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Key Comparison for Air Kerma From Therapy Level and Radiation Protection Gamma-ray Beams

Summary:

Comparisons for the national standards of air kerma from therapy level and radiation protection gamma-ray beams were conducted by the NIST and the Bureau International des Poids et Mesures (BIPM).

Description:

Transfer ionization chambers were calibrated in terms of air kerma in the radiation beams of both institutes. For the therapy level comparison, carried out in a 60Co gamma-ray beam, two transfer chambers were used with volumes of 1 cm3 and 3 cm3. The comparison result, K R , taken as the mean of the results for both chambers, was K R = 1.0039 with a combined standard uncertainty for the comparison of 0.0034. The radiation protection level comparison was conducted in both 137Cs and 60Co gamma-ray beams. For this part of the comparison, two transfer chambers of the same model and volume of 100 cm3 were used. The comparison result for 60Co was K R = 1.0023 and for 137Cs was K R = 0.9990. The results from the therapy level comparison are available on the BIPM website.

Key Comparison for Air Kerma
Photograph by: Ronaldo Minniti

Lead Organizational Unit:

pml