Abstract: A superconducting high-field magnet coil system comprising several radially nested main coil sections (1, 2, 3, 4, 5) which are connected to each other in series in such a fashion that currents of the same direction flow through them during operation, wherein a first main coil section (EHS) is disposed radially further inward than a second main coil section (ZHS) and at least one intermediate main coil section (ZW) is disposed radially between the first and the second main coil section (EHS, ZHS), and with a superconducting switch (11) via which all main coil sections (1, 2, 3, 4, 5) can be superconductingly short-circuited in series, is characterized in that the first main coil section (EHS) and the second main coil section (ZHS) are directly successively series-connected and the first main coil section (EHS) and the second main coil section (ZHS) are bridged by a common quench protection element, which does not bridge the at least one intermediate main coil section (ZW).

Abstract: A demountable current lead unit and a superconducting magnet apparatus employing the same include an inserting module that is demountably inserted into a superconducting magnet apparatus and electrode leads electrically connected to a superconducting coil and cooling pipes disposed in the respective electrode leads; a service module including a power supply source for supplying a current to the electrode leads, a refrigerant storage tank for supplying a refrigerant to the cooling pipe, and a controller for controlling a flow of the refrigerant to the cooling pipe; and a transmission pipe line for connecting the inserting module and the service module.

Abstract: A re-condensation device allows an NMR analysis device to be reduced in overall size and minimizes heat penetration into a liquid helium tank. An NMR analysis device provided with said re-condensation device. The re-condensation device includes: a second cooling member, part of which is inserted into a neck tube, and which re-condenses liquid helium; and a first cooling member, part of which is inserted into the neck tube. The second cooling member is thermally connected to a chiller's second cooling stage, and the first cooling member is thermally connected to the chiller's first cooling stage. The first cooling member has: a first insertion part, which has a diameter that allows insertion into the neck tube; and an inside contact part on the outer surface of the first insertion part and that cools heat seals by contacting, from the inside, a part of the neck tube that outside contact parts contact.

Abstract: The method for cancellation of low frequency noise in a magneto-resistive mixed sensor (1) comprising at least a superconducting loop with at least one constriction and at least one magneto-resistive element (6) comprises a set of measuring steps with at least one measuring step being conducted with the normal running of the mixed sensor and at least another measuring step being conducted whilst an additional super-current is temporarily injected in the at least one constriction of the at least one superconducting loop of the mixed sensor (1) up to a critical super-current of the constriction so that the result of the at least another measuring step is used as a reference level of the at least one magneto-resistive element (6).

Abstract: A persistent-mode High Temperature Superconductor (HTS) shim coil is provided having at least one rectangular shaped thin sheet of HTS, wherein the thin sheet of HTS contains a first long portion, a second long portion parallel to first long portion, a first end, and a second end parallel to the first end. The rectangular shaped thin sheet of high-temperature superconductor has a hollow center and forms a continuous loop. In addition, the first end and the second end are folded toward each other forming two rings, and the thin sheet of high-temperature superconductor has a radial build that is less than 5 millimeters (mm) and able to withstand very strong magnetic field ranges of greater than approximately 12 Tesla (T) within a center-portion of a superconducting magnet of a superconducting magnet assembly.

Abstract: A magnetic resonance imaging apparatus has a plurality of cooling pipes disposed while being spaced apart from each other along a longitudinal length of the coil assembly, a first manifold connected to a lower end of the plurality of cooling pipes to distribute and supply a coolant to the plurality of cooling pipes, and a second manifold connected to an upper end of the plurality of cooling pipes to be supplied with the coolant from the plurality of cooling pipes, thereby able to evenly cool off the coil assembly in a longitudinal direction thereof.

Abstract: A superconductive electromagnet apparatus and a magnetic resonance imaging apparatus including the superconductive electromagnet apparatus are provided. The superconductive electromagnet apparatus includes a thermal anchor, a cryogenic cooling device which cools the thermal anchor, and at least one connecting ring into which the thermal anchor is inserted and a plurality of wires which are connected to the connecting ring.

Abstract: Systems and methods which employ a high temperature superconductor (HTS) receiver coil configuration for MRI analysis of small volume subjects, such as infants, are shown. Embodiments provide a HTS tape RF phase array receiver coil implementation. The foregoing HTS tape receiver coil implementation may be provided in a Helmholtz coil configuration. With such a Helmholtz coil configuration, circuitry is preferably provided to provide tuning, matching, and/or decoupling with respect to the HTS receiver coils. Embodiments implement a cryostat configuration to maintain one or more HTS receiver coils at a desired operating temperature (e.g., ?77° K.) while providing a safe environment for a subject (e.g., infant) being imaged.

