Activation Detectors
Mostrando 1-12 de 13 artigos, teses e dissertações.
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1. Caracterização do campo de nêutrons na instalação para estudo em BNCT no Reator IEA-R1 / NEUTRON FIELD CHARACTERIZATION IN THE INSTALLATION FOR BNCT STUDY IN THE IEA R1 REACTOR.
This work aims to characterize the mixed neutron and gamma field, in the sample irradiation position, in a research installation for Boron Neutron Capture Therapy (BNCT), in the IPEN IEA-R1 reactor. The BNCT technique has been studied as a safe and selective option in the treatment of resistant cancerigenous tumors or considered non-curable by the convention
Publicado em: 2008
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2. Medida do espectro de energia dos nêutrons no núcleo do Reator IPEN/MB-01 / Measurements of the neutron energy spectra in the core of IPEN/MB-01 reactor
Este trabalho apresenta a medida do espectro de energia dos nêutrons no núcleo do Reator IPEN/MB-01. Para tal, foram inseridos detectores de ativação na forma de diminutas folhas metálicas no núcleo do reator, na região moderadora, utilizando um dispositivo articulado que permite que as folhas fiquem posicionadas na posição central do núcleo do rea
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 24/11/2006
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3. Desenvolvimento de cristais baseados em iodeto de Césio para aplicação como detectores de radiação / Development of crystals based in cesium iodide for application as radiation detectors
Cintiladores inorgânicos com tempo de decaimento de luminescência rápido, densidade alta e boa produção de luz têm sido objeto de estudos para aplicações em física nuclear, física de energias altas, tomografia nuclear e outros campos da ciência e da engenharia. Cristais de cintilação baseados em iodeto de césio (Csl) são materiais que apresent
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/06/2006
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4. Detection of water by neutron scattering using a small Plasma Focus
A compact Plasma Focus operated in deuterium which produces 2 10(8) neutrons per pulse, has been used as a radiation source for water detection by neutron scattering. The detecting system is composed by two silver activation sensors operated simultaneously on every shot. These detectors have quite different responses depending on whether the incoming neutron
Brazilian Journal of Physics. Publicado em: 2004-12
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5. Instrumental neutron activation analysis with Compton suppression for the evaluation of foodstuff composition / "Supressão Compton na análise por ativação neutrônica instrumental de produtos agrícolas destinados à alimentação humana"
Instrumental neutron activation analysis (INAA) is a good option for studying chemical composition of food, allowing the simultaneous determination of several elements. However, the incomplete deposition of gamma-ray energies in the detector crystal due to Compton scatter can elevate the spectrum baseline making difficult the determination of some elements.
Publicado em: 2004
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6. Thin films of lead iodide (PbI2) produced by spray pyrolysis / Filmes finos de iodeto de chumbo (PbI2)produzidos por spray pyrolysis
Researchers in the whole world search alternative methods that minimize the time of deposition of thin films of promising semiconductor candidates for medical applications, such as X-rays detectors for digital radiography. Lead iodide (PbI2) has been among those as a good candidate for the fabrication of room temperature detectors. Other authors have fabrica
Publicado em: 2003
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7. Neutron anisotropy and X-ray production of the FN-II dense plasma focus device
The FN-II Dense Plasma Focus is a small (< 5kJ ) Mather type device, where the dependence of neutron yield and its anisotropy, in terms of deuterium filling pressure, and the neutron emission angular distribution have been studied. Two diferent electrode configurations have been tested, showing that their geometry plays an important role both on neutron yiel
Brazilian Journal of Physics. Publicado em: 2002-03
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8. Deuterium plasma focus measurements using solid state nuclear track detectors
A camera obscura technique was used to investigate the spatial distribution of fusion protons emitted from a small deuterium plasma focus device operated in its neutron-optimized regime (14 kV, 3 kJ, and 400 Pa D2 gas). An indium-foil activation detector was employed simultaneously to measure the shot-to-shot neutron yield. The camera obscura was positioned
Brazilian Journal of Physics. Publicado em: 2002-03
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9. GABA-mediated giant depolarizing potentials as coincidence detectors for enhancing synaptic efficacy in the developing hippocampus
Spontaneously occurring neuronal oscillations constitute a hallmark of developmental networks. They have been observed in the retina, neocortex, hippocampus, thalamus, and spinal cord. In the immature hippocampus, the so-called “giant depolarizing potentials” (GDPs) are network-driven synaptic events generated by γ-aminobutyric acid (GABA), which at thi
National Academy of Sciences.
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10. Detection of synchrony in the activity of auditory nerve fibers by octopus cells of the mammalian cochlear nucleus
The anatomical and biophysical specializations of octopus cells allow them to detect the coincident firing of groups of auditory nerve fibers and to convey the precise timing of that coincidence to their targets. Octopus cells occupy a sharply defined region of the most caudal and dorsal part of the mammalian ventral cochlear nucleus. The dendrites of o
The National Academy of Sciences.
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11. Transduction heats in retinal rods: tests of the role of cGMP by pyroelectric calorimetry.
The sensory dark current of vertebrate retinal rods is believed to be controlled by light activation of a chain of coupled biochemical cycles that finally regulate the cationic conductance of the plasma membrane by hydrolytically reducing the level of cGMP in rod outer segment cytoplasm. The scheme has been tested by measuring heat production by live frog re
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12. A mechanism for synaptic frequency detection through autophosphorylation of CaM kinase II.
A model for the regulation of CaM kinase II is presented based on the following reported properties of the molecule: 1) The holoenzyme is composed of 8-12 subunits, each with the same set of autophosphorylation sites; 2) Autophosphorylation at one group of sites (A sites) requires the presence of Ca2+ and causes a subunit to remain active following the remov