EP2039979A1 - Cryostat with reinforced inner vessel - Google Patents

Abstract

The cryostat has a hollow space arranged between an inner tank (112) and an outer tank. The inner tank has a bottom part (136), and a side wall (134) that is connected with the bottom part in a connection region (140). The inner tank has a circulating reinforcement element (142) in the region. The element has a fiber composite material with an anisotropic oriented fibrous material including a local orientation, which is oriented in circumferential direction of the cryostats. The fibrous material comprises a glass fiber material, carbon fiber material or mineral fiber material. Independent claims are also included for the following: (1) a bio-magnetic measuring system with a cryostat (2) a method for manufacturing a cryostat for use in a bio-magnetic measuring system.

Description

Field of the invention

The invention relates to a cryostat, which is particularly suitable for use in a biomagnetic measuring system, as well as a biomagnetic measuring system comprising such a cryostat. The invention further relates to a method for producing a cryostat, which is particularly suitable for biomagnetic measurements. Such cryostats and measuring systems can be used in particular in the field of cardiology or in other medical fields, such as neurology. Other applications, such as non-medical applications, such as applications in materials research, are conceivable.

State of the art

In recent years and decades, magnetic measuring systems, which until then were largely reserved for basic research, have found their way into many areas of biological and medical sciences. In particular, neurology and cardiology benefit from such biomagnetic measurement systems.

The basis of biomagnetic measurement systems is the fact that most cell activities in the human or animal body are associated with electrical signals, in particular electrical currents. The measurement of these electrical signals themselves, which are caused by the cell activity, is known for example from the field of electrocardiography. However, in addition to the purely electrical signals, the electrical currents are also connected to a corresponding magnetic field whose measurement is made use of the various known biomagnetic measurement methods.

While the electrical signals or their measurement outside the body are linked by various factors, such as the different electrical conductivities of the tissue types between the source and the body surface, magnetic signals penetrate these tissue areas almost undisturbed. The measurement of these magnetic fields and their changes thus allows conclusions about the currents flowing within the tissue, for example electrical currents within the heart muscle. A measurement of these magnetic fields with high time and / or spatial resolution over a certain range thus allows imaging methods which can reproduce, for example, a current situation of different areas of a human heart. Other known applications are, for example, in the field of neurology.

The measurement of magnetic fields of biological samples or patients, or the measurement of temporal changes of these magnetic fields, however, represents a metrological challenge. For example, the magnetic field changes in the human body, which are to be measured in the magnetocardiography, about one million times weaker than the magnetic field of the earth. The detection of these changes thus requires extremely sensitive magnetic sensors. In most cases, superconducting Quantum Interference Devices (SQUIDs) are therefore used in the field of biomagnetic measurements. Such sensors typically need to be cooled to 4 ° K (-269 ° C) to achieve the superconducting state, typically using liquid helium. The SQUIDs are therefore usually arranged individually or in a SQUID array in a so-called. Dewar vessel and are cooled there accordingly. Alternatively, laser-pumped magneto-optic sensors are currently being developed that can have approximately comparable sensitivity. Also in this case, the sensors are usually arranged in an array arrangement in a container for temperature stabilization.

Such containers for temperature stabilization, in particular containers for the cooling of magnetic sensors and so-called Dewar vessels are hereinafter generally referred to as "cryostat". In particular, these may be helium cryostats or other types of cryostat. Between the cryostat and the cryostat vessel, which is also referred to as dewar, is not distinguished below, even if the actual cryostat next to the cryostat vessel may include more parts.

The production of the cryostat for receiving biomagnetic sensor systems constructively presents a great challenge. The sensors are usually in one predetermined arrangement in these cryostats introduced, for example in the form of a hexagonal arrangement of SQUIDs or other magnetic sensors. In this case, usually the cryostat comprises an inner vessel, with sensors received therein, as well as an outer vessel. The space between inner vessel and outer vessel is evacuated. However, it is of considerable importance that the distance between the sensors housed in the inner cryostat vessel and the skin surface of the patient is kept as small as possible, since, for example, the signal strength decreases with a high power of the distance between sensor and skin surface. Accordingly, the distance between the bottoms of the inner and outer vessels must be kept small and extremely constant.

