Accession Number : ADA187274

Title :   Cryogenic Acoustic Microscopy.

Descriptive Note : Final technical rept. 1 Apr 85-31 Mar 87,

Corporate Author : STANFORD UNIV CA EDWARD L GINZTON LAB OF PHYSICS

Personal Author(s) : Quate, C F ; Hadimioglu, B

PDF Url : ADA187274

Report Date : Aug 1987

Pagination or Media Count : 62

Abstract : This work describes the advancements in the field of acoustic microscopy in superfluid helium at temperatures near 0.1 K. The microscope is presently capable of imaging materials using 300 A sound waves with 200 A resolution. Current developments include the search for operation of higher frequencies in order to get better resolution and improvements in the signal-to-noise ratio to get better images. A new technique has been developed to fabricate high efficiency acoustic transducers at ultra high frequencies. These transducers consist of multilayers of zinc oxide with alternating crystal structure. Multilayer transducers fabricated with the new technique have shown to convert nearly 10% of the electrical input power to acoustic power at frequencies as high as 30 GHz. This is several orders of magnitude better than any of the previous experiments. Keywords: Acoustic microscopy; Superfluid helium, Sound waves; Super; Acoustic transducers.

Descriptors :   *ACOUSTICS, *CRYOGENICS, *ELECTROACOUSTIC TRANSDUCERS, *MICROSCOPY, CRYSTAL STRUCTURE, EFFICIENCY, ELECTRIC POWER, FREQUENCY, HELIUM, HIGH RATE, IMAGES, INPUT, LAYERS, MATERIALS, OPERATION, POWER, SIGNAL TO NOISE RATIO, SOUND WAVES, SUPERFLUIDITY, TRANSDUCERS, ULTRAHIGH FREQUENCY

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE