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What do we expect to learn from
No full textThis paper addresses some of the of open problems in photonuclear physics which await to be resolved using high-brilliance γ-ray beams, such as precise measurements of total or partial cross sections of photonuclear reactions related to astroparticle physics and nuclear astrophysics. The readiness for such measurements at ELI-NP, as well as the state-of-the-art instrumentation which is available are discussed. The possibility to utilize γ-beams with orbital angular momentum in photonuclear experiments is addressed, too
Nuclear astrophysics studies with γ-ray beams: What do we expect to learn from them?
No full textAn overview of the main directions of present-day studies with quasimonochromatic γ beams is discussed with an emphasis on the research opportunities which will be offered at the Extreme Light Infrastructure Nuclear Physics (ELI-NP) facility at Magurele near Bucharest in Romania. Experiments with γ beams at the extremes of high temperatures are outlined, with an emphasis on prospective studies related to nuclear astrophysics and astroparticle physics. Some of the experimental setups for nuclear structure, reaction, and astrophysics studies, which are available at ELI-NP, are described
Nuclear photonics and nuclear isomers
No full textNuclear photonics is a emerging field of science which combines research with new generation -ray sources based on traditional and laser-based electron accelerators. Here, we discuss isomeric studies carried out with -ray beams having either continuous, or quasi-monochromatic photon spectra. In experiments with high-power lasers, intense secondary radiation sources are generated. Such experiments explore isomer population or de-excitation in plasma environments. Laser-accelerated particle beams with high charge also facilitate high-energy nuclear excitations, leading to efficient production of nuclear isomers with higher lying isomeric state (reaching MeV energy level) within very-short time scales. The population of isomeric states is a sensitive diagnostic method for characterization of the laser-driven secondary radiation sources
80 years of experimental photo-fission research
No full textHigh energy photons, or -rays, were among the very first probes used to induce fission. Their significant impact in this field is due to particular properties of the -rays, such as the lack of a Coulomb barrier and the low, well-defined angular momentum transfer, but also to the variety of -ray sources developed over the years. This variety, going from simple but intense bremsstrahlung beams, through complex virtual photon excitations, to high resolution monochromatic sources of several types, gave rise to extensive photo-fission research programs. The review presents the evolution over more than 80 years of the methodology and instrumentation used in photo-fission experiments. The most important developments in fundamental and applied science are summarized and discussed. The main improvements necessary for the progression of this field into the age of nuclear photonics are outlined
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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
Get PDFWe 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
Nuclear physics and astrophysics experiments at ELI-NP: The emerging future
Get PDFThe status of implementation of the ELI-NP high-power laser system and the high-brilliance gamma beam system is reported. The emerging experimental program at the facility in nuclear physics in astrophysics is discussed, with emphasis of the considered day-one experiments
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