Gamma-spectrometric determination of natural radionuclides and 137Cs concentrations in environmental samples. The improved scintillation technique

Azimov, A. N.; Hushmuradov, Sh.Kh.; Muminov, I. T.; Muminov, T.M.; Osmanov, B.; Safarov, A. N.

doi:10.1016/j.radmeas.2007.11.006

Cited by 15 publications

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“…1). The methods used for measuring and analyzing the spectra are examined in [4].It has been established that the specific activity of 7 Be in the samples varies, depending on the sampling time, in the range A = 10-295 Bq/m 2 (see Table 1). The contribution of the other natural radionuclides (uranium-thorium families and 40 K) does not exceed ~15 Bq/m 2 .…”

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Effect of natural factors on 7Be activity in atmospheric precipitation in 2007 in Samarkand

Bazarbaev

Muminov

et al. 2009

At Energy

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Cosmogenic 7 Be (half-life T 1.2 = 54 days, E γ = 478 keV) is formed in upper layers of the atmosphere in reactions where cosmic radiation splits the atoms in the air. The 7 Be atoms formed stick to aerosol particles and together with dry particles (dust, dew, hoarfrost, frost) and wet precipitation (rain, snow) fall onto the Earth's surface.The 7 Be concentration in near-Earth space is largely determined by the solar component of the cosmic radiation, moving from the upper to the lower layers of the atmosphere -geophysical processes, fallout on the Earth's surface -dry and wet precipitation, the content in objects of the environment -soil erosion and formation of bottom deposits.The present work is a continuation of the investigations started in 2002 [1-3] of 7 Be activity in monthly atmospheric precipitation in Samarkand.The samples of atmospheric fallout were obtained by the method of monthly exposure of 100 × 100 cm and 10 cm high cell placed at height 8 m. The bottom of the cell was covered with a layer of gauze swabbed with glycerin. The method of preparing samples was described in [3].The samples were packed in 1-liter Marinelli vessels, whose radiation was measured using a gamma spectrometer with a 63 × 63 mm NaI(Tl) crystal and resolution ~10% on the 1332 keV line of 60 Co. The γ-radiation detection efficiency was determined and the γ spectra were analyzed using 226 Ra, 232 Th, and 40 K sources from the OMACH set. The 7 Be activity in the samples was determined according to the area of the 478 keV photopeak, separated from the experimental spectrum of the 7 Be component (Fig. 1). The methods used for measuring and analyzing the spectra are examined in [4].It has been established that the specific activity of 7 Be in the samples varies, depending on the sampling time, in the range A = 10-295 Bq/m 2 (see Table 1). The contribution of the other natural radionuclides (uranium-thorium families and 40 K) does not exceed ~15 Bq/m 2 .The 7 Be activity in the samples was compared with the following indicators:• solar activity, for which the inverse average monthly Wolf numbers (number of sun spots) W i were used [5];• exchange processes between the upper and lower layers of the atmosphere -monthly sums of daytime geomagnetic indices D i of the perturbations of the Earth's magnetic field [5]; and • dry and wet precipitations, average monthly temperature T i and moisture content V i of air, monthly amounts of precipitation H i (according to the data from the Hydrometeorological Bureau for the Samarkand Region). For convenience of making comparisons, the reduced (dimensionless) values of the quantities normalized to the corresponding average yearly values are used: 7 Be activity a i = A i /101 Bq/m 2 , Wolf number w i = W i /6.5, geomagnetic index d i = D i /399 nT, temperature t i = T i /15 °C, moisture content v i = V i /60.3 %, and amount of precipitation h i = H i /30.8 mm.

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Effect of natural factors on 7Be activity in atmospheric precipitation in 2007 in Samarkand

Bazarbaev

Muminov

et al. 2009

At Energy

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“…O 137 Cs podem ser medido por métodos de cintilação, utilizando um detector gama [98][99][100][101], diretamente por espectrometria gama [102][103][104][105][106], espectrometria de massa com plasma indutivamente acoplado (do inglês -ICP-MS) porém, neste caso, é necessária separação prévia da amostra para remoção do 137 Ba que é um interferente [86,107]. Juntamente com outros isotopos, pode ser medido por espectrometria de massa com plasma indutivamente acoplado com tripla-quadrupla colisão/célula de reação.…”

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Determinação da atividade de emissores beta e gama em rejeitos radioativos operacionais da central nuclear de Angra

