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Статті в журналах з теми "Radioactivity signal":
1
Ambrosino, Fabrizio, Lenka Thinová, Miroslav Hýža, and Carlo Sabbarese. "214Bi/214Pb radioactivity ratio three-year monitoring in rainwater in Prague." Nukleonika 65, no. 2 (June 1, 2020): 115–19. http://dx.doi.org/10.2478/nuka-2020-0018.
Анотація:
AbstractContinuous monitoring of natural gamma radiation in air has been carried out, during December 2014 – January 2018, with 1-min cyclic measurement in Prague, Czech Republic using a NaI(Tl) probe. The 214Bi/214Pb ratio as a tracer in rainwater has been investigated to study its variations related to both the ambient dose equivalent rate per hour and the amount of rainfall. A hybrid methodology for time series analysis, composed of the aggregation of two signal decomposition methods (multiple linear regression and empirical mode decomposition) and one forecasting method (support vector regression), has been applied to identify the anomalies in the studied signals in order to better find correlations among them. The results show a strong correlation between the ambient dose equivalent rate and the 214Bi/214Pb ratio values and between both these signals and rainfall amount ≥5 mm/h. Furthermore, the considered descendants of radon are mainly responsible for the overall ambient dose equivalent rate.
2
Giokaris, N. D., D. F. Anderson, and B. J. Kross. "Signal from the natural radioactivity of depleted uranium in liquid argon." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 248, no. 2-3 (August 1986): 389–92. http://dx.doi.org/10.1016/0168-9002(86)91023-5.
3
Bellotti, E., C. Broggini, G. Di Carlo, M. Laubenstein, and R. Menegazzo. "STUDY OF THE TIME DEPENDENCE OF RADIOACTIVITY." Acta Polytechnica 53, A (December 18, 2013): 524–27. http://dx.doi.org/10.14311/ap.2013.53.0524.
Анотація:
The activity of a <sup>137</sup>Cs source was measured using a germanium detector installed deep underground in the Gran Sasso Laboratory. In total about 5100 energy spectra, one hour measuring time each, were collected and used to search for time variations of the decay constant with periods from a few hours to 1 year. No signal with amplitude larger than 9.6 × 10<sup>−5</sup> at 95% C.L. was detected. These limits are more than one order of magnitude lower than the values on the oscillation amplitude reported in the literature. The same data give a value of 29.96±0.08 years for the <sup>137</sup>Cs half life, which is in good agreement with the world mean value of 30.05 ± 0.08 years.
4
Smith, John N., Robin M. Brown, William J. Williams, Marie Robert, Richard Nelson, and S. Bradley Moran. "Arrival of the Fukushima radioactivity plume in North American continental waters." Proceedings of the National Academy of Sciences 112, no. 5 (December 29, 2014): 1310–15. http://dx.doi.org/10.1073/pnas.1412814112.
Анотація:
The large discharge of radioactivity into the northwest Pacific Ocean from the 2011 Fukushima Dai-ichi nuclear reactor accident has generated considerable concern about the spread of this material across the ocean to North America. We report here the first systematic study to our knowledge of the transport of the Fukushima marine radioactivity signal to the eastern North Pacific. Time series measurements of 134Cs and 137Cs in seawater revealed the initial arrival of the Fukushima signal by ocean current transport at a location 1,500 km west of British Columbia, Canada, in June 2012, about 1.3 y after the accident. By June 2013, the Fukushima signal had spread onto the Canadian continental shelf, and by February 2014, it had increased to a value of 2 Bq/m3 throughout the upper 150 m of the water column, resulting in an overall doubling of the fallout background from atmospheric nuclear weapons tests. Ocean circulation model estimates that are in reasonable agreement with our measured values indicate that future total levels of 137Cs (Fukushima-derived plus fallout 137Cs) off the North American coast will likely attain maximum values in the 3–5 Bq/m3 range by 2015–2016 before declining to levels closer to the fallout background of about 1 Bq/m3 by 2021. The increase in 137Cs levels in the eastern North Pacific from Fukushima inputs will probably return eastern North Pacific concentrations to the fallout levels that prevailed during the 1980s but does not represent a threat to human health or the environment.
5
Koo, Kil-Mo, Jin-Ho Song, Sang-Baik Kim, Kwang-Il Ahn, Won-Pil Baek, Kil-Nam Oh, and Gyu-Tae Kim. "Response Analysis on Electrical Pulses under Severe Nuclear Accident Temperature Conditions Using an Abnormal Signal Simulation Analysis Module." Science and Technology of Nuclear Installations 2012 (2012): 1–15. http://dx.doi.org/10.1155/2012/656590.
Анотація:
Unlike design basis accidents, some inherent uncertainties of the reliability of instrumentations are expected while subjected to harsh environments (e.g., high temperature and pressure, high humidity, and high radioactivity) occurring in severe nuclear accident conditions. Even under such conditions, an electrical signal should be within its expected range so that some mitigating actions can be taken based on the signal in the control room. For example, an industrial process control standard requires that the normal signal level for pressure, flow, and resistance temperature detector sensors be in the range of 4~20 mA for most instruments. Whereas, in the case that an abnormal signal is expected from an instrument, such a signal should be refined through a signal validation process so that the refined signal could be available in the control room. For some abnormal signals expected under severe accident conditions, to date, diagnostics and response analysis have been evaluated with an equivalent circuit model of real instruments, which is regarded as the best method. The main objective of this paper is to introduce a program designed to implement a diagnostic and response analysis for equivalent circuit modeling. The program links signal analysis tool code to abnormal signal simulation engine code not only as a one body order system, but also as a part of functions of a PC-based ASSA (abnormal signal simulation analysis) module developed to obtain a varying range of theR-Ccircuit elements in high temperature conditions. As a result, a special function for abnormal pulse signal patterns can be obtained through the program, which in turn makes it possible to analyze the abnormal output pulse signals through a response characteristic of a 4~20 mA circuit model and a range of the elements changing with temperature under an accident condition.
