[en] Some aspects related to the use of standard glass microscope slide as solid state track detector are presented, as well as studies of measurement of distribution of uranium in various solids determined by means of this technique. The behavior of the various parameters related to the properties of the detector and the results of their measurements are treated. Results obtained on the determination of distribution of uranium in samples of fuel elements of the 'ARGONAUTA' research reactor of Instituto de Engenharia Nuclear - Rio de Janeiro, are included. The samples were taken from the fuel-cladding interface. Finally, some data on levels of contamination of the laboratory equipment in use by uranium during the course of this work are presented

[en] The determination of Pb-210 and U-238 by γ spectrometry in environmental samples was carried out using the 47 KeV (4%) line for Pb-210 and the 63 KeV (3,9%) line from Th-234 to U-238. An intrinsic Ge detector with 0,8 KeV resolution for the 60 KeV line of Am-41 was employed. The eficiency was determined by using the radionuclide water solution. The samples were measured in a cylindric geometry with 7 cm diameter and 3 cm hight with a mass ranging from 25 to 180g, depending on the density. The self absorption correction factor for each sample was determined by using an external source of Pb-210 and Am-241. The results showed good agreement with the radiochemical analysis values. The diferences were lower than 20%; the detection limit changed from sample to sample staying on the pCi/g range for the 200 minutes couting time. (Author)

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[en] Full text. Meteorological conditions and soil characteristics are the important factors which affect the behaviour of the radon and its short lived daughters concentration in the environment. Tropical climates present extreme conditions for those characteristics and so a strong variability on the radon and its short lived daughters concentration is expected to occur on a daily and seasonally basis. This work will present some preliminary data obtained at a seaside region in Rio de Janeiro. Continuous sampling of the radon short lived daughters were performed at 1 m above the ground using the WLM (Working Level Monitor) where a alpha spectrometry was simultaneously carried out. Temperature and humidity were hourly registered. The results pretended concentrations ranging from 2 to 30 Bq/m³ depending on the time of the day and on the period of the year with a strong relationship with the meteorological conditions. The highest values were observed in the morning and the lowest at the late afternoon. It was also observed a direct relationship with the humidity and inverse correlation with the temperature. This pattern influence the dynamic of radon between indoors and outdoors environment. The knowledge of this dynamic is very important on the sampling and interpretation of dose results

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[en] Cellulose nitrate films LR-115 type II (Kodak-Pathe) have been exposed, at right angles, to alpha-particle beams in the energy range 2.5 - 5.5 MeV. From measurements of both through etched track density, a critical rate of energy lo ss for track registration of (0.85 +- 0.05) MeV cm²/mg has been derived, which corresponds to a critical alpha-particle energy of (4.6 +- 0.4) MeV. These results are compatible with those obtained by other authors whenever similar etching conditions are used. The concepts of threshold rate of energy loss and a threshold energy for etched-track formation are introduced, and their values are obtained from the experiment as being (0.80 +- 0.05) MeV cm²/mg and (5.1 +- 0.4) Mev, respectively. In addition, the present work provides a suitable set of useful, reference data for further applications of such plastic nuclear track detector in problems concerned with the detection of low-energy alpha particles. (Author)

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[en] The determination of ²²⁶Ra in environmental samples using alpha spectrometry in liquid scintilation is studied. The Radon^1-2 emanation method and ²²⁶Ra separation process of other radionuclides alpha emissors are analyzed. The use of ²²⁶Ra coprecipitation with barium sulphate is evaluated. (M.J.C.)

[en] The calibration system consists of deep the neutron source, protected by plastic container, at the center of spherical polietilene tank, in a concentrated solution of manganese sulphate. The neutrons emitted by the source are moderated and when reach the termal energy are catched by manganese atoms activating the solution. After the saturation activity has been reached the source is removed and one scintilation detector (NaI(Tl) 3' x 3') is put in the same place to follow the decay activity. The gama couting rate (845 KeV ⁵⁴Mn photopeak), after the corrections is used to estimate the saturation activity, and calculate the neutron source emission rate. These calculations are executed by one computer program. The uncertainties in the final value of emission rate are about 2.5 - 3.0 % to AmBe sources in the 1.11 x 10¹⁰ Bq (0,3 Ci) - 3.7 x 10¹¹ Bq (10 Ci) range. (author)