He worked with NIST researchers Keith Lykke and Steven Brown to deploy NIST's Travelling SIRCUS to Ball Aerospace & Technology Corp.
To enable implementation of the recommendations NIST has built an easily deployable travelling SIRCUS to provide SI-traceable system-level radiance and irradiance calibrations at customer sites.
Responding to the recommendations NIST has built a travelling SIRCUS that is easily deployable at customer sites.
Later calibrations need not be as extensive and may be performed on-site using a traveling version of SIRCUS
These activities began prior to SIRCUS and its ability to provide absolute radiance responsivities, so measurements of the relative spectral radiance responsivity and NIST reference spheres were used to derive the calibration coefficients (2), (9).
7) that takes full advantage of the SIRCUS uncertainties while also including the effects of the source's relative spectral distribution.
As a further test the calibration constants were calculated using a FASCAL calibration of the NPR sphere performed in June 2009 and the same SIRCUS 2003 data.
As an example of the use of the first technique, we will use a calibration of the VXR in 2003 by SIRCUS and the spectral radiance of the NPR sphere calibrated by FASCAL in 2003.
Future measurements with SIRCUS
should result in a relative uncertainty in the spectral radiance response of about 0.
An advantage of this facility is that by knowing the aperture areas of the detectors and the aperture area of the integrating sphere exit port, SIRCUS can be used as a radiance source to calibrate sensor systems that are designed to measure spectral radiance.
The development of SIRCUS is expected to improve the measurement of ASR and irradiance by a factor of five or so and thereby improve the photometric scales by a similar amount (34).
As with the candela, the improvements that are envisioned in ASR measurements utilizing SIRCUS and other new facilities will have a direct impact upon this important photometric quantity.