Standardization of125I by the sum-peak method and the results of a bilateral comparison between ENEA (Italy) and INP (Albania)

An intercomparison on absolute activity measurements of¹²⁵I sources by the sumpeak method was carried out in 1993 between the Primary Standard Laboratories for Ionizing Radiations of Italy (ENEA) and Albania (INP). The sources were prepared by ENEA starting from a¹²⁵I solution. The sources were measured at ENEA and successively at INP. The results were in good agreement, the deviation of the INP results from the ENEA results being about –0.5% with an overall uncertainty of both results about 0.3% (1). This paper describes the instrumentation and the experimental procedures used in this comparison by the two Institutes.