A calibration service for protection-level beta-particle sources and instrumentation has been in place at NIST for several years.
The measurement system is automated and capable of measuring extremely low absorbed-dose rates. The second-generation beta-particle secondary-standard system (BSS2), which includes the isotope 85Kr, is utilized routinely for calibrations and research into standard extrapolation-chamber data-handling techniques. The sources were calibrated both at the Physikalisch-Technische Bundesanstalt (PTB) and at NIST, allowing a direct intercomparison of calibrations. The standardized techniques developed at PTB and NIST have been implemented in the NIST protection-level beta source and instrument calibration services.