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Endo, Akira
Radiation Protection Dosimetry, 200(13), p.1266 - 1273, 2024/08
Times Cited Count:0 Percentile:0.00(Environmental Sciences)This study examines the relationship between ambient dose , ambient dose equivalent
, and effective dose for external neutron irradiation over 163 operational spectra from different workplaces. The results show that
provides a reasonable estimate with a controlled margin, even if overestimated, to assess effective dose compared with
, which can lead to a significant overestimation or underestimation of effective dose depending on the neutron spectra. The results highlight the limitations of
and the superiority of
in estimating effective dose according to the requirements of the operational quantity, especially in environments with high-energy neutrons.
Endo, Akira
JAEA-Research 2024-002, 90 Pages, 2024/05
This report presents a comprehensive analysis of the relationship between three quantities used for area monitoring - ambient dose equivalent , maximum dose equivalent
, and ambient dose
- and effective dose for external irradiation by photons, neutrons, electrons, positrons, protons, muons, pions, and helium ions. For the analysis, calculations were performed using PHITS (Particle and Heavy Ion Transport code System) and the ICRU sphere. The analysis result shows that
and
can induce large differences in the estimation of effective dose over a wide energy range for various particle types covered by ICRP Publication 116 while
can conservatively estimate effective dose within the acceptable range for area monitoring. In other words,
and
have limitations in estimating effective dose, and using
is recommended as a more appropriate quantity for the purpose. This conclusion supports the proposal of ICRU Report 95 to use
for estimating effective dose in various external exposure situations. The use of ambient dose
is particularly important in situations where various types of radiation are encountered, such as the use of radiation in the medical and academic fields and exposure in aviation and can meet the evolving requirements of radiation monitoring for the expansion of the field of radiological protection.
Endo, Akira
Radiation Protection Dosimetry, 175(3), p.378 - 387, 2017/07
Times Cited Count:11 Percentile:67.55(Environmental Sciences)The International Commission on Radiation Units and Measurements (ICRU) has been discussing to propose a new system of the operational quantities for external radiations based on protection quantities. The aim of this study is to provide a set of conversion coefficients for use in defining personal dose equivalent for individual monitoring. Fluence-to-effective dose conversion coefficients have been calculated for photons, neutrons, electrons, positrons, protons, muons, pions and helium ions for various incident angles of radiations. The data sets comprise effective dose conversion coefficients for incident angles of radiations from 0 to 90
in steps of 15
and at 180
. Conversion coefficients for rotational, isotropic, superior hemisphere semi-isotropic and inferior hemisphere semi-isotropic irradiations are also included. The conversion coefficients are used to define the operational quantity personal dose equivalent which is being considered by ICRU and utilized for the design and calibration of dosemeters.
Endo, Akira
Annals of the ICRP, 45(1_suppl.), p.178 - 187, 2016/06
The protection quantities, equivalent dose in an organ or tissue and effective dose, were developed by ICRP to allow quantification of the extent of exposure of the human body to ionizing radiation to be used for the implementation of the limitation and optimization principles. The body-related protection quantities are not measurable in practice. Therefore, ICRU developed a set of operational dose quantities for use in radiation measurements for external radiations that provide assessment of the protection quantities. ICRU has examined the rationale for operational quantities taking into account the changes in the definitions of the protection quantities in the ICRP 2007 Recommendations. The committee has investigated a set of alternative definitions for operational quantities different to the existing quantities. The major change in the currently favoured set of quantities is the redefinition of the operational quantities for area monitoring from being based on doses at a point in the ICRU sphere to ones based on particle fluence and the relationship to the protection quantities.
Murakami, Hiroyuki; Takahashi, Fumiaki
JAERI-Conf 95-014, 160 Pages, 1995/06
no abstracts in English
Minami, Kentaro; Murakami, Hiroyuki
Hokeikyo Nyusu, (7), p.2 - 3, 1990/00
no abstracts in English