Encontrados 8 documentos, a visualizar página 1 de 1
Activity measurements of 192Ir solid sources using a well-type ionization chamber
Gonçalves, J. A. C.; Botelho, S.; Pascholati, P. R.; Ridenti, M. A.; Fraga, M. M. F. R.; Camara, J. R.; Calvo, W. A.; Bueno, C. C.This work presents the preliminary activity measurements of 192Ir solid sources, applied in industrial gammagraphy, produced by the Sealed Sources Laboratory in the Radiation Technology Center (CTR) at IPEN-CNEN/SP. The pellets' activity measurements were carried out with a well-type ionization chamber developed at CTR. The chamber current-voltage response was studied as a function of 192Ir activities ranging f...
Performance of an optical readout GEM-based TPC
Margato, L. M. S.; Fraga, F. A. F.; Fetal, S. T. G.; Fraga, M. M. F. R.; Balau, E. F. S.; Blanco, A.; Marques, R. Ferreira; Policarpo, A. J. P. LWe report on the operation of a GEM-based small TPC using an optical readout. The detector was operated with a mixture of Ar+CF4 using 5.48 MeV alpha particles obtained from a 241Am source and the GEM scintillation was concurrently read by a CCD camera and a photomultiplier. Precision collimators were used to define the track orientation. Qualitative results on the accuracy of the track angle, length and charge...
The scintillation of GEMS coated with wavelength shifters
Fraga, F. A. F.; Fetal, S. T. G.; Fraga, M. M. F. R.; Balau, E. F. S.; Margato, L. M. S.; Marques, R. Ferreira; Policarpo, A. J. P. L; Sauli, F.The optical readout of GEMs, presented a few years ago, is currently being considered for several detector projects. Although using suitable gaseous mixtures the GEM avalanches emit a large number of photons in the visible and/or NIR regions, many gaseous mixtures of great interest for detectors scintillate mainly in the UV, and the readout of these detectors is usually inefficient or very expensive. In this wo...
Luminescence and imaging with gas electron multipliers
Fraga, F. A. F.; Margato, L. M. S.; Fetal, S. T. G.; Fraga, M. M. F. R.; Marques, R. Ferreira; Policarpo, A. J. P. L.Although the GEM has been mainly used as a gaseous preamplifier device, it has been shown that using suitable gaseous mixtures the avalanches emit a large number of photons, in the UV, visible and/or NIR bands. This scintillation, readout by CCDs, has been used recently for the development of imaging detectors to be used with X-rays, alpha particles and neutrons. The luminescence process in the GEM and a summar...
Time analysis of the light pulses on gaseous active scintillators using GEMs wi...
Margato, L. M. S.; Fraga, F. A. F.; Fetal, S. T. G.; Fraga, M. M. F. R.; Marques, R. Ferreira; Policarpo, A. J. P. L; Guerard, B.; Manzin, G.The time structure of light pulses from GEM detectors operated in scintillation mode with He/CF4 mixtures, previously used with integrating readout devices for neutron detection, has been investigated. A system using photomultipliers (PMs) and charge preamplifiers coupled to a fast digitizer has been used to measure simultaneously both the charge and light signals of the avalanches and the dependence of these s...
CCD readout of GEM-based neutron detectors
Fraga, F. A. F.; Margato, L. M. S.; Fetal, S. T. G.; Fraga, M. M. F. R.; Marques, R. Ferreira; Policarpo, A. J. P. L; Guerard, B.; Oed, A.; Manzini, G.We report on the optical readout of the gas electron multiplier (GEM) operated with a gaseous mixture suitable for the detection of thermal neutrons: 3He-CF4. A CCD system operating in the 400-1000 nm band was used to collect the light. Spectroscopic data on the visible and NIR scintillation of He-CF4 are presented. Images of the tracks of the proton and triton recorded with a triple GEM detector are also shown...
Optical readout of GEMs
Fraga, F. A. F.; Margato, L. M. S.; Fetal, S. T. G.; Fraga, M. M. F. R.; Marques, R. Ferreira; Policarpo, A. J. P. L.We present an overview of results from our recent studies on the use of the visible and NIR scintillation emitted by the gas electron multiplier (GEM) and on the possibility of using detectors operated with cascaded GEMs to build tracking chambers. ; http://www.sciencedirect.com/science/article/B6TJM-44DHYY7-10/1/0076b77e06804d2654d892c3d6126c90
Modelling of an IR scintillation counter
Fraga, M. M. F. R.; Fraga, F. A. F.; Policarpo, A. J. P. L.A systematic study of the excitation and de-excitation mechanisms in ternary gas mixtures Ar+CO2+N2 is presented regarding the possibility of developing a proportional scintillation counter based on the detection of the infrared molecular emissions associated with the lowest vibrational states of molecules. The use of visible or near-infrared photons ([lambda]<1Â [mu]m) for applications like imaging and quality...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||