M. García-León

The energy and resolution calibration of germanium detectors being basic procedures in gamma-ray spectrometry have not been usually studied in depth. In this paper a new approach to these calibration methods based on the Orthogonal Distance Regression (ODR) algorithm is presented. This algorithm treats more adequately all uncertainties involved in the calibration process and produces better results than the usual

ABSTRACT Several radioactive particles from the Palomares area have been analyzed with the nuclear microprobe of the National Accelerator Centre (CNA) in Seville exploring the advantages of combining µ-PIXE using a 5.5 MeV 4He beam with conventional µ-PIXE analysis using 3 MeV protons. The measurements performed with the α-particles are more sensitive to the sample surface, while the results collected with protons are indicative of the average composition of the hot particle. In this way, important information about the depth distribution of Pu and U in the particles has been obtained. In addition, the particles have been analyzed by SEM (EDX) and one of them has been sacrificed for the determination of its U and Pu isotopic composition by ICP-MS and α-spectrometry, being gained in this way important information about the composition of the weapons involved in the Palomares accident.

Résumé/Abstract In this work, the 137 Cs dating technique with improved accuracy is shown to be a powerful tool for establishing chronologies in different (lacustrine, marine) young aquatic deposits. The method has special importance when the 210 Pb method gives partial or unclear results.

The analytical techniques based on ion beams or IBA techniques give quantitative information on elemental concentration in samples of a wide variety of nature. In this work, we focus on PIXE technique, analyzing thick target biological specimens (TTPIXE), using 3 MeV protons produced by an electrostatic accelerator. A nuclear microprobe was used performing PIXE and RBS simultaneously, in order to

The measurement of plutonium isotopes, 239Pu and 240Pu, at 670kV on the compact accelerator mass spectrometry (AMS) system at the Centro Nacional de Aceleradores (CNA) in Seville, Spain, is now a reality. In this work, we present first Pu AMS results for environmental samples: a sediment core collected in a submarine canyon in the Mediterranean coast of the Spanish region

210Pb radioimpurities in different lead pieces used for shielding low-level gamma-ray spectrometers have been determined through the application of two independent radiometric techniques: alpha-particle spectrometry (210Po) and Cherenkov counting (210Bi). Associated to each technique, simple radiochemical procedures have been developed for the isolation of the radionuclides of interest and/or their adaption to the measurement conditions. These determinations are very useful

In this paper coincidence summing corrections in gamma-ray spectrometry have been analyzed in depth. Experimental setup included a n-type germanium detector and two efficient geometries of measurement (Marinelli beaker and air filter) calibrated with multi gamma radionuclides in the energy range of 40-1500 keV. Monte Carlo simulations were carried out using the GEANT4 code in order to develop this work.

Phosphate rocks are used for phosphoric acid production, which is the basis of agricultural phosphate fertilizers. It is known that phosphate ores contain, due to geological reasons, important amounts of natural radioactivity, mainly U-isotopes and daughters. By studying a specific case in Southwestern Spain, it is shown that the operation of phosphate fertilizer factories clearly enhance the natural radiation levels

Abstract A marine sediment core from the Kattegat area (Sweden) has been studied for dating purposes. The 137 Cs and 210 Pb profiles have been measured and described by a model of incomplete activity mixing. A time-dependent 137 Cs flux function for the sediment has been constructed from atmospheric data and the 137 Cs contents in water from the Sellafield nuclear reprocessing plant. It has been used as the 137 Cs input function for our model. The results show that the model clearly reproduces the measured profile.

ABSTRACT The complex dielectric functions, ε(ω)=ε1(ω)+iε2(ω) , of CuIn 3 Se 5 and CuIn 5 Se 8 crystals with different Cu contents have been determined in the 0.8–4.7 eV photon energy range by using spectroscopic ellipsometry. The spectral dependence of the real, ε1(ω) , and imaginary, ε2(ω) , parts of ε(ω) , as well as the complex refractive index, the absorption coefficient, and the normal-incidence reflectivity, has been modeled by using a modification of Adachi’s model. The results are in excellent agreement with the experimental data over the entire range of photon energies. The model parameters, including the energies corresponding to the lowest direct gap, E0 , and to higher critical points, have been determined by using the simulated annealing algorithm.

In this paper coincidence summing corrections in gamma-ray spectrometry have been analyzed in depth. Experimental setup included a n-type germanium detector and two efficient geometries of measurement (Marinelli beaker and air filter) calibrated with multi gamma radionuclides in the energy range of 40-1500 keV. Monte Carlo simulations were carried out using the GEANT4 code in order to develop this work.