6
Mebinck, K., H. Middelkoop, N. van Diepen, E. R. van der Graaf, and R. J. de Meijer. "Radiometric fingerprinting of fluvial sediments in the Rhine-Meuse delta, the Netherlands – a feasibility test." Netherlands Journal of Geosciences 86, no. 3 (September 2007): 229–40. http://dx.doi.org/10.1017/s0016774600077829.
Анотація:
AbstractThe deposits of the Rhine and the Meuse in the Netherlands alternate in their delta in a complex way. This paper discusses a method to distinguish the deposits of the Rhine and the Meuse based on the differences in natural radioactivity of 40K, 238U and 232Th, and the effect of the age of the deposits on the radiometrie signal. In total, six channel belts of the Rhine and the Meuse were selected for sampling with an approximate age of about 2000, 4000 and 6000 14C years B.P. Of each channel belt 5 samples of different lithology were taken: clay (C), clay leads (CL), sandy clay loam (sCL), sandy loam (sL) and sand (S). All samples were analysed on organic matter content, grain size, geochemistry and radioactivity of the radionuclides 40K, 238U and 232Th. The radioactivity of the sample is mainly influenced by the grain size of the sample. Therefore, this signal is divided in partial radioactivities for three grain size fractions – clay (<16 μm), silt (16 – 63 μm) and sand (>63 μm) – to make the radiometric fingerprint, which is independent of the grain size of the sample. These fingerprints show a difference between the Rhine and the Meuse. Additionally, the radiometric signal strongly depends on the age of the deposits. Remarkably, this trend with age is opposite in the deposits of the Rhine and the Meuse and opposite in the clay and silt fraction. Because the radiometrie differences between the samples seem more distinct than the geochemical differences, the radiometric fingerprints are more suitable to distinguish the deposits of the Rhine and the Meuse. A method is presented to derive the contribution of the Rhine and the Meuse in a deposit of unknown origin, assuming that the radiometric fingerprints found are consistent and valid for the Rhine-Meuse delta. To distinguish the deposits of the Rhine and the Meuse, both the grain size composition and the age of the deposits have to be known.
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Harte, Robert J. A., Julian C. Matthews, Susan M. O'Reilly, D. W. Owen Tilsley, Safiye Osman, Gavin Brown, Sajinder J. Luthra, Frank Brady, Terry Jones, and Patricia M. Price. "Tumor, Normal Tissue, and Plasma Pharmacokinetic Studies of Fluorouracil Biomodulation With N-Phosphonacetyl-l-aspartate, Folinic Acid, and Interferon Alfa." Journal of Clinical Oncology 17, no. 5 (May 1999): 1580. http://dx.doi.org/10.1200/jco.1999.17.5.1580.
Анотація:
PURPOSE: To evaluate the effect of N-phosphonacetyl-l-aspartate (PALA), folinic acid (FA), and interferon alfa (IFN-α) biomodulation on plasma fluorouracil (5FU) pharmacokinetics and tumor and liver radioactivity uptake and retention after [18F]-fluorouracil (5-[18F]-FU) administration. PATIENTS AND METHODS: Twenty-one paired pharmacokinetic studies were completed on patients with colorectal, gastric, and hepatocellular cancer, utilizing positron emission tomography (PET), which allowed the acquisition of tumor, normal tissue, and plasma pharmacokinetic data and tumor blood flow (TBF) measurements. The first PET study was completed when the patient was biomodulator-naive and was repeated on day 8 after the patient had been treated with either PALA, FA, or IFN-α in recognized schedules. RESULTS: TBF was an important determinant of tumor radioactivity uptake (r = .90; P < .001) and retention (r = .96; P < .001), for which radioactivity represents a composite signal of 5-[18F]-FU and [18F]-labeled metabolites and catabolites. After treatment with PALA, TBF decreased (four of four patients; P = .043), as did tumor radioactivity exposure (five of five patients; P = .0437), with no change in plasma 5FU clearance. With FA treatment, there were no differences observed in whole-body metabolism, plasma 5FU clearance, or tumor and liver pharmacokinetics. IFN-α had measurable effects on TBF and 5-[18F]-FU metabolism but had no apparent affect on liver blood flow. CONCLUSION: The administration of PALA and IFN-α produced measurable changes in plasma, tumor, and liver pharmacokinetics after 5-[18F]-FU administration. No changes were observed after FA administration. In vivo effects may negate the anticipated therapeutic advantage of 5FU biomodulation with some agents.
8
Szemraj, Janusz, Khalid N. I. Al-Nedawi, Ewa Chabielska, Wlodzimierz Buczko, and Zofia Pawlowska. "Tissue distribution of a menthyl-conjugated oligodeoxyribonucleotide antisense to PAI-1 mRNA." Acta Biochimica Polonica 52, no. 4 (November 21, 2005): 849–56. http://dx.doi.org/10.18388/abp.2005_3397.
Анотація:
The inhibitory effect of numerous analogues of PO-16, an hexadecadeoxyribonucleotide antisense to sequences -22 to -17 of PAI-1 mRNA coding for a fragment of the signal peptide, on the expression of PAI-1 in endothelial cells, and physiological consequences of the subsequently reduced PAI-1 activity tested in vitro and in vivo, were described in our previous studies. Of particular interest was PO-16 5'-O-conjugated with menthyl phosphorothioate (MPO-16R). In this work, tissue localisation of MPO-16R labelled with [(35)S] phosphorothioate at the 3'-end, was determined. [(35)S]MPO-16R and control [(35)S]MPO-16R-SENSE oligonucleotides were administered intravenously into 22 rats and organ distribution of the labelled bioconjugates was assessed after 24 and 48 h. For this purpose, tissue sections were subjected to autoradiography, and quantitated by liquid scintillation after solubilisation. Overall clearance of radioactivity was already seen after 24 h, with the radioactivity recovered mainly in the kidney and liver. A smaller fraction of radioactivity was also retained in the spleen and heart. The kidney concentration of the labelled probe was higher than that of liver by 50%. The distribution of PAI-1 mRNA in untreated rat kidney, liver, spleen and heart established by two independent techniques: Ribonuclease Protection Assay and Real-Time PCR, shows the same pattern as that observed for [(35)S]MPO-16R antisense.
