Accelerator-based research activities at "Centro Nacional de Aceleradores", Seville (Spain)

5 páginas.-- PACS nrs.: 29.17.+w; 29.20.−c; 82.80.−d; 07.30.Kf.In February 1998, almost 10 years ago, the set-up of the first IBA (ion beam analysis) facility in Spain took place with the arrival of a 3 MV tandem accelerator [J. García-López, F.J. Ager, M. Barbadillo-Rank, F.J. Madrigal, M.A. Ontalba, M.A. Respaldiza, M.D. Ynsa, Nucl. Instr. and Meth. B 161–163 (2000) 1137]. Since then, an intensive research program using IBA techniques has been carried out. Subsequently, a cyclotron for 18 MeV protons has been also installed at the “Centro Nacional de Aceleradores” (CNA), devoted mainly to isotope production for PET (positron emission tomography) techniques, but possibly applied to material analysis and damage studies on a dedicated beam line. Moreover, a 1 MV tandem has been recently installed for AMS (accelerator mass spectrometry) 14C dating and environmental research with other isotopes.In the present paper we describe the new facilities and the developments of the 3 MV tandem beam lines occurred during the past years, as well as some examples of the most recent research activities in our Center in the fields of Material Science, Archaeometry, Biomedicine and Environment.Thanks are due to the three host Institutions, Universidad de Sevilla, Junta de Andalucía and CSIC, for the continuous support given to our Centre.Peer reviewe

Ion beam analysis of pottery from Teotihuacan, Mexico

et al.This work presents the characterization of sherds and pottery paints from Teotihuacan, Mexico, belonging to the Mesoamerican Epiclassic (700-900 AD) and Postclassic (900-1521 AD) periods. A simultaneous analysis by Particle Induced X-ray Emission (PIXE) and Rutherford Backscattering Spectroscopy (RBS) was carried out to measure the elemental composition of pottery and clays sources of the Teotihuacan region. Also, a semiquantitative X-Ray Diffraction study (XRD) was performed to determine the mineralogical phases. From elemental and mineralogical composition, groups of local and foreign sherds were established. Results showed that the PIXE-RBS method combined with XRD proved to be a very powerful and general procedure for archaeological characterization. Moreover, non-vacuum differential PIXE analysis was carried out on colored regions of some representative vessels to study the layered structure of the paints-clay system.Peer Reviewe

Gold and electrum jewellery in the strategic area of Gadir in Phoenician period

A set of ancient gold jewellery was found in Cádiz (formerly Gadir, south Spain) in tombs dated in Phoenician-Archaic period (VII-VI century BC), and nowadays is exhibited in the local Museum. The production of this strategic area is of great interest for the knowledge of the commercial routes along the Mediterranean Sea at that time. Part of this production has already been analyzed by the authors, finding compositional differences and identifying soldering procedures, thanks to the use of the external microbeam. Absolutely non destructive analysis was performed. For this work we have again employed PIXE spectrometry with 2.2 MeV protons from the 3 MV Pelletron accelerator at the CNA to characterize the metallic alloys and the manufacturing techniques. We have found an unusual composition characterized by around 50 wt.% gold, 50 wt.% silver and some copper, which can be identified as ELECTRUM. Few analytical data of this particular kind of alloy are reported in the bibliography. The study of these objects can help to follow the trade of metals in the Phoenician-colonial period. © 2007 Elsevier B.V. All rights reserved.This work has been supported by the “Applications of nuclear techniques to the knowledge of the old jewellery in the Iberian Peninsula” research project (BFM2002-01313, Ministerio de Ciencia y Tecnología, Spain).Peer Reviewe

PIXE-PIGE analysis of late roman glass fragments

A set of Roman glass fragments, excavated at Sevilla and dated in the 5th century A.D., has been analysed by PIXE and PIGE techniques using the external beam set-up of the 3 MV tandem Pelletron accelerator of the CNA at the University of Sevilla. Using a simple quantification method, based on the indirect charge calculation on the sample by monitoring the X-ray induced by the proton beam on the exit window, the composition of the glasses has been determined. From the obtained results, the use of soda as flux has been inferred and colouring manufacture procedures have been identified. © 2006 Elsevier B.V. All rights reserved.Peer Reviewe

External-beam PIXE spectrometry for the study of Punic jewellery (SW Spain): The geographical provenance of the palladium-bearing gold

This paper presents the study of a set of Punic gold items (400 B.C.), from the Museum of Cádiz (Spain). An external beam set-up has been employed for the absolutely non-destructive analysis of the objects. PIXE spectrometry has been performed in order to characterize the metallic alloys and the manufacturing techniques. Compositional differences have been found and soldering procedures have been identified. By comparison with the rings and other coetaneous jewellery, the presence of palladium in the bulk alloy of the earrings can be pointed out. The geographical provenance of the palladium-bearing gold is discussed based on geological and archaeological considerations. © 2006 Elsevier B.V. All rights reserved.This work has been supported by the ‘Applications of nuclear techniques to the knowledge of the old jewellery in the Iberian Peninsula’ research project (BFM2002-01313, Ministerio de Ciencia y Tecnología, Spain), and, partially, by the Contract IAPH 2005-509 (Instituto Andaluz del Patrimonio Histórico).Peer Reviewe