Junqueira¹

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Agradeço a CAPES pela bolsa de mestrado.Antes de começar a agradecer, quero dizer que eu jamais agradeceria ninguém por mera formalidade ou boas práticas sociais, todas as palavras escritas aqui são genuínas e dirigidas às pessoas que fizeram parte desta caminhada.Agradeço ao Guilherme Zahn pelo bom humor quase inabalável que animou meus dias no CERPq, por todas as conversas sem pé nem cabeça que tivemos, por sua grande disposição para ajudar em qualquer assunto que estivesse a seu alcance, por tudo que me ensinou ao longo destes anos e por todo carinho demonstrado a sua maneira.Agradeço ao Frederico Genezini, por toda ajuda em assuntos paralelos ao meu mestrado e principalmente por me aturar falando besteira a tarde toda em sua sala. Eu não esqueci que você acabou com meus sonhos e nunca vou esquecer, porque isso foi muito importante também.Agradecer aos professores Francisco de Souza, Mauricio Moralles e Mauro Dias por todas as dúvidas tiradas sobre suas disciplinas e também por todas as dúvidas tiradas sobre temas totalmente desconexos com meu mestrado.Agradeço aos meus pais que ajudaram muito a tornar este sonho em realidade.Agradeço ao Mateus Assis, pela companhia no sofrimento diário da época em que tudo dava errado no laboratório.Agradeço ao Matheus Angelini por todos os momentos, desde o começo da iniciação científica até o final do mestrado, se tornando um grande amigo.Por último e mais importante, gostaria de agradecer meu orientador, Paulo Sergio, pela infinita paciência, por sempre ter ajudado desde em coisas simples até as mais complexas, por se disponibilizar em finais de semanas, feriados e férias, pela calma inacreditável, pelas brincadeiras, discussões idiotas, conversas aleatórias, pausas para o café (foram muitas), por todos os ensinamentos que foram muito além do âmbito deste trabalho, pelas oportunidades oferecidas e pelo carinho que ele se nega a demonstrar, mas que seus alunos sabem que ele tem. Serei sempre grato por ter sido orientado por você. ResumoTodo rejeito radioativo precisa ser caracterizado para que seu repositório final seja definido conforme os critérios de segurança apresentados nas normas CNEN 6.06 e CNEN 6.09. Neste trabalho foram adaptadas metodologias para analisar os rejeitos radioativos de concentrado de evaporador e resinas de troca iônica das usinas nucleares de Angra dos Reis e determinar a concentração de atividade dos seguintes radionuclídeos de difícil medição: 63 Ni, 59 Ni, 90 Sr, 129 I e 135 Cs, que apresentaram rendimento de separação, em média de 93, 40, 97 e 73% respectivamente. O 63 Ni e o 59 Ni foram separados por cromatografia de troca iônica em coluna de Ni resin da Eichron Technologies, o 63 Ni foi medido por cintilação líquida e o 59 Ni por espectrometria gama. O 90 Sr foi separado por cromatografia de troca iônica em coluna Sr-spec e precipitação com oxalato. O 135 Cs foi separado por cromatografia de troca iônica em coluna com resina Dowex 50W-X12 e coprecipitação com molibdato de amônio e o 129 I foi separado por precipitação com PdCl 2 . As concentra...

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7Be variation in monthly atmospheric precipitation in 2002–2005 in Samarkand

Azimov¹,

Safarov²,

Kungurov

et al. 2011

At Energy

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7 Be (T 1/2 = 54 days, E γ = 478 keV, a γ = 10.3% per decay) is produced in the upper layers of the Earth's atmosphere in reactions where cosmic rays split 16 O and 14 N nuclei. In addition,7 Be nuclei formed as a result of the fragmentation of heavy nuclei and in thermonuclear fusion reactions 3 He + 4 He = 7 Be + γ on the surface of the Sun and in other parts of the Universe penetrate into enter the Earth's atmosphere. 7 Be ions stick to aerosols and are transported together with them into the lower layers of the atmosphere whence they fall with wet (rain, sleet, snow) and dry (dust, dew) precipitation onto the Earth' surface. Studies performed over many years in different regions of the Earth have established that the 7 Be concentration in the air layer at the ground is correlated with solar activity and the local physical-geographic characteristics while for atmospheric precipitation there is a correlation with the amount of the wet precipitation [1][2][3][4]. Systematic studies of monthly atmospheric precipitation of 7 Be in Samarkand began in 2002 [5][6][7].The present work compares the regularities observed in variations of 7 Be activity in atmospheric precipitation in 2002-2005 in Samarkand with those found in other regions of the Earth.Methodology. Atmospheric precipitation (dry and wet) was sampled by the "sticky table" method: monthly exposure of a container (area 100 × 100 cm, depth 10 cm) whose inner surface was smeared with glycerin and screened with gauze. After exposure was completed, the gauze was removed from the container and the liquid was poured into a vessel and evaporated to dry residue. The container and vessel were carefully rubbed with clean gauze, and the exposed and rubbing gauze with mass 180-250 g were placed into one-liter Marinelli vessels or incinerated in a muffle furnace and packed into 40 × 40 mm (8-25 g) polyethylene packages.The γ-spectra of the samples were measured in a gamma-spectrometer with a Ge(Li) detector with volume V = 100 cm 3 and energy resolution ΔE γ = 6.2 keV at E γ = 1332 keV or with a scintillation detector with a 63 × 63 mm Na(Tl) crystal with detection efficiency ΔE γ /E γ~ 10% on the 1332 keV line.The semiconductor spectra were processed with a computer program developed at the Mendeleev All-Russia Research Institute of Metrology. It was found that the detection efficiency of the Ge(Li) detector entered into the code is overstated. As a result, the 7 Be activity presented in [5, 6] in 2002-2003 for the samples is understated by a factor of 2.25 (the corrected values are given in Table 1).The scintillation spectra were processed by decomposing them into background components -radionuclides of the uranium-thorium families, 40 K, and 7 Be [8].Correlation of 7 Be Content in Atmospheric Precipitation with Precipitation Amount, Solar Activity, and Air Temperature. In Samarkand, there is a nonlinear correlation between 7 Be activity A in atmospheric precipitation and the precipitation amount H, solar activity W, and air temperature T.

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Gamma-spectrometric determination of natural radionuclides and 137Cs concentrations in environmental samples. The improved scintillation technique

Cited by 15 publications

References 1 publication

Effect of natural factors on 7Be activity in atmospheric precipitation in 2007 in Samarkand

Effect of natural factors on 7Be activity in atmospheric precipitation in 2007 in Samarkand

Determinação da atividade de emissores beta e gama em rejeitos radioativos operacionais da central nuclear de Angra

7Be variation in monthly atmospheric precipitation in 2002–2005 in Samarkand

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