Numerous cryostats are known from the prior art, which can be used for magnetic measurements. For example, describes WO 94/03754 a cryostat vessel with an inner Dewar and an outer Dewar. In this case, a series of radiation shields is provided. Also DE 298 09 387 U1 describes a cryostat for radiomagnetic probing methods in which SQUIDs are preferably used. The cryostat has a high electromagnetic high-frequency transparency. In this case, a double vessel is again proposed, wherein a sensor is received at the bottom of an inner vessel. This inner vessel is formed in two parts and shows a bottom part with a raised edge which partially encloses a side wall.

The conventional cryostat used for magnetic measurements, however, in practice have a number of disadvantages and difficulties which can affect the reliability and reproducibility of the measurements. For example, when pumping the gap between the inner and outer vessel deformations occur, which can lead to the formation of thermal bridges between the bottoms of the vessels. In addition, it has been found that, especially in the transition region between the bottom part and the side wall of the inner vessel, tensions can easily occur, which can lead to cracks, which in turn can have a strong negative impact on the quality of the cryostat.

Object of the invention

It is therefore an object of the present invention to provide a cryostat which is particularly suitable for use in biomagnetic measuring systems and which at least largely avoids the disadvantages of the cryostats known from the prior art. In particular, the cryostat should be reliable and reproducible to produce and should avoid the quality problems described above.

Description of the invention

This object is achieved by a cryostat and a method for producing a cryostat having the features of the independent claims. Advantageous developments of the invention, which can be implemented individually or in combination, are shown in subclaims. The wording of all claims is hereby incorporated by reference into the content of the description.

It is proposed a cryostat for use in a biomagnetic measuring system, which has at least one inner vessel and at least one outer vessel, and at least one arranged between the inner vessel and the outer vessel cavity. Analogously, a plurality of such inner and / or outer vessels and / or a plurality of cavities may be provided. The cavity should be acted upon by a negative pressure, so it should be able to be sealed in order to be evacuated. For this purpose, inner and outer vessels may, for example, have corresponding seals (for example, separate sealing rings and / or sealing adhesions at joints or similar types of seals), a pump port for connection to a device for generating a vacuum (e.g., a vacuum pump), or the like.

The outer vessel and the inner vessel can be made of a variety of possible materials, which ensure the required mechanical stability of these vessels. It is particularly preferred if these vessels are wholly or partly made of a fiber composite material, ie a composite of a fiber material and a matrix material made of a plastic. Alternatively or additionally, however, a variety of other materials can be used, such as metals, plastics, ceramics or a combination of these materials.

The inner vessel has a bottom part and a side wall connected in a circumferential connection region with the bottom part. This modular construction has proved advantageous over one-piece structures as already in this way Most of tension in the transition region between the floor and side walls can be avoided.

In order to additionally provide a reinforcement in the connection area between the base part and the side wall, it is proposed according to the invention that the inner vessel has a circumferential reinforcing element in this connection region. This reinforcing element should have a first fiber composite material with an anisotropically oriented first fiber material having a local preferred direction. This local preferred direction should be oriented substantially in the circumferential direction of the cryostat. In other words, the fiber material comprises fibers which are arranged substantially tangentially at each location of the reinforcing element. By "essentially" is preferably to be understood an oriented orientation of the fibers, which is at least 10%, more preferably at least 20%. Also, the local preferred direction of the fibers of the fiber material should preferably deviate by less than 20 ° from the circumferential direction, preferably even less than 10 ° or less than 5 °. However, this should not affect the possibility that the fiber material comprises fiber mats or a fibrous tissue. A fiber fabric may comprise, for example, warp threads and weft threads. In this case, for example, the warp threads or the weft threads should be oriented substantially in the circumferential direction, whereas the respective other type of thread is oriented perpendicular thereto, for example parallel to an axis of the cryostat. As such, in this example preferably at least 40% or even at least half of the fibers are oriented substantially in the circumferential direction. The fiber mats as a whole should also have a tangential orientation in their longitudinal extent. If an elongated band of a fiber mat is used, for example in the context of a winding technique, so should preferably extend the longer axis of this band in the circumferential direction.