9
MacPhee, C. H. "Granulocyte/macrophage colony-stimulating factor affects myo-inositol metabolism in a novel manner. Implications for its priming action on human neutrophils." Biochemical Journal 286, no. 2 (September 1, 1992): 535–40. http://dx.doi.org/10.1042/bj2860535.
Анотація:
Little is known about the signal transduction processes involved in the priming action of granulocyte/macrophage colony-stimulating factor (GM-CSF) on neutrophils. This study has used myo-[3H]inositol-labelled human neutrophils to determine whether preincubation with GM-CSF influences myo-inositol (Ins) metabolism in control cells, or in cells stimulated with the bacterial chemoattractant N-formyl-methionyl-leucyl-phenylalanine (fMetLeuPhe). GM-CSF pretreatment did not influence the total cellular 3H radioactivity content, demonstrating that the cytokine had no effect on Ins uptake. However, neutrophils pretreated with GM-CSF showed a dramatic 25-40% fall in the free [3H]Ins content of the cell, which was almost quantitatively recovered in a 2-4-fold increase in radioactivity within PtdIns. The remainder of the 3H radioactivity was found proportionately distributed throughout all other [3H]Ins-containing metabolites. Interestingly, in comparison with controls, the GM-CSF-stimulated increases in [3H]polyphosphoinositide (including 3-phosphorylated lipids) and [3H]Ins polyphosphate contents were consistently higher than that observed with PtdIns. This observation suggests that GM-CSF influences the hormone-sensitive pool of PtdIns, possibly through the activation of a PtdIns synthase which is rate-limiting to subsequent metabolic pathways. This is the first report of an action of GM-CSF on Ins metabolism, and highlights the conversion of Ins to PtdIns as a key regulatory metabolic step.
10
Franchini, P. "DarkSide-20k Veto Photon-Detector Units: construction and characterization." Journal of Instrumentation 19, no. 05 (May 1, 2024): C05013. http://dx.doi.org/10.1088/1748-0221/19/05/c05013.
Анотація:
Abstract DarkSide-20k is a global direct dark matter search experiment situated underground at LNGS (Italy), designed to reach a total exposure of 200 tonne-years nearly free from instrumental backgrounds. The core of the detector is a dual-phase Time Projection Chamber (TPC) filled with 50 tonne of low-radioactivity liquid argon. The entire TPC wall is surrounded by a gadolinium-loaded polymethylmethacrylate (Gd-PMMA), which acts as a neutron veto, immersed in a second low-radioactivity liquid argon bath enclosed in a stainless steel vessel. The neutron veto is equipped with large-area Silicon PhotoMultiplier (SiPM) array detectors, placed on the outside of the TPC wall. SiPMs are arranged in a compact design meant to minimize the material used for PCBs, cables and connectors: the so-called Veto Photon-Detector Units (vPDUs). A vPDU comprises 16 vTiles, each containing 24 SIPMs, together with front-end electronics, and a motherboard, which distributes voltage and control signals, sums vTiles channels, and drives the electrical signal transmission. The neutron veto will be equipped with 120 vPDUs. The paper will focus on the production of the first vPDUs, describing the assembly chain in the U.K. institutes, in order to underline the rigorous QA/QC procedures, up to the final characterization of the first completed prototypes. Tests will be extensively performed in liquid nitrogen baths either for the single vTiles and for the assembled vPDUs, with the purpose of assigning a “quality passport” to each component.
Дисертації з теми "Radioactivity signal":
1
Hachem, Ali. "Characterization of radioactivity signals by embedded machine learning." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASP017.
Анотація:
Dans diverses applications, la classification des signaux de détecteurs de rayonnements revêt une importance cruciale. Cette thèse se concentre sur un cas d'utilisation spécifique et complexe, à savoir la discrimination des neutrons et des rayonnements gamma dans un scintillateur plastique organique, en utilisant l'apprentissage automatique embarqué. Les solutions explorées dans cette étude pourraient potentiellement être étendues à la discrimination d'autres types de radiations dans des détecteurs différents. Nous présentons tout d'abord une méthode pour créer des ensembles de données neutron-gamma étiquetés, acquis par un scintillateur organique. Ce point est crucial car toutes les sources de neutrons émettent des rayonnements gamma. Les modèles Multilayer Perceptron (MLP) et 1D Convolution Neural Network (CNN) supervisés sont entraînés et évalués avec les signaux bruts préparés en utilisant la méthode d'étiquetage. Le modèle 1D CNN surpasse le modèle MLP, qui, à son tour, surpasse l'état de l'art, en particulier pour les radiations à faible énergie ([100, 250] keVee). Une deuxième approche d'apprentissage basée sur l'extraction d'attributs a été explorée pour faire la discrimination, permettant à un signal d'être représenté par une dimension indépendante de la chaîne d'acquisition, facilitant ainsi l'utilisation de méthodes d'adaptation non supervisées. Les résultats montrent que les modèles supervisés sur les signaux bruts sont plus performants que l'approche basée sur les attributs extraits. Dans cette étude, l'attribut de "Form Factor" est exploré en tant que nouvelle méthode de discrimination, offrant des performances similaires à l'algorithme de l'état de l'art sans nécessiter d'ajustement de paramètres. Enfin, nous avons implémenté les modèles d'apprentissage proposés et l'algorithme de l'état de l'art sur Field Programmable Gate Array (FPGA), pour une discrimination en temps réel, en respectant une latence inférieure à la durée du signal. En prenant en compte la latence et la consommation de ressources comme une référence de comparaison, l'order des méthodes s'inverseIn various applications, the classification of radiation detector signals is of crucial importance. This thesis focuses on a specific and complex use case, namely the discrimination of neutrons and gamma-rays in an organic plastic scintillator using integrated machine learning (ML). The solutions explored in this study could potentially be extended to the discrimination of other types of radiations in different detectors. We present a method for creating labeled neutron-gamma datasets acquired through an organic scintillator. This is critical as all neutron sources emit gamma-rays. Supervised Multilayer Perceptron (MLP) and 1D Convolution Neural (CNN) models are trained and evaluated with the prepared dataset using the labeling method. The 1D CNN model outperforms the MLP model, which, in turn, surpasses the state-of-the-art, especially for low-energy radiations ([100, 250] keVee). A second ML approach based on features extraction was explored for discrimination, allowing a signal to be represented by a dimension independent of the acquisition chain, thus facilitating the use of unsupervised adaptation methods. The results indicate that supervised models on raw signals perform better than the attribute-based approach. In this study, the "Form Factor" attribute is explored as a novel discrimination method, offering performance similar to the state-of-the-art algorithm without requiring parameter tuning. Finally, we implemented the proposed ML models and state-of-art algorithm on Field Programmable Gate Array (FPGA) for a discrimination on the fly, while maintaining latency below less than the signal duration. Considering latency and resource consumption as a basis for comparison, the order of the methods is reversed
2
Moline, Yoann. "Une architecture programmable de traitement des impulsions zéro-temps mort pour l'instrumentation nucléaire." Thesis, Dijon, 2015. http://www.theses.fr/2015DIJOS075/document.
