Publication Date:
2018-06-23
Description:
Publication date: Available online 22 June 2018 Source: Radiation Measurements Author(s): Ryo Kakino, Akihiro Nohtomi, Genichiro Wakabayashi We previously evaluated ambient neutron dose equivalent by using the self-activation of a CsI scintillator around a high-energy medical linear accelerator (linac) 128 I saturated activities were successfully converted to neutron spectrum and ambient neutron dose equivalent by neutron spectrum unfolding with the “three-group approximation.” The principle of the three-group approximation is based on the assumption of fixed shapes of neutron energy spectra for each of the three energy regions to evaluate the neutron spectrum effectively. However, such a neutron dose evaluation with the unfolding method might be affected by the difference between the actual fast neutron energy spectrum and the assumed spectrum. In the present work, we modified the unfolding method by taking into account the differences in the shapes of fast neutron energy spectra for various medical linacs. We verified the unfolding method using Monte Carlo simulation with several neutron spectra obtained from published research articles. The modified three-group approximation evaluates the neutron doses more accurately than the conventional unfolding method.
Print ISSN:
1350-4487
Electronic ISSN:
1879-0925
Topics:
Electrical Engineering, Measurement and Control Technology
,
Physics
