LNMRI/IRD的热中子校准通道。

Thermal neutron calibration channel at LNMRI/IRD.

作者信息

Astuto A, Salgado A P, Leite S P, Patrão K C S, Fonseca E S, Pereira W W, Lopes R T

机构信息

Universidade 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

出版信息

Radiat Prot Dosimetry. 2014 Oct;161(1-4):185-9. doi: 10.1093/rpd/ncu040. Epub 2014 Mar 13.

DOI:10.1093/rpd/ncu040

PMID:24625545

Abstract

The Brazilian Metrology Laboratory of Ionizing Radiations (LNMRI) standard thermal neutron flux facility was designed to provide uniform neutron fluence for calibration of small neutron detectors and individual dosemeters. This fluence is obtained by neutron moderation from four (241)Am-Be sources, each with 596 GBq, in a facility built with blocks of graphite/paraffin compound and high-purity carbon graphite. This study was carried out in two steps. In the first step, simulations using the MCNPX code on different geometric arrangements of moderator materials and neutron sources were performed. The quality of the resulting neutron fluence in terms of spectrum, cadmium ratio and gamma-neutron ratio was evaluated. In the second step, the system was assembled based on the results obtained on the simulations, and new measurements are being made. These measurements will validate the system, and other intercomparisons will ensure traceability to the International System of Units.

摘要

巴西电离辐射计量实验室（LNMRI）的标准热中子通量设施旨在为小型中子探测器和个人剂量计的校准提供均匀的中子注量。这种注量是通过在一个由石墨/石蜡复合材料块和高纯度碳石墨建造的设施中，对四个活度均为596 GBq的（241）Am-Be源进行中子慢化而获得的。本研究分两步进行。第一步，使用MCNPX代码对慢化剂材料和中子源的不同几何排列进行模拟。从能谱、镉比和γ-中子比方面评估所得中子注量的质量。第二步，根据模拟结果组装系统，并进行新的测量。这些测量将验证该系统，其他比对将确保可溯源至国际单位制。