The tensile strength of liquid helium four

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5095050

Nissen, J A

In this study, a piezoelectric transducer in the form of a hemispherical shell was used to focus high-intensity ultrasound into a small volume of {sup 4}He. The transducer was gated at its resonant frequency of 566 kHz with gate widths of less than 1 msec in order to minimize the effects of transducer heating and acoustic streaming. The onset of the nucleation was detected from the absorption of acoustic energy and the scattering of laser light from microscopic bubbles. A new theory for the diffraction of light from the focal zone of a spherical converging sound wave was developed to confirm calculations of the acoustic pressure amplitude at the focus of the piezoelectric transducer, calculations which were based on the acoustic power radiated into the liquid and the nonlinear absorption of sound. The experimental results were in agreement with homogeneous nucleation theory for a nucleation rate of approximately 10{sup 15} critical size bubbles/sec-cm{sup 3}. This is only the third liquid for which the theoretical tensile strength has been reached and it confirms homogeneous nucleation theory over a range three times greater than any other experiment. A noticeable decrease in the magnitude of the tensile strength was noted at temperatures near the lambda transition and a hypothesis that bubbles are being nucleated heterogeneously on quantitized vortices is presented.

• Research Organization: Portland State Univ., OR (USA)
• OSTI ID: 5095050
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400101 -- Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures
640300* -- Atomic
Molecular & Chemical Physics
640302 -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
COMPUTER CALCULATIONS
DATA
EVEN-EVEN NUCLEI
EXPERIMENTAL DATA
HELIUM 4
HELIUM ISOTOPES
INFORMATION
ISOTOPES
LIGHT NUCLEI
MEASURING INSTRUMENTS
MEASURING METHODS
MECHANICAL PROPERTIES
NUCLEI
NUMERICAL DATA
SOUND WAVES
STABLE ISOTOPES
TENSILE PROPERTIES
ULTRASONIC WAVES