Rillo, Conrado Gabal, Miguel Lozano Bernal, María Pilar Sesé, Javier Spagna, Stefano Diederichs, Jost Sager, Ronald Chialvo, Cesar Terry, Jeremy Rayner, Grant Warburton, Richard Reineman, Richard Enhancement of the Liquefaction Rate in Small-Scale Helium Liquefiers Working Near and Above the Critical Point Phys. rev. appl. 10.1103/PhysRevApplied.3.051001 2015 2015