TECHNICAL FIELD

The invention relates to at least one magnet comprising at least one inner jacket in which the air inside can be vacuumed to obtain the magnetic field required in Magnetic Resonance Imaging (MRI) devices, at least one magnetic field area on the side of the said inner jacket facing the atmosphere, at least one coil wheel in which at least one superconductor coil is wound around the said magnetic field area, and at least one shim coil wrapped in copper wire to remain inside the said coil wheel to regulate homogeneity.

BACKGROUND

Superconductor magnets are used in medical imaging on magnetic resonance imaging (MRI) devices. Today, low temperature superconductors (LTS) are used in most modern MRI magnets to create a strong and homogeneous magnetic field for the necessary magnetic resonance. LTS magnets are generally cooled in liquid helium so that they remain below the critical temperature (Tc) of the superconductor. Magnetic resonance imaging (MRI) systems use a significant proportion of the world's liquid helium supply. In recent years, the cost of liquid helium has increased significantly.

As the superconductor magnets suddenly pass into the normal conductive state (quench), the energy of the magnetic field turns into heat. In this way, liquid helium evaporates and the resulting high amount of cold helium gas must be safely delivered to the atmosphere. This transmission can be provided by creating an outlet on the tank where the magnet is located.

In liquid helium cooling, difficulties and losses encountered during helium filling are among the main problems of the current art. The fact that the need for liquid helium is too high, and the fact that it is increasingly difficult to obtain, etc. causes the risk of helium use. Since the liquid helium usage temperature is 4.2 K, there is a need for a high vacuumed area in the cooling containers. In this case, the area where the magnetic field is formed moves away from the superconductor magnet. This situation reveals either the need for the magnetic field to fall or the need to increase the current for the same magnetic field intensity. At the same time, the amount of superconductor used increases. Thermal interaction at other points of contact with the outside of the power lead and coil causes liquid helium to evaporate, making it difficult to achieve thermal balance. In the event of a possible quench, a high thermal gradient is formed by the formation of high steam pressure exceeding 4.2 K of the liquid helium temperature.

Since the Magnetic Resonance Imaging systems made with the previous art are both quite large and do not have a mobile platform, it is impossible to move them to another place in working condition when desired.

All the problems mentioned above have made it necessary to make an innovation in the relevant technical field as a result.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a magnet in order to eliminate the above-mentioned disadvantages and bring new advantages to the relevant technical field.

It is an object of the invention to provide a magnet for obtaining magnetic fields for MRI devices.

Another object of the invention is to provide an improved magnet with a cooling feature.

In order to achieve all the objectives mentioned above and which will emerge from the detailed description below, the present invention is a magnet comprising at least one inner jacket in which the air inside can be vacuumed to obtain the magnetic field required in Magnetic Resonance Imaging (MRI) devices, at least one magnetic field area on the side of the said inner jacket facing the atmosphere, at least one coil wheel in which at least one superconductor coil is wound around the said magnetic field area, and at least one shim coil wrapped in copper wire to remain inside the said coil wheel (30) to regulate homogeneity. Accordingly, its novelty is that it comprises at least one cryocooler for cooling the superconductor coil by associating it with the said coil wheel. Thus, a magnet that can be cooled without the need for liquid helium filling is obtained.

A possible embodiment of the invention is characterized in that the coil wheel comprises at least one lower bar and at least one upper bar for associating the said cryocooler with the coil wheel.

Another possible embodiment of the invention is characterized in that it comprises at least one flexible cable between the said upper bar and the said lower bar and cryocooler. Another possible embodiment of the invention is characterized in that the said superconductor coil comprises an NbTi superconductor.

Another possible embodiment of the invention is characterized in that the cryocooler comprises at least one first stage and at least one second stage.

Another possible embodiment of the invention is characterized in that the said first stage of the cryocooler is at least 65 W to reduce the temperature to 50 K and the said second stage is at least 1 W to reduce the temperature to 4 K.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows a representative perspective view of the magnet of the invention.

Figure 2 shows a representative cross-sectional view of the magnet of the invention.

DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, the subject of the invention is explained with examples that do not have any limiting effect only for a better understanding of the subject.

Referring to Figures 1 and 2, the invention relates to a magnet (10). The magnet (10) of the invention is used for obtaining a magnetic field for MRI devices. Magnetic Resonance Imaging (MRI) is a technique in which magnetic fields and radio waves are used to create detailed images of organs and tissues in the body and a device in which this technique is used. Large size magnets (10) are used in MRI devices. In MRI machines, the magnetic field temporarily rearranges the hydrogen atoms in the body. Radio waves cause these aligned atoms to produce very weak signals. Thus, the body is imaged.

The magnet (10) of the invention is used in the production of a predetermined magnetic field in MRI devices. In a possible embodiment of the invention, the magnetic field is 1.5 Tesla. There are several components on the magnet (10) for this. It is ensured that the magnetic field is obtained under the desired conditions by the synchronous operation of these components. The most distinctive feature of the magnet (10) is that the components are cooled by means of at least one cryocooler (70).

The cryocooler (70) preferably has two stages of cooling. The first stage of the cryocooler (70) is preferably configured to reduce the temperature to 50 K and the second stage is preferably up to 1 .8 K. If the temperature of the cryocooler (70) is reduced to 4 K, the superconductor coil (40) is cooled. For this, the first stage of the cryocooler (70) is 65 W and the second stage is 1 W.

