Ionising radiation metrology for the metallurgical industry

Every year millions tons of steel are produced worldwide from recycled scrap loads. Although the detection systems in the steelworks prevent most orphan radioactive sources from entering the furnace, there is still the possibility of accidentally melting a radioactive source. The MetroMetal project, carried out in the frame of the European Metrology Research Programme (EMRP), addresses this problem by studying the existing measurement systems, developing sets of reference sources in various matrices (cast steel, slag, fume dust) and proposing new detection instruments. This paper presents the key lines of the project and describes the preparation of radioactive sources as well as the intercomparison exercises used to test the calibration and correction methods proposed within the project.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

LINE-1 methylation in leukocyte DNA, interaction with phosphatidylethanolamine N-methyltransferase variants and bladder cancer risk

BACKGROUND: Aberrant global DNA methylation is shown to increase cancer risk. LINE-1 has been proven a measure of global DNA methylation. The objectives of this study were to assess the association between LINE-1 methylation level and bladder cancer risk and to evaluate effect modification by environmental and genetic factors. METHODS: Bisulphite-treated leukocyte DNA from 952 cases and 892 hospital controls was used to measure LINE-1 methylation level at four CpG sites by pyrosequencing. Logistic regression model was fitted to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs). Interactions between LINE-1 methylation levels and environmental and genetic factors were assessed. RESULTS: The risk of bladder cancer followed a nonlinear association with LINE-1 methylation. Compared with subjects in the middle tertile, the adjusted OR for subjects in the lower and the higher tertiles were 1.26 (95% CI 0.99–1.60, P=0.06) and 1.33 (95% CI 1.05–1.69, P=0.02), respectively. This association significantly increased among individuals homozygous for the major allele of five single-nucleotide polymorphisms located in the phosphatidylethanolamine N-methyltransferase gene (corrected P-interaction<0.05). CONCLUSIONS: The findings from this large-scale study suggest that both low and high levels of global DNA methylation are associated with the risk of bladder cancer

GEAL, un programa general para el analisis de espectros alfa

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Eficiencia de recuento en espectrometros de centelleo con un solo fotomultiplicador

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Aplicacion del metodo de Monte Carlo al calculo de la probabilidad de interaccion fotonica en tolueno

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Espectros beta. Espectros simples de positrones

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Determinacion de isotopos de uranio por espectrometria alfa

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Calculo de la eficiencia de deteccion en liquidos centelleadores. Nucleidos que se desintegran por emision simple de negatrones

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Calculo de la eficiencia de recuento de nucleidos que experimentan desintegracion beta y desexcitacion gamma simple

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

U-234/U-235 Activity Ratios as a Probe for the U-238/U-235 Half-Life Ratio

The uranium isotopes U-235 and U-238, because of their long half-lives, have important applications, in particular for nuclear geochronology. The most accurate measurements, by Jaffey et al., have up to now not been confirmed by other measurements of comparable accuracy. Hence, the validity of dating via the uranium-lead system is predominantly dependent on this single experiment. In this work, we supply some additional experimental information on the U235 and U-238 half-lives. High resolution alpha spectrometry was performed on three enriched U-235 materials, containing also impurity traces of U-234. Assuming the U-234 in the material to be in equilibrium with its parent, U-238, it can be used as a probe for the half-life of the latter. Relying on the isotopic composition of the uranium, as determined by mass spectrometry techniques, the ratio of half-lives of U-238 and U-235 was determined via the activity ratio of U-234 and U-235. Preliminary results on one material confirm the half-life ratio within a few tenths of percent. Yet, a discrepancy was detected with another material, which raises questions about the attainable accuracy with mass spectrometry on ultra-low amounts of U-234.JRC.D.4-Isotope measurement