Анотація:
Dans l'instrumentation nucléaire, les architectures de traitement numérique du signal doivent faire face à la nature poissonienne du signal, composée d'impulsions d'arrivées aléatoires qui imposent aux architectures actuelles de travailler en flux de données. En effet, si le débit d'impulsion est trop élevé, les besoins en temps réel impliquent de paralyser l'acquisition du signal durant le traitement d'une impulsion. Durant ce délai, appelé temps mort, des impulsions peuvent être perdues. Cette contrainte conduit les architectures actuelles à utiliser des solutions dédiées à base de FPGA. Les utilisateurs finaux doivent cependant pouvoir mettre en oeuvre un large éventail d'applications sur un nombre de canaux d'acquisition qui varie. Ce besoin en flexibilité conduit à proposer une architecture programmable (C, C ++). Cette thèse présente une architecture numérique « dirigée par les impulsions » qui répond à ces contraintes. En premier lieu, cette architecture se compose d'extracteurs d'impulsions capables d'extraire de façon dynamique les impulsions en fonction de leur taille pour n'importe quel type de détecteur délivrant des impulsions. Ces impulsions sont ensuite distribuées sur des unités fonctionnelles programmables (FU) indépendante. Ces FUs gèrent l'arrivée d'événements aléatoires et des durées d'exécution de programme non-déterministes. Le simulateur de l'architecture est développé en SystemC au cycle d'horloge près. Il montre des résultats prometteurs en termes de passage à l'échelle, tout en maintenant le zéro-temps mort. Cette architecture permet d'embarquer de nouveaux algorithmes de traitement des impulsions traditionnellement utilisés hors ligneIn the field of nuclear instrumentation, digital signal processing architectures have to deal with the poissonian characteristic of the signal, composed of random arrival pulses which requires current architectures to work in dataflow. Thus, the real-time needs implies losing pulses when the pulse rate is too high. Current architectures paralyze the acquisition of the signal during the pulse processing inducing a time during no signal can be processed, this is called the dead time. These issue have led current architectures to use dedicated solutions based on reconfigurable components such as FPGAs. The requirement of end users to implement a wide range of applications on a large number of channels leads to propose an easily programmable architecture platform (C, C++). This thesis present presents a digital “pulse-driven” architecture that meets these constraints. This architecture is first composed of pulse extractors. They are capable of dynamically extracting the pulses according to their size for any type of detector that delivering pulses. These pulses are then distributed on a set of programmable and independent Functional Units (FU) which are "pulses driven". These FUs are able to handle the arrival of non-deterministic events and variable program execution times and indeterminate in advance. The virtual prototype of the architecture is developed in cycle accurate SystemC and shows promising results in terms of scalability while maintaining zero dead time. This architecture paves the way for novel real time pulse processing by reducing the gap between embedded real time processing and offline processing
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Aouadi, Mehdi. "Détermination du rapport d’embranchement de la transition super-permise du carbone 10 et développement et intégration de la ligne de faisceau PIPERADE au CENBG." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0926/document.
