Atmospheric muon background in the ANTARES detector

An evaluation of the background due to atmospheric muons in the ANTARES high energy neutrino telescope is presented. Two different codes for atmospheric shower simulation have been used. Results from comparisons between these codes at sea level and detector level are presented. The first results on the capability of ANTARES to reject this class of background are given.Comment: 4 pages, 4 figures, To appear in Proceedings of the 29th International Cosmic Ray Conference (ICRC 2005), Pune, India, 3 - 10 Aug 200

Geophysical and stratigraphical research into deep groundwater and intruding seawater in the mediterranean area (the Salento Peninsula, Italy)

International audienceGeological, geophysical and hydrological surveys were performed in an area between Lecce to the North and Otranto to the South on the Lower Adriatic coast of Italy in order to verify the ``state of health'' of the ground water in the deep aquifer, which is characterised by Mesozoic carbonatic formations and is permeable due to fracturing and karstic phenomena. This area was chosen because it is highly urbanised, and contains many wells, some of which were intensively studied from a geological and hydro-geological point of view in 1987. The first phase of the research consisted of a stratigraphical and geological study, based on geological surveys of the surface and the subsoil by direct observation of borehole cores and the collection and analysis of existing stratigraphical data on wells in the area. The stratigraphical and hydrogeological data are kept in the archives of local agencies. The collected data were organised in a single database managed by an appropriate software (ARCVIEW). Numerous geological cross sections of the territory were studied in order to characterise the subsoil. Subsequently, multi-parameter surveys (O2, pH, temperature, TDS, conductivity) were carried out on the water-column of certain wells selected from those studied in 1987. This was to verify possible changes in the state of the groundwater since 1987. The surveys were carried out in two different periods (May and September) in order to identify potential differences between rainy and dry periods. Moreover, electrical tomography was used to characterise the various subsurface geological formations and possible saline water intrusion where direct information collected from the wells was lacking. From the research conducted it was possible to effect a stratigraphical characterisation of the subsoil and to verify overexploitation of the water resources resulting from the increasing number of wells, and the consequent deterioration of the aquifer due to saline water intrusion. The research also confirms the validity of geophysical methods for the study of hydro-geological issues

Planning through a GIS the potential recovery of rural buildings for the development of new forms of tourism hospitality

The results of the territorial analysis on an agricultural area located in the Province of Matera (Southern Italy) with significant historical and natural interest, (i.e., the “San Giuliano” protected area) are here reported. The study has been focused on the census of farm buildings and related rural infrastructures in this area, even though most of them are currently in a state of abandonment. Indeed, through their potential static and functional recovery - which appears technically feasible, given their intrinsic architectural and structural attributes – they would be re-considered, even owing to the progressively growing tourist vocation of this area, leaded by the attractive role that the City of Matera is currently playing. This analysis has been conducted through the implementation of a Geographical Information System (GIS), associated with detailed survey techniques and dendrochronology analysis of the existing wooden construction elements. Thus, it has been possible to conclude how an adequately supported process of analysis and planning of territory can reveal as a valid tool to be used in decision-making dynamics. This recovery and reuse process would be especially valuable, if conceived in a perspective of new fruition purposes, such as those leading to the achievement of an increased diffused tourist hospitality

Ground penetrating radar surveys in a karst area for identification of geomorphological hazards.

Many coastal areas along the apulian coastlines (SE Italy) are intensely affected by sinkhole problems, which periodically cause damage to the main infrastructures, including the coastal roads and sparse settlements. Torre Castiglione is a locality situated at the boundary between the provinces of Lecce and Taranto, on the Jonian sea. Several sinkholes have in time affected the province road 340, which is a very important communication route during the summer, due to the tourist vocation of the area. Proximity of the site to the sea results in the mixing between sea water and fresh water, which determines a higher aggressivity toward the carbonate rock mass, and development of karst features and landforms, including caves. Due to the above reasons, the whole coastal sector is classified as with high geomorphological hazard. Aimed at investigating such hazard, a variety of direct and indirect surveys have been performed in the last years. Geological surveys, carried out through detailed field surveys, highlighted the presence of multi-storey cave systems, which upward stoping might eventually produce the formation of sinkholes. As concerns geomorphology, the population of identified sinkholes (more than 50) has been morphometrically characterized by measuring their depth, length, and width. The present contribution focuses on the geophysical surveys performed in the area. In detail, Ground Penetrating Radar (GPR) surveys have been carried out, due to the good resolution and the high penetration of the electromagnetic signal in geological settings characterized by presence of carbonate rocks. However, the presence of a karst aquifer in the area causes problems in the absorbing capacity of the signal. The main goal of this study is the analysis of the subsoil, aimed at testing the capability of GPR in a karst setting. A GSSI instrument was used, with antennae of 400 MHz, 200MHz and 100 MHz. The surveys were addressed to evaluate the capability of the method in such a setting, and to verify the velocity of propagation of the electromagnetic waves. Some scanlines were addressed to investigate, in particular, a sinkhole crossing the province road 340, by carrying out GPR profiles with a 200 MHz antenna at 90ns and 120 ns. The signal appeared to penetrate the subsoil at velocity of about 8 cm/ns. Elaboration of the data pointed out a series of cavities along the rural road running parallel to province road 340. In addition, the GPR survey highlighted the presence of complex karst systems at different depths, with cave size on the order of some tens of meters. A likely alignment in the cave direction seems to be shown, too