Abstract: A cryogenic cooling system includes a chamber defined by an outer wall and an inner wall, the chamber housing at least one component to be cooled; a wicking structure in thermal contact with one of the outer wall and the inner wall of the chamber; and a delivery system in a spaced apart relationship with the chamber and fluidly connected to the wicking structure for transporting a working fluid to and from the wicking structure. Also provided is a magnetic resonance imaging system including the cryogenic cooling system.

Abstract: A cryostat (1) with a magnet coil system including superconductors for the production of a magnet field B0 in a measuring volume (3) has a plurality of radically nested solenoid-shaped coil sections (4, 5, 6) and which are electrically connected in series, at least one of which being an LTS section (5, 6) with a conventional low temperature superconductor (LTS) and at least one of which being an HTS section (4) including a high temperature superconductor (HTS), wherein the magnet coil system is located in a helium tank (9) of the cryostat (1) along with liquid helium at a helium temperature TL<4 K. The apparatus is characterized in that heating means are provided which always keep the HTS at an increased temperature TH>TL and TH>2.2 K. The cryostat in accordance with the invention can maintain the HTS section over a long period of time in a reliable manner.

Abstract: When cooling a superconducting magnet for use in a magnetic resonance imaging (MRI) device, a two-stage cryocooler (42) employs a first stage cooler (52) to cool a working gas (e.g., Helium, Hydrogen, etc.) to approximately 25 K. The working gas moves through a tubing system by convection until the magnet (20) is at approximately 25K. Once the magnet (20) reaches 25 K, gas flow stops, and a second stage cooler (54) cools the magnet (20) further, to about 4 K.

Abstract: A superconducting switch is provided in which the structural strength of the superconducting switch is kept, and thermal efficiency between a superconducting film and a heater is high when an ON state (superconducting state) and an OFF state (normal conducting state) of the superconducting switch are switched. The superconducting switch includes a substrate, a heater for generating heat by energization, a conductive film, and a MgB2 film evaporated on the conductive film. The heater, the conductive film and the MgB2 film are laminated in this order on one surface of the substrate.

Abstract: A penetration assembly for a cryostat is presented. The penetration assembly includes a wall member having a first end and a second end and configured to alter an effective thermal length of the wall member, where a first end of the wall member is communicatively coupled to a high temperature region and the second end of the wall member is communicatively coupled to a cryogen disposed within a cryogen vessel of the cryostat.

Abstract: The invention provides a magnetic induction system and an operating method for it in which the magnetic force can be made to act deeply and widely in any desired direction. The magnetic induction system of the invention contains multiple magnetic field generation means formed of a superconductive bulk magnet, a drive means for arranging the magnetic field generation means at a desired site and angle, and a drive control means for driving the driving means and controlling the position and the angle of the multiple magnetic field generation means so that a magnetic complex can be inducted to the desired position in a body by the synthetic magnetic field formed by the multiple magnetic field generation means, whereby the magnetic complex is inducted to be concentrated in the cartilage defected part.

Abstract: In order to attach an add-on unit to a low temperature pressure chamber unit having a low temperature pressure chamber, and an external housing surrounding the low temperature pressure chamber, an attachment device is used to attach at least one add-on unit to the external housing, and the attachment device has an adhesive unit designed for the arrangement and/or attachment of the at least one add-on unit to the external housing.

Abstract: A magnetic resonance system is provided which employs a shielded, electromagnetically asymmetric and low-stress magnet to produce a superior sized imaging region close to the patient side. The magnet has a double layered configuration. In the primary layer, the magnet includes at least two strongest coils at two ends of the magnet (end coils), which carry current in the same direction. The magnet may include at least one coil close to the end coils which carries current in a direction opposite to that of the end coils. The magnet employs a plurality of smaller sized coils (4-7, relative to the large end-coils) in the central region of the primary layer, and these coils are located asymmetrically relative to the imaging region centre. The magnet is shielded by a plurality (1-5) of shielding coils, which carry current in a direction opposite to that of the end-coils at primary layer.

