Materials Science in Semiconductor Processing, 2016
Abstract We present results on an investigation about the chemical–physical properties of the Si ... more Abstract We present results on an investigation about the chemical–physical properties of the Si surface after molecular doping (MD) method and successive annealing. The purpose of this work is to study the atomic structure of the first layers of silicon after the doping procedure in order to evaluate the possible intermixing between the carbon atoms constituting the precursor molecule and the Si atoms of the substrate. Moreover the role of this intermixed layer on the electrical characteristics of the semiconductor is also examined. The chemical characteristics of the samples after the doping procedure are obtained by performing X-ray spectroscopy, while the electrical characteristics are studied by four probe point and spreading resistance profiling. In order to clean the Si from the presence of the surface intermixed layer a wet chemical etch based on HNO3 is proposed. Four probe point measurements have been performed also after the etching to demonstrate that it is possible to modulate the sample sheet resistance as a function of the post-doping chemical treatment of the surface.
ABSTRACT The Muon Portal is a recently born project that plans to build a large area muon detecto... more ABSTRACT The Muon Portal is a recently born project that plans to build a large area muon detector for a noninvasive inspection of shipping containers in the ports, searching for the presence of potential fissile (U, Pu) threats. The technique employed by the project is the well-known muon tomography, based on cosmic muon scattering from high-Z materials. The design and operational parameters of the muon portal under construction will be described in this paper, together with preliminary simulation and test results.
2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC), 2012
ABSTRACT In recent years the need to have a better control of potentially dangerous materials acr... more ABSTRACT In recent years the need to have a better control of potentially dangerous materials across the borders has raised the opportunity to search for alternative detection techniques. In particular, to detect the presence of hidden high-Z materials inside containers, traditional techniques based on X-rays or neutron scattering are of limited use, and prototypes of detection systems based on cosmic muon scattering from high-Z materials are being tested worldwide to overcome these limitations. The use of this method is particularly suited to this aim, since it does not introduce additional radiation levels to the already existing natural dose. Since the technique is based on the scattering process of muons and not on their absorption, each event may in principle contribute to produce the tomographic image. A new Project has recently started by the Muon Portal Collaboration, which plans to build a large area muon detector, able to reconstruct muon tracks with good spatial and angular resolution. The design and operational parameters of the to- mograph under construction are here described, together with preliminary simulation and test results of the individual detection modules. Due to the large acceptance of the detector for cosmic rays, coupled to the good angular reconstruction of the muon tracks, it is also planned to employ such detector in the future for cosmic ray studies, complementing its detection capabilities with a set of trigger detectors located some distance apart, in order to measure multiple muon events associated to extensive air showers.
Materials Science in Semiconductor Processing, 2016
Abstract We present results on an investigation about the chemical–physical properties of the Si ... more Abstract We present results on an investigation about the chemical–physical properties of the Si surface after molecular doping (MD) method and successive annealing. The purpose of this work is to study the atomic structure of the first layers of silicon after the doping procedure in order to evaluate the possible intermixing between the carbon atoms constituting the precursor molecule and the Si atoms of the substrate. Moreover the role of this intermixed layer on the electrical characteristics of the semiconductor is also examined. The chemical characteristics of the samples after the doping procedure are obtained by performing X-ray spectroscopy, while the electrical characteristics are studied by four probe point and spreading resistance profiling. In order to clean the Si from the presence of the surface intermixed layer a wet chemical etch based on HNO3 is proposed. Four probe point measurements have been performed also after the etching to demonstrate that it is possible to modulate the sample sheet resistance as a function of the post-doping chemical treatment of the surface.
ABSTRACT The Muon Portal is a recently born project that plans to build a large area muon detecto... more ABSTRACT The Muon Portal is a recently born project that plans to build a large area muon detector for a noninvasive inspection of shipping containers in the ports, searching for the presence of potential fissile (U, Pu) threats. The technique employed by the project is the well-known muon tomography, based on cosmic muon scattering from high-Z materials. The design and operational parameters of the muon portal under construction will be described in this paper, together with preliminary simulation and test results.
2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC), 2012
ABSTRACT In recent years the need to have a better control of potentially dangerous materials acr... more ABSTRACT In recent years the need to have a better control of potentially dangerous materials across the borders has raised the opportunity to search for alternative detection techniques. In particular, to detect the presence of hidden high-Z materials inside containers, traditional techniques based on X-rays or neutron scattering are of limited use, and prototypes of detection systems based on cosmic muon scattering from high-Z materials are being tested worldwide to overcome these limitations. The use of this method is particularly suited to this aim, since it does not introduce additional radiation levels to the already existing natural dose. Since the technique is based on the scattering process of muons and not on their absorption, each event may in principle contribute to produce the tomographic image. A new Project has recently started by the Muon Portal Collaboration, which plans to build a large area muon detector, able to reconstruct muon tracks with good spatial and angular resolution. The design and operational parameters of the to- mograph under construction are here described, together with preliminary simulation and test results of the individual detection modules. Due to the large acceptance of the detector for cosmic rays, coupled to the good angular reconstruction of the muon tracks, it is also planned to employ such detector in the future for cosmic ray studies, complementing its detection capabilities with a set of trigger detectors located some distance apart, in order to measure multiple muon events associated to extensive air showers.
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