In situ gamma-ray spectrometry (GRS) use for non-destructive archaeological exploration

Pre-print versionLandscape, Heritage and Paleoenvironment Laboratory, University of Santiago, Spain Geophysical prospection methods are used in archaeology to locate features of archaeological sites before excavation. Among geophysical methods, those mostly used in archaeology are seismic methods, electromagnetical surveys, and georadar. All of them allow assessing properties of soil, sediment and/or rock, providing cross section of soil properties that can be related to buried archaeological structures and objects. Gamma-ray spectrometry (GRS) is a technique used for different geological purposes including mineral exploration and mapping. However, it has not been applied in archaeology: the only study case known by the authors was successful (Moussa, 2001) but no later reports or more extensive studies have been found. In situ GRS is a non-destructive method that allows direct assessment of potassium-40 (40K), uranium-238 (238U) and thorium-232 (232Th) and daughter radionuclides of their decay chains on rock outcrops and soils. Such radionuclides are ubiquitous in most rocks and soils and the main causes of natural gamma radiation. The technique allows assessing their concentration in topsoil, being of potential use for archaeological exploration but two assumptions must be made: the archaeological buried objects must contain a different concentration of radionuclides than the surrounding sediment or soil, and they must be buried in the topsoil (25-30 cm depth). Thus, it is potentially applicable for exploration of shallow structures or objects. However, it does not provide cross -sections of the ground, but maps of the structures and objects buried. In this work, we have tested in situ GRS in an archaeological site that was partially excavated. In the site, remains of walls made of stone have been excavated, being buried in other parts of the site, but near the ground surface, being the top of the structures at 10-30 cm depth. We have tested in situ GRS in small parcel of 10 x 7 m, located beside nearby excavated areas which wall remains are partially buried in the studied parcel. The purpose of the study is to assess if the technique is reliable for the exploration of structures. Rocks used as building materials in the walls are mostly metamorphic rocks of very low radionuclide content with negligible 40K. However, the sediment that uries the structures contains significant amounts of K, U and Th radioisotopes. Results showed reliable results for surface exploration where shallow structures exist, despite the low radioactive content of the archaeological materials in the site.Este trabalho insere-se nas atividades do Projeto Lab2PT- Laboratório de Paisagens, Património e Território - AUR/04509 que tem o apoio financeiro da FCT/MCTES através de fundos nacionais (PIDDAC) e o cofinanciamento do Fundo Europeu de Desenvolvimento Regional (FEDER), refª POCI-01-0145-FEDER-007528, no âmbito do novo acordo de parceria PT2020 através do COMPETE 2020 – Programa Operacional Competitividade e Internacionalização (POCI).info:eu-repo/semantics/publishedVersio

Rapid probe of the nicotine spectra by high-resolution rotational spectroscopy

Nicotine has been investigated in the gas phase and two conformational forms were characterized through their rotational spectra. Two spectroscopic techniques have been used to obtain the spectra: a new design of broadband Fourier transform microwave (FTMW) spectroscopy with an in-phase/quadrature- phase-modulation passage-acquired-coherence technique (IMPACT) and narrowband FTMW spectroscopy with coaxially oriented beam-resonator arrangement (COBRA). The rotational, centrifugal distortion and hyperfine quadrupole coupling constants of two conformers of nicotine have been determined and found to be in N-methyl trans configurations with the pyridine and pyrrolidine rings perpendicular to one another. The quadrupole hyperfine structure originated by two 14N nuclei has been completely resolved for both conformers and used for their unambiguous identification. © 2011 the Owner Societies

Volume modulus inflection point inflation and the gravitino mass problem

Several models of inflection point inflation with the volume modulus as the inflaton are investigated. Non-perturbative superpotentials containing two gaugino condensation terms or one such term with threshold corrections are considered. It is shown that the gravitino mass may be much smaller than the Hubble scale during inflation if at least one of the non-perturbative terms has a positive exponent. Higher order corrections to the Kahler potential have to be taken into account in such models. Those corrections are used to stabilize the potential in the axion direction in the vicinity of the inflection point. Models with only negative exponents require uplifting and in consequence have the supersymmetry breaking scale higher than the inflation scale. Fine-tuning of parameters and initial conditions is analyzed in some detail for both types of models. It is found that fine-tuning of parameters in models with heavy gravitino is much stronger than in models with light gravitino. It is shown that recently proposed time dependent potentials can provide a solution to the problem of the initial conditions only in models with heavy gravitino. Such potentials can not be used to relax fine tuning of parameters in any model because this would lead to values of the spectral index well outside the experimental bounds.Comment: 27 pages, 9 figures, comments and references added, version to be publishe

Electron energy loss and induced photon emission in photonic crystals

The interaction of a fast electron with a photonic crystal is investigated by solving the Maxwell equations exactly for the external field provided by the electron in the presence of the crystal. The energy loss is obtained from the retarding force exerted on the electron by the induced electric field. The features of the energy loss spectra are shown to be related to the photonic band structure of the crystal. Two different regimes are discussed: for small lattice constants $a$ relative to the wavelength of the associated electron excitations $\lambda$, an effective medium theory can be used to describe the material; however, for $a\sim\lambda$ the photonic band structure plays an important role. Special attention is paid to the frequency gap regions in the latter case.Comment: 12 pages, 7 figure

Integration of all FSSIM components within SEAMLESS-IF and a stand alone Graphical User Interface for FSSIM

Agricultural and Food Policy, Environmental Economics and Policy, Farm Management, Land Economics/Use,

Eocene-Oligocene magnetostratigraphy from the central part of the SE margin of the Ebro Basin

Previous magnetostratigraphic studies focused in the Eocene successions of the eastern Ebro Basin have provided some absolute age for the basin infill. These results were based on some biostratigraphic constraints wich have been recently challenged. Our new results from the approximately 3000 m thick Montserrat and Maians-Rubió magnetostratigraphic sections have been integrated into the both marine and continental biochronology data, providing a more independent chronology. The resulting absolute chronology of the Montserrat-Rubió composite section represents about 10 My, covering the Lutetian to Rupelian (approximately 40.7 to 30.5 Ma). This leads to the re-evaluation of the age of the La Salut Fm. (Lutetian to Bartonian) and the Montserrat conglomerates (Bartonian to Priabonian). The last marine regression in the central part of the SE margin of the Ebro Basin yields an approximate age of about 36.0 Ma (Priabonian)