Abstract: An open-structure magnetic assembly is adapted to generate a homogeneous magnetic field in an accessible space region, including a first and second independent source of magnetic field (10, 12), each generating a contribution to the resulting magnetic field. The first source includes a conducting or superconducting plate (20), carrying an unidirectional current flow (I) from an input side (22) to an output side (24) and at least one external current recirculating path (30) between the output side (24) and the input side (22) of the plate. The second source includes a volume of magnetized material or an arrangement of coils, arranged for generating a magnetic field component oriented according to the magnetic field generated by the first source (10), and whose intensity exhibits a gradient in a direction perpendicular to the conducting plate (20) adapted to compensate, in a region of interest, an opposite gradient in the magnetic field intensity generated by the first source (10).

Abstract: A superconducting magnet assembly and method of cooling a superconducting magnet assembly.

Abstract: A precooling device for a thermal radiation shield of a superconducting magnet has a mechanical heat conductive member in contact with the thermal radiation shield of a superconducting magnet, for cooling the thermal radiation shield down to a second temperature before the second stage of precooling of the superconducting magnet, this second temperature being below the temperature of the thermal radiation shield after a first stage of precooling of the superconducting magnet. A superconducting magnet and magnetic resonance imaging equipment embody such a precooling device. The precooling device reduces the external radiation heat onto a cryogen vessel, thereby reducing the consumption of cryogen.

Abstract: In a superconducting electromagnet system or method, cryogenically cooled magnet coils are arranged to provide a static magnetic field in an imaging region. A gradient coil assembly is arranged to provide oscillating magnetic fields within the imaging region. An electrically conductive shield is positioned between the cryogenically cooled magnet coils and the gradient coil assembly. The cryogenically cooled magnet coils are located within an outer vacuum chamber, and the electrically conductive shield is positioned outside the outer vacuum chamber between a surface of the outer vacuum chamber and the gradient coil assembly and inside a bore tube of the outer vacuum chamber. The conductive shield is supported on resilient damping mounts between the conductive shield and the gradient coil assembly and between the conductive shield and the bore tube of the outer vacuum chamber.

Abstract: A high-temperature superconducting magnetic sensor having a superconducting layer formed on a substrate and a plurality of superconducting quantum interference devices fabricated on the superconducting layer, which includes: a plurality of input coils that are formed on the superconducting layer and connected to or magnetically coupled with each of the plurality of the superconducting quantum interference devices; a pickup coil that is formed on the superconducting layer and connected so as to form a closed loop together with the plurality of the input coils; and a plurality of trimming wires that are formed on the superconducting layer and can be cut off, while making a short-circuit between both ends of each of the plurality of the input coils.

Abstract: Provided is a group of rare-earth regenerator material particles having an average particle size of 0.01 to 3 mm, wherein the proportion of particles having a ratio of a long diameter to a short diameter of 2 or less is 90% or more by number, and the proportion of particles having a depressed portion having a length of 1/10 to ½ of a circumferential length on a particle surface is 30% or more by number. By forming the depressed portion on the surface of the regenerator material particles, it is possible to increase permeability of an operating medium gas and a contact surface area with the operating medium gas.

Abstract: The invention relates to a measuring instrument for time-variable magnetix fluxes, or flux gradients, to electrical resistance elements, and to a measuring system comprising a measuring instrument or electrical resistance element according to the invention. The core component of the measuring instrument is a flux transformer composed of a base material which has a phase transition to the superconducting state. According to the invention, even when the base material is in the superconducting state, this flux transformer comprises at least one load region having electrical resistance that is other than zero for dissipating the electric energy in the conductor loop thereof. For this purpose, according to the invention the conductor loop and the magnetic field source are disposed in one plane and are typically photolithographically structured. The resistance elements according to the invention, having resistance values of ?10?4?, are used as core components in the measuring instrument.

Abstract: A magnetic field source is provided comprising a support structure upon which is positioned a conducting surface path of superconductor material. The support structure has an at least partially radially overlapping layer of material arranged in a spiral. A corresponding conducting surface path of superconductor material is arranged on the surface of the support structure such that the conducting path has a first point for the introduction of current and a second point for the extraction of current.

Abstract: A superconducting metallic glass transition-edge sensor (MGTES) and a method for fabricating the MGTES are provided. A single-layer superconducting amorphous metal alloy is deposited on a substrate. The single-layer superconducting amorphous metal alloy is an absorber for the MGTES and is electrically connected to a circuit configured for readout and biasing to sense electromagnetic radiation.

