The National Institute of Standards and Technology (NIST) has selected Laser Gold as the new gold standard for infrared reflectivity.
Laser Gold is a proprietary electroplated process developed by the hundred-year-old New York precious metals plating firm, Epner Technology Inc. The process is unique in that it is both ultra-pure, (.9999), while also three times harder than any other 24 Kt. gold.
NIST, formally known as the National Bureau of Standards, calibrated some 20 copper mirror substrates that had been single-point diamond fly-cut to a surface roughness of 50 Å, by the Kugler Group, located in Salem Germany and then plated, first with pure nickel followed by Laser Gold, each about a micron thick.
The Gaithersburg, Md. laboratory in which the reflectance measurements are preformed is the "Fourier Transform Infrared Spectrophotometry (FTIS)" facility, which is described here.
The specific instrument used to measure the standards is the "Infrared Reference Integrating Sphere (IRIS), which is described here.
The result was an astounding 99% throughout the mid- infrared the range of from 2 to 14 microns. The new gold standard entered the NIST catalog of Standard Reference Material as SRM #1929.
"It all started with a chance meeting with a Xerox engineer at a 1972 trade show which took our 65-year-old company into the world of high technology electroplating for infrared reflectivity," said David Epner, President of Epner Technology.
"Xerox needed a gold-plated aluminum reflector behind a quartz infrared lamp which generated the heat that fused the toner onto the paper. That's why Xerox copies come out of the machine warm.
"They were having difficulty finding a supplier whose plating could withstand the extreme heat of the lamp without blistering the plating off the aluminum while also meeting their reflective requirements.
"After a successful sample, Xerox tooled our company with a $60,000 infrared spectrophotometer which gave our engineers the "eyes" to inspect the reflective performance of the gold plating and continuously tweak the process to achieve higher and higher reflectivity. That effort culminated in this NIST designation."
NASA is currently using Laser Gold because of its peerless heat reflecting properties and has specified this process for thermal control on countless spacecraft instruments beginning some 35 years ago to the early GOES weather satellites as well as the Hubble camera housing and more recently, on both the near and mid infrared cameras aboard the James Webb Space Telescope.