Development of Innovative Technology for Detection and Identification of Radioactive Materials

During the last 20 years, 2477 incidents related with the smuggling of radioactive materials have been reported to the IAEA. The implementation of systems for detection of radioactive materials at borders, ports, airports, etc. is a critical issue to contrast the contraband and prevent further consequences. The neutron detector based in 3He has been a common component in radiation portals, but the increasing demand of 3He has caused its shortage with a very large cost increase. This situation has motivated the scientific community to develop a new generation of neutron detectors to replace the 3He-based systems. In this work is reported a complete characterization, based on experiments and Monte Carlo simulations, of a set of modern organic liquid scintillator detectors with neutron/gamma discrimination capabilities. New results with respect to the light output function and the neutron and gamma efficiencies of the EJ-309 scintillator are presented. The EJ-309 scintillator coupled to a PMT H8500C was used also in a prototype of a compact and portable neutron/gamma spectrometer. A complete study of the first commercial plastic scintillator with neutron/gamma discrimination capabilities (EJ-299-33) was performed. The response of the EJ-339A detector (a liquid loaded with 4.6 % of 10B) was studied in order to discriminate between gamma, fast neutron and thermal neutron events coming from a shielded 252Cf source. Finally, as another alternative to the standard 3He systems, the use of the EJ-420 detector (based on ZnS(Ag)/6Li scintillator) for thermal neutron detection was tested. The pulse processing of all the detectors was performed using modern CAEN nuclear electronics based in fast digitizers

Absolute fraction of emitted Ps determined by GEANT4 supported analysis of gamma spectra

The fraction of positronium (Ps) emitted from a surface of a germanium single crystal at high temperature is usually assumed to approach unity at zero positron implantation energy. In the experiment, however, the determination of the absolute Ps fraction is not straight forward since recording a reference spectrum with $100\,\%$ Ps formation remains demanding. We use GEANT4-simulated detector responses to $2\gamma$ and $3\gamma$ radiation sources mimicking positron and Ps annihilation inside the (coincidence) Doppler-broadening spectrometer at NEPOMUC, FRM II, in order to derive a reliable value for the Ps fraction reemitted from a Ge(100) target heated close to its melting point. Analysis of the measured spectra by fitting the simulated spectra shows an absolute value of $(72\,\pm{4})\,\%$ maximum Ps formation, contradicting the $100\,\%$ assumption

Performance comparison between signal digitizers and low-cost digital oscilloscopes: spectroscopic, pulse shape discrimination and timing capabilities for nuclear detectors

Signal digitizers revolutionized the approach to the electronics readout of radiation detectors in Nuclear Physics. These highly specialized pieces of equipment are designed to acquire the signals that are characteristic of the detectors in nuclear physics experiments. The functions of the several modules that were once needed for signal acquisition, can now be substituted by a single digitizer. As suggested by the name, with such readout modules, signals are first digitized (i.e. the signal waveform is sampled and converted to a digital representation) and then either stored or analyzed on-the-fly. The performances can be comparable or better than the traditional analog counterparts, in terms of energy, time resolution, and acquisition rate. In this work, we investigate the use of general-purpose digital oscilloscopes as signal digitizers for nuclear detectors. In order to have a proper comparison, we employ a distributed data acquisition system (DAQ), that standardizes the interface between the hardware and the on-line data analysis. The signals, from a set of typical radiation detectors, are digitized and analyzed with the very same algorithms in order to avoid biases due to different software analysis. We compare two traditional signal digitizers (CAEN DT5725 and CAEN DT5751) to two low-cost digital oscilloscopes (Digilent Analog Discovery 2, and Red Pitaya STEMLab 125-14), in terms of their capabilities for spectroscopy (energy resolution), time resolution, pulse shape discrimination, and maximum acquisition rate.Comment: 17 pages, 8 figures, 4 tables, Prepared for submission to JINS

a distributed data acquisition system for nuclear detectors

Nowadays, many examples of data acquisition (DAQ) software for experimental nuclear physics are monolithic processes that run on a computer attached to the DAQ hardware. In this article we present a distributed DAQ system developed for the C-BORD project. With our system, we propose a novel approach, in which each task related to the different DAQ parts (acquisition, pre-process, analysis, etc.) runs in a separate process. In particular, the system is composed of a set of servers that exchange information through dedicated communication sockets. Therefore, with this architecture, an important advantage is the possibility to run the processes on different computers to distribute the computational load. The initial tests of the system have been giving excellent results, both in terms of performance (i.e., maximum acquisition rates) and stability. The project entitled "Effective container inspection at BORDer control points" (C-BORD) is funded by the European H2020 programme. Its aim is to develop a comprehensive set of technologies for the generalized non-intrusive inspection (NII) of containers and large-volume freight at the European Union border

