Determination of a consensus scaling factor to convert a Co-60-based alanine dose reading to yield the dose delivered in a high energy electron beam

An analysis of the published literature has been carried out to determine a consensus value for the scaling factor required to convert a dose determination using alanine based on a Co-60 calibration to yield the dose delivered in a high energy electron beam (≥6 MeV incident). Published data from the last 15 years were reviewed and combined to give a single, average, scaling factor. In carrying out this analysis, no attempt was made to deconstruct each experiment. The final results of each investigation were used as a coherent ensemble of independent determinations, irrespective of method or alanine dosimeter supplier. Experimental and Monte Calculations were considered separately and only the experimental data was used to determine the scaling factor. The results from six investigations were found to be consistent within their uncertainties and an overall conversion factor of 1.014 (standard uncertainty = 0.5%) was obtained. To be explicit, alanine dose readings determined from a Co-60 alanine calibration should be multiplied by this factor to yield the dose delivered in an electron beam. This scaling factor represents the consensus recommendations of the National Research Council, the National Institute for Standards and Technology, the Technical University of Denmark and the National Physical Laboratory for electron beams (≥6 MeV incident) used in radiation processing applications. By adopting a common factor, it is hoped to improve the consistency of dosimetry at industrial dose levels using high-energy electron beams.