C. Pistagna

Muon tomography imaging algorithms for nuclear threat detection inside large volume containers with the Muon Portal detector

Abstract Muon tomographic visualization techniques try to reconstruct a 3D image as close as possible to the real localization of the objects being probed. Statistical algorithms under test for the reconstruction of muon tomographic images in the Muon Portal Project are discussed here. Autocorrelation analysis and clustering algorithms have been employed within the context of methods based on the Point Of Closest Approach (POCA) reconstruction tool. An iterative method based on the log-likelihood approach was also implemented. Relative merits of all such methods are discussed, with reference to full G eant 4 simulations of different scenarios, incorporating medium and high-Z objects inside a container.

Science gateway technologies for the astrophysics community

The availability of large‐scale digital surveys offers tremendous opportunities for advancing scientific knowledge in the astrophysics community. Nevertheless, the analysis of these data often requires very powerful computational resources. Science gateway technologies offer Web‐based environments to run applications with little concern for learning and managing the underlying infrastructures that execute them. This paper focuses on the issues related to the development of a science gateway customized for the needs of the astrophysics community. The VisIVO Science Gateway is wrapped around a WS‐PGRADE/grid User Support Environment portal integrating services for processing and visualizing large‐scale multidimensional astrophysical data sets on distributed computing infrastructures. We discuss the core tools and services supported including an application for mobile access to the gateway. We report our experiences in supporting specialized astrophysical communities requiring development of complex workflows for visualization and numerical simulations. Further, available platforms are discussed for sharing workflows in collaborative environments. Finally, we outline our vision for creating a federation of science gateways to benefit astrophysical communities by sharing a set of services for authentication, computing infrastructure access and data/workflow repositories. Copyright

A large area cosmic ray detector for the inspection of hidden high-Z materials inside containers

Traditional inspection methods are of limited use to detect the presence of fissile (U, Pu) samples inside containers. To overcome such limitations, prototypes of detection systems based on cosmic muon scattering from high-Z materials are being tested worldwide. This technique does not introduce additional radiation levels, and each event contributes to the tomographic image, since the scattering process is sensitive to the charge of the atomic nuclei being traversed. A new Project, started by the Muon Portal Collaboration, plans to build a large area muon detector able to reconstruct muon tracks with good spatial and angular resolution. Experimental tests of the individual detection modules are already in progress. The design and operational parameters of the muon portal under construction are here described, together with the preliminary simulation and test results. 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 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.

Search for hidden high-Z materials inside containers with the Muon Portal Project

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.

An Innovative Science Gateway for the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) is currently building the next generation, ground-based, very high-energy gamma-ray instrumentation. CTA is expected to collect very large datasets (in the order of petabytes) which will have to be stored, managed and processed. This paper presents a graphical user interface built inside a science gateway aiming at providing CTA-users with a common working framework. The gateway is WS-PGRADE/gUSE workflow-oriented and is equipped with a flexible SSO (based on SAML) to control user access for authentication and authorization. An interactive desktop environment is provided, called Astronomical & Physics Cloud Interactive Desktop (ACID). Users are able to exploit the graphical interface as provided natively by the tools included in ACID. A cloud data service shares and synchronizes data files and output results between the user desktop and the science gateway. Our solution is a first attempt towards an ecosystem of new technologies with a high level of flexibility to suit present and future requirements of the CTA community.

Design of a large area tomograph to search for high-Z materials inside containers by cosmic muons

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 tomograph 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.

VisIVO Workflow-Oriented Science Gateway for Astrophysical Visualization

Nowadays visualization-based knowledge discovery can play an important role in astrophysics. Collaborative visualization can enable multiple users to share visualization experiences, e.g. by interacting simultaneously with astrophysical datasets giving feedback on what other participants are doing/seeing. Further, workflow-driven applications allow reproduction of specific visualization results, a challenging task as selecting suitable visualization parameters may not be a straightforward process. This paper presents VisIVO Science Gateway, a web-based workflow-enabled framework integrating large-scale, multidimensional datasets and applications for visualization and data filtering on Distributed Computing Infrastructures (DCIs). Advanced users are able to create, change, invoke, and monitor workflows while standard users are provided with easy-to-use customised web interfaces hiding all technical aspects of the visualization algorithms and DCI configurations.

Design of a muonic tomographic detector to scan travelling containers

The Muon Portal Project aims at the construction of a large volume detector to inspect the content of travelling containers for the identification of high-Z hidden materials (U, Pu or other fissile samples), exploiting the secondary cosmic-ray muon radiation. An image of these materials is achieved reconstructing the deviations of the muons from their original trajectories inside the detector volume, by means of two particle trackers, placed one below and one above the container. The scan is performed without adding any external radiation, in a few minutes and with a high spatial and angular resolution. The detector consists of 4800 scintillating strips with two wavelength shifting (WLS) fibers inside each strip, coupled to Silicon photomultipliers (SiPMs). A smart strategy for the read out system allows a considerable reduction of the number of the read-out channels. Actually, an intense measurement campaign is in progress to carefully characterize any single component of the detector. A prototype of one of the 48 detection modules (1 × 3 m2) is actually under construction. This paper presents the detector architecture and the preliminary results.

The Muon Portal Project: Development of an innovative scanning portal based on muon tomography

The Muon Portal is a recent Project [1] which aims at the construction of a 18 m2 tracking detector for cosmic muons. This apparatus has been designed as a real-size prototype to inspect containers using the muon tomography technique, i.e. by measuring the deflection of muons when traversing high-Z materials. The detection setup is based on eight position-sensitive X-Y planes, four placed below and four above the volume to be inspected, with good tracking capabilities for charged particles. The detection planes are segmented into strips of extruded plastic scintillators with WLS fibres to transport the light produced in the scintillator material to the photo-sensors (SiPMs) at one of the fibre ends. Detailed GEANT4 simulations have been carried out under different scenarios to investigate the response of the apparatus. The tomographic images are reconstructed by tracking algorithms and suitable imaging software tools. Simulations have demonstrated the possibility to reconstruct a 3D image of the volume to be inspected in a reasonable amount of time, compatible with the requirement of a fast inspection technique. The first two of the 48 detection modules are presently under construction.

Clustering analysis for muon tomography data elaboration in the Muon Portal project

Clustering analysis is one of multivariate data analysis techniques which allows to gather statistical data units into groups, in order to minimize the logical distance within each group and to maximize the one between different groups. In these proceedings, the authors present a novel approach to the muontomography data analysis based on clustering algorithms. As a case study we present the Muon Portal project that aims to build and operate a dedicated particle detector for the inspection of harbor containers to hinder the smuggling of nuclear materials. Clustering techniques, working directly on scattering points, help to detect the presence of suspicious items inside the container, acting, as it will be shown, as a filter for a preliminary analysis of the data.