Photon Detectors
Mostrando 1-12 de 15 artigos, teses e dissertações.
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1. Performance assessment of the single photon emission microscope: high spatial resolution SPECT imaging of small animal organs
The single photon emission microscope (SPEM) is an instrument developed to obtain high spatial resolution single photon emission computed tomography (SPECT) images of small structures inside the mouse brain. SPEM consists of two independent imaging devices, which combine a multipinhole collimator, a high-resolution, thallium-doped cesium iodide [CsI(Tl)] col
Braz J Med Biol Res. Publicado em: 06/11/2013
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2. CMOS image system wiht high responsivity and high dynamic range / Sistemas de imagem CMOS com alta responsividade e elevada faixa dinamica
This thesis adresses two important challenges imposed by CMOS technology trends, the reduction of the junctions s responsivity and voltages levels. A new photodetector with high responsivity and a multi-sampling time domain image system are investigated. This thesis proposes to use the gate controlled lateral bipolar junction transistor (GCLBJT) as a four te
Publicado em: 2008
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3. Filmes finos de iodeto de chumbo como detector de raios-X para imagens médicas / Lead Iodide Thin Films as X-ray detectors for Medical Imaging
In the last few years, great interest has been focused to high atomic number and wide band gap semiconductor materials for applications in room temperature ionizing radiation detection using the direct detection method. Some materials such as PbI2, HgI2, TlBr, CdTe and CdZnTe are good photoconductors and can be used at room temperature. As a good candidate,
Publicado em: 2007
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4. Teoria e implementaÃÃo de detectores de fÃtons isolados para comunicaÃÃes quÃnticas em redes Ãpticas / Theory and implementation of sigle-photon detectors for quantum communications in optical networks
Tecnologia da InformaÃÃo QuÃntica à uma Ãrea multidisciplinar nova que tem recebido muita atenÃÃo por ser promissora e devido a seu alto potencial em resolver problemas ainda nÃo solucionados. Dentro desta grande Ãrea, as ComunicaÃÃes QuÃnticas estÃo bastante desenvolvidas. Nesta sub-Ãrea, distribuiÃÃo QuÃntica de Chaves à o campo mais avan
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 13/06/2006
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5. First results from the Pierre Auger Observatory
We review in these notes the status of the construction of the Pierre Auger Observatory and present the first Physics results, based on the data collected during the first year and a half of operation. These results are preliminary, once the work to understand the systematics of the detectors are still underway. We discuss the cosmic ray spectrum above 3 EeV
Brazilian Journal of Physics. Publicado em: 2006-12
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6. Growth of mercuric iodide crystals
Mercuric Iodide (HgI2) is a semiconductor candidate for the construction of X- and gamma-ray detectors for digital medical imaging due to its high atomic number (Z Hg = 80, Z I = 53). Also, HgI2 has a wide optical band-gap (2.13 eV) and high photon absorption coefficient for high-energy radiation. Different structures can lead to varying electrical and optic
Brazilian Journal of Physics. Publicado em: 2006-06
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7. Análise do potencial de calibração da força óptica através de dispositivos de microscopia de força atômica / Analysis of the calibration potential of optical force through atomic force microscopy devices
O microscópio de força atômica é uma ferramenta que possibilita a medida de forças precisamente localizadas com resoluções no tempo, espaço e força jamais vistas. No coração deste instrumento está um sensor a base de uma viga (cantilever) que é responsável pelas características fundamentais do AFM. O objetivo desta pesquisa foi usar a deflexã
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 19/12/2005
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8. Monte Carlo simulation of a position sensitive gamma ray detector
The Monte Carlo method was employed to obtain the response of a position sensitive gamma ray detector. The basic unit consists of a scintillator bar coupled to two photon detectors. Determination of the position of interaction is obtained from the ratio of the light intensity measured at each extremity of the bar. Association of two or more detectors of this
Brazilian Journal of Physics. Publicado em: 2005-09
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9. Efficiency loss in HPGe detectors due to beta and gamma sum coincidence
Among the secondary detection effects in gamma-ray spectroscopy with HPGe detectors that reduce the peak area and must be properly taken into account in accurate measurements, the less well known is counting loss by beta and gamma-ray sum coincidence. The fraction of lost counts was estimated assuming that a photon detection event can sum either with the coi
Brazilian Journal of Physics. Publicado em: 2005-09
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10. Development of a tomographic system for online dose measurements in BNCT (Boron Neutron Capture Therapy)
Within our activities on accelerator-based boron neutron capture therapy (BNCT) carried out at the Tandar Laboratory (Comisión Nacional de Energía Atómica, Argentina) we present here the study and design of a tomographic imaging system for the measurement of the spatial distribution of the absorbed dose during a BNCT session. The 10B (n,alpha) 7Li boron n
Brazilian Journal of Physics. Publicado em: 2005-09
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11. Individual monitoring for external exposures: experimentation and simulation with Monte Carlo Method / Monitoração individual externa: experimentos e simulações com o método de Monte Carlo
In this work, we have evaluated the possibility of applying the Monte Carlo simulation technique in photon dosimetry of external individual monitoring. The GEANT4 toolkit was employed to simulate experiments with radiation monitors containing TLD-100 and CaF2:NaCl thermoluminescent detectors. As a first step, X ray spectra were generated impinging electrons
Publicado em: 2005
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12. High precision system for magnetic field measurements of insertion devices of the Brazilian Synchroton Light Source / Sistema de alta precisão para as medições dos campos magneticos dispositivos de inserção do Laboratorio Nacional de Luz Sincroton
This Thesis was a consequence of the need for an accurate and precise magnetic field measurement bench for insertion devices characterization (IDs). Such devices are versatile radiation sources installed in Electron Storage Rings. From their magnetic field profile, they provide high photon fluxes, with broad or monochromatic spectrum, being possible, dependi
Publicado em: 2005