I. Construction of an ultralow temperature laboratory. II. Thermal relaxation in superfluid helium-3
The first part of this thesis describes the construction of an ultralow temperature laboratory capable of reaching temperatures below 0.002 K. Continuous refrigeration to 0.012 K is provided by a cold plate/dilution refrigerator system. Single-cycle cooling to 0.002 K is accomplished by adiabatic demagnetization of cerous magnesium nitrate (CMN), a paramagnetic salt. Thermometry is done by measuring the resistance of carbon and germanium sensors, the magnetic susceptibility of lanthanum-diluted CMN, and the anisotropy of gamma radiation from a cobalt-60 nuclear orientation thermometer. Systems have been developed to allow precise control of the temperature and pressure of the liquid helium-3 sample. Measurements of thermal relaxation of liquid helium-3 in the ultralow temperature cell following sudden magnetic cooling of the CMN refrigerant are described. Analysis of the transient response of a thermal model of the cell indicates that the ratio of the time constants immediately below and above the superfluid-to-normal transition temperature provides a close estimate of the ratio of the corresponding helium-3 heat capacities, at least in the superfluid A-phase.
- Research Organization:
- Stanford Univ., CA (USA)
- OSTI ID:
- 5239591
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
640450 -- Fluid Physics-- Superfluidity
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
CERIUM COMPOUNDS
CERIUM NITRATES
EVEN-ODD NUCLEI
HELIUM 3
HELIUM 3 A
HELIUM DILUTION REFRIGERATORS
HELIUM ISOTOPES
ISOTOPES
LABORATORIES
LIGHT NUCLEI
MAGNESIUM COMPOUNDS
MAGNESIUM NITRATES
NITRATES
NITROGEN COMPOUNDS
NUCLEI
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
REFRIGERATORS
RELAXATION
SPECIFIC HEAT
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
ULTRALOW TEMPERATURE