A Closed Cycle Refrigerator-based, Programmable Voltage Standard System

Researchers at the NIST have demonstrated a programmable Voltage Standard (VS) chip based on SNS (superconductor-normal-superconductor) tunnel junction technology. Excellent programmable voltage standards were demonstrated using this SNS technology in a liquid helium-based system. At HYPRES, we have developed and commercialized a Closed Cycle Refrigerator (CCR)-based DC voltage standard system using a VS chip previously developed and integrated into a liquid helium-based system at NIST. Under the Phase 1 SBIR project, we developed a high performance cryogenic package for the programmable VS chip for integration with a CCR system. This developmental work involved collaborations between NIST and HYPRES to develop the package that was integrated with a NIST-provided CCR. In the Phase 2 program, we will continue to improve the packaging technology and design and implement a flexible cable technology to interface to the chip. In addition, we will procure a CCR system and develop and demonstrate a complete CCR-based programmable VS system. This system, based on a new CCR system developed by Sumitomo, will be compact and portable. The programmable Voltage Standard system has many other applications such as D/A converters and signal synthesizers. Phase 1 established the feasibility of the concept and Phase 2 will lead to a prototype compact system.