Gold Plating Technique Combined with Electroforming Increases Sensitivity of Infrared Gas Sensors

A new process that combines a gold plating technique developed for the Space Program's YAG Laser Pump Cavities with the age-old manufacturing technique of electroforming, is now dramatically increasing the sensitivity of infrared gas analyzers and sensors—products that have long used infrared light to detect CO, CO₂ and many other trace gases in the atmosphere. At the heart of many of these designs is an IR gas cell sometimes called a light-pipe.

The new process involves "growing" the gas cell around a highly polished mandrel or tool. The first layer that is electroplated onto this tool is a proprietary ultrahigh infrared reflective gold .98@800nm and .99 @2 microns) achieved from a unique plating process known as Laser Gold. This is followed by a somewhat heavier layer of pure nickel plating, which gives structural strength to the gas cell.  At this point, the mandrel is removed, leaving a stand-alone cylinder, lined with the most efficient infrared reflective surface in the industry (see photo). This same technique with slight modification is also used to fabricate Nd-Yag laser pump chambers.

"Our original design, a stainless tube with a gold plated interior, could not achieve the sensitivity our customers required," said the Engineering Manager at Servomex, a leading UK manufacturer of gas sensors. "The shift to an electroform was a minor part of the improved performance. We really got our boost in sensitivity and noise reduction from the Laser Gold that lined the electroform."

From the infrared reflective coating on instruments aboard every weather satellite launched in the past 30 years, to the cooling plumbing on the James Webb Next Generation Space Telescope, the proudest order in their hundred-year history is being the sole supplier to NIST of the Infrared Standard Reference mirrors that are calibrated and sold worldwide.

"Laser Gold is the trademark for an electroplating process that creates tightly packed gold atoms," said David Epner, President. "The coating exceeds the reflectivity and hardness of an evaporated gold, and was originally developed for NASA some 30 years ago," he continued. Epner Technology, the New York high-tech contract plating company, is the world's sole source for this process.

For more information about Laser Gold, electroforming, light-pipes, YAG Laser Pump Cavities, or general specification plating, contact: David Epner 718 782 5948, via email or at www.epner.com