Optical Properties

Absorptance Testing

Solar absorptance testing is currently done with a dual beam, ratio recording Beckman DK-2A UV-VIS-NIR spectrophotometer. The beam is incident at 5 degrees from normal. The reflected light is scattered into a 6 inch diameter integrating sphere and detected by either a lead-sulfide cell or a photomultiplier tube. The instrument records reflectance data as a percentage of a working standard's reflectance. The working standards are calibrated against a NIST specular reflectance standard. We record data from 280 nanometers to 2500 nanometers.

Solar absorptance (Alpha) is computed based on 25 equal energy intervals centered on wavelengths from 314 nanometers to 2191 nanometers. The wavelengths are computed from tables of spectrum NASA SP-8005 and ASTM-E-490-73a.

We also use a Perkin-Elmer Lambda-9 dual beam, ratio recording UV-VIS-NIR spectrophotometer. This instrument can record data from 185 to 3200 nanometers, is computer controlled and has data processing capabilities. It uses a 6.0 inch diameter integrating sphere. We record data from 280 to 2500 nanometers. The incident beam impinges on the sample at 8 degrees from normal.

Emittance Testing

Certified room temperature emittance testing is currently done two different ways. A good approximation of total hemispherical emittance is obtained from a Lion Research Corporation emissometer. This instrument responds to the IR energy emitted from a sample through a potassium bromide window into the detector. The wavelength range is 3-30 microns. This method equates to ASTM-E-408, Method B.

We measure normal emittance with a Gier-Dunkle DB100 infrared reflectometer. This instrument's detector is also behind a potassium bromide window. The wavelength range is 5-25 microns. This method equates to ASTM-E-408, Method A.

We also have a portable instrument from Devices and Services Company which is reasonably accurate for emittance values greater than 0.1.

Mechanical and Electrical Properties

Resistivity Testing

Sheldahl Q000322 describes large or small 4 point, in-line, 4 wire probe sampling for ohm/square on sheet or roll stock. Sheldahl Q000331 describes a 2 point, 6 inch x 1 inch sample and Sheldahl Q000379 describes a 2 point 1 inch x 1 inch sample.

Metal Adhesion Testing

Sheldahl Q000084 describes testing metal adhesion to film with the "scotch-tape" test. The tape is selected and inspected per ASTM-D-1000 to assure metal adhesion. The tape is pressed onto the metalizing and removed for examination of metalizing removal.

Adhesion to Stainless Steel Testing

ASTM-D-1000 and ASTM-D-3330 both describe peel testing of Pressure Sensitive Adhesive (PSA) to a stainless steel plate. ASTM-D-903 describes peel testing of fabric laminates.