MODELO LIGERO PARA LA EVALUACIÓN DE PROCESOS SOFTWARE

 RESUMENLa mejora en los procesos de desarrollo de software garantiza a las empresas, alcanzar altos niveles de madurez en los procesos e incrementa la competitividad internacional. Es necesario adecuar los modelos de mejora, evaluación y calidad que son reconocidos internacionalmente, a las características propias de los países donde son aplicados. Estos modelos difícilmente pueden ser aplicados en la mayoría de las empresas de muchos países iberoamericanos debido a la gran inversión en dinero, tiempo y recursos que requieren, así como a la complejidad de las recomendaciones que proporcionan y a un retorno de la inversión a largo plazo. Especialmente, las pequeñas empresas que inicien una cultura de mejora continua tienen la necesidad de realizar una evaluación respecto a un modelo de calidad. El primer paso en el proceso de mejora es determinar el estado en el que se encuentran sus procesos software. El proceso de evaluación permite conocer las fortalezas y debilidades que guían un programa de mejora de procesos al interior de la organización. El objetivo de este articulo es presentar MECPDS, un modelo ligero de evaluación de la calidad de procesos de desarrollo de software basado las normas ISO/IEC 12207:2002 e ISO/IEC 15504:2003 aplicable a las micro, pequeñas y medianas empresas, de manera fácil y económica, con pocos recursos y en poco tiempo.   PALABRAS CLAVESModelos de EvaluaciónFramework de MedidaModelos de Proceso de ReferenciaCapacidad del ProcesoCumplimiento del ProcesoISO/IEC 12207:2002ISO/IEC 15504:2003.  ABSTRACTThe Software Process Improvement guarantees to organizations, to reach high maturity levels in processes and increases international competitiveness. It is necessary to adapt the Improvement, Evaluation and Quality Models that are recognized internationally, to the own characteristics of countries where they are applied. These models hardly can be applied in the companies of many Latin American countries due to the great investment in money, time and resources that they require, as well as the complexity of the recommendations that they provide and a return of the investment in the long term. Specially, small organizations that initiate a culture of continuous improvement have the necessity to make an evaluation with respect to a Quality Model. The first step in the improvement process is to determine the current state of their software processes. The evaluation process allows us to know the strengths and weaknesses that guide a processes improvement program within an organization. The goal of this paper is to present MECPDS, a light model of evaluation of the quality of software development processes based on norms ISO/IEC 12207:2002 and ISO/IEC 15504:2003 applicable to micro, small and medium organizations, of easy and economic way, with investment of few resources and time. KEYWORDSEvaluation ModelsMeasurement FrameworkProcess Reference ModelsProcess CapabilityFulfillment of ProcessISO/IEC 12207:2002ISO/IEC 15504:2003

Proyecto LLAMA

In this paper we briefly describe a joint scientific and technological effort between Argentina and Brazil, whose first goal is to install and run, in the northwestern part of Argentina, a millimetre and submillimetre observational facility. In the long run, we would like to incorporate this dish to existing ones (ALMA, APEX, ASTE) in the northern extreme of Chile, to be able to carry out, for the first time in Latinamerican soil, very long base- line interferometry at mm/submm wavelengths. We also succintly mention a long term campaign that is under way in order to monitor the transparency of the atmosphere at those wavelengths. The science that can be accom- plished with this instrument, the technology transfer spin-offs related to this project, and the scientific and strategic importance of this project within both the Argentinean and Latinamerican radioastronomy is described.Fil: Arnal, Edmundo Marcelo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Mirabel Miquele, Igor Felix. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Morras, Ricardo. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Romero, Gustavo Esteban. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Abraham, Zulema. Universidade de Sao Paulo; BrasilFil: de Gouveira dal Pino, Elisabete M. de. Universidade de Sao Paulo; BrasilFil: Lepine, Jacques. Universidade de Sao Paulo; Brasi