The proposal of the reinforcing element is based on the fact that, after numerous experiments with fiber composite materials, it has been found that the random arrangement of the fibers in fiber composite materials in the connection region can cause considerable problems. Thus, for example, for the production of the bottom part of methods can be used, in which the fiber orientation is aligned substantially in a radial arrangement. However, due to the slight deflection of the fibers upon application of force in the radial direction instabilities in the vessel wall can occur, in particular when pumping out of the cavity.

The proposed reinforcing element with the circumferentially oriented fibers of the fiber material, however, acts like a "reinforcing belt" and is based on the same Basic ideas such as radial tires in automotive technology. The individual fibers of the fiber material can be hooked into each other, so that the circumferential reinforcing element is additionally reinforced in its stability relative to radially outward loads.

In this way, the above-described quality and stability problem of the inner vessel in the particularly critical connection region between the bottom part and side wall can be greatly reduced. Even after a variety of Abpumpprozessen occur no significant damage or signs of wear in this area.

The proposed cryostat can be advantageously developed in various ways. Thus, for example, the reinforcing element may be formed as a separate reinforcing element, for example as a belt-shaped, hoop-shaped or annular separate reinforcing element. However, it is particularly preferred if the reinforcing element is formed integrally with the side wall or, more preferably, in one piece with the bottom part. In the latter case, for example, the reinforcing element may be part of a raised edge of the bottom part, which is in contact with the side wall and, for example, glued thereto.

In general, various joining techniques can be used for the connection between the bottom part and the side wall, whereby welding, gluing, potting or other techniques or combinations of these techniques are conceivable. However, other techniques can be used.

In the case where the reinforcing member is formed integrally with the bottom part, it is particularly preferable that the bottom part outside the reinforcing member also has a second fiber composite material. For example, this second composite fiber material may be wholly or partially material-identical to the first composite fiber material, i. it may, for example, have identical matrix materials and / or identical types of fiber materials. The second fiber composite material has a second fiber material, which may be oriented isotropically, for example, or in turn anisotropic with, for example, radial orientation.

As described above, it is particularly preferred if the reinforcing element is designed in the form of a cylinder ring. In this case, this cylinder ring can also have stages, such as a step on which the side wall is placed.

The bottom part can, as described above, have a raised edge, which is oriented substantially parallel to the side wall. The reinforcing element may be an integral part of this raised edge, for example, an upper portion of this raised edge. As described above, this raised edge, in particular in the region of the reinforcing element, can furthermore have a step, with a deeper step surface pointing into the interior of the inner vessel. The side wall can sit on this deeper step surface. In this way, for example, the side wall may be enclosed in the lower region of a raised ring or collar of gradation. In this case, it is particularly preferred if this raised ring of the step, which comprises the side wall, includes the reinforcing element.

The side wall may in principle have any desired cross-section, wherein an axial symmetry about an axis of the cryostat is preferred. In this case, round or polygonal cross sections are particularly preferred, so that the side wall can be produced, for example, as a hollow cylinder with a circular or polygonal cross section.

The first fiber material and / or optionally also the second fiber material may in particular comprise at least one of the following fiber materials: a glass fiber material, a carbon fiber material, a mineral fiber material. Combinations of these and / or other materials are possible. As illustrated above, it is particularly preferred if the fiber material has a multiplicity of fibers interlocked with one another. It is particularly preferred if the fiber material comprises at least one fiber mat, which may include, for example, substantially parallel oriented fibers, with deviations of preferably not more than 10 ° -20 ° from the parallelism are still tolerable. This fiber mat can then, for example, have an elongated shape, for example the shape of a long strip, in which case preferably the fibers are arranged parallel to the longitudinal extension of this strip. The fiber mat should extend at least once around the circumference of the reinforcing element, and it is particularly preferred if this fiber mat reaches around this circumference several times. In this case, a winding technique can be used, resulting in a particularly stable reinforcing member.