Abstract: There, is provided a directly-coupled high-temperature superconductor SQUID magnetic sensor in a single thin film structure, which suppresses flux trapping or jumping generated in the sensor in a magnetic field, prevents the degradation in performance of the SQUID sensor, and operates stably with high sensitivity even in the magnetic field. The SQUID magnetic sensor including a bi-crystal substrate 1 having a bi-crystal grain boundary, pickup loops 7a-7d formed from a first high-temperature superconducting thin film on the bi-crystal substrate 1, and a SQUID ring 3 formed from the first high-temperature superconducting thin film on the bi-crystal grain boundary, directly connected with the pickup loops 7a-7d, wherein a plurality of pickup loops 7a-7d are disposed equally spaced from a bi-crystal grain boundary line 2 so as not to overlap with the bi-crystal grain boundary.

Abstract: A coil comprises a set of windings with a generally annular shape and formed by a plurality of series-connected partial windings made of a superconductor with a high critical temperature, in which these partial windings are arranged next to each other in stratified form, and at least one cooling sheet which is made of thermally conductive material and arranged in contact with this set of windings and which is designed to be connected in a thermally conductive manner to a cryogenic cooling system.

Abstract: Systems and methods for operating a magnetic resonance imaging (MRI) during ramping are provided. One method includes reducing pressure in a cryogen vessel of an MRI system during magnet ramping. The method also includes returning pressure in the cryogen vessel to a normal operating pressure level after magnet ramping is complete.

Abstract: There is provided a superconducting joint for electrically connecting a first multifilamentary superconducting wire including a plurality of first superconducting filaments embedded in a first stabilizer matrix and a second multifilamentary superconducting wire including a plurality of second superconducting filaments embedded in a second stabilizer matrix.

Abstract: An RF coil adjacent an imaging region includes a plurality of conducting coil elements, with each conducting coil element including a proximal portion and a distal portion. The RF coil also includes a capacitance between the distal portions of the at least two conducting coil elements. A mutual coupling inductance between at least two conducting coil elements of the plurality of conducting coil elements is substantially cancelled by the capacitance between the distal portions of the at least two conducting coil elements.

Abstract: There is provided a superconducting magnet including a superconducting coil, in which the superconducting coil includes: a bobbin; one or more superconducting wires wound around the bobbin in a plurality of turns, each superconducting wire being one or more superconducting filaments embedded in a matrix; and one or more metallic members, each metallic member being in electrical and thermal contact with a plurality of portions of the one or more superconducting wires.

Abstract: New MRI coil and resonators are disclosed based solely on superconducting inductive element and built-in capacitive elements as well as hybrid superconducting-metal inductive and capacitive elements having superior SNR. Single and multiple small animal MRI imaging units are also disclosed including one or more resonators of this invention surrounding one or more small animal cavities. Methods for making and using the MRI coils and/or arrays are also disclosed.

Abstract: A superconducting magnet structure has a thermally conductive former with a former body having a former surface and a channel in said former surface that is open at said former surface, a thermally conductive tube disposed in the channel and configured to receive a circulating coolant therethrough, and the former body has at least one deformable retaining element integrally formed as a part of said former body and projecting from said surface of the former body next to the channel and being deformed over said tube in the channel to cover the tube in said channel and retain the tube in the channel.

Abstract: A superconducting magnet system for generating high homogeneity and high magnetic field consists of a main coil, an outer coil, a quench protection circuit, a quench heater and a power supply. The main coil is composed of many concentric solenoid coils which are arranged from inside to outside. The outer coil out of the main coil includes a first back roll coil, a second back roll coil, a first superconducting coil for compensating sixth harmonic component, a second superconducting coil for compensating sixth harmonic component, a shielding ring and a shielding coil from inside to outside. Every loop circuit of the quench protection circuit is composed of a corresponding protection resistor, a diode and coil which is connected in series each other, and each coil has a corresponding quench protection heater. The classification linear diameter difference of the superconducting coils which contact each other in main coil is less than 0.05 mm.

Abstract: SQUIDs may detect local magnetic fields. SQUIDS of varying sizes, and hence sensitivities may detect different magnitudes of magnetic fields. SQUIDs may be oriented to detect magnetic fields in a variety of orientations, for example along an orthogonal reference frame of a chip or wafer. The SQUIDS may be formed or carried on the same chip or wafer as a superconducting processor (e.g., a superconducting quantum processor). Measurement of magnetic fields may permit compensation, for example allowing tuning of a compensation field via a compensation coil and/or a heater to warm select portions of a system. A SQIF may be implemented as a SQUID employing an unconventional grating structure. Successful fabrication of an operable SQIF may be facilitated by incorporating multiple Josephson junctions in series in each arm of the unconventional grating structure.

