Abstract: A cold head (20; 30) for a cryo refrigerator comprises at least one refrigerator tube (5), at least one pulse tube (6, 9), and one feed line (4) for feeding a working gas from a turning valve (3) of the cryo refrigerator to a warm end of the regenerator tube (5), wherein a cold end of the pulse tube (6, 9) is connected to a cold end of the regenerator tube (5) via a connecting line (7, 8), and wherein a buffer line (10, 11) extending to a buffer volume (14, 15) of the cryo refrigerator is provided at a warm end of the pulse tube (6, 9), is characterized in that a first reversing valve (21) is provided in the feed line (4), and a second reversing valve (23; 31, 32) is provided in the buffer line (10, 11), such that, in a rinsing state of the reversing valves (21, 23; 31, 32), the turning valve (3) and the buffer volume (14, 15) are separated from the regenerator tube (5) and from the pulse tube (6, 9), and the regenerator tube (5) and the pulse tube (6, 9) can be rinsed via the reversing valves (21, 23; 31, 32

Abstract: An NMR apparatus comprising a superconducting magnet coil system, in particular, an NMR spectrometer, with a cryostat which comprises an outer shell and a helium tank which contains the magnet coil system, and with an NMR probe head which is disposed in a room temperature bore of the cryostat and which contains a cooled RF resonator for receiving NMR signals from a sample to be examined and is cooled, together with the NMR probe head, by a cold head of a common, multi-stage, compressor-operated refrigerator, is characterized in that the cold head of the refrigerator is disposed in a neck tube, the upper end of which is connected to the outer shell of the cryostat and the lower end of which is connected to the helium tank in such a manner that the neck tube and the helium tank delimit a helium space, with at least one cooling circuit with thermally insulated transfer lines being provided between the helium space and the NMR probe head, wherein the cryogenic helium in the helium space is used as coolant for the

Abstract: An NMR spectrometer comprising a magnet coil system disposed in the helium tank (8) of a cryostat and an NMR probe head (4) which is disposed in a room temperature bore of the cryostat and contains a cooled RF resonator (13) for receiving NMR signals from a sample to be examined, wherein the helium tank (8) and the NMR probe head (4) are cooled by a common, multi-stage, compressor-operated refrigerator, is characterized in that the common refrigerator comprises a cold head (6) and several heat exchangers (21, 24, 25, 28, 31, 33, 34) at different temperature levels, wherein the refrigerator is disposed at a spatial separation from the cryostat in a separate, evacuated and thermally insulated housing (5), and several cooling circuits (1a, 1b, 1c, 1d, 2a, 2b, 3a, 3b) having thermally insulated transfer lines (14a, 14b, 15) are provided between the housing (5) containing the heat exchangers (21, 24, 25, 28, 31, 33, 34) and the cryostat, and also between the housing (5) and the NMR probe head (4).

Abstract: A cryostat configuration for keeping liquid helium comprising an outer jacket (3) surrounding a helium container (1) connected at at least two suspension tubes (2) to the outer jacket (3), wherein the helium container (1) also comprises a neck tube (5) whose upper warm end is connected to the outer jacket (3) and whose lower cold end is connected to the helium container (1) and into which a multi-stage cold head (6) of a cryocooler is installed, wherein the outer jacket (3), the helium container (1), the suspension tubes (2) and the neck tube (5) delimit an evacuated space (7), and the helium container (1) is surrounded by at least one radiation shield (4) which is connected in a heat-conducting fashion to the suspension tubes (2) and also to the neck tube (5) of the helium container (1) is characterized in that there is a direct connection (8) between the warm ends of the suspension tubes (2) and the neck tube (5) through which helium gas can flow.

Abstract: A cryostat configuration for keeping liquid helium, comprising an outer jacket (2) accommodating a helium container (5), a neck pipe (3) which is filled with gaseous helium during operation, and a refrigerator (1; 1b), wherein the outer jacket (2), the helium container (5) and the neck pipe (3) delimit an evacuated chamber (9) which surrounds the helium container (5); and wherein the refrigerator (1; 1b) has a cooling finger (4) which has a condensation body (15; 15b) in the region of the lower end of the neck pipe (3), is characterized in that the condensation body (15; 15b) is partially surrounded by a condensation chamber (16; 16b) which has a first lower opening (17) to permit draining of liquid helium, and a second opening which communicates with a lower end of a gas supply pipe (18), wherein the upper end of the gas supply pipe (18) terminates in the region of the upper end of the neck pipe (3). This improves the thermal properties of the cryostat configuration.

Abstract: A cryostat configuration for keeping liquid helium, comprising an outer jacket (2) accommodating a helium container (5), a neck pipe (3) which is filled with gaseous helium during operation, and a refrigerator (1; 1b), wherein the outer jacket (2), the helium container (5) and the neck pipe (3) delimit an evacuated chamber (9) which surrounds the helium container (5); and wherein the refrigerator (1; 1b) has a cooling finger (4) which has a condensation body (15; 15b) in the region of the lower end of the neck pipe (3), is characterized in that the condensation body (15; 15b) is partially surrounded by a condensation chamber (16; 16b) which has a first lower opening (17) to permit draining of liquid helium, and a second opening which communicates with a lower end of a gas supply pipe (18), wherein the upper end of the gas supply pipe (18) terminates in the region of the upper end of the neck pipe (3). This improves the thermal properties of the cryostat configuration.

Abstract: A cryostat arrangement for keeping liquid helium comprising an outer shell (2), a helium container (6) installed therein and a neck pipe (4) extending from the helium container to the outer shell whose upper warm end is connected to the outer shell and whose lower cold end is connected to the helium container, wherein the outer shell, the helium container and the neck pipe define an evacuated space (13) containing a radiation shield (15) surrounding the helium container and being connected at a coupling to the neck pipe in a heat-conducting fashion, wherein a refrigerator is installed in the neck pipe having a cold finger (5a) which consists of at least one pipe and projects into the neck pipe, is characterized in that at least one pipe of the cold finger is surrounded by at least one separating body (3a) which divides the neck pipe into two partial volumes (8a and 9a) which are connected to one another through a lower opening (10a) and an upper opening (7a).

Abstract: A cryostat arrangement for keeping liquid helium comprising an outer shell (2), a helium container (6) installed therein and a neck pipe (4) extending from the helium container to the outer shell whose upper warm end is connected to the outer shell and whose lower cold end is connected to the helium container, wherein the outer shell, the helium container and the neck pipe define an evacuated space (13) containing a radiation shield (15) surrounding the helium container and being connected at a coupling to the neck pipe in a heat-conducting fashion, wherein a refrigerator is installed in the neck pipe having a cold finger (5a) which consists of at least one pipe and projects into the neck pipe, is characterized in that at least one pipe of the cold finger is surrounded by at least one separating body (3a) which divides the neck pipe into two partial volumes (8a and 9a) which are connected to one another through a lower opening (10a) and an upper opening (7a).