Personal Dose Equivalent Conversion Coefficients Research Articles

IMPACT OF THE ENDF/B-VIII.0 LIBRARY ON MCNP6.2-COMPUTED AMBIENT AND PERSONAL DOSE EQUIVALENT CONVERSION COEFFICIENTS.

The 2018 release of the Evaluated Nuclear Data File (ENDF)/B-VIII.0 library initiated several examinations of the impact of the revised nuclear data on Monte Carlo models. This study used version 6.2 of the Monte Carlo N-Particle® code (MCNP6.2) with the ENDF/B-VI and ENDF/B-VIII.0 libraries to compute conversion coefficients for fluence-to-ambient and fluence-to-personal dose equivalent from neutron energy groups described by an International Atomic Energy Agency 53-bin structure and 47 monoenergetic neutron sources listed in International Commission on Radiological Protection (ICRP) 74. The MCNP6.2 models with ENDF/B-VI data were validated against results published in 2005 by Veinot and Hertel. Conversion coefficients computed with MCNP6.2 and ENDF/B-VIII.0 slightly underestimated the ICRP 74 values but were within ICRP-specified tolerances and do not justify revising the ICRP coefficients. Conversion coefficients for personal dose equivalent were computed with MCNP6.2 and ENDF/B-VIII.0 at four angles of incidence greater than those available in ICRP 74. These new coefficients are relevant to radiation protection studies of interest to US defence-focused organisations.

Neutron conversion coefficients of ambient dose equivalent and personal dose equivalent

Abstract Introduction: This work aims to calculate the ambient and personal dose equivalent conversion coefficients. Material and methods: The conversion coefficients have been calculated using MC simulation. Additionally, this paper proposes a new method that depends on an analytical approach. Results: The obtained results in good agreement between MC and an analytical approach were observed. The obtained results were compared to those published in ICRU 57 report. Conclusions: We deduced that the analytical approach is as effective and suitable as the MC simulation to calculate the operational quantity conversion coefficients.

Air-Kerma to Personal Dose Equivalent $$\mathbf{H}_{\mathbf{p}}\mathbf{(0.07,\boldsymbol{\alpha})}$$ Conversion Coefficients for Monoenergetic Photons

This study aims to calculate the air Kerma to personal dose equivalent conversion coefficients $${H}_{p}(0.07)$$ for mono-energetic photons from 0.015 to 10 MeV for angles of incidence from 0 $${}^{\circ}$$ to a 75 $${}^{\circ}$$ in steps of 15 $${}^{\circ}$$ using Monte Carlo (MC). In addition to this, we propose a new equation to perform an analytical fit of our Monte Carlo calculated conversion coefficients for photons. $${H}_{p}(0.07)/K_{air}$$ values have been determined by two terms: in term of absorbed dose, according to the definition of this quantity, and also with the term of Kerma approximation. The results obtained are compared to those published in Joint report of ICRU and ICRP, 2017. A good agreement with reference data with a local difference less than $$2\%$$ was observed.

Air-kerma to Hp(0.07), Hp(3), and Hp(10) conversion coefficients for monoenergetic photons

This work aims for calculating a new set of the personal dose equivalent conversion coefficients Hp(d)/Kair when d = 0.07, 3, and 10 mm, for monoenergetic photons beams ranged from 0.015 to 10 MeV, which have incident on ICRU slab phantom for Hp (0.07) and Hp (10) and cylindrical phantom for Hp (3). The new cylindrical phantom of the ORAMED project was proposed for calculating the eye lens dose equivalent as a cylinder much better approximates the form of a head than a slab. The calculations were carried out with MC and an analytical fit is applied to the data. Our results are found in a good agreement with those previously published, with a local difference less than 1.5%. We have concluded that new analytical fits provide a suitable method for determining conversion coefficients for discrete incident such as MC.

An analytical fit and EGSnrc code (MC) calculations of personal dose equivalent conversion coefficients for mono-energetic electrons

This study aims for calculating a new set of the personal dose equivalent conversion coefficients Hp(d)/Φ when d = 0.07, 3, and 10 mm, for mono-energetic electron beams ranged from 0.06 MeV to 50 MeV for Hp(0.07), from 0.7 MeV to 50 MeV for Hp(3) and from 2 MeV to 50 MeV for Hp(10), which has incident on ICRU slab phantom. Additionally, we have calculated the conversion coefficients of a dose to the lens eye of into a new cylindrical phantom of the ORAMED project. The cylindrical phantom was proposed for calculating the eye lens dose equivalent as a cylinder much better approximates the form of a head than a slab. The ICRU tissue of density of 1 g/cm3 which is consists of 4-elemental has been used in slab and cylindrical phantoms. The calculations were carried out with EGSnrc code Monte Carlo (MC) and a new an analytical fit is applied to the data. Our results are found in a good agreement with those published by Veinot and Hertel (2012)) , with a local difference less than 1.5%. We have concluded that new analytical fits provide a convenient approach for determining conversion coefficients for discrete incident such as MC.

Personal Dose Equivalent Conversion Coefficients Skins Dose for Mono-Energetic Photons, Electrons, and Positrons: Monte Carlo Approach and Development of an Analytical Approach

The present work seeks to calculate and development of a new set of the personal dose equivalent conversion coefficients (Skins Dose) for mono-energetic photons (in absorbed dose and Kerma approximations), electrons and positrons from 10 keV to 10 MeV on the phantom ICRU tissue. The conversion coefficients calculations were two ways: Monte Carlo and development an analytical approach using FORTRAN program. The results obtained in this work were found to be in good agreement with to those published in joint report of ICRU and ICRP, 2017 [1]. The numerical comparison was made to validate DOSRZnrc code for conversion coefficients calculations as well as testing the developed of an analytical a new approach using FORTRAN. Our study can be useful to improve standards of protection for medical workers for procedure resulting in potentially high exposures and to develop methodologies for the best assessing and for reducing exposures.

Cálculo de Coeficientes de Fluência de Nêutrons para Equivalente de Dose Individual Utilizando o Geant4

Fluence to dose equivalent conversion coefficients provide the basis for the calculation of area and personal monitors. Recently, the ICRP has started a revision of these coefficients, including new Monte Carlo codes for benchmarking. So far, little information is available about neutron transport below 10 MeV in tissue-equivalent (TE) material performed with Monte Carlo Geant4 code. The objective of this work is to calculate neutron fluence to personal dose equivalent conversion coefficients, H p (10)/ϕ, with Geant4 code. The incidence of monoenergetic neutrons was simulated as an expanded and aligned field, with energies ranging between thermal neutrons to 10 MeV on the ICRU slab of dimension 30 x 30 x 15 cm 3 , composed of 76.2% of oxygen, 10.1% of hydrogen, 11.1% of carbon and 2.6% of nitrogen. For all incident energy, a cylindrical sensitive volume is placed at a depth of 10 mm, in the largest surface of the slab (30 x 30 cm 2 ). Physic process are included for neutrons, photons and charged particles, and calculations are made for neutrons and secondary particles which reach the sensitive volume. Results obtained are thus compared with values published in ICRP 74. Neutron fluence in the sensitive volume was calculated for benchmarking. The Monte Carlo Geant4 code was found to be appropriate to calculate neutron doses at energies below 10 MeV correctly.

Personal dose equivalent angular response factors for photons with energies up to 1 GeV

When performing personal dosemeter calibrations, the dosemeters are typically irradiated while mounted on slab-type phantoms and oriented facing the source. Performance testing standards or intercomparison studies may also specify various rotational angles to test the response of the dosemeter and associated algorithm as this rotation introduces changes in the quantity of delivered dose. Correction factors for rotational effects are available, but many have not been updated in recent years and were typically calculated using the kerma approximation. The personal dose equivalent, Hp(d), is the quantity recommended by the International Commission on Radiation Units and Measurements to be used as an approximation of the protection quantity effective dose when performing personal dosemeter calibrations. The personal dose equivalent can be defined for any location and depth within the body, but typically the location of interest is the trunk where personal dosemeters are worn and in this instance a suitable approximation is a 30 cm × 30 cm × 15 cm slab-type phantom. In this work personal dose equivalent conversion coefficients for photons with energies up to 1 GeV have been calculated for depths of 0.007, 0.3 and 1.0 cm in the slab phantom for rotational angles ranging from 15° to 75°. Angular response factors have been determined by comparing the conversion coefficients for each angle and energy to those reported in an earlier work for a non-rotational (e.g. perpendicular to the phantom face) geometry. The angular response factors were determined for discrete angles, but fits of the factors are provided.

Personal dose equivalent conversion coefficients for electrons to 1 Ge V

In a previous paper, conversion coefficients for the personal dose equivalent, H(p)(d), for photons were reported. This note reports values for electrons calculated using similar techniques. The personal dose equivalent is the quantity used to approximate the protection quantity effective dose when performing personal dosemeter calibrations and in practice the personal dose equivalent is determined using a 30×30×15 cm slab-type phantom. Conversion coefficients to 1 GeV have been calculated for H(p)(10), H(p)(3) and H(p)(0.07) in the recommended slab phantom. Although the conversion coefficients were determined for discrete incident energies, analytical fits of the conversion coefficients over the energy range are provided using a similar formulation as in the photon results previously reported. The conversion coefficients for the personal dose equivalent are compared with the appropriate protection quantity, calculated according to the recommendations of the latest International Commission on Radiological Protection guidance. Effects of eyewear on H(p)(3) are also discussed.