Анотація:
Les études de la radioactivité bêta dans les milieux nucléaires permettent en partie de participer à la détermination d’un des paramètres qui décrit l'interaction faible (la constante de couplage vectoriel). Pour cela, de nombreuses mesures permettent déjà d’atteindre de grandes précisions sur ce paramètre pour un grand nombre de noyaux des transitions bêta super-permise. Cependant, pour le carbone 10, l'incertitude relative du rapport d'embranchement reste encore élevée par rapport aux autres noyaux pères avec une valeur de l’ordre de 0,13 %. Ceci est dû à l’énergie du photon émis par l’état 0+ du noyau fils qui est de 1021,6 keV, c’est-à-dire proche de l’énergie d’empilement de deux signaux de photons de 511 keV. En mai 2015, notre groupe a réalisé, à ISOLDE au CERN, une expérience afin de mesurer très précisément cette transition. Pour produire le carbone 10,nous avons réalisé des réactions nucléaires qui produisaient en grandes parties les noyaux d’intérêts mais aussi des contaminants de mêmes masses émetteurs de bêta+. Afin de réduire l’empilement, il aurait été nécessaire de mieux séparer les éléments ou d’estimer celui-ci à partir de données équivalentes avec le néon 19. Ainsi, nous avons calculé une constante d’empilement qui dépend du temps de mise en forme est qui est de l’ordre de 0,1μs. Par la suite, l’analyse de nos données carbone 10 a permis d’obtenir un rapport d’embranchement de 1,500(4) % alors que la moyenne des valeurs de la littérature donne1,4645(19) %. Dans le but de produire plus d’espèces de noyaux et d'augmenter l'intensité des faisceaux, le GANIL (Grand Accélérateur National d'Ions Lourds) développe actuellement un nouvel accélérateur ainsi qu'un ensemble de cibles basées sur la méthode ISOL. Pour réduire le dépôt de contaminants aux points de mesures, tel que c'était le cas pour la mesure du carbone 10 à ISOLDE, la communauté de physiciens souhaite aussi développer un ensemble d'outils de séparations. Dans ce cadre, notre groupe participe depuis 2011 au développement de deux de ces outils : un séparateur de haute-résolution (HRS) pour séparer des noyaux dont le pouvoir de résolution en masse nécessaire (m/Δm) souhaité est de 20000et un double piège de Penning (PIPERADE) pour séparer les noyaux qui nécessite au maximum d’un pouvoir de résolution en masse de 100000. Ainsi, au CENBG, une ligne faisceau de test qui comprend une source d'ions FEBIAD, le quadrupôle radiofréquence regroupeur-refroidisseur GPIB, un aiguillage électrostatique et le double piège de Penning (PIPERADE) est en cours de développement. Lors des tests de ces dispositifs, nous avons observé une efficacité de transmission de l’ordre de 80 % du faisceau qui traverse le GPIB.Également, nous avons mesuré une émittance transverse de 3 pi.mm.mrad en comparaison de celle de 26 pi.mm.mrad observées en aval du GPIB. Par la suite, les simulations de laligne d’injection dans le piège de Penning ont permis de définir une décélération qui permet d’injecter 98 % des ions extraits du GPIB.Cette thèse se compose donc de deux parties : la détermination du rapport d'embranchement du carbone 10 et le développement et l'intégration au CENBG de la ligne de faisceau PIPERADEThe beta radioactivity studies in nuclear medium allow to participate in thedetermination of one of the parameters that describes the weak interaction (the vectorcoupling constant). For this purpose, numerous measurements have already been made todetermine this parameter with great precision for superallowed transition nuclei. However,for carbon 10, the relative uncertainty of the branching ratio is still high compared to otherparent nuclei with a value of the order of 0.13%. This high uncertainty is due to photonenergy emitted of 1021.6 keV which is really closed to the energy due to pile-up of twophotons of 511 keV. In May 2015, our group conducted an experiment at ISOLDE at CERN tomeasure the branching ratio very precisely. The nuclear reactions needed to produce thenuclei gave a large amount of nuclei of interest but also contaminants of the same massewhich also emit beta+ particles. A pile-up ratio of around 0.1 μs was calculated. Then, wefound a branching ratio of 1.500(4) % whereas the average from litterature is 1.4645(19) %.To study more species of nuclei and increase the intensity of the beams, GANIL(Grand Accélérateur National d’Ions Lourds) is currently developing a new accelerator as wellas a set of targets based on ISOL method. In order to reduce the contaminants deposit atthe measurement points, as we saw for the measurement of carbon 10 at ISOLDE, thecommunity of physicists also wants to develop separation apparati. In this context, since2011, our group has been involved in the development of two of these tools: a highresolutionseparator (HRS) to separate nuclei which need a mass resolving power (m / Δm)around 20,000 and a double Penning trap (PIPERADE) to separate the nuclei which require amaximum resolution of 100,000. Thus, at CENBG, a test beam line that includes a FEBIAD ionsource, a RFQ cooler-buncher (GPIB), an electrostatic switch, and a double Penning trap(PIPERADE) is under development. During apparati tests, we observe a transmissionefficiency around 80 %. Also, we measure a transverse emittance about 3 pi.mm.mrad whichis lower than 26 pi.mm.mrad observed before the GPIB. By the way, simulations of the beamline permitted to decelerate the beam and inject 98 % of ions.This thesis consists of two parts: the determination of the carbon 10 branching ratioand the development and integration of the PIPERADE beam line at CENBG
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Di, Marco Marie. "Réduction du bruit de fond en vue de la détection de la matière sombre avec le projet PICASSO." Thèse, 2004. http://hdl.handle.net/1866/14759.
Книги з теми "Radioactivity signal":
1
Nakhostin, Mohammad. Signal Processing for Radiation Detectors. Wiley & Sons, Incorporated, John, 2017.
2
Nakhostin, Mohammad. Signal Processing for Radiation Detectors. Wiley & Sons, Incorporated, John, 2017.
3
Nakhostin, Mohammad. Signal Processing for Radiation Detectors. Wiley & Sons, Incorporated, John, 2017.
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Nakhostin, Mohammad. Signal Processing for Radiation Detectors. Wiley & Sons, Limited, John, 2017.
5
Garcia, Ernest V., James R. Galt, and Ji Chen. SPECT and PET Instrumentation. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199392094.003.0003.
Анотація:
Nuclear cardiac imaging is solidly based on many branches of science and engineering, including nuclear, optical and mathematical physics, electrical and mechanical engineering, chemistry and biology. This chapter uses principles from these scientific fields to provide an understanding of both the signals used, and the imaging system that captures these signals. Nuclear cardiology’s signals are the x-rays or ?-rays photons emitted from a radioactive tracer and its imaging systems are either single-photon emission computed tomography (SPECT) or positron emission tomography (PET) cameras. This combination has met with remarkable success in clinical cardiology. This success is due to the combination of sophisticated electronic nuclear instruments with a highly specific and thus powerful signal. The signal is as important as or more important than the imaging system. There is a misconception that cardiac magnetic resonance (CMR) cardiac computed tomography (CCT) and echocardiography are superior to nuclear cardiology imaging because of their superior spatial resolution. Yet, in detecting perfusion defects what is really necessary is superior contrast resolution. It is this superior contrast resolution that allows us to differentiate between normal and hypoperfused myocardium facilitating the visual analysis of nuclear cardiology perfusion images. Because these objects are bright compared to the background radioactivity, computer algorithms have been developed that allow us to automatically and objectively process and quantify our images. This chapter explains many of the important scientific principles necessary to understand nuclear cardiology imaging in general, i.e., how these sophisticated imaging systems detect the radiation emitted from the radiotracers.