Speech Motor Profiles in Primary Progressive Aphasia

Purpose: Previous research on motor speech disorders (MSDs) in primary pro-gressive aphasia (PPA) has largely focused on patients with the nonfluent/ agrammatic variant of PPA (nfvPPA), with few systematic descriptions of MSDs in variants other than nfvPPA. There has also been an emphasis on studying apraxia of speech, whereas less is known about dysarthria or other forms of MSDs. This study aimed to examine the qualitative and quantitative characteristics of MSDs in a prospective sample of individuals with PPA independent of subtype. Method: We included 38 participants with a root diagnosis of PPA according to current consensus criteria, including one case with primary progressive apraxia of speech. Speech tasks comprised various speech modalities and levels of complexity. Expert raters used a novel protocol for auditory speech analyses covering all major dimensions of speech. Results: Of the participants, 47.4% presented with some form of MSD. Individ-ual speech motor profiles varied widely with respect to the different speech dimensions. Besides apraxia of speech, we observed different dysarthria syn-dromes, special forms of MSDs (e.g., neurogenic stuttering), and mixed forms. Degrees of severity ranged from mild to severe. We also observed MSDs in patients whose speech and language profiles were incompatible with nfvPPA. Conclusions: The results confirm that MSDs are common in PPA and can man-ifest in different syndromes. The findings emphasize that future studies of MSDs in PPA should be extended to all clinical variants and should take into account the qualitative characteristics of motor speech dysfunction across speech dimensions. Supplemental Material: https://doi.org/10.23641/asha.2255553

Speech motor profiles in primary progressive aphasia

Purpose: Previous research on motor speech disorders (MSDs) in primary progressive aphasia (PPA) has largely focused on patients with the nonfluent/agrammatic variant of PPA (nfvPPA), with few systematic descriptions of MSDs in variants other than nfvPPA. There has also been an emphasis on studying apraxia of speech, whereas less is known about dysarthria or other forms of MSDs. This study aimed to examine the qualitative and quantitative characteristics of MSDs in a prospective sample of individuals with PPA independent of subtype. Method: We included 38 participants with a root diagnosis of PPA according to current consensus criteria, including one case with primary progressive apraxia of speech. Speech tasks comprised various speech modalities and levels of complexity. Expert raters used a novel protocol for auditory speech analyses covering all major dimensions of speech. Results: Of the participants, 47.4% presented with some form of MSD. Individual speech motor profiles varied widely with respect to the different speech dimensions. Besides apraxia of speech, we observed different dysarthria syndromes, special forms of MSDs (e.g., neurogenic stuttering), and mixed forms. Degrees of severity ranged from mild to severe. We also observed MSDs in patients whose speech and language profiles were incompatible with nfvPPA. Conclusions: The results confirm that MSDs are common in PPA and can manifest in different syndromes. The findings emphasize that future studies of MSDs in PPA should be extended to all clinical variants and should take into account the qualitative characteristics of motor speech dysfunction across speech dimensions

Milky Way Disk-Halo Transition in HI: Properties of the Cloud Population

Using 21cm HI observations from the Parkes Radio Telescope's Galactic All-Sky Survey, we measure 255 HI clouds in the lower Galactic halo that are located near the tangent points at 16.9 < l < 35.3 degrees and |b| < 20 degrees. The clouds have a median mass of 700 Msun and a median distance from the Galactic plane of 660 pc. This first Galactic quadrant (QI) region is symmetric to a region of the fourth quadrant (QIV) studied previously using the same data set and measurement criteria. The properties of the individual clouds in the two quadrants are quite similar suggesting that they belong to the same population, and both populations have a line of sight cloud-cloud velocity dispersion of sigma_cc ~ 16 km/s. However, there are three times as many disk-halo clouds at the QI tangent points and their scale height, at h=800 pc, is twice as large as in QIV. Thus the observed line of sight random cloud motions are not connected to the cloud scale height or its variation around the Galaxy. The surface density of clouds is nearly constant over the QI tangent point region but is peaked near R~4 kpc in QIV. We ascribe all of these differences to the coincidental location of the QI region at the tip of the Milky Way's bar, where it merges with a major spiral arm. The QIV tangent point region, in contrast, covers only a segment of a minor spiral arm. The disk-halo HI cloud population is thus likely tied to and driven by large-scale star formation processes, possibly through the mechanism of supershells and feedback.Comment: 14 pages, 20 figures, to be published in ApJ (accepted August 3 2010