Removal naturally occurring radionuclides from drinking water using a filter specifically designed for Drinking Water Treatment Plants

The occurrence of naturally occurring radionuclides in drinking water can pose health hazards in some populations, especially taking into account that routine procedures in Drinking Water Treatment Plants (DWTPs) are normally unable to remove them efficiently from drinking water. In fact, these procedures are practically transparent to them, and in particular to radium. In this paper, the characterization and capabilities of a patented filter designed to remove radium from drinking water with high efficiency is described. This filter is based on a sandwich structure of silica and green sand, with a natural high content manganese oxide. Both sands are authorized by Spanish authorities to be used in Drinking Water Treatment Plants. The Mn distribution in the green sand was found to be homogenous, thus providing a great number of adsorption sites for radium. Kinetic studies showed that the Ra adsorption on green sand was influenced by the content of major cations solved in the treated water, but the saturation level, about 96–99%, was not affected by it. The physico-chemical parameters of the treated water were unaltered by the filter. The efficiency of the filter for the removal of Ra remained unchanged with large water volumes passed through it, proving its potential use in DWTP. This filter was also able to remove initially the uranium content due to the presence of FeO particles in it, although it is saturated faster than radium.We wish to thank ENRESA (Empresa Nacional de Residuos Radiactivos S.A.) and CSN (Consejo de Seguridad Nuclear) for the financial support to the project entitled “Implantación de sistemas para la eliminación del contenido radioactivo natural en las aguas de consumo humano”. This work was partially made possible by the financial support granted to the LARUEX research group (FQM001).Peer Reviewe

TTPIXE analysis of Guadiamar river sediments collected before the environmental disaster of 1998

Thirteen sediment samples were collected along the Guadiamar riverbed (SW of Spain) in the spring of 1996 for the determination of their composition by thick target proton induced X-ray emission (TTPIXE), using the accelerator of the ITN (Portugal). Our results indicate a S, Cu, Zn, As and Pb contamination along the riverbed due to the mining activity developed around the beginning of the Guadiamar river. The obtained results will serve, in first place, as reference levels to show the situation of the riverbed before the environmental disaster of mining origin occurred in April 1998, and in second place, to evaluate properly in the future the works carried out for the cleaning and restoration of the affected areas.Peer reviewe

External microbeam set-up at the CNA (Sevilla) and its application to the study of Tartesic jewellery

6 pages.-- PACS nrs.: 81.70.Jb; 82.80.Ej; 82.80.Yc; 89.90.+n.-- et al.A new external microbeam system has been installed recently at the +45° beam line of the 3 MV Pelletron accelerator at the Centro Nacional de Aceleradores (Sevilla, Spain). The facility, based on the system from Oxford Microbeams (OM), includes two sets of slits, a doublet of magnetic quadrupole focusing lenses, a Faraday cup and an accurate positioning device. In addition, a beam profile monitor (BPM) and a quartz viewer have been installed in the line to facilitate the microbeam production. The first PIXE application of the new facility was made in the field of Archaeometry, on the study of Tartesic gold artefacts (700–500 BC, SW of Spain) from Ébora and other archaeological sites. The aim of the analysis was to perform an exhaustive and systematic study about the soldering procedures that were employed by the goldsmiths along the Valley of Guadalquivir River after the Phoenician colonisation.Peer reviewe

CNA: The first accelerator-based IBA facility in Spain

6 pages.-- PACS nrs.: 29.17.+w; 07.50.Qx; 07.30.Kf.The recently created Centro Nacional de Aceleradores (National Center for Accelerators, CNA) in Seville emerges as the first ion beam analysis facility in Spain. The laboratory is based on a 3 MV tandem accelerator model 9SDH-2 of NEC and it is primarily focused on material research and modification by means of IBA techniques: PIXE, RBS, NRA, PIGME and ERDA. The ions are delivered by two ion sources: Alphatross radio-frequency source and SNICS-II sputtering source. The ion beam handling system includes equipment for beam focusing, steering and diagnosis, a 90° analyzing magnet and a seven-port switcher magnet. A system based on magnetic steerers has been installed for high-precision beam energy scanning. In this paper the main elements of the laboratory will be described, focusing on the electronic equipment, detectors and the four beamlines planned for the moment: channeling line, microbeam line, multipurpose vacuum chamber and external microbeam. Moreover, the characteristics of the system as observed until now by means of performance tests, beam energy spread measurements and energy calibration experiments will be summarized.Peer reviewe