project title: Critical phase separation in solid isotopic helium mixtures
project leader: Brian Cowan
access given (in days): 14
access used (in days): 4
local host: Juha Tuoriniemi
home institution: Royal Holloway, University of London
country of institution: UK
starting date (yyyy-mm-dd): 2006-03-26
The two stable isotopes of helium, 3He and 4He (fermion and boson), behave quite differently at very low temperatures. Their liquid and solid mixtures show a rich spectrum of physical phenomena. There is a finite solubility of 3He to liquid 4He at arbitrarily low temperatures but the solid phases become isotopically pure when the temperature approaches zero. The physics of these phase changes can be investigated by means of pressure transducers and NMR techniques. The purpose here is to study the state of the 3He population as functions of pressure, temperature, and concentration.
Studies of the migration processes of 3He atoms in host solid 4He have been considered as well as the application for thermometry of the measurements of the crystallization pressure of the phase separated liquid mixture system under certain circumstances. Means for determining the 3He concentration in the solid phase at very low temperatures were investigated.