[en] The performance of a dosemeter based on thermoluminescent materials, ⁷ LiF and ⁶ LiF, was investigated. The verification if the dosemeter response complies with tests recommended by national and international regulatory organizations was performed. Tests of angular and energy dependence, reproducibility, detectability threshold, batch homogeneity and others were carried out and the obtained response is herein presented. Dosemeter response was evaluated in terms of H_p(10). The tests were carried out taking into account the IRD-RT No 001.01/95 and IEC 1066 reporters that gave the guidelines for this evaluation. The obtained response showed that the studied dosemeter complies with the tests and can be employed for individual monitoring. (author)

[en] Radionuclide metrology laboratories aim to provide radioactive standards for detector calibrations in nuclear safety areas with low uncertainties. Such standards are applied in nuclear industries, according to the requirements of monitoring programmes. The standard radionuclides of ¹³³Ba, ¹⁵²Eu and ^166mHo are suitable to the determination of efficiency curves in HPGe detectors due to their multi-gamma emissions, which are intense and well separate in the spectrum. With efficiency curves it is possible to do the measurements without needing to use standards. In this work was made a verifying of the uncertainties obtained for the two relative methods: comparative (sample-standard) and efficiency curve. The total uncertainties obtained by sample-standard method varied from 0.4 to 1.2 % (k=1). The results using efficiency curve method are between 0.9 to 2.2 % (k=1). (author)

[en] In this article we will describe the radionuclide standardization system TDCR, Triple-to-Double Coincidence Ratio, of the National Metrology Laboratory of Ionizing Radiation and its stage of development to provide a method to standardize radionuclides difficult by other techniques. The TDCR is an absolute measurement method, therefore, it does not depend on a reference standard to determine the radioactive activity of the samples, initially developed to standardize radionuclides that decay by pure beta emission (electrons and positrons), such as ³H, ¹⁴C, ⁴⁵Ca and ⁶³Ni and electronic capture, such as the ⁵⁵Fe. However, it is possible to standardize alpha emitters, such as ²⁴¹Am, and other radionuclides with a complex decay scheme. The method uses three photomultiplier tubes aligned at an angle of 120° to each other, and double and triple coincidences between the three photomultiplier tubes are collected. The method is currently used in 26 radionuclide metrology laboratories around the world. In this article we also present the radionuclides that will be standardized by the method. (author)

[en] The National Laboratory of Metrology Ionizing Radiation (LNMRI/IRD/CNEN) has several measurement methods in order to ensure low uncertainties about the results. Through gamma spectrometry analysis by sum-peak absolute method they were performed the standardization of "1"3"3Ba activity and your emission probability determination of different energies with reduced uncertainties. The advantages of radionuclides calibrations by absolute method are accuracy, low uncertainties and is not necessary the use of radionuclides reference standards. "1"3"3Ba is used in research laboratories on calibration detectors in different work areas. The uncertainties for the activity and for the emission probability results are lower than 1%. (author)

[en] In order to study the effect of sum by coincidence in X-ray and gamma spectrometry of Ba-133, a method is presented for, through an Excel spreadsheet, to apply the theory developed by Novkovic et al. Based on the tracking or tracing of all routes or decay trajectories of radioisotopes with complex decay scheme and its consequences in a detector, that is, the energies susceptible to be deposited associated with the corresponding probability of detection. It Is, initially using a matrix technique, to derive equations of peak count rate in photonic spectra, equations that describe the sums by coincidence of X-rays and gamma of radionuclide, as the Ba-133, in which the cascade of deexcitation of the nucleus takes place simultaneously with the cascade de-excitation of the atomic layer. By means of the detailed analysis of the spectrum of the Ba-133, from the 1860 theoretical results obtained from the 14 different decay routes, the method allows to determine, between the 167 possible peaks (photo-peaks and peaks-sum), the influence of the effects summing-in (cascade sum effects) in about 50 peaks normally recorded in a HPGe spectrometer with a relative efficiency of 50%.

[en] The 4πβ-γ coincidence counting and CIEMAT/NIST liquid scintillation method were used in the standardization of a solution of ¹⁵²Eu. In CIEMAT/NIST method, measurements were performed in a Liquid Scintillation Counter model Wallac 1414. In the 4πβ-γ coincidence counting, the solution was standardized using a coincidence method with 'beta-efficiency extrapolation'. A simple 4πβ-γ coincidence system was used, with acrylic scintillation cell coupled to two coincident photomultipliers at 180° each other and NaI(Tl) detector. The activity concentrations obtained were 156.934 ± 0.722 and 157.403 ± 0.113 kBq/g, respectively, for CIEMAT/NIST and 4πβ-γ coincidence counting measurement methods. (author)

