Simultaneous determination of²²⁶Ra and²³⁸U in soil and environmental materials by gamma-spectrometry in the absence of radium progeny equilibrium

Using atmospheric fallout to date organic horizon layers and quantify metal dynamics during decomposition

“…We determined detector efficiency for U-series radionuclides in different counting geometries using certified uranium ore (Canadian Certified Reference Materials Project BL-5 U ore) and used a mixed radionuclide solution (Isotope Products) for efficiency calibration at other energies. Corrections are made for self-attenuation of the 46 keV 210 Pb photon using standard techniques (Cutshall et al, 1983), and the 186 keV 226 Ra line was corrected for the 235 U interference by simultaneously measuring the uranium content of the sample at 63 keV (Dowdall et al, 2004;Kaste et al, 2006b). Samples were measured for weaponsderived fallout radionuclides 241 Am and 207 Bi by quantifying their gamma emissions at 59.5 and 569.7 keV, respectively, and cosmogenic 7 Be was measured via its 477.6 keV gamma emission.…”

Natural radioelement concentrations in fertilizers and the soil of the Mila region of Algeria

“…Activity concentrations (Bq:kg À1 ) of 226 Ra, 232 Th, 40 K and 137 Cs for each of the measured samples.The226 Ra or 238 U activities for samples assumed to be in To measure the 235 U isotope we have used two approaches. The first one is based on using the gÀ lines of 234 Th (63.3 keV) and234m Pa(1001.0 keV) to estimate 238 U and calculated 235 U from the natural 238 U/ 235 U activity ratio of 21.7(Dowdall, Selnaes, Gwynn, & Davids, 2004). In the second one, we have calculated the activity of 235 U by using directly its g rays(143.8 keV, 163.3 keV).…”

A radiological index for evaluating the impact of an abandoned uranium mining area in Salamanca, Western Spain

“…Las concentraciones de actividad de los grupos del A al E en el punto de muestreo de referencia, fueron equivalentesal valor promedio mundial de la serie radiactiva del 238 U de 40 Bq kg -1 (Janković and Todorović, 2011), y superiores en las restantes muestras tanto en el caso de las muestras de suelo como de rizosfera. La relación entre la serie radiactiva del 238 U (grupo A) y 235 U (grupo E) fue de 22,5 ± 2,5 correspondiente al uranio natural (Dowdall et al, 2004) (véase tabla S1.1 del anexo S1).Asimismo, las concentraciones de actividad fueron directamente proporcionales a la distancia de la escombrera indicando la dispersión de los minerales extraídos de la mina. En las muestra tomadas en el perímetro de 100 metros de la escombrera ("PER 100 N", "PER 100 S", "PER 100 E", "PER 100 W") se observó que se produjo una dispersión de los radionucleidos en las direcciones norte, sur y este mientras que en la dirección oeste no existió dispersión,ya que no se observóen ninguno de los puntos un aumento del 210 Pb no soportado ( 210 Pb ex ).…”