Abstract: A superconducting high-field magnet coil system comprising several radially nested main coil sections (1, 2, 3, 4, 5) which are connected to each other in series in such a fashion that currents of the same direction flow through them during operation, wherein a first main coil section (EHS) is disposed radially further inward than a second main coil section (ZHS) and at least one intermediate main coil section (ZW) is disposed radially between the first and the second main coil section (EHS, ZHS), and with a superconducting switch (11) via which all main coil sections (1, 2, 3, 4, 5) can be superconductingly short-circuited in series, is characterized in that the first main coil section (EHS) and the second main coil section (ZHS) are directly successively series-connected and the first main coil section (EHS) and the second main coil section (ZHS) are bridged by a common quench protection element, which does not bridge the at least one intermediate main coil section (ZW).

Abstract: A method of searching for a material fated to generate an interband phase difference soliton includes the steps of generating an AC in a soliton candidate material, identifying a loss of AC magnetic susceptibility of the siliton candidate material due to a turn and a twist cut of a vortex line and judging whether or not the soliton candidate material is capable of generating soliton.

Abstract: A magneto-encephalographic equipment superconducting magnetic-shield comprising a vacuum-tight body comprising an outer enclosure wall, a first inner enclosure wall inserted in the outer enclosure wall to define a upper closed space, and a second inner enclosure wall to define a lower open space. The first and second inner enclosure walls are arranged with the bottom of the first inner enclosure wall facing the ceiling of the second inner enclosure wall. A first enclosure of HTSC and a second enclosure of high-permeability material are concentrically arranged in the annular vacuum space defined between the first and second inner enclosure walls and the outer enclosure wall. A head-accommodating area is delimited by the hollow partition between, the bottom of the first inner enclosure wall and the ceiling of the second inner enclosure wall both facing each other, and a plurality of SQUID sensors are arranged in the upper closed space, encircling the head-accommodating area.

Abstract: A superconducting main magnet system for a head-dedicated MRI system is provided, and a head-only MRI system may comprise such a superconducting main magnet and a cryogenically-cooled superconducting RF head-coil array. The superconducting main magnet may comprise a first and second set of high temperature superconductor coils which are configured to be coaxial relative to a common longitudinal axis. The first coil set includes at least two coils having an inner radius and disposed in a first region of a length along the common axis to cover a head and neck of a human body, and the second coil set includes at least one coil having an inner radius and disposed in a second region of a length along the common axis to cover a portion of a human torso, wherein the inner radius of the second coil set is greater than the inner radius of the first coil set.

Abstract: Multiple SQUID magnetometers that include at least two SQUID loops, each of which is composed of at least two Josephson Junctions connected in parallel with superconducting wires, are provided. The SQUID loops are fabricated such that they share a common Josephson Junction. Devices and application that employ the multiple SQUID magnetometers are also provided.

Abstract: An electromagnet comprises: a ferromagnetic core (50, 72); electrically conductive windings (34, 76) disposed around the ferromagnetic core such that current flowing in the windings magnetizes the ferromagnetic core; and a superconducting film (60, 80, 82) arranged to support eddy current cancelling supercurrent that suppresses eddy current formation in the ferromagnetic core when the windings magnetize the ferromagnetic core. A magnetic resonance scanner embodiment includes a main magnet (20) generating a static magnetic field and a magnetic field gradient system (30) with a plurality of said electromagnets (34, 50, 60) configured to superimpose selected magnetic field gradients on the static magnetic field.

Abstract: A superconducting magnet assembly and method of cooling a superconducting magnet assembly.

Abstract: The present invention provides a low-noise MEG apparatus of high sensitivity. A MEG apparatus using a magnetic shield of high critical temperature superconductor is set on the floor of a building via mechanical vibration suppressor supports to prevent appearance of noise signals. Also, the apparatus is equipped with means for preventing any relative displacement between the SQUID magnetic sensors and the magnetic shield of high critical temperature superconductor, thereby not letting an inevitable mechanical vibration of least strength produce any variable components of the trapped static magnetic field, which the SQUID magnetic sensors could be sensitive to.

Abstract: The present invention relates to a magnetic resonance examination system (10) and to a method of operating such a magnetic resonance examination system (10). In particular the present invention relates to a magnetic resonance examination system (10) comprising a superconducting main magnet (20) surrounding an examination region (18) and generating a main magnetic field in the examination region (18), and further comprising a magnetic field gradient system (30) selectively causing alternating gradient magnetic fields in the examination region (18), said magnetic field gradient system (30) being coupled to the main magnet (20).

