Method and apparatus for millimeter-wave detection of thermal waves for materials evaluation

Patent · Tue Jun 04 04:00:00 EDT 1991

OSTI ID:5787944

Gopalsami, N; Raptis, A C

This patent describes a method and apparatus for generating thermal waves in a sample and for measuring thermal inhomogeneities at subsurface levels using millimeter-wave radiometry. An intensity modulated heating source is oriented toward a narrow spot on the surface of a material sample and thermal radiation in a narrow volume of material around the spot is monitored using a millimeter-wave radiometer; the radiometer scans the sample point-by-point and a computer stores and displays inphase and quadrature phase components of thermal radiations for each point on the scan. Alternatively, an intensity modulated heating source is oriented toward a relatively large surface area in a material sample and variations in thermal radiation within the full field or an antenna array are obtained using an aperture synthesis radiometer technique.

• Assignee: Dept. of Energy, Washington, DC (USA)
• Patent Number(s): A; US 5020920
• Application Number: PPN: US 7-431363
• OSTI ID: 5787944
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPE AND RADIATION SOURCES
070204* -- Radiation Sources-- Industrial Uses
Radiometric
42 ENGINEERING
420500 -- Engineering-- Materials Testing
440100 -- Radiation Instrumentation
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
CHEMICAL ANALYSIS
DENSITY
ELECTROMAGNETIC RADIATION
INDUSTRIAL RADIOGRAPHY
MATERIALS TESTING
MEASURING INSTRUMENTS
PHYSICAL PROPERTIES
QUANTITATIVE CHEMICAL ANALYSIS
RADIATION DETECTORS
RADIATIONS
RADIOMETERS
RADIOMETRIC ANALYSIS
RADIOMETRIC GAGES
TESTING
THERMAL CONDUCTIVITY
THERMAL RADIATION
THERMODYNAMIC PROPERTIES
WAVE PROPAGATION