Частини книг з теми "Radioactivity signal":
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Huber, Josef Georg, Horst Schmidt-Böcking, and Bretislav Friedrich. "Walther Gerlach (1889–1979): Precision Physicist, Educator and Research Organizer, Historian of Science." In Molecular Beams in Physics and Chemistry, 119–61. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63963-1_8.
Анотація:
AbstractWalther Gerlach’s numerous contributions to physics include precision measurements related to the black-body radiation (1912–1916) as well as the first-ever quantitative measurement of the radiation pressure (1923), apart from his key role in the epochal Stern-Gerlach experiment (1921–1922). His wide-ranging research programs at the Universities of Tübingen, Frankfurt, and Munich entailed spectroscopy and spectral analysis, the study of the magnetic properties of matter, and radioactivity. An important player in the physics community already in his 20s and in the German academia in his later years, Gerlach was appointed, on Werner Heisenberg’s recommendation, Plenipotentiary for nuclear research for the last sixteen months of the existence of the Third Reich. He supported the effort of the German physicists to achieve a controlled chain reaction in a uranium reactor until the last moments before the effort was halted by the Allied Alsos Mission. The reader can find additional discussion of Gerlach’s role in the supplementary material provided with the online version of the chapter on SpringerLink. After returning from his detention at Farm Hall, he redirected his boundless elan and determination to the reconstruction of German academia. Among his high-ranking appointments in the Federal Republic were the presidency of the University of Munich (1948–1951) and of the Fraunhofer Society (1948–1951) as well as the vice-presidency of the German Science Foundation (1949–1961) and the German Physical Society (1956–1957). As a member of Göttinger Achtzehn, he signed the Göttingen Declaration (1957) against arming the Bundeswehr with nuclear weapons. Having made history in physics, Gerlach became a prolific writer on the history of physics. Johannes Kepler was his favorite subject and personal hero—as both a scientist and humanist.
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Mavi, Ahmet, Ahmet Özmen, and Mehmet Ertuğrul. "Analyzing and Presenting Data with LabVIEW." In LabVIEW - A Flexible Environment for Modeling and Daily Laboratory Use. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96130.
Анотація:
LabVIEW is an abbreviation for Laboratory Virtual Instrument Engineering Workbench and allows scientists and engineers to develop and implement an interactive program. LabVIEW has been specially developed to take measurements, analyze data, and present the results to the user. You determine what the device looks like, rather than the manufacturer of the device. LabVIEW has a very large library of functions and subprograms (subVIs) that can help you during your programming and use without occupying memory. Hidden programming problems that you may encounter in traditional programming languages are less common in LabVIEW. LabVIEW also includes different applications such as serial device control, data analysis, data presentation, data storage and communication over the internet. Analysis library; It includes versatile and useful functions such as signal generation, signal processing filters, Windows statistics and regressions, linear algebra and array arithmetic. Due to the graphical nature of LabVIEW, it is an innate data presentation package. You can view the data in any form you want. Chart, graph and user-defined graph are among the output options that can be used. As a scientist or an engineer, you frequently measure physical changes such as temperature, pressure, time, mass, electric current, light intensity, radioactivity etc. You generally need to analyze and present the data. When you have large amounts of data, you need to use software to analyze and present the data. LabVIEW makes these actions easy for you. Because LabVIEW includes hundreds of built-in and add-on functions you need that make it easy to create a user-friendly interface. In this chapter, we focus on data analysis and presentation.
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Buckle, V. J., and K. A. Rack. "Fluorescent in situ hybridization." In Human Genetic Disease Analysis, 59–82. Oxford University PressOxford, 1993. http://dx.doi.org/10.1093/oso/9780199633098.003.0004.
Анотація:
Abstract The hybridization of RNA in situ to the DNA of a cytological preparation was first described by Gall and Pardue in 1969 (1) and the general principles of the technique they developed remain the basis of contemporary studies. During the 1970s this procedure was used to localize repeated sequences within the human genome by autoradiographic detection of radioactively labelled probes, and during the 1980s the sensitivity of this approach was refined sufficiently to permit detection of unique sequences of only 500 base pairs in length. At the same time non-isotopic detection procedures were being developed, which have several advantages over autoradiography including speed, safety, and resolution of signal. Advances in this area in recent years have revolutionized the applications for in situ hybridization as a tool in genome research. In particular the use of competitive hybridization means an enormous size range of cloned DNA sequences are now available for use as probes, and fluorescent detection systems now permit the concurrent visualization of multiple probes. These powerful new techniques provide a tool not only for examining the location and distribution of sequences on metaphase chromosomes but also for investigating organization within the interphase nucleus.
Тези доповідей конференцій з теми "Radioactivity signal":
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Guinn, I., N. Abgrall, I. J. Arnquist, F. T. Avignone, C. X. Baldenegro-Barrera, A. S. Barabash, F. E. Bertrand, et al. "Low background signal readout electronics for the MAJORANA DEMONSTRATOR." In LOW RADIOACTIVITY TECHNIQUES 2015 (LRT 2015): Proceedings of the 5th International Workshop in Low Radioactivity Techniques. AIP Publishing LLC, 2015. http://dx.doi.org/10.1063/1.4927982.
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Wu, Guohua, Liguo Zhang, and Jiejuan Tong. "Online Fault Diagnosis of Nuclear Power Plants Using Signed Directed Graph and Fuzzy Theory." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-66367.
