Obtaining the national optical measurement units from an accurate cryogenic radiometer allows for their simultaneous improvement as the techniques for better utilization of the cryogenic radiometer are developed. While improvement in the accuracy of the cryogenic radiometer itself would not necessarily be of immediate benefit, the ability to perform improved transfer measurements to other devices can produce corresponding improvements to the measurement chain. Improvements in transfer standard detectors in all wavelength regions will assist the efforts to propagate the benefits of the high accuracy of the HACR to radiometric enterprises in general. NIST has programs in these areas to develop better mechanisms for calibrations in the infrared and the ultraviolet. An additional effort is underway to improve the accuracy of the NIST synchrotron ultraviolet radiation facility, SURF II, by relating its spectral output to the HACR through a FR system. The SURF II facility provides a source of radiation from about 1 nm to the far infrared for use in a variety of scientific endeavors including far UV radiometry. This will assist the effort to unify the NIST radiometric units maintained in differing ways by various technologies.
NIST customers of radiometric and photometric services are encouraged to renew their thinking on calibration strategies for the future to take advantage of the savings and increased accuracy suggested by the developments outlined in this note. Using a well characterized detector system offers the possibility of a significant reduction in the number of calibration artifacts necessary to maintain a direct traceability to NIST.