1,721,106 research outputs found
RaDoM: A lung dosimeter for radon progeny
Full text linkThis paper discusses a novel Timepix-based on-line radon dose monitor called RaDoM. The detector provides a direct estimate of the effective dose to the lung via a system of filters having the same absorption characteristics as this organ and a measurement of the PAEC (the potential alpha energy concentration). Measurements performed in a reference radon chamber and in normal environmental conditions showed that RaDoM well follows changes in the radon concentration and is accurate in both long- and short-term measurements. The paper describes the detector and associated software for data acquisition and analysis, and compares the measurement of the lung dose with the value derived from a measurement of the radon concentration
B-RAD: a radiation survey meter for operation in intense magnetic fields
Full text linkB-RAD is a hand-held radiation survey meter, specifically designed for operation in regions of strong magnetic field. The instrument has been jointly developed by CERN Radiation Protection group and the Department of Energy of the Polytechnic of Milan (POLIMI), originally to perform measurements of the residual radioactivity (radiation surveys) in the experimental areas of CERN Large Hadron Collider (LHC) and inside the ATLAS detector without switching the magnetic field off. B-RAD is based on a scintillating crystal coupled to Silicon Photomultipliers, and its operation is unaffected by magnetic field intensity up to 3 T. Five engineered prototype units were built and made available for routine use at CERN. The design of the instrument has subsequently been licenced to a company in order to industrialise it. This paper describes the CERN-POLIMI engineered version of the instrument, discusses its characterization in details and provides an overview of the commercial unit
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Real-time measurements of radon activity with the Timepix-based RADONLITE and RADONPIX detectors
Full text linkRadon gas is the most important source of ionizing radiation among those of natural origin. Two new systems for radon measurement based on the Timepix silicon detector were developed. The positively charged radon daughters are electrostatically collected on the surface of the Si detector and their energy spectrum measured. Pattern recognition of the tracks on the sensor and particle identification are used to determine number and energy of the alpha particles and to subtract the background, allowing for efficient radon detection. The systems include an algorithm for real-time measurement of the radon concentration and the calculation of the effective dose to the lungs
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
RaDoM2: an improved radon dosimeter
Full text linkA new dosimeter for radon progeny called RaDoM (Radon Dose Monitor) was recently developed at CERN . RaDoM is an active detector able to directly estimate the effective dose due to the radon progeny. The first version, which used the Timepix hybrid pixel detector, a system of filters and a pump, correctly assessed the effective dose in situations where the environmental conditions are characterized by a standard equilibrium factor, but showed low efficiency for low radon concentrations and in clean air environments. In this improved version, RaDoM2, the Timepix has been replaced by a silicon pin diode. This solution has allowed the optimization of the geometry, the pump flow rate and the associated electronics, improving the performance of RaDoM and substantially reducing its manufacturing costs. This paper describes the RaDoM2, its improved performance compared to RaDoM, the cloud and user interface, tests in a radon chamber and on-the-field measurements
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