Cryogenic cell.

摘要

A cryogenic cell comprises a sealed external annular chamber (6) adapted to be maintained under vacuum which chamber surrounds a heat shield 4. A section of the shield is exposed and is adapted to make contact with a closed cycle cooler. The shield encloses a sealed inner chamber 1 adapted for the storage of a solid/liquid refrigerant (2). The shield 4 has a relatively thin base and sidewall and the section which is exposed is a relatively thick upper collar which has a well 9 leading to the top of the inner chamber 1 immediately above and in contact with the top of the inner chamber. The inner chamber 1 is connected at its lower end to a section 10 containing an absorbent 11 and the latter tsection is connected at its lower end to a further chamber (12) suitable for the reception of a gamma radiation detector. The cryogenic cell is suitable for keeping the semiconductor detector of a neutron borehole logging tool at the required low temperature.