THE PERFORMANCE OF AN OPEN-CYCLE DILUTION REFRIGERATOR

The idea of an open cycle. dilution refrigerator is that two separate flows of 3-helium an 4-helium are mixed at low temperature, overcoming the influence of tile gravitation. We have measured the performance o f the refrigerator for a high concentration of He-3, where the mixture appears in two phases, and lie discuss tile possibility of running at a lower concentration (single phase). We discuss tile use of such a r efrigerator to cool bolometers for telescopes, on earth or in space.