 103a may have a plurality of holes 611. The Litz wires 12 may be inserted into the holes 611 to cool the SQUID sensor 646.

[0173] Figure 13A is a perspective view showing a SQUID sensor module according to an exemplary embodiment of the present disclosure.

[0174] Figure 13B shows Figure 13A an exploded perspective view of the SQUID sensor module.

[0175] Figure 13C is a cross-sectional view showing a SQUID sensor module according to an exemplary embodiment of the present disclosure.

[0176] Referring Figures 13A to 13C , the SQUID sensor module 103a / 103b may include: a fixed occlusion 610 having one end fixed to the helmet 322 / 332 on which the sensor is mounted; a bobbin 630 having one end connected to the other end of the fixed occlusion 610 and provided with a groove around the pickup coil 601; a bobbin fixing device 650 fixed to the other end of the fixed occlusion 610 through a through hole formed in the center of the bobbin 630; a superconducting quantum interference device (SQUID) printed circuit board (PCB) 640 disposed on the upper surface of the bobbin 630 and including a SQUID sensor 646; and a signal line connection PCB 620 inserted into the outer circumferential surface of the fixed occlusion 610 and transmitting a signal detected by the SQUID sensor 646 to an external circuit.

[0177] The helmet 322 on which the sensor is mounted and the helmet 332 on which the sensor is mounted may be mounted with a SQUID sensor module and may be disposed in a vacuum space between an outer container and an inner container. The helmet 322 on which the sensor is mounted and the helmet 332 on which the sensor is mounted may be formed of a non-magnetic material. The helmet 322 on which the sensor is mounted and the helmet 332 on which the sensor is mounted may include a first sensor-mounted helmet 322 and a second sensor-mounted helmet 332 on which the SQUID sensor module is mounted.

[0178] The fixed occlusion 610 may be integrally formed of a non-magnetic material such as G10 epoxy resin. The fixed occlusion 610 may be inserted into a through hole 322b formed in the helmet on which the sensor is mounted and fixed by an adhesive. The fixed occlusion 610 may include a fixed occlusion protrusion 612, a fixed occlusion threshold portion 614, a fixed occlusion main body portion 616, and a fixed occlusion extension portion 618. The fixed occlusion 610 may have a plurality of holes 611 in the central axis direction into which a litz wire for cooling is inserted. The litz wire is inserted into each of the plurality of holes 611 to cool the SQUID sensor 646.

[0179] The fixed occlusion protrusion 612 may have a disk shape and may be connected to a groove or a through-hole 322b formed in a helmet equipped with a sensor. In addition, the fixed occlusion protrusion 612 may be fixed to the through-hole by an adhesive.

[0180] The fixed occlusion threshold portion 614 may have a disk shape and may be continuously connected to the fixed occlusion protrusion 612. The fixed occlusion threshold portion 614 may have a diameter larger than that of the fixed occlusion protrusion 612. The fixed occlusion threshold portion 614 may have a flat side surface 614a. One side surface 614a of the fixed occlusion threshold portion 614 may be a plane at a predetermined first perpendicular distance from a central axis having a cylindrical shape. The fixed occlusion threshold portion 614 may be used to perform alignment in the central axis direction. A through-hole 619 may be formed outside the fixed occlusion threshold portion 614.

[0181] The fixed occlusion main body portion 616 may be a portion connected to the signal line connection PCB 620. The signal line connection PCB 620 may be arranged to be inserted into the outer peripheral surface of the fixed occlusion main body portion 616. The signal line connection PCB 620 may include holes 623 on its outer periphery. The through-hole 619 of the fixed occlusion threshold portion 614 may be aligned with the holes 623 of the signal line connection PCB 620. A fixing device may be inserted into the through-hole 619 of the fixed occlusion threshold portion 614 and the holes 623 of the signal line connection PCB 620 to fix the fixed occlusion threshold portion 614 and the signal line connection PCB 620 to each other. The inner diameter of the signal line connection PCB 620 may be substantially the same as the outer diameter of the fixed occlusion main body portion 616. In addition, the outer diameter of the signal line connection PCB 620 may be substantially the same as the outer diameter of the fixed occlusion threshold portion 614.

[0182] The signal line connection PCB 620 has a washer shape with a central through-hole therein. When the signal line connection PCB 620 is connected to the outer circumferential surface of the fixed occlusion 610, one side of the central through-hole may be flat to prevent rotational movement. The signal line connection PCB 620 may include a first connector 622. The first connector 622 may be a female connector. The first connector 622 may be arranged on the edge of the lower surface of the signal line connection PCB 620. Connection terminals 624 and wiring may be arranged on the upper surface of the signal line connection PCB 620. The connection terminals 624 may be connected to the first connector 622 through the wiring. The connection wiring connected to an external circuit may be connected to the connection terminals 624.