A multi-disciplinary approach combining geological, geomorphological and geophysical data for mapping the susceptibility to sinkholes

The Salento region of southern Italy has a great number of active sinkholes, related to both natural and anthropogenic cavities. The presence of sinkholes is at the origin of several problems to the built-up environment, due to the increasing population growth and development pressures. In such a context, the detection of cavities, and therefore the assessment of the sinkhole hazard presents numerous difficulties. Multidisciplinary – approach, comprising geological, geomorphological and geophysical analyses, is therefore necessary to obtain comprehensive knowledge of the complex phenomena in karstic areas. Geophysical methods can also be of great help to identify and map the areas at higher risk of collapse. In this case it is important to identify the features related to the underground voids, likely evolving to sinkholes, by contrasts in physical properties such as density, electrical resistivity, and so on, with the surrounding sediments. At the same time, identification of the presence of sinkholes by geophysical methods has to adapt to the different geological conditions, so that there is not the possibility to use the same techniques everywhere. At this aim, the present paper illustrates the advantages of integrating geological and geomorphological surveys with surface geophysical techniques such as seismic, geoelectrical and ground penetrating radar methods for the identification of sinkhole-prone areas. The present work illustrates the results concerning a sinkhole system at Nociglia (inland Salento, southeastern Italy) where the shallow phreatic speleogenesis operates close to the water table level with formation of karst conduits and proto-caves whose evolution occurs through successive roof collapse, formation of wide caverns and sinkhole development at the surface. All of this creates serious problems to the nearby infrastructures, including a province road that has often been threatened by the sinkhole development. Geological and geomorphological analyses provided the basic data necessary to constitute a framework to understand the mechanism of sinkholes formation and at the same time to guide the choice of the most suitable geophysical techniques, and the interpretation of the measurements as well. The different geophysical methods are eventually discussed in order to point out their ability to locate the main karst conduits and caves

Fragmentation studies of high energy ions using CR39 nuclear track detectors

We report on the measurements of the total charge changing fragmentation cross sections in high-energy nucleus-nucleus collisions using Fe, Si and Pb incident ions. Several stacks of CR39 nuclear track detectors with different target combinations were exposed at normal incidence to high energy accelerator beams to integrated densities of about 2000 ions/cm^2. The nuclear track detector foils were chemically etched, and ion tracks were measured using an automatic image analyzer system. The cross section determination is based on the charge identification of beam ions and their fragments and on the reconstruction of their path through the stacks.Comment: 5 pages, 4 EPS figures. Corrected Eq. 3 and Table 1. Presented at the 10th Inter. Symp. Radiat. Phys., Coimbra, Portugal, 17-22 Sept. 200

Integrated geophysical and geological investigations applied to sedimentary rock mass characterization

The Salento Peninsula (south-eastern Italy) is characterized by sedimentary rocks. The carbonatic nature of the rocks means they are affected by karst phenomena, forming such features as sinkholes, collapsed dolines and caverns, as a result of chemical leaching of carbonates by percolating water. The instability of these phenomena often produces land subsidence problems. The importance of these events is increasing due to growing urbanization, numerous quarries affecting both the subsoil and the surface, and an important coastline characterized by cliffs. This paper focuses on geological and geophysical methods for the characterization of soft sedimentary rock, and presents the results of a study carried out in an urban area of Salento. Taking the Q system derived by Barton (2002) as the starting point for the rock mass classification, a new approach and a modification of the Barton method are proposed. The new equation proposed for the classification of sedimentary rock mass (Qsrm) takes account of the permeability of the rock masses, the geometry of the exposed rock face and their types (for example, quarry face, coastal cliff or cavity), the nature of the lithotypes that constitute the exposed sequence, and their structure and texture. This study revises the correlation between Vp and Q derived by Barton (2002), deriving a new empirical equation correlating P-wave velocities and Qsrm values in soft sedimentary rock. We also present a case history in which stratigraphical surveys, Electrical Resistivity Tomography (ERT), and seismic surveys were applied to in situ investigations of subsidence phenomena in an urban area to estimate rock mass quality. Our work shows that in the analysis of ground safety it is important to establish the rock mass quality of the subsurface structures; geophysical exploration can thus play a key role in the assessment of subsidence risk

Fragmentation cross sections of Fe^{26+}, Si^{14+} and C^{6+} ions of 0.3-10 A GeV on CR39, polyethylene and aluminum targets

New measurements of the total and partial fragmentation cross sections in the energy range 0.3-10 A GeV of Fe^{26+}, Si^{14+} and C^{6+} beams on polyethylene, CR39 and aluminum targets are presented. The exposures were made at Brookhaven National Laboratory (BNL), USA, and Heavy Ion Medical Accelerator in Chiba (HIMAC), Japan. The CR39 nuclear track detectors were used to identify the incident and survived beams and their fragments. The total fragmentation cross sections for all targets are almost energy independent while they depend on the target mass. The measured partial fragmentation cross sections are also discussed.Comment: 4 pages, 5 eps figures. Talk given at the 24th International Conference on Nuclear Tracks in Solids, Bologna, Italy, 1-5 September 200