As described above, the fiber composite material further comprises a matrix material. This matrix material may comprise at least one or more of the following materials: a thermoplastic plastic material, a thermosetting plastic material, in particular an epoxy resin, an elastomeric material. It is particularly preferred if the matrix material comprises an initially deformable (ie, for example, flowable) matrix material which can subsequently be cured, for example by a thermal and / or photochemical and / or chemical curing or curing by simply waiting. Many such materials are known in the art and can be used. Examples of such resins are shown in more detail below.

Furthermore, it is particularly preferred if the bottom part for receiving the biomagnetic sensors, which may be, for example, SQUIDs and / or magneto-optical sensors, having a plurality of wells. These depressions should be arranged in the interior of the inner vessel and point to the bottom side of the cryostat. For example, the pits may be arranged in a hexagonal array and e.g. 64 wells. However, other numbers of wells and / or arrangements of wells are possible.

Furthermore, a biomagnetic measuring system is proposed, which includes at least one cryostat according to one of the embodiments described above, and at least one biomagnetic sensor for detecting a magnetic field. For the design of these sensors can, for example WO 03 / 073117A1 . EP 0359 864 B1 or other publications from the field of biomagnetic sensors are referenced.

• Mindestens ein zweites Fasermaterial wird in eine Form für das Bodenteil eingebracht, wobei die Form einen Bereich zur Erzeugung des Verstärkungselements aufweist. Das erste Faserverbundmaterial wird im Wesentlichen außerhalb des Bereichs zur Erzeugung des Verstärkungselements angeordnet.
• Mindestens ein erstes Fasermaterial wird in die Form eingebracht, wobei das erste Fasermaterial im Wesentlich innerhalb des Bereichs zur Erzeugung des Verstärkungselements angeordnet wird und wobei das erste Fasermaterial im Wesentlichen in Umfangsrichtung orientiert wird.
• Mindestens ein aushärtbares Matrixmaterial wird in die Form eingebracht und ausgehärtet.

Furthermore, a method for producing a cryostat for use in a biomagnetic measuring system is proposed. This method can be used, for example, to produce a cryostat according to one of the above embodiments, so that with regard to possible variants of the method can be made to a large extent to the above description. The cryostat in turn has at least one inner vessel and at least one outer vessel and at least one cavity arranged between the inner vessel and the outer vessel, which can be subjected to a negative pressure. The inner vessel again has a base part and a side wall which is connected to the base part in a circumferential connection region, wherein the inner vessel has a circumferential reinforcing element in the connection region. The method comprises the following steps:

• At least one second fibrous material is introduced into a mold for the bottom part, the mold having a region for producing the reinforcing element. The first fiber composite material is disposed substantially outside the region for producing the reinforcing member.
• At least one first fibrous material is introduced into the mold, the first fibrous material substantially within the region for producing the reinforcing element is arranged and wherein the first fiber material is oriented substantially in the circumferential direction.
• At least one curable matrix material is introduced into the mold and cured.

The method steps can be carried out in the specified sequence or else in a different order or overlapping in time.

The mold may, for example, comprise a conventional casting mold (also called a tool) for casting processes. However, other forms are conceivable, depending on the production technique used.

As described above, in the introduction of the first fiber material, for example, a winding technique can be used. For example, an elongated fiber mat may be used having circumferentially oriented fibers which are disposed at least once, preferably multiple times, over the entire circumference of the region for forming the reinforcing element in the mold.

Furthermore, it is preferred for serial use, if a variety of different bottom parts for the inner vessel can be kept, which can be used for different types of sensors. For example, different sensors may be used, each requiring a different distance to the skin surface of a patient. However, this modular technique would mean in conventional methods that a new mold has to be designed for each sensor system with different sensors, which involves considerable costs. In order nevertheless to be able to implement the above-described fiber technology cost-effectively and to enable the production of a "modular system" for various sensors in the proposed, very stable cryostat, it is therefore proposed to produce the depressions for receiving the biomagnetic sensors in that the Form having a plurality of interchangeable cores. These cores may have the desired negative shape to the recesses and may be selected according to the desired depth of the recesses. In this way, even in large-scale use, cryostats can be produced for a large number of sensors, which nevertheless have the above-described positive quality properties.

embodiments

Further details and features of the invention will become apparent from the following description of preferred embodiments in conjunction with the subclaims. In this case, the respective features can be implemented on their own or in combination with one another. The invention is not limited to the embodiments. The embodiments are shown schematically in the figures. The same reference numerals in the individual figures designate the same or functionally identical or with respect to their functions corresponding elements.

