Metrological Activity Determination Of Ba-133 By Sum-Peak Absolute Method

The National Laboratory for Metrology of Ionizing Radiation provides gamma sources of radionuclide and standardized in activity with reduced uncertainties. Relative methods require standards to determine the sample activity while the absolute methods, as sum-peak, not. The activity is obtained directly with good accuracy and low uncertainties. Ba-133 is used in research laboratories and on calibration of detectors for analysis in different work areas. Classical absolute methods don't calibrate Ba-133 due to its complex decay scheme. The sum-peak method using gamma spectrometry with germanium detector standardizes Ba-133 samples. Uncertainties lower than 1% to activity results were obtained.