[en] The ¹⁵²Eu has a half-life of 13.5 years and a very complex decay scheme with two branches of decay. It disintegrates in ¹⁵²Sm by electronic capture (72.1%) or by emission of positrons (0.027%) and in ¹⁵²Gd by beta emission minus (27.9%). The child nucleus, ¹⁵²Sm, has 19 excited levels, while ¹⁵²Gd has 15. The direct decay of the parent nucleus to the fundamental state of the child nucleus does not exist. The decay of a ¹⁵²Eu source results in emissions of 4 KX photons and 132 gamma rays, which is the reason for a lot of true coincidence-sum. The particular interest in this radionuclide is explained by its wide use in the calibration in energy and efficiency of gamma spectrometers with semiconductor detectors, since the range of energy of the emitted photons, varying from 40 to 1769 keV. But, because of such a complex decay scheme, the determination of ¹⁵²Eu activity presents many difficulties. The CIEMAT / NIST liquid scintillation counting method and the peak-sum coincidence method, an absolute measurement technique using coincidence counts and photon spectrometry, have been tested in the LNMRI-IRD to standardize ¹⁵²Eu solutions

[en] In the case of a radiological accident, there are characteristic phases: discovery and initial assistance with first aid; the triage and monitoring of the affected population; the release of the affected people; forward the victims to medical care; as well as the preparation of the report on the accident. In addition, studies and associated researches performed in the later period. Monitors, dosimeters and measuring systems should be calibrated by contaminating radionuclide standards. The radioactive sources used must be metrologically reliable. In Brazil, this function is performed by LNMRI/IRD/CNEN, designated by INMETRO, which Radionuclide Metrology Laboratory is responsible for the standardization and supply of radioactive sources in diverse geometries and matrices. This laboratory has a stock of radionuclide solutions with controlled environmental variables for the preparation of sources, which are calibrated and standardized by mean of primary and secondary systems. It is also responsible for the dissemination of standards and, in order to establish the metrological traceability of national standards, participates in international key-comparisons promoted by BIPM and regional metrology organizations. Internally, it promotes the National Comparison Programs for laboratories for the analysis of environmental samples and the traceability for producing centers of radiopharmaceuticals and Nuclear Medicine Services in the country. The paper presents the demand for ¹³⁷Cs related to the radioactive accident in Goiania/Brazil and the significant results for the main radionuclides standardized by the Radionuclide Metrology Laboratory for international key-comparisons and national comparisons to provide metrological traceability. With the obtained results, the LNMRI of Brazil integrates the international metrology BIPM network and fulfills its function of supplying, with about a hundred of radioactive standards, the country's needs in different applications, including attendance to radiological accident. (author)

[en] In the case of a radiological accident, there are characteristic phases: discovery and initial assistance with first aid; the triage and monitoring of the affected population; the release of the affected people; forward the victims to medical care; as well as the preparation of the report on the accident. In addition, studies and associated researches performed in the later period. Monitors, dosimeters and measuring systems should be calibrated by contaminating radionuclide standards. The radioactive sources used must be metrologically reliable. In Brazil, this function is performed by LNMRI/IRD/CNEN, designated by INMETRO, which Radionuclide Metrology Laboratory is responsible for the standardization and supply of radioactive sources in diverse geometries and matrices. This laboratory has a stock of radionuclide solutions with controlled environmental variables for the preparation of sources, which are calibrated and standardized by mean of primary and secondary systems. It is also responsible for the dissemination of standards and, in order to establish the metrological traceability of national standards, participates in international key-comparisons promoted by BIPM and regional metrology organizations. Internally, it promotes the National Comparison Programs for laboratories for the analysis of environmental samples and the traceability for producing centers of radiopharmaceuticals and Nuclear Medicine Services in the country. The paper presents the demand for ¹³⁷Cs related to the radioactive accident in Goiania/Brazil and the significant results for the main radionuclides standardized by the Radionuclide Metrology Laboratory for international key-comparisons and national comparisons to provide metrological traceability. With the obtained results, the LNMRI of Brazil integrates the international metrology BIPM network and fulfills its function of supplying, with about a hundred of radioactive standards, the country's needs in different applications, including attendance to radiological accident. (author)

[en] Recently, the idea of generating radon map of Brazil has emerged. First attempts of coordinating radon surveys-carried out by different groups across the country-and initial discussions on how to proceed on a larger scale were made at the First Brazilian Radon Seminary, Natal, September 2012. Conventionally, it is believed that indoor radon is no major problem in Brazil, because the overall benign climate usually allows high ventilation rates. Nevertheless, scattered measurements have shown that moderately high indoor radon concentrations (up to a few hundred Bq m^-3) do occur regionally. Brazilian geology is very diverse and there are regions where an elevated geo-genic radon potential exists or is expected to exist. Therefore, a Brazilian Radon Survey is expected to be a challenge, although it appears an important issue, given the rising concern of the public about the quality of its environment. (authors)