David T Burns et al 2007 Metrologia 44 L53 doi:10.1088/0026-1394/44/6/N02
David T Burns, Penelope J Allisy and Cecilia Kessler
Show affiliationsA re-evaluation of the BIPM standard for air kerma in 60Co radiation has been made. The changes to the air-kerma rate determination arise from four sources: (i) the results of Monte Carlo calculations of correction factors for the standard; (ii) a re-evaluation of the correction factor for saturation; (iii) a new evaluation of the air volume of the standard using an experimental chamber of variable volume; (iv) the adoption of a new reference beam at the BIPM. The combined effect of these changes is an increase in the BIPM determination of air-kerma rate by the factor 1.0054 and a reduction of the relative standard uncertainty of this determination to 1.5 parts in 103. A full uncertainty budget is presented. The new standard is effective from 1 November 2007.
06.20.fb Standards and calibration
29.40.Cs Gas-filled counters: ionization chambers, proportional, and avalanche counters
Accelerators, beams and electromagnetism
Instrumentation and measurement
Issue 6 (December 2007)
Received 10 September 2007
Published 11 October 2007
David T Burns et al 2007 Metrologia 44 L53
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