Cryostat with PTR cooling and two stage sample holder thermalization

摘要

A cryostat with a PTR cooling and a boiling fluid medium including a two stage sample holder thermalization, especially convenient for AC susceptibility measurement; wherein: a 1st PTR stage is connected to a recondenser with a thermal link only; the recondenser partially penetrates through the walls of a chamber into a dewar region above a boiling fluid level, wherein the recondenser includes an integrally built thermalization point with the internal thread; whereby a 2nd PTR stage thermally connected to the thermalization block by the use of a non-flexible thermal link, wherein said thermal block includes an another thermalization point. The thermalization block enables relative vertical movement of a sample holder with respect to the cryostat without loss of excellent thermal contact with the thermalization point. Outside the vacuum chamber there are magnetic coils immersed in the boiling fluid, thus achieving substantial reduction of the parasitic effects in measurements.

主权项

1. A cryostat with a PTR cooling and a two-stage thermalization of a sample holder, said cryostat comprising a dewar, a vacuum chamber with a tube for the vacuum chamber evacuation and a two-staged PTR cooling unit partially positioned inside the vacuum chamber, wherein said vacuum chamber is partially immersed in a boiling fluid, whereby said vacuum chamber further comprises:
a PTR 1st stage connected to a recondenser by the use of a thermal link, wherein said recondenser partially penetrates through walls of the chamber into the dewar region above a fluid level, wherein the recondenser comprises an integrally built thermalization point with an internal thread and guiding tube; and a PTR 2nd stage thermally linked to a thermalization block by the use of a non-flexible thermal link, wherein said thermalization block is thermally isolated from the guiding tubes and comprises a thermalization point, wherein said thermalization block enables vertical positioning of the sample holder with respect to the rest of cryostat without breaking the thermal contact with the thermalization point; whileoutside the vacuum chamber, in the fluid, there are situated measuring coils and a coil for the magnetic field forming, positioned coaxially with a closed tube, wherein the interior of said closed tube extends the guiding tubes positioned inside the vacuum chamber, wherein there is vacuum both in the closed tube and in the vacuum chamber; while the cylindrical symmetry axes of the closed tube, the guiding tubes and the thermalization points overlap with the vertical cryostat axis passing through a tube of a sample replacement chamber constructed on a flange.