Encontrados 47 documentos, a visualizar página 1 de 5
Performance of Argon-Xenon Mixtures in a Gas Proportional Scintillation Counter...
Carmo, S. J. C. do; Borges, F. I. G. M.; Conde, C. A. N.The performance of a gas proportional scintