Characterization of 226Ra activity in low-level slag reference standards

Within the EURAMET European Metrology Research Programme project IND04 named MetroMetal, several different reference standards have been developed for the metallurgical industry. This paper describes the characterisation of low-levels of 226Ra in samples of slag. The activity was determined through spiking with a known amount of solution containing 226Ra to a previously characterised slag material. The measurements were performed at both 225 m underground and aboveground. The total (spiked + natural) massic activity of 226Ra obtained from the gamma-ray spectrometry measurements was (126.3 ± 5.6) Bq/kg. A comparison of the different measurements and studies of the distribution of radon-daughters in the samples is presented.