NMI is responsible for maintaining and disseminating Australia's standard for luminous intensity (the candela), and providing traceability for associated radiometric and photometric measurements.
Recent research and development activities have centred on establishing a cryogenic radiometer as the Australian standard for the candela.
We have designed and built four-element transmission trap detectors and a new generation of transmission traps having a larger active area is under construction. The larger area allows for easier alignment and reduces problems with clipping of the beam inside the trap. The first trap, which has a volume of 50 mm x 50 mm x 50 mm, has been calibrated using the cryogenic radiometer at nine wavelengths in the visible region to within an accuracy of 0.02%.
JL Gardner (1994) Transmission Trap Detectors. Appl. Opt. 33, 5914–5918