| 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 ( 5 a ) 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 ( 3 a ) which divides the neck pipe into two partial volumes ( 8 a and 9 a ) which are connected to one another through a lower opening ( 10 a ) and an upper opening ( 7 a ). A cryostat arrangement of this type with active cooling through refrigerators shows considerable improvements over conventional cryostats with respect to thermal properties. In particular, it is possible to completely stop consumption of liquid helium. |