The National Physical Laboratory (NPL) and Cryogenic Ltd have designed and developed the most accurate instrument for comparative measurements of electric current. The instrument can now be used by National Measurement Institutes (NMI) and laboratories around the world, providing a more accurate standard for current ratio, and ensuring current measurement is not a limiting factor in innovation.

Cryogenic Current Comparator

This new Cryogenic Current Comparator (CCC) provides the world's most accurate ratio of current, which together with the Quantum Hall effect allows resistance to be measured to very high accuracy. It is the primary standard of resistance. If you measure in milliamps or ohms, the CCC can relate this back to primary standards more simply and more accurately than ever before.

Accurately measuring current is vitally important for a range of applications. It is essential for billing people for electricity use thereby ensuring a stable electricity market. The right current input is important for controlling doses of ionising radiation in cancer treatment.

Challenges arise when measuring current. Ionising radiation is measured in picoamps, whilst undersea cables carry hundreds of amps; some industries measure resistance or voltage, rather than current itself. These all need to be related back to the ampere, the SI unit of current.

NPL and Cryogenic Ltd have been involved in the development of CCC technology for over two decades, the system was originally built for NPL, and is used on a daily basis for its measurements. The CCC is now commercially available from Cryogenic Ltd for any laboratories which require very precise electrical measurements. Cryogenic Ltd have already signed a contract to install one at Singapore's NMI, where it will underpin all their electrical measurements, including: improving the accuracy of temperature measurements; analysis of the super-material graphene; and fundamental physics research.

Jonathan Williams, Principal Research Scientist in NPL's Quantum Detection Group, said: "This partnership will allow NMIs and other laboratories to benefit from our combined R&D and expertise in this area. Cryogenic were our partner of choice to develop the system. They are an established, naturally innovative, and are experts at making bespoke products like this."

Find out more about NPL's Quantum Detection research

Find out more about Cryogenic Ltd

Contact: Jonathan Williams