[0183] The fixed occlusion main body 616 may have a disc shape and may be continuously connected to the fixed occlusion threshold portion 614. The fixed occlusion main body 616 may have a smaller diameter than the fixed occlusion threshold portion 614 and may have a planar side surface 616a. One side surface 616a of the fixed occlusion main body 616 may be a plane that is at a predetermined second perpendicular distance from the central axis having a cylindrical shape.

[0184] The fixed occlusion extension portion 618 may have the same diameter as the fixed occlusion main body 616 and may have a planar side surface 618a. The side surface 618a may be a plane that is at a predetermined third perpendicular distance from the central axis having a cylindrical shape. The third perpendicular distance may be less than the second perpendicular distance.

[0185] One planar side surface 614a of the fixed occlusion threshold portion 614 and one planar side surface 616a of the fixed occlusion main body 616 may be connected to each other. One side surface 616a of the fixed occlusion main body 616 and one side surface 618a of the fixed occlusion extension portion 618 may be spaced apart from each other and parallel to each other. The perpendicular distance between the central axis and one side surface of the fixed occlusion extension portion 618 may be less than the perpendicular distance between the central axis and one side surface of the fixed occlusion main body 616.

[0186] The spool 630 may be formed of a non-magnetic material such as G10 epoxy resin. The spool 630 may have a cylindrical shape. The spool 630 includes: a first planar portion 634 formed on the upper side surface at a first perpendicular distance from the central axis; and a second planar portion 636 formed on the lower side surface at a second perpendicular distance greater than the first perpendicular distance. The spool 630 may have a groove 632 formed around its lower side surface. The groove may form a closed loop. The pick-up coil 601 may be wound around the groove 632. A hole 635 may be formed in the first planar portion 634. The hole 635 may be connected to a fixing device for fixing the SQUID PCB 640. The SQUID PCB 640 may be disposed on the first planar portion 634. Both ends of the pick-up coil 601 may be fixed to the second planar portion 636 by an adhesive. The pick-up coil 601 may be electrically connected to the SQUID sensor 646 through a connection wire 648 formed of a superconducting material. The connection wire 648 may include the material niobium (Nb).

[0187] The SQUID PCB 640 may include a second connector 642 and a SQUID sensor 646, and be arranged on a PCB substrate 644. The SQUID sensor 646 may be in the form of a semiconductor chip. The SQUID sensor 646 may include an input coil and a Josephson junction. The SQUID sensor 646 may include conductive pads for electrically connecting to a pick-up coil 601. The conductive pads may connect the pick-up coil 601. The second connector 642 may be electrically connected to another conductive pad. The second connector 642 may be a male pin connector. Thus, the second connector 642 may be separated from or connected to the first connector 622.

[0188] The pick-up coil 601 may be a first-order axial gradiometer. Thus, the length of the bobbin around which the pick-up coil 601 is wound may be increased. The pick-up coil 601 may include a pair of single-turn coils that are continuously connected and wound in opposite directions to each other. The pick-up coil 601 and the SQUID sensor 646 are joined using a connecting wire 648 of a heat-treated superconducting material to be directly connected to each other, and an integrated-type SQUID magnetometer may be manufactured. The material of the pick-up coil 601 may be niobium-titanium (NbTi) wire.

[0189] The connecting wire of niobium (Nb) material for joining may be subjected to vacuum heat treatment at a temperature of 1900 degrees Celsius to increase ductility. A superconducting bond may be performed using an ultrasonic wedge bonder. The two end portions of the pick-up coil may be twisted together. Thus, the noise of the pick-up coil may be significantly reduced. The pick-up coil may be a first-order gradiometer or a magnetometer.

[0190] The bobbin fixing device 650 may be inserted into a through hole 638 passing through the central axis of the bobbin 630. Thus, the bobbin fixing device 650 may be fixed to the lower surface of the fixed plug 610. The bobbin fixing device 650 may include a non-magnetic material such as G10 epoxy resin.

[0191] When the SQUID PCB 640 fails, the bobbin fixing device 650 may be removed to replace the SQUID PCB 640. In this case, the bobbin 630 and the fixed plug 610 may be separated from each other. Thus, the faulty SQUID PCB may be simply replaced with a new SQUID PCB. Therefore, maintenance may be facilitated.

