Accession Number:

ADA280208

Title:

Josephson Acoustic Radiation in Superfluid Helium.

Descriptive Note:

Progress rept.

Corporate Author:

CALIFORNIA UNIV BERKELEY DEPT OF PHYSICS

Personal Author(s):

Report Date:

1994-05-01

Pagination or Media Count:

2.0

Abstract:

The project to observe and measure Josephson acoustic radiation has begun. The most significant accomplishments in these first months are the following A prototype cell has been designed and constructed. Various aspects of the cell have been tested. The apparatus have been designed in a modular form so that individual components can be optimized separately. We have developed a displacement liquid Helium pump to force superfluid through a submicron apertures for times on the order of 100 seconds. The pump consists of a flexible plastic membrane which is metal coated on one side. Application of a voltage between the membrane and a nearby fixed electrode forces the membrane to move, thus pushing superfluid through the aperture.

Descriptors:

• *RADIATION
• *ACOUSTICS
• *JOSEPHSON JUNCTIONS
• *SUPERFLUIDITY
• *HELIUM
• ELECTRONICS
• LIQUIDS
• DISPLACEMENT
• NOISE
• MICROPHONES
• VACUUM PUMPS
• CAVITY RESONATORS
• CAPACITANCE
• CURRENTS
• APERTURES
• OSCILLATION
• AMPLITUDE
• SIGNALS
• PIEZOELECTRICITY
• RESONANCE
• PRESSURE
• SOUND

Subject Categories:

• Inorganic Chemistry
• Electrical and Electronic Equipment
• Acoustics
• Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE