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

Rosane Moreira Ribeiro; Denison de Souza Santos; Pedro Pacheco de Queiróz Filho; Claudia L. P. Mauricio; Livia Kelli da Silva; Paula Rocha Pessanha

doi:10.15392/bjrs.v3i1A.73

Authors

Rosane Moreira Ribeiro Instituto de Radioproteção e Dosimetria
Denison de Souza Santos Instituto de Radioproteção e Dosimetria
Pedro Pacheco de Queiróz Filho Instituto de Radioproteção e Dosimetria
Claudia L. P. Mauricio Instituto de Radioproteção e Dosimetria
Livia Kelli da Silva Instituto de Radioproteção e Dosimetria
Paula Rocha Pessanha Instituto de Radioproteção e Dosimetria

DOI:

https://doi.org/10.15392/bjrs.v3i1A.73

Keywords:

Geant4, nêutrons, dosimetria

Abstract

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 cm³, 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 cm²). 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.

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References

LEUTHOLD G.; MARES V.; SCHRAUBE, H., Calculation of the neutron ambient dose equivalent on the basis of the ICRP revised quality factors, Radiation Protection Dosimetry, v. 40. n 2, p. 77-84 , 1992.

ICRU - International Commission on Radiation Units and Measurements. Measurement of dose equivalents from external photon and electron radiations. ICRU Report 47, Bethesda: ICRU , 1992a.

ICRP - International Commission on Radiological Protection. The 2007 Recommendations of the International Commission on Radiological Protection. ICRP Publication 103, Ann: ICRP 37 (2-4), 2007.

ICRU - International Commission on Radiation Units and Measurements. Determination of dose equivalents resulting from external radiation sources. ICRU Report 39, Bethesda: ICRU, 1985.

A General Monte Carlo N-Particle (MCNP) Transport Code. Available at: <http://mcnp.lanl.gov/> (2013). Last accessed: 10 Jul. 2014.

National Research Council Canada. EGSnrc: software tool to model radiation transport, Available at: <http://www.nrc-cnrc.gc.ca/eng/solutions/advisory/egsnrc_index.html> (2013). Last accessed: 10 Jul. 2014.

PENELOPE 2011, A Code System for Monte-Carlo Simulation of Electron and Photon Transport, Available at: <http://www.oecd-nea.org/tools/abstract/detail/nea-1525> (2013). Last accessed: 10 Jul. 2014

“GEANT4: A toolkit for the simulation of the passage of particles through matter”, http://geant4.cern.ch/ (2013). Last accessed: 10 Jul. 2014

SCHUHMACHER H.; SIEBERT B. R. L. Quality factors and ambient dose equivalent for neutrons based on the new ICRP recommendations, Radiation Protection Dosimetry, v. 40. n 2, p. 85-89,1992.

SIEBERT B. R. L.; SCHUHMACHER H. Quality factors, ambient and personal dose equivalent for neutrons, based on the new ICRU stopping power data for protons and alpha particles. Radiation Protection Dosimetry, v. 58, n 3, p. 177-183, 1995.

ICRP - International Commission on Radiological Protection. Conversion Coefficients for use in Radiological Protection against External Radiation, ICRP Publication 74. Ann: ICRP 26 (3-4), 1996.

AGOSTINELLI S. ET AL., GEANT4 - a simulation toolkit. Nuclear Instruments and Methods in Physics Research”, Elsevier Science, v. 506, p. 250-303, 2003.

ICRU - International Commission on Radiation Units and Measurements. Conversion coefficients for use in radiological protection against external radiation. ICRU Report 57, Bethesda: ICRU, 1998.

GARNY S., ET AL., GEANT4 Transport Calculations for Neutrons and Photons below 15 MeV”, IEEE Transactions On Nuclear Science, v. 56, n 4, p. 2392-2396, 2009.

ICRU - International Commission on Radiation Units and Measurements, Stopping Powers and Ranges for Protons and Alpha Particles, ICRU Report 49, Bethesda: ICRU, 1993.

ICRU - International Commission on Radiation Units and Measurements, Stopping of Ions Heavier Than Helium, ICRU Report 73, Bethesda: ICRU, 2005.

ICRP - International Commission on Radiological Protection, 1990 Recommendations of the International Commission on Radiological Protection”, ICRP Publication 60. Ann: ICRP 21 (1-3), 1991.

CIRRONE G. A. P. ET AL. A Goodness-of-fit Statistical Toolkit, IEEE Transactions On Nuclear Science, v. 51, n 5. p. 2056-2063, 2004.

DARLING D. A., The Kolmogorov-Smirnov, Cramer-von Mises tests. Ann. Math. Statist, v. 28, p. 823-838, 1957.

GARNY S., Development of biophysical treatment planning system for the FRM II neutron therapy beamline, 189 f. Tese (Doutorado) – Universidade Técnica de Munique (TUM), Munique (2009).