Figur 1

ein Ausführungsbeispiel für einen Kryostaten für den Einsatz in einem biomagnetischen Messsystem in einer Schnittdarstellung;

Figur 2

einen Ausschnitt der Darstellung gemäß Figur 1 im Bereich eines Überganges zwischen einem Bodenteil und einer Seitenwand eines Innengefäßes;

Figur 3

einen Ausschnitt aus der Darstellung gemäß Figur 1, welcher das Bodenteil des Innengefäßes zeigt; und

Fig. 4A-4C

Teilschritte eines Ausführungsbeispiels eines erfindungsgemäßen Verfahrens zur Herstellung eines Kryostaten für den Einsatz in einem biomagnetischen Messsystem.

In detail shows:

FIG. 1

an embodiment of a cryostat for use in a biomagnetic measuring system in a sectional view;

FIG. 2

a section of the representation according to FIG. 1 in the region of a transition between a bottom part and a side wall of an inner vessel;

FIG. 3

a section of the illustration according to FIG. 1 showing the bottom part of the inner vessel; and

Fig. 4A-4C

Partial steps of an embodiment of a method according to the invention for producing a cryostat for use in a biomagnetic measuring system.

In FIG. 1 is a possible embodiment of a cryostat 110 according to the invention shown in a sectional view. The cryostat 110 has an inner vessel 112 and an outer vessel 114 enclosing the inner vessel 112.

The outer vessel 114 is configured substantially cylindrical and has various flanges 116 and 118. While the lower of these flanges 116 substantially performs support functions, the upper flange 118 serves to receive a lid 120 of the outer vessel 114. Through this cover 120 projects a neck 122 of the inner vessel 112. Through this neck 122, biomagnetic sensors (shown in FIG FIG. 1 not shown) into the interior of a (also substantially cylindrical) main vessel 124 of the inner vessel 112 are introduced. In addition, leads to these sensors can be led through the neck 122 to the outside and connected to a corresponding electronics, so that measurement signals of these sensors can be queried.

Between the inner vessel 112 and the outer vessel 114, a cavity 126 is formed. This cavity 126 can by means of a in FIG. 1 Vacuum socket not shown are evacuated. By this evacuation and formation of a negative pressure in this cavity 126, an insulating effect of the cryostat 110 is increased. In this way, the interior of the main vessel 124 of the inner vessel 112 can be cooled, for example, by means of liquid helium, without requiring a replacement or replacement of this liquid helium at short intervals.

Both the inner vessel 112 and the outer vessel 114 have substantially continuous fiber composite materials as materials. Furthermore, both the inner vessel 112 and the outer vessel 114 are modular. Thus, for example, the outer vessel 114 next to the lid 120 has a side wall 128 and a bottom part 130. The inner vessel 112 has, in addition to the neck 122 in the region of the main vessel 124, a circular ring 132, which seals the neck 122 relative to the main vessel 124. Furthermore, the inner vessel 112 has a side wall 134 and a bottom part 136. In this embodiment, the side walls 128,134 are provided with a cylindrical shape, which is not absolutely necessary. Thus, for example, polygonal cross sections or irregular cross sections can be used.

A particularly critical area in the production of the cryostat 110 is the in FIG. 1 The region of the transition between the bottom part 136 and the side wall 134 of the inner vessel 112, designated by reference numeral 138 FIG. 3 shown in enlarged detail. As a further enlarged area is in FIG. 2 a connection area 140 is shown in detail. Both figures will be explained together below.

