A three-stage Stirling pulse tube cryocooler operating below the critical point of helium-4
Abstract
Precooled phase shifters can significantly enhance the phase shift effect and further improve the performance of pulse tube cryocoolers. A separate three-stage Stirling pulse tube cryocooler (SPTC) with a cold inertance tube was designed and fabricated. Helium-4 instead of the rare helium-3 was used as the working fluid. The cryocooler reached a bottom temperature of 4.97 K with a net cooling power of 25 mW at 6.0 K. The operating frequency was 29.9 Hz and the charging pressure was 0.91 MPa. It is the first time a refrigeration temperature below the critical point of helium-4 was obtained in a three-stage Stirling pulse tube cryocooler.
- Publication:
-
Cryogenics
- Pub Date:
- October 2011
- DOI:
- 10.1016/j.cryogenics.2011.07.007
- Bibcode:
- 2011Cryo...51..609Q