Анотація:
When nuclear power plant (NPPs) is in fault, it may release radioactivity into the environment. Therefore, extremely high safety standards specification are required during its working. So it is critically important for fault detection and diagnosis (FDD). NPPs are composed of large and complex systems, it is of great significance to obtain the up-to-date information of NPPs’ running state. So FDD is used to provide the state of system accurately and timely in NPPs. Signed directed graph (SDG) can show the complex relationship between parameters and has advantages of conveniently modeling, flexible inference and so on, so SDG is adopted for FDD. To achieve SDG inference better, fuzzy theory is utilized for signal processing in the paper. Firstly, SDG model is built according to the basic steps and principles of SDG modeling, and the parameters are divided into three states which is monitored by fuzzy theory. Secondly, according to the status of parameters, SDG is used for FDD and to reveal the fault propagation path, thus possibility of each fault occurred is achieved. Finally, to verify the validity of the method, the simulation experiments are done for NPPs and the simulation experiments show that SDG-fuzzy theory framework for FDD can get the fault possibility and deeply explain the reasons of fault.
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Ivanov, Oleg, Alexey Danilovich, Vyacheslav Stepanov, Sergey Smirnov, and Victor Potapov. "Remote Measurements of Radioactivity Distribution With BROKK Robotic System." In ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2009. http://dx.doi.org/10.1115/icem2009-16147.
Анотація:
Robotic system for the remote measurement of radioactivity in the reactor areas was developed. The BROKK robotic system replaces hand-held radiation measuring tools. The system consists of a collimated gamma detector, a standard gamma detector, color CCD video camera and searchlights, all mounted on a robotic platform (BROKK). The signals from the detectors are coupled with the video signals and are transferred to an operator’s console via a radio channel or a cable. Operator works at a safe position. The video image of the object with imposed exposure dose rate from the detectors generates an image on the monitor screen, and the images are recorded for subsequent analysis. Preliminary work has started for the decommissioning of a research reactor at the RRC «Kurchatov Institute». Results of the remote radioactivity measurements with new system during radiation inspection waste storage of this reactor are presented and discussed.
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Pandola, L. "Muon-induced signals and isotope production in the GERDA experiment." In TOPICAL WORKSHOP ON LOW RADIOACTIVITY TECHNIQUES: LRT 2006. AIP, 2007. http://dx.doi.org/10.1063/1.2722076.
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TOHMATSU, T., S. NAKASHIMA, H. HATTORI, A. SUGANUMA, and Y. NOZAWA. "A ROLE OF DIACYLGLYCEROL KINASE IN STIMULUS-SECRET I ON COUPLING OF HUMAN PLATELETS -DISSOCIATION OF SEROTONIN SECRETION FROM Ca2+ MOBILIZATION-." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644502.
Анотація:
Diacylglycerol (DG) kinase catalyzes the reaction: DG + ATP phosphatidic acid + ADP and it is widely distributed in animal tissues. The enzyme seems to play a pivotal role in removing a second messenger, DG, which activates protein kinase C. DG kinase inhibitor, R 59 022 (6-[2-[4-[(4-fluorophenyl)pheny1- methylene] -1-piperidinyl] ethyl] -7-methyl-5H-thiazolo [3,2-a] -pirimidin-5-one) has recently been developed. In order to gain further insight into the role of DG in the secretory response, effects of the DG kinase inhibitor on secretory responses and Ca2+ mobilization were investigated in human platelets.The addition of the DG kinase inhibitor (10 μM) potentiated thrombin-induced accumulation of [3H]radioactivity of DG in platelets loaded with [3H] arachidonate. Thrombin-induced release of [3H] arachidonic acid and its metabolites was not affected by the inhibitor. The inhibitor did not cause significant secretion of [14C] serotonin by itself. However, the pretreatment with this agent potentiated the level of secretion in thrombin-stimulated platelets. When l-oleoyl-2-acetylglycerol(OAG) was added to [32pjpi-iabeled platelets in the presence of the DG kinase inhibitor, the formation of [32P] l-oleoyl-2-acetylphosphatidic acid was greatly prevented. The pretreatment with the inhibitor also potentiated OAG-induced serotonin secretion. With the view that Ca2+ is thought to be another important second messenger, we investigated the effect of the DG kinase inhibitor on Ca2+ mobilization. Two types of Ca2+ indicators, Quin2 and aequorin were used to measure cytosolic free Ca2+ concentration ([Ca2+]i). The inhibitor alone did not affect [Ca2+]i. Interestingly, thrombin-induced increase in [Ca2+]i was suppressed by the pretreatment with this agent both in the Quin2-loaded and aequorin-loaded platelets.These results indicate that diacylglycerol kinase may operate as an attenuator in the signal transduction system involving protein kinase C and that Ca2+ mobilization may not be tightly coupled to serotonin secretion.
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Bibby, S. R., M. J. Crow, S. R. Puri, S. J. Sheehan, S. M. Rajah, and R. C. Kester. "THE EARLY THROMBOGENICITY OF IMPREGNATED DACRON GRAFTS ASSESSED IN AN ARTIFICIAL CIRCULATION." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643093.
