Secondary discharge studies in single- and multi-GEM structures Deisting, A.; Garabatos, C.; Gasik, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2019, Letnik:
937
Journal Article
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Secondary discharges, which consist of the breakdown of a gap near a GEM foil upon a primary discharge across that GEM, are studied in this work.
Their main characteristics are the occurrence a few ...10μs after the primary, the relatively sharp onset at moderate electric fields across the gap, the absence of increased fields in the system, and their occurrence under both field directions.
They can be mitigated using series resistors in the high-voltage connection to the GEM electrode facing towards an anode. The electric field at which the onset of secondary discharges occurs indeed increases with increasing resistance. Discharge propagation from GEM to GEM in a multi-GEM system affects the occurrence probability of secondary discharges in the gaps between neighbouring GEMs.
Furthermore, evidence of charges flowing through the gap after the primary discharge are reported. Such currents may or may not lead to a secondary discharge. A characteristic charge, of the order of 1010 electrons, has been measured as the threshold for a primary discharge to be followed by a secondary discharge, and this number slightly depends on the gas composition. A mechanism involving the heating of the cathode surface as trigger for secondary discharges is proposed.
The article is devoted to the analysis of “psychological” argument for the existence of God of Viktor Nesmelov, professor of Kazan Theological Academy, represented in his fundamental work “Science of ...Man”. The main interpretations of this argument, formulated both contemporaries of Nesmelov (Nikolay Berdiaev, bishop Anthony (Khrapovitsky)) and modern researchers of his legacy (priest D. Lushnikov, bishop K. Goryanov) are considered. The basic prerequisites and origins of Nesmelov’s anthropological doctrine are analyzed. The main of them were V. Snegiryov’s psychological doctrine and anthropological ideas of St. Gregory of Nyssa. The main ideas of Nesmelov’s Christian anthropology, related directly to his formulation of “the idea of God” (the doctrine of consciousness and self-consciousness of man; idea of man as the “main riddle” of the universe; idea of the fundamental “duality” of human nature; doctrine of Theosis and God-manhood, doctrine of sin and universal salvation (apokatastasis), etc.) are revealed. Besides that, Nesmelov’s criticism of the main existing arguments for the existence of God (ontological, cosmological, teleological, psychological, etc.) is analyzed. The main conclusion based on the analysis of Nesmelov’s anthropological system is made: his argument for the existence of God represents rather a methodological program for creating such argument in the future. The base of this argument should be made of not only by an “ abstract knowledge”, but the “living worldview” and the “living unity of God and man”.
Computer simulations of cylindrical Compton Ar-Xe gamma camera are described in the current report. Detection efficiency of cylindrical Ar-Xe Compton camera with internal diameter of 40 cm is ...estimated as1-3%that is 10-100 times higher than collimated Anger's camera. It is shown that cylindrical Compton camera can image Tc-99m radiotracer distribution with uniform spatial resolution of 20 mm through the whole field of view.
A method for lateral localization of a gamma source in a medium with a miniature single channel scintillation detector is developed and experimentally tested. Method is based on simultaneous ...registration of two (or more) gamma lines emitted from an area of increased uptake of a radiopharmaceutical in the patients body. The proposed method is tested with the most widely used medical radioisotope technetium-99m which has a 140 keV gamma emission line and a 18 keV characteristic x-ray line. The results of experimental studies show that the lateral coordinate of a point-like 99mTc source can be determined with an accuracy of ± 4 mm at the depth of soft tissues equivalent phantom up to 30 mm.
The main article is devoted to the historical and philosophical reconstruction of controversy between Vladimir Solovyov and the authors of the “Faith and Reason” - a magazine of the Kharkov ...Theological Seminary. This controversy took its place in the “theological and journalistic” or the “theocratic” period of Solovyov’s works (1880s). Particular attention is paid to the disputes of Solovyov and T. Stoyanov (Konstantin Istomin), A.P. Shost'in and the French Orthodox priest Fr. Vladimir Gette on the theory of dogmatic development in the church. In the context of this controversy, the arguments for the “defense” of Solovyov's position, cited in the magazine “Orthodox Review” by a theologian and Konstantin Leontyev's follower Ivan Kristi are also analyzed. The reception of Solovyov's theocratic ideas and reaction to his ecclesiastical views in both the Catholic and Orthodox circles of Russian and Western society is shown. Especially it concerns the criticism of Solovyov’s ideas in the pages of the French magazines “L’Univers”, “L'Union Chrétienne”, “Revue d’Eglise greque-unie”, etc. The evolution of Solovyov's views on the problem of the union of Eastern and Western churches, the renewal of church communication between Orthodoxy and Catholicism, the main result of which was his fundamental but unfinished work “The History and Future of the Theocracy” (Zagreb, 1887) was demonstrated. A conclusion about the “superficiality” of the judgments of the majority of Vladimir Solovyov's ideological opponents, as well as later interpreters of his legacy, following the French Jesuit Michel d'Erbigny, who tried to present him as a “Russian Newman” who converted from Orthodoxy into the Catholic faith is drawn. It is shown that Solovyov’s projects of the “religion of the Holy Spirit” and the “Universal Church”, created on its basis, should be considered primarily in the context of his own philosophical quest, and not in connection with the confessional and ideological divergences of his time.
The article describes a clinical case of comorbid peripheral lung cancer and extraskeletal chondroma of the diaphragm detected in the patient during chest computed tomography performed as a part of ...examination after renal colic. The X-ray signs of the masses were completely different, and those lesions were immediately identified as two different pathologies.
To determine the depth of the area of radiopharmaceutical accumulation a method of simultaneous recording of two lines of gamma rays of different energies and quantitative comparison of the intensity ...of these lines on the surface of the patient's body is provided. Since the coefficient of linear absorption of gamma radiation in the medium depends not only on the characteristics of the medium, but also on the gamma radiation energy, the intensity of gammas of different energies is attenuated differently after passing through the same absorber layer (soft tissues). Thus, the quantitative comparison of the relative intensities of gamma lines on the surface of the patient's body allows to determine the depth of area of the accumulation of the radiopharmaceutical. The result is achieved by analyzing the energy spectrum of the source, obtained with a semiconductor spectrometer, by measuring the ratio of areas of the absorption peaks of the radioisotope and defining the depth of gamma source using the calibration dependence between the areas ratio and the medium layer thickness. The most widely used medical radioisotope technetium-99m has two gamma-lines - 140 keV and 18.5keV, which allows one to apply the proposed method to search for the sentinel lymph nodes and non-palpable malignant tumors in the soft tissues.
The RED-100 (Russian Emission Detector) is being constructed for the experiment to search for elastic coherent neutrino scattering off atomic nuclei. This fundamental process was predicted several ...decades ago by the Standard Model of electroweak interactions but has not been discovered yet. The RED-100 is a two-phase emission xenon detector containing ∼200 kg of the liquid Xe (∼ 100 kg of that is in a fiducial volume). One of the possible sites to carry out the experiment is the SNS (Spallation Neutron Source) facility at Oak Ridge National Laboratory, USA. SNS is the world's most intense pulsed source of neutrinos and unique place to study neutrino properties. The energy spectrum of neutrinos produced at the SNS extends up to ∼ 50 MeV and satisfies coherence condition. These neutrinos give kinetic energies of Xe recoils up to a few tens of keV where the response of nuclear recoils is well-known from neutron calibrations of dark matter detectors. The detector will be deployed in the basement under the experimental hall at a distance of ∼30 meters from the SNS target. The expected signal and background (neutron and gamma) are estimated for this specific location. The detector details, current status and future plans are provided.
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