Thesis presented September 26, 2011

Abstract:
Pulse Tubes are a kind of cryocoolers similar to Stirling refrigerators, apart from the cold mobile element, absent in the first, which lessens their exported vibrations and increases their reliability. Spatial applications seek these characteristics for the instruments embarked, along with small weight and size. These needs stimulate the research on pulse tube miniaturization; to achieve this reduction, one can decrease the swept volume per cycle, whilst increasing the frequency of operation. To understand the barriers to carry out very high frequency operation, simulations on the behavior of the regenerator and inertances were made, as well as an experimental study on the thermal losses of the expansion tube. Finally, several very high frequency pulse tube prototypes were built and benchmarked, one of which fulfills the requirements we had initially set: 0.25 W at 120 K, with 20 W of input power at 100 Hz.

Keywords:
Cryocooler, Cryogenics, High Frequencies, Inertances, Regenerator, Pulse tube

On-line thesis.