There is at least one vacuum jacket (20) on the magnet (10). The vacuum jacket (20) is essentially in the form of a hollow chamber. The vacuum jacket (20) is preferably cylindrical and made of stainless steel. The entire system on the magnet (10) is provided in this vacuum jacket (20). There is at least one magnetic field area (22) on the vacuum jacket (20). The magnetic field area (22) is essentially the form of an open hole in the atmosphere extending through the vacuum jacket (20).

There is at least one inner jacket (21 ) around the hole on the magnet (10). The inner jacket (21 ) is preferably made of deoxygenated copper. The inner jacket (21 ) is used to minimize thermal fluctuation and radiation-induced heat. After a vacuum is applied in the vacuum jacket

(20), the remaining air molecules are cooled and adhered to the surface of the inner jacket

(21 ). It is mounted in the first stage of the cryocooler (70) and has a temperature of approximately 50 K.

There is at least one coil wheel (30) on the magnet (10). The coil wheel (30) is preferably made of deoxygenated copper. It allows at least one superconductor coil (40) to be wound on the coil wheel (30). The coil wheel (30) allows the temperature of the superconductor coil (40) to be reduced depending on the high contact area. For this, in a possible embodiment of the invention, there may be small slits across the coil wheel (30) to prevent surface currents caused by the magnetic field on the coil wheel (30).

NbTi superconductor is preferably used in the superconductor coil (40) used on the magnet (10). The operating temperature of the NbTi superconductor coil (40) is 9.2 K. The diameter of the wire used in the superconductor coil (40), together with the insulation and stabilizer, is preferably 0.9 mm and can have a current carrying capacity of 450 A.

At least one bar is positioned on opposite sides of the coil wheel (30) in the magnet (10). One of them is at least one lower bar (31 ) and the other is at least one upper bar (32). The lower bar (31 ) and the upper bar (32) are preferably made of copper material. The lower bar (31 ) and the upper bar (32) allow the superconductor coil (40) to be cooled. For this, the connection can be made with at least one flexible cable (71 ) to provide thermal transmission between the cryocooler (70) and the superconductor coil (40). Flexible cables (71 ) are oxygen-free, thermally and electrically highly conductive copper cables. Thus, the temperature of the superconductor coil (40) is reduced to 4.2 K.

There is at least one coil support rod (33) on the magnet (10) to prevent the movement of the superconductor coil (40). The coil support rod (33) is made of G-10 composite material and stainless steel. The coil support rod (33) prevents the unwanted movement of the superconductor coil (40). The use of G-10 in the coil support rod (33) is ensured to minimize heat transfer.

At least one shim coil (23) is positioned in the inner volume of the superconductor coil (40). The said shim coil (23) can keep the homogeneity of the magnetic field formed in the magnet (10) below at least 2 ppm. For this, the shim coil (23) is positioned in the inner volume of the superconductor coil (40) and on the inward-facing side of the coil wheel (30), wrapped in copper wire. Thus, the homogeneity of the magnetic field can be arranged in a predetermined manner.

The superconductor coil (40) on the magnet (10) is configured to be associated with at least one power source. The magnetic field is obtained with the energy received from the mentioned power source. For this, the superconductor coil (40) is associated with at least one power head

(50). The said power head (50) allows the energy received from the power sources to be transmitted between them by means of at least one power cable (51 ) and at least one connection element (52). The connection element (52) is produced using YBCO High Temperature Superconductor. It is positioned between the power cable (51 ) and the superconductor coil (40). The connection element (52) can carry approximately 300 A and operates below 92 K. The connection element (52) is connected to the first stage of the cryocooler (70). The power cable (51 ) is used to transfer current from the power supply to the connection element (52). The power head (50) may include an insulation material made of ceramic so that the current is not transferred to the vacuum jacket (20).

There is at least one vacuum port (60) on the magnet (10). The said vacuum port (60) allows the air inside the vacuum jacket (20) to be sucked in by means of a vacuum pump. Flexible cables (71 ) on the magnet (10) allow the transfer of heat between various parts. It provides thermal transmission between the cold head of the cryocooler (70) and the lower bar (31 ) and the upper bar (32) of the coil wheel (30). The flexible cable (71 ) is also used in the power cable

(51 ) to transfer current. There is at least one sensor port (80) on the structure of the magnet (10) of the invention. The said sensor port (80) allows various sensors that may be located inside the magnet (10) to be connected to the external environment. The sensor port (80) may be provided on the magnet (10) for a plurality of sensor connections.

The magnets (10) are cooled using a cooler without the need for any liquid helium filling in contact cooling with the whole embodiment. Since liquid helium is not used in the cooling process, there is no need for an extra vacuum zone. Thus, the magnetic field area (22) formed according to the previous designs is closer to the superconductor magnet (10). This paves the way for less superconductor use for the same magnetic field strength. The thermal gradient is minimized if the power of the cryocooler (70) is selected at a power above the heat loss created by the power cable (51 ) and other parts in contact with the outside of the superconductor magnet (10). Since no helium vapor pressure will occur in the case of quench, it is facilitated to ensure thermal balance.

The scope of protection of the invention is specified in the attached claims and cannot be limited to those explained for sampling purposes in this detailed description. It is evident that a person skilled in the art may exhibit similar embodiments in light of the above-mentioned facts without drifting apart from the main theme of the invention.

REFERENCE NUMBERS GIVEN IN THE FIGURE

10 Magnet

20 Vacuum Jacket

21 Inner Jacket

22 Magnetic Field Area

23 Shim Coil

30 Coil Wheel

31 Lower Bar

32 Upper Bar

33 Coil Support Rod

40 Superconductor Coil

50 Power Head

51 Power Cable

52 Connection Element

60 Vacuum Port

70 Cryocooler

71 Flexible Cable

80 Sensor Port