[en] The toxic elements Cd and Pb in 3 zinc ores, are determined precisely and nondestructively by 45-MeV bremsstrahlung activation, using a rotating device for intermittent irradiations of the samples and the standard by the same gamma-flux. The induced activities of ¹¹⁵Cd, sup(115m)In and ²⁰³Pb are measured using a single open-ended coaxial Ge(Li) detector and the photopeak integrations are calculated using the total peak area method and the Cutipie computer program. High concentrations of Pb and Cd in zinc ores are determined with a relative uncertainty of 0.7-1.2%. (author)

[en] A large number of toxic elements, including Th and U, in Scheldt and NBS river sediments, have been determined non-destructively by high energy photon activation. The time-length of irradiation varies between 1.5 hours for short-lived nuclides and 7-18 hours for long-lived nuclides. The induced activities are measured using a single open-ended coaxial Ge(Li) detector and the photopeak integrations are calculated using the total peak area method and the Cutipie computer program after substraction of the intrinsic background of the detector from each spectrum (Angela program). The photonuclear reactions and the best detection limits for 36 elements are indicated. (author)

[en] An installation for photon activation analysis recently completed at CBNM, Geel, is described. Synthetic standards prepared from pure graphite are used for the non-destructive determination of lanthanides in boron carbide. The induced activities of ¹⁵³Sm, sup(152m)Eu, ¹⁵⁹Gd and ¹⁵⁷Dy were measured using a single open-ended coaxial Ge(Li) detector and the photopeak areas were calculated using the GAFIT program. For the irradiation parameters used, the limits of detection are communicated. (author)

No abstract available

[en] In connection with a programme using non-destructive multielement photon activation analyses, especially for the determination of heavy elements, 22 natural elements are activated in the 44 MeV-bremsstrahlung produced by an electron linear accelerator, in order to evaluate the interferences. Using a rotating device, the element samples (4 or 5) and also the sample containing cobalt as reference element, are alternately irradiated under the same conditions during 16-18 hours with the bremsstrahlung produced by the impact of an electron beam (35-51 μA) on a platinum target. It is observed that photon activations at 44 MeV tend to favour the (γ,2n) and (γ,3n) reactions and interferences are important for some isotopes of neighbouring elements. From the results obtained for heavy elements, interferences are more severe in X-ray spectrometry than in γ-ray spectrometry. A figure of merit, A/sigma, is attributed to each photopeak and gives an indication of the photopeak sensitivity in practical conditions of photon activation analyses. (author)

[en] Instrumental photon activation analysis can be used advantageously for the homogeneity control and the determination of uranium concentration in minerals and ores to be certified as uranium reference materials. The homogeneity control of high contents of uranium can also be performed by passive gamma-ray spectrometry with high energy resolution. Interferences of ²³⁷U characteristic lines with gamma-rays from other radionuclides produced in the 44 MeV bremsstrahlung are evaluated. (author)

[en] Reference samples for bulk or surface analysis prepared using different methods have been examined applying photon activation analysis and Rutherford backscattering. Well defined bulk samples and thin evaporated layers were used to determine the longitudinal and lateral gradient of the bremsstrahlung produced by the impact of an electron beam at 44 MeV and 56 μA. (author)