[0192] The SQUID sensor modules 103a / 103b may include: a fixed plug 610, one end of which is fixed to a support portion; a spool 630, one end of which is connected to the other end of the fixed plug 610 and has a groove around which a pick-up coil 601 is wound; a spool fixing device that is fixed to the other end of the fixed plug 610 through a through hole formed in the center of the spool 630; a superconducting quantum interference device (SQUID) printed circuit board (PCB) 640 that includes a SQUID sensor; and a signal line connection PCB 620 that is inserted into the outer circumferential surface of the fixed plug 610 and transmits a signal detected by the SQUID sensor to an external circuit.

[0193] Figure 14 is a perspective view showing a SQUID sensor module according to another exemplary embodiment of the present disclosure.

[0194] Referring to Figure 3 and Figure 14 , the first reference SQUID sensor module 105a may be disposed on the first sensor-mounted helmet 322, and the second reference SQUID sensor module 105b may be disposed on the second sensor-mounted helmet 332. The first reference SQUID sensor module 105a may be used as a sensor for measuring a background magnetic field when the second SQUID sensor module 103b is operating. The second reference SQUID sensor module 105b may be used as a sensor for measuring a background magnetic field when the first SQUID sensor module 103a is operating.

[0195] Each of the first reference SQUID sensor module 105a and the second reference SQUID sensor module 105b may be a three-axis magnetic field sensor. Each of the first reference SQUID sensor module 105a and the second reference SQUID sensor module 105b may include a first pick-up coil 743a that detects a magnetic field component in the x-axis direction, a second pick-up coil 743b that detects a magnetic field component in the y-axis direction, and a third pick-up coil 743c that detects a magnetic field component in the z-axis direction. Each of the first pick-up coil 743a to the third pick-up coil 743c may be connected to a SQUID sensor 746.

[0196] The first reference SQUID sensor module 105a may include a cylindrical fixed plug 741 and a spool 742 in which pick-up coils connected to the fixed plug 741 are disposed. The spool 742 may have a rectangular parallelepiped shape. The fixed plug 741 may have through holes in a plurality of central axis directions, and the litz wire 12 may be inserted into the through holes. The litz wire 12 may be connected to the main thermal anchor 170.

[0197] Although the present disclosure has been described in detail along with its advantages, it should be understood that various modifications, substitutions, and alterations can be made herein without departing from the spirit and scope of the present disclosure as defined by the appended claims.

Claims

1. A dual - helmet magnetoencephalogram measuring device, comprising: An inner container that stores a liquid refrigerant; An outer container that is arranged to surround the inner container and includes a first outer helmet and a second outer helmet that are arranged to be spaced apart from each other; A first sensor - equipped helmet that is arranged to surround the first outer helmet between the outer container and the inner container; A second sensor - equipped helmet that is arranged to surround the second outer helmet between the outer container and the inner container; A plurality of first SQUID sensor modules that are arranged on the first sensor - equipped helmet; And A plurality of second SQUID sensor modules that are arranged on the second sensor - equipped helmet; Wherein, the space between the outer container and the inner container is in a vacuum state, Wherein, the inner container includes: A neck into which a baffle plug is inserted; and A main body portion having a diameter larger than that of the neck, Wherein, the dual - helmet magnetoencephalogram measuring device further includes: A refrigerant discharge pipe that is arranged at the baffle plug and discharges vaporized refrigerant; A refrigerant injection pipe that is arranged at the baffle plug and injects refrigerant; and A condenser that is connected to the refrigerant discharge pipe and the refrigerant injection pipe and condenses the vaporized refrigerant discharged through the refrigerant discharge pipe, and Wherein, the refrigerant injection pipe has a coaxial structure inserted in the refrigerant discharge pipe.

2. The dual-helmet magnetoencephalogram measuring device according to claim 1, wherein, Both the refrigerant discharge pipe and the refrigerant injection pipe are double - pipes including an inner pipe and an outer pipe.

3. A magnetic field measuring device, comprising: An outer container; A cylindrical inner container that stores a liquid refrigerant and is inserted into the outer container; A baffle plug that is inserted into the inner container; A refrigerant discharge pipe that is arranged at the baffle plug and discharges vaporized refrigerant; A refrigerant injection pipe that is arranged at the baffle plug and injects refrigerant; And A condenser that is connected to the refrigerant discharge pipe and the refrigerant injection pipe and condenses the vaporized refrigerant discharged through the refrigerant discharge pipe, Wherein, the refrigerant injection pipe has a coaxial structure inserted in the refrigerant discharge pipe, and Both the refrigerant discharge pipe and the refrigerant injection pipe are double - pipes including an inner pipe and an outer pipe.

4. The magnetic field measuring device according to claim 3, wherein, The inner container includes: A neck into which the baffle plug is inserted; and A main body portion having a diameter larger than that of the neck, and Wherein, the neck has a double - wall structure including an inner cylinder and an outer cylinder surrounding the inner cylinder.

Images