Abstract: Provided is a highly accurate optical pumping magnetometer, in which a static magnetic field and an oscillating field to be applied to a vapor cell are stabilized. To this end, the optical pumping magnetometer includes: Helmholtz coils for applying a constant static magnetic field to a vapor cell serving as a magnetic field detector; fluxgate magnetometers for detecting environmental magnetic noise in two directions of X-axis direction and Y-axis direction other than Z-axis direction which is a direction for detecting a magnetic field coming out of a measurement object while locating the vapor cell in the center thereof; magnetometer drive circuits for driving the fluxgate magneotometers; current converters for converting outputs of the magnetometer drive circuits into amount of currents; and magnetic field generating coils for generating a magnetic field in a phase opposite to the environmental magnetic noise in the two directions.

Abstract: In an apparatus and method for transporting cryogenically cooled goods or equipment, a cryostat containing the cryogenically cooled goods or equipment and partially filled with liquid cryogen is provided with a cryogenic refrigerator for active cooling; and auxiliary equipment sufficient to maintain the cryogenic refrigerator in operation, are all mounted on a transportable carrier such that the transportable carrier may be transported with the cryogenic refrigerator in operation without connection of any of the cryostat, refrigerator and auxiliary equipment to any supplies located off of the transportable carrier.

Abstract: A cryostat (1) with a magnet coil system including superconductors for the production of a magnet field Bo in a measuring volume (3) has a plurality of radially nested solenoid-shaped coil sections (4, 5, 6) which are electrically connected in series, at least one of which being an LTS section (5, 6) with a conventional low temperature superconductor (LTS) and at least one of which being an HTS section (4) including a high temperature superconductor (HTS), wherein the LTS section (5, 6) is located in a first helium tank (9) of the cryostat (1) along with liquid helium at a helium temperature TL<4 K. The apparatus is characterized in that the HTS section (4) is disposed radially within the LTS section (5, 6) in a separate helium tank (19) of the cryostat (1) having normal liquid helium and is separated from the LTS section (5, 6) by means of at least one wall disposed between the two helium tanks.

Abstract: A coreless and brushless direct-current motor includes an armature coil wound without core and formed in the shape of a saddle; an outside rotor magnet formed by a permanent magnet, the outside rotor magnet being provided at an outside of the armature coil in the shape of a cylinder so as to face the armature coil, the outside rotor magnet being rotated by the magnetic field; an inside rotor magnet formed by a permanent magnet, the inside rotor magnet being provided in the shape of a cylinder at an inside of the armature coil so that the inside rotor magnet has a pole opposite to the outside rotor magnet and a rotational shaft is independently provided; an output shaft connected to the inside rotor magnet; and a sealing part of a barrier structure which sealing part partitions the armature coil and the outside rotor magnet to an outside of the inside rotor magnet and seals the armature coil and the outside rotor magnet.

Abstract: In a magnet system for MRI imaging comprising a superconducting magnet (10) mounted within a cryogen vessel (12), apparatus is provided for controlling egress of cryogen gas from the cryogen vessel. The apparatus comprises a controlled valve (42) linking the interior of the cryogen vessel to a gas exit path; and a controller (30) arranged to control the valve. The valve is arranged such that a gas pressure in the cryogen vessel exceeding a gas pressure in the gas exit path acts on the valve to open the valve and allow venting of cryogen gas. The valve is also arranged such that a gas pressure in the cryogen vessel inferior to a gas pressure in the gas exit path acts on the valve to urge it closed, so restricting flow of gas into the cryogen vessel.

Abstract: A cryostat (1) with a magnet coil system including superconductors for the production of a magnet field B0 in a measuring volume (3) has a plurality of radially nested solenoid-shaped coil sections (4, 5, 6) and which are electrically connected in series, at least one of which being an LTS section (5, 6) with a conventional low temperature superconductor (LTS) and at least one of which being an HTS section (4) including a high temperature superconductor (HTS), wherein the magnet coil system is located in a helium tank (9) of the cryostat (1) along with liquid helium at a helium temperature TL<4 K. The apparatus is characterized in that heating means are provided which always keep the HTS at an increased temperature TH>TL and TH>2.2 K. The cryostat in accordance with the invention can maintain the HTS section over a long period of time in a reliable manner.