When evacuating the cavity 126 in FIG FIG. 1 acts on the side wall 134 of the inner vessel 112 an outward, directed toward the cavity 126 force. This force leads in the peripheral connection region 140 between the bottom part 136 and the side wall 134 of the inner vessel 112 to tension. In order to avoid cracking due to these distortions in this connection region 140, the connection region 140 has a circumferential reinforcing element 142, which in this exemplary embodiment is formed integrally with the bottom part 136. The bottom part 136 has a raised, annular edge 144, which is formed in its upper region as a step 146. This step 146 has a lower step surface 148, on which the lower edge of the side wall 134 of the inner vessel 112 rests. Furthermore, the step 146 includes a collar 150 which annularly surrounds the lower edge of the side wall 134.

The reinforcing element 142 differs from the rest of the bottom part 136 essentially by its structural properties. Thus, the entire bottom part 136 is made of a fiber composite material, which preferably comprises an epoxy resin as a matrix material and, for example, glass fibers as a fiber material. In addition, other additives may be included. In the region of the reinforcing element 142 is this fiber material, which in the FIGS. 2 and 3 is not shown, oriented in the circumferential direction and thus has in FIG. 2 into the drawing plane. In the rest of the bottom part 136, however, the fiber orientation of the fiber material is substantially radially extending, ie in FIG. 2 parallel to the drawing plane. The orientation of the fiber materials will be described below with reference to Figures 4A-4C explained in more detail.

Furthermore, in the FIGS. 2 and 3 it can be seen that the bottom part 136 has a series of depressions 152. These recesses 152 are used to hold biomagnetic sensors, which are not shown in the figures. For example, SQUIDs can be used for this purpose, which are mounted, for example, on a linkage introduced through the neck 122 of the inner vessel 112 into the main vessel 124. The biomagnetic sensors may, for example, be accommodated in a hexagonal arrangement in the base part 136 so that they can receive measurement signals over a surface area and thus for example map a chest area of a patient. The depressions 152 serve, for example, for the purpose of fixing the biomagnetic sensors and, moreover, shortening the distance between the sensor and the skin surface of the patient in that the effective bottom thickness of the bottom part 136 is increased from the original D to the distance d in FIG FIG. 2 is reduced. Furthermore, in the bottom part 136 threaded holes 154 to which, for example, a linkage for holding the biomagnetic sensors can be fixed.

In the Figures 4A-4C are shown partial steps of a method for producing a cryostat, for example a cryostat according to the above FIGS. 1 to 3 , In this case, only the partial steps of the method are shown, which lead to the production of the bottom part 136, and thereof in each case again only a section, which essentially corresponds to the cutout FIG. 2 corresponds and thus in particular the reinforcing element 142 comprises.

In a first method step according to FIG. 4A If a fiber material 156 is arranged in a first mold half 160. This first mold half 160 substantially corresponds to the later outer contour of the bottom part 136, for example according to FIG FIG. 2 ,

Within the first mold half 160, two regions are to be distinguished: a first region 162, in which the reinforcing element 142 is later formed, and a second region 164, which comprises the bottom part 136 outside the reinforcing element 164. In this embodiment, it is assumed that the fiber material 156, 158 is a mat-shaped fiber material, wherein identical fiber materials 156, 158 can be used for both regions 162, 164, for example.

During production, the two regions 162, 164 essentially differ in the orientation of the fiber material 156, 158. While in the region 164 the fiber material is inserted into the first mold half 160 substantially in radial alignment, the fiber material 158 is formed in the region 162, in FIG which later the reinforcing element 142 is formed, oriented in the circumferential direction. For example, in this example, fiber mats with parallel, interlocked fibers can be pressed into this region 162 of the first mold half 160 such that these fiber mats circulate several times around the raised edge of this first mold half 160. This technique can be called a "winding technique". However, the fiber mats 156 may also project at least partially into the region 162.

