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Published on: December 14, 2017
Thermal neutron calibration channel at LNMRI/IRD
A Astuto1, A P Salgado2, S P Leite3
1Universidade Federal do Rio de Janeiro, COPPE/UFRJ, Av. Horácio Macedo, 2030, Bloco G/Sala 206, Centro de Tecnologia, Cidade Universitária, Ilha do Fundão, CEP: 21941-914, Rio de Janeiro, RJ, Brazil Fundação Técnico Educacional Souza Marques, FTESM, Av. Ernani Cardoso, 335, Cascadura, CEP: 21310-310, Rio de Janeiro, RJ, Brazil achillesbr@gmail.com karla@ird.gov.br.
The Brazilian Metrology Laboratory of Ionizing Radiations developed a standard thermal neutron flux facility using MCNPX simulations and graphite/paraffin moderators. This facility ensures uniform neutron fluence for calibrating detectors and dosemeters, maintaining traceability to the International System of Units.
Area of Science:
- Metrology
- Nuclear Physics
- Radiation Detection
Background:
- The Brazilian Metrology Laboratory of Ionizing Radiations (LNMRI) requires a standard thermal neutron flux facility.
- Accurate calibration of neutron detectors and individual dosemeters is crucial for radiation safety and research.
Purpose of the Study:
- To design and validate a standard thermal neutron flux facility at LNMRI.
- To provide uniform neutron fluence for calibrating radiation detection equipment.
Main Methods:
- Neutron moderation using (241)Am-Be sources within a graphite/paraffin moderator.
- Monte Carlo N-Particle eXtreme (MCNPX) code simulations for optimizing geometric arrangements.
- Evaluation of neutron spectrum, cadmium ratio, and gamma-neutron ratio.
Main Results:
- Simulations identified optimal configurations for the neutron flux facility.
- The facility utilizes moderated neutrons from (241)Am-Be sources for uniform fluence.
- Ongoing measurements aim to validate the simulated system performance.
Conclusions:
- The developed facility is expected to provide uniform neutron fluence for detector calibration.
- Validation through measurements and intercomparisons will ensure traceability to the International System of Units.
- This work enhances metrological capabilities in ionizing radiation measurements in Brazil.
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