SIMULATION USING THE MONTE CARLO METHOD FOR THE SMEAR/FIELD FILTER COUNTER WITH POINT SOURCES

Fernando Soares Santos; Ana Beatriz Caldeira de Andrade; Davi Silveira Azevedo; Laila Fernanda Moreira de Almeida; Sara Suely Ventura da Silva Lima; Bruno Melo Mendes

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Título do Trabalho

SIMULATION USING THE MONTE CARLO METHOD FOR THE SMEAR/FIELD FILTER COUNTER WITH POINT SOURCES

Autores

Fernando Soares Santos
Ana Beatriz Caldeira de Andrade
Davi Silveira Azevedo
Laila Fernanda Moreira de Almeida
Sara Suely Ventura da Silva Lima
Bruno Melo Mendes

Modalidade

Artigo

Área temática

CIÊNCIAS DAS RADIAÇÕES - Dosimetria das Radiações

Data de Publicação

23/11/2024

País da Publicação

Brasil

Idioma da Publicação

Português

Página do Trabalho

https://www.even3.com.br/anais/vii-sencir-semana-nacional-de-engenharia-nuclear-e-da-energia-e-ciencias-das-radiacoes-449507/916556-simulation-using-the-monte-carlo-method-for-the-smearfield-filter-counter-with-point-sources

ISBN

978-65-272-0986-7

Palavras-Chave

Monte Carlo Simulation; PHITS; Smear Counter/Field Filter.

Resumo

Introduction: The Smear/Field Filter Counter is a device used for detecting and measuring radioactive contamination on surfaces, commonly found in radiation laboratories and nuclear facilities. The sensitive region of the counter consists of a sodium iodide crystal activated with thallium (NaI(Tl)). To enhance its performance and better understand its operation, computational simulation methods, such as Monte Carlo, are often employed to model the behavior of radioactive particles within the counter. Objective: This study aims to model and validate a Smear/Field Filter Counter using the Particle and Heavy Ion Transport Code System (PHITS). The simulated data were evaluated by comparison with experimental data acquired using Cesium-137 and Barium-133 point sources. Methodology: The geometries of the counter components were modeled in the PHITS code, including a 2 x 2” NaI(Tl) detector and the counter’s shielding. The densities and chemical compositions of the modeled materials were obtained from the literature. The PHITS simulation also considered the distribution of channels in the real detector. Four different scenarios were simulated, each containing a type of point source, either Cs-137 (from three different models) or Ba-133 inside the counting chamber. Each simulated case resulted in a spectrum from the modeled detector using the t-deposit tally. The number of counts in the photopeak channel per photon emitted from the source corresponds to the system's absolute efficiency for the photopeak energy. A sufficient number of histories was simulated to obtain a statistical error of less than five percent. Validation with experimental data involved the same sources, in the same geometry, with each being counted three times for 6 minutes. The simulated and experimental absolute efficiencies were compared. Results: The simulated efficiency ranged from 4.4% to 5.2% for the Cs-137 sources (662 keV) and was 9.7% for the Ba-133 source (356 keV). Experimentally, efficiencies ranged from 4.5% to 4.6% for the Cs-137 sources and 9.2% for the Ba-133 source. Differences between the experimental and simulated values ranged from 3.5% to 11.3%, depending on the evaluated source. Conclusions: The smear counter was modeled in the PHITS code. The simulations showed comparable results with the experimental data, with differences ranging from 3.5% to 11.3%. Accuracy in modeling the sources and the distance between the source and the detector are crucial for the fidelity of the simulation results relative to the experimental values.

Título do Evento: VII SENCIR - Semana Nacional de Engenharia Nuclear e da Energia e Ciências das Radiações
Cidade do Evento: Belo Horizonte
Título dos Anais do Evento: Semana Nacional de Engenharia Nuclear e da Energia e Ciências das Radiações
Nome da Editora: Even3
Meio de Divulgação: Meio Digital

Como citar

SANTOS, Fernando Soares et al.. SIMULATION USING THE MONTE CARLO METHOD FOR THE SMEAR/FIELD FILTER COUNTER WITH POINT SOURCES.. In: Semana Nacional de Engenharia Nuclear e da Energia e Ciências das Radiações. Anais...Belo Horizonte(MG) UFMG, 2024. Disponível em: https//www.even3.com.br/anais/vii-sencir-semana-nacional-de-engenharia-nuclear-e-da-energia-e-ciencias-das-radiacoes-449507/916556-SIMULATION-USING-THE-MONTE-CARLO-METHOD-FOR-THE-SMEARFIELD-FILTER-COUNTER-WITH-POINT-SOURCES. Acesso em: 13/05/2025