In FIG. 4B It is shown how, as the next method step, the fiber material 156, 158 is cast with a curable matrix material 166. This matrix material 166 may be, for example, a curable epoxy resin. As a possible embodiment, an epoxy resin type L 20 (for example, R & G Faserverbundwerkstoffe GmbH, 71107 Waldenbuch, Germany) with a hardener, for example, the type EPH 161 (for example, also from R & G Faserverbundwerkstoffe GmbH, 71107 Waldenbuch, Germany) used. Another useful example is the two-component adhesive Stycast 2850 FT (AAT Aston GmbH, Nuremberg, Germany), where, for example, as a hardener of Catalyst 9 (also AAT Aston GmbH, Nuremberg, Germany) can be used. As fiber material 156, 158, for example, an E glass with a glass fabric having a density of 160 g / m ² (for example, by R & G Faserverbundwerkstoffe GmbH, 71107 Waldenbuch, Germany) can be used. However, other types of fiber materials 156, 158 and / or thermosetting matrix materials 166 are of course applicable.

Subsequently, as in FIG. 4C shown, a second mold half 168 is pressed onto the first mold half 160. The matrix material 166 and the fiber material 156,158 is thereby compressed, wherein, for example, openings may be provided through which excess matrix material 166 can escape from the interior space between the two mold halves 160, 168. Due to the interaction of the two mold halves 160, 168, the interior area between these mold halves substantially includes the shape of the later bottom portion 136. The matrix material 166 may now harden, which curing process may include, for example, a polymerization process, a drying process, or the like. The curing can be favored for example by thermal activation, by chemical activation, by photochemical activation or by the addition of starters. Even a simple wait is possible. The exact configuration of the curing process generally depends on the choice of matrix material 166. In this way, during curing, the bottom part 136 forms, which can be configured, for example, as in FIG FIG. 2 comprising the reinforcing element 142 in the connection region 140.

Furthermore, in FIG. 4C nor an additional, optional process variant shown, in which the recesses 152 according to the FIGS. 2 and 3 can be produced. For this purpose, the second mold half 168 has a plurality of interchangeable cores 170, which constitute a negative of these depressions 152. For example, with one and the same second mold half 168, a plurality of cores 170 may be provided to, for example, cryostats 110 having varying depths of the cavities 152 (ie, varying in size d in FIG FIG. 2 ) to produce. A variation of this size d, ie the depth of the depressions 152, also has only a marginal effect on the stability of the connecting region 140 between the bottom part 136 and side wall 134 of the inner vessel 112, since this stability acts essentially through the reinforcing element 142, which acts like a reinforcing belt , is conditional.

LIST OF REFERENCE NUMBERS

110

cryostat

112

inner vessel

114

outer vessel

116

flange

118

flange

120

cover

122

Neck of the inner vessel

124

main vessel

126

cavity

128

Sidewall outer vessel

130

Bottom part outer vessel

132

annulus

134

Side wall inner vessel

136

Bottom part of the inner vessel

138

Critical area

140

connecting area

142

reinforcing element

144

Raised edge

146

step

148

step surface

150

collar

152

wells

154

threaded holes

156

fiber material

158

fiber material

160

First half of the mold

162

Area of the reinforcing element

164

Area outside the reinforcing element

166

matrix material

168

Second half of the mold

170

Interchangeable core

Claims (21)