Personal dose equivalent conversion coefficients for photons to 1 GeV

The personal dose equivalent, H(p)(d), is the quantity recommended by the International Commission on Radiation Units and Measurements (ICRU) to be used as an approximation of the protection quantity effective dose when performing personal dosemeter calibrations. The personal dose equivalent can be defined for any location and depth within the body. Typically, the location of interest is the trunk, where personal dosemeters are usually worn, and in this instance a suitable approximation is a 30 × 30 × 15 cm(3) slab-type phantom. For this condition, the personal dose equivalent is denoted as H(p,slab)(d) and the depths, d, are taken to be 0.007 cm for non-penetrating and 1 cm for penetrating radiation. In operational radiation protection a third depth, 0.3 cm, is used to approximate the dose to the lens of the eye. A number of conversion coefficients for photons are available for incident energies up to several megaelectronvolts, however, data to higher energies are limited. In this work, conversion coefficients up to 1 GeV have been calculated for H(p,slab)(10) and H(p,slab)(3) both by using the kerma approximation and tracking secondary charged particles. For H(p)(0.07), the conversion coefficients were calculated, but only to 10 MeV due to computational limitations. Additionally, conversions from air kerma to H(p,slab)(d) have been determined and are reported. The conversion coefficients were determined for discrete incident energies, but analytical fits of the coefficients over the energy range are provided. Since the inclusion of air can influence the production of secondary charged particles incident on the face of the phantom, conversion coefficients have been determined both in vacuo and with the source and slab immersed within a sphere in air. The conversion coefficients for the personal dose equivalent are compared with the appropriate protection quantity, calculated according to the recommendations of the latest International Commission on Radiological Protection (ICRP) guidance.

Performance testing of selected types of electronic personal dosimeters used in Sudan

Measurements were carried out for calibration and performance testing of a set of 10 electronic personal dosimeters (EPDs) at the Secondary Standard Dosimetry Laboratory of Sudan. Calibrations were carried out at three X-ray beam qualities described in ISO standard 4037 in addition to 137Cs and 60Co gamma ray beams. The experimental was performed with EPDs mounted on ICRU Slab phantom. X-ray and γ-ray beams were characterized in terms of air kerma free-in-air which were converted to the known delivered personal dose equivalent, Hp(10) using appropriate the air kerma to personal dose equivalent conversion coefficients. Dosimeters tested showed excellent energy and angular response and relative error of indication within the recommended limit for photon energies from 65 keV to 1.25 MeV. The study showed encouraging results for using electronic dosimeters in personal dosimetry.

Personal dose equivalent conversion coefficients for neutron fluence over the energy range of 20-250 MeV

Monte Carlo simulations were performed to extend existing neutron personal dose equivalent fluence-to-dose conversion coefficients to an energy of 250 MeV. Presently, conversion coefficients, H(p,slab)(10,alpha)/Phi, are given by ICRP-74 and ICRU-57 for a range of angles of radiation incidence (alpha = 0, 15, 30, 45, 60 and 75 degrees ) in the energy range from thermal to 20 MeV. Standard practice has been to base operational dose quantity calculations <20 MeV on the kerma approximation, which assumes that charged particle secondaries are locally deposited, or at least that charged particle equilibrium exists within the tally cell volume. However, with increasing neutron energy the kerma approximation may no longer be valid for some energetic secondaries such as protons. The Los Alamos Monte Carlo radiation transport code MCNPX was used for all absorbed dose calculations. Transport models and collision-based energy deposition tallies were used for neutron energies >20 MeV. Both light and heavy ions (HIs) (carbon, nitrogen and oxygen recoil nuclei) were transported down to a lower energy limit (1 keV for light ions and 5 MeV for HIs). Track energy below the limit was assumed to be locally deposited. For neutron tracks <20 MeV, kerma factors were used to obtain absorbed dose. Results are presented for a discrete set of angles of incidence on an ICRU tissue slab phantom.

Calculated Fluence-to-Directional and Personal Dose Equivalent Conversion Coefficients for Neutrons

Calculated Fluence-to-Directional and Personal Dose Equivalent Conversion Coefficients for Neutrons

Calculated Fluence-to-Directional and Personal Dose Equivalent Conversion Coefficients for Neutrons

Calculated Fluence-to-Directional and Personal Dose Equivalent Conversion Coefficients for Neutrons