Анотація:
The impregnation of knitted Dacron grafts with biodegradable protein removes the need for preclotting at implantation. The effect of such impregnation on the thrombogenic potential of these prostheses is, however, unknown. We have compared the early thrombogenicity of two impregnated knitted Dacron grafts - Hemashield ( collagen-impregnated Dacron, Meadox) and Gelseal (gelatin-impregnated Dacron, Vascutek) -with conventionally preclotted knitted Dacron in an artificial circulation. Fresh, heparinised human blood, containing 111Indium-labelled platelets, was circulated around identical twin circuits of silicone tubing by a Sarns roller pump at 180 ml/min and 120 mmHg. Into each circuit a different 15 cm × 8 mm type of graft material was mounted. Changes in platelet count, platelet aggregation to collagen, plasma haemoglobin and blood radioactivity were recorded and after 60 minutes of perfusion each graft was sectioned and counted for radioactivity prior to scanning electron microscopy (SEM) of the luminal surface. The mean graft radioactivity divided by the mean blood radioactivity yields a Graft Activity Index (GAI) allowing comparison of platelet deposition and thus thrombogenicity.RESULTS: (mean ± s.e.m.) 8 examples of each graftSEM confirmed these findings with preclotted Dacron having the highest platelet deposition. Both impregnated grafts produced significant early haemolysis within 4 minutes of blood contact. Our findings indicate that the early thrombogenicity of these impregnated grafts is significantly less than conventionally preclotted Dacron, (p< 0.01, Wilcoxon signed rank test), despite the early haemolytic phenomenon and that Hemashield grafts are less thrombogenic than Gelseal grafts. (p<0.05, Wilcoxon signed rank test)
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Fesina, Yulia, Dmitrii Smirnov, Stanislav Uralsky, Vasilii Skitin, Artur Butaev, Sulaimi Ghadna, Abdullah Hadhrami, and Mahrooqi Alkhattab. "Enhancing Production From Low-Permeable Reservoirs With Advanced Hydraulic Fracturing Monitoring Techniques." In ADIPEC. SPE, 2023. http://dx.doi.org/10.2118/216835-ms.
Анотація:
Abstract Hydraulic fracturing is an important technology that can improve the production of oil and gas from low-permeable reservoirs, but it can also be challenging and requires ongoing monitoring and assessment to ensure that the fractures are performing as expected. The height of the fracture can significantly affect the efficiency of production. Spectral noise logging and tracer analysis are two methods that can be used to determine the height of the fracture and assess its performance. The Tracer analysis technique involves mixing a tracer material with the hydraulic fluid used during the fracturing process. The subsequent monitoring of the radioactivity level versus depth provides information about the fractures' placement and extent along the wellbore. On the other hand, a passive spectral acoustics survey will record the acoustic signal that is generated by the flow through the fractures during production, thus enabling the exact determination of the fractures' position and their active heights along the wellbore axis. By combining these techniques with temperature and hydrodynamic modelling, it is possible to calculate the specific performance of each fracture.The results from three wells' surveys confirmed the effectiveness of this methodology. Both Tracer and Passive spectral acoustic methods were able to determine the location of the fractures along the wellbore axis. However, the spectral noise determination is a lot more informative due to the nature of the measurement, which responds properly to the contributing or active height of each fracture whilst the GR response opposite the Tracer represents the physical extent of the fracture along the wellbore. One more point; the Tracer fluid can migrate away from the fractures due to poor cement bonding, etc. which could confuse the interpretation by falsely indicating a fracture extent at a certain depth.In addition to the findings described above, this methodology allows the pinpointing of the fracture depths behind the casing, away from the fracturing ports. The coupling of these measurements with a High Precision Temperature sensor and with Temperature Modelling allows the determination and quantification of the flow rates inside and outside the wellbore, thus providing a full and comprehensive picture of the downhole flow profile.
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Lang, Minggang. "The ATWS Analysis of One Control Rod Withdrawal Out of the HTR-10GT Core Under the Loss of the System Pressure." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30015.
Анотація:
The 10MW High Temperature Gas Cooled Test Reactor (HTR-10) has been built in Institute of Nuclear and New Energy Technology (INET) and has been operating successfully since the beginning of 2003. The core outlet temperature of HTR-10 is 700°C. To verify the technology of gas-turbine direct cycle, at first INET had a plan to increase its core outlet temperature to 750°C and to use a helium gas turbine instead of the steam generator (then the reactor is called HTR-10GT). Though HTR-10 has good intrinsic safety, the design basis accidents and beyond design basis accidents of HTR10-GT must be analyzed according to China’s nuclear regulations due to changed operation parameters. THERMIX code system is used to study the ATWS accident of one control rod withdrawal out of the core by a mistake under the loss of the system pressure. After a control rod in the side reflector was withdrawn out at a speed of 1 cm/s by a mistake, a positive reactivity was inserted. At the same time, the system pressure was supposed to lose by some reason. Thus the reactor power increased and the temperature of the core increased. And the protection system warns with two scram signal: too high of the negative varying rate of the system pressure and too high of the reactor power, which should induce the reactor to scram. It was supposed that all the control rods in the reflectors had been blocked and the reactor could not scram. Thus the accident went on and the core temperature and the system pressure continued to increase but the reactor shutdown at last because of its natural negative temperature reactivity feedback mechanism. The residual heat would be removed out of the core by the cavity cooling system. During the accident sequence the maximum fuel temperature was 1203.4°C. It was a little bit lower than 1230°C — the fuel temperature limitation of HTR-10 and there is no release of any radioactivity. So the HTR-10GT is safe during the ATWS of one control rod withdrawal out of the core. The paper also compares the analysis result of HTR10-GT to those of HTR-10. The results shows that the HTR-10GT is still safe during the accident though its operating temperature is higher than HTR-10.
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Vijayakumaran, P. M., C. P. Nagaraj, C. Paramasivan Pillai, R. Ramakrishnan, and M. Sivaramakrishna. "Nuclear Instrumentation Systems in Prototype Fast Breeder Reactor." In 12th International Conference on Nuclear Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/icone12-49354.
Анотація:
The nuclear instrumentation systems of the Prototype Fast Breeder Reactor (PFBR) primarily comprise of global Neutron Flux Monitoring, Failed Fuel Detection & Location, Radiation Monitoring and Post-Accident Monitoring. High temperature fission chambers are provided at in-vessel locations for monitoring neutron flux. Failed fuel detection and location is by monitoring the cover gas for fission gases and primary sodium for delayed neutrons. Signals of the core monitoring detectors are used to initiate SCRAM to protect the reactor from various postulated initiating events. Radiation levels in all potentially radioactive areas are monitored to act as an early warning system to keep the release of radioactivity to the environment and exposure to personnel well below the permissible limits. Fission Chambers and Gamma Ionisation Chambers are located in the reactor vault concrete for monitoring the neutron flux and gamma radiation levels during and after an accident.