A cryostat (110) for use in a biomagnetic measurement system comprising at least one inner vessel (112) and at least one outer vessel (114) and at least one cavity (126) disposed between the inner vessel (112) and the outer vessel (114), the cavity (126), wherein the inner vessel (112) has a bottom part (136) and a side wall (134) connected to the bottom part (136) in a circumferential connection region (140), characterized in that the inner vessel (112 ) in the connecting region (140) has a circumferential reinforcing element (142), wherein the reinforcing element (142) comprises a first fiber composite material with an anisotropically oriented first fiber material (158) with a local preferred orientation, wherein the local preferred orientation substantially in the circumferential direction of the cryostat ( 110) is oriented. A cryostat (110) according to the preceding claim, wherein the local preferential direction deviates over the entire circumference of the reinforcing element (142) by less than 20 ° from the circumferential direction. A cryostat (110) according to any one of the preceding claims, wherein the anisotropically oriented first fibrous material (158) has an orientation degree of at least 20%. A cryostat (110) according to any one of the preceding claims, wherein the reinforcing member (142) is integral with bottom member (136) or side wall (134). A cryostat (110) as claimed in the preceding claim, wherein the reinforcing member (142) is integrally formed with bottom member (136), the bottom member (136) having a second fiber composite outside the reinforcing member (142). A cryostat (110) according to the preceding claim, wherein the second fiber composite material comprises a second isotope material (156) substantially isotropically or anisotropically radially oriented. A cryostat (110) according to any one of the preceding claims, wherein the fiber composite material and the second fiber composite material are substantially material identical. Cryostat (110) according to one of the preceding claims, wherein the reinforcing element (142) is designed in the form of a cylinder ring. A cryostat (110) according to any one of the preceding claims, wherein said bottom portion (136) has a raised edge (144), said edge (144) being oriented substantially parallel to said side wall (134). A cryostat (110) according to the preceding claim, wherein the reinforcing element (142) is an integral part of the raised edge (144). A cryostat (110) according to any one of the preceding claims, wherein the raised edge (144) has a step (146) with a deeper step surface (148) facing inside the inner vessel (112), the side wall (134) being on the step surface (148) is seated. A cryostat (110) according to any one of the preceding claims, wherein the side wall (134) has a round or polygonal cross-section. A cryostat (110) according to any one of the preceding claims, wherein the first fibrous material (158) comprises at least one of the following fibrous materials: a fiberglass material; a carbon fiber material; a mineral fiber material. A cryostat (110) according to any one of the preceding claims, wherein the first fibrous material (158) comprises a plurality of interlocked fibers. A cryostat (110) according to any one of the preceding claims, wherein the first fibrous material (158) comprises at least one fibrous mat having a longitudinal extent over at least once the circumference of the reinforcing element (142). The cryostat (110) of any one of the preceding claims, wherein the fiber composite material further comprises a matrix material (166), wherein the matrix material (166) comprises at least one of the following materials: a thermoplastic plastic material; a thermosetting plastic material, in particular an epoxy resin; an elastomeric material. A cryostat (110) according to any one of the preceding claims, wherein the bottom portion (136) comprises a plurality of cavities (152) for receiving biomagnetic sensors. A biomagnetic measuring system comprising at least one cryostat (110) according to one of the preceding claims, further comprising at least one biomagnetic sensor for detecting a magnetic field. Method for producing a cryostat (110) for use in a biomagnetic measuring system, wherein the cryostat (110) has at least one inner vessel (112) and at least one outer vessel (114) and at least one between the inner vessel (112) and the outer vessel (114) arranged cavity (126), wherein the cavity (126) is acted upon by a negative pressure, wherein the inner vessel (112) has a bottom part (136) and a in a peripheral connecting portion (140) connected to the bottom part (136) side wall (134) wherein the inner vessel (112) has a circumferential reinforcing element (142) in the connecting region (140), the process comprising the following steps: at least one second fibrous material (156) is introduced into a mold (160, 168) for the bottom part (136), the mold (160, 168) having a region (162) for producing the reinforcing element (142), the second Fiber material (156) is disposed substantially outside of the region (162) for producing the reinforcing element (142); at least one first fibrous material (158) is introduced into the mold (160, 168), wherein the first fibrous material (158) is disposed substantially within the region (162) for producing the reinforcing element (142), the first fibrous material (158 ) is oriented substantially in the circumferential direction; - At least one curable matrix material (166) is introduced into the mold and cured. Method according to the preceding claim, wherein the first fiber material (158) comprises at least one elongated fiber mat, wherein the elongated fiber mat is placed upon insertion into the mold such that it extends over the entire circumference of the region (162) at least once, preferably several times. for generating the reinforcing element (142). Method according to one of the two preceding claims, wherein the bottom part (136) has a plurality of recesses (152) for receiving biomagnetic sensors wherein the mold (160, 168) comprises a plurality of interchangeable cores (170) for producing the recess (152), wherein different cores (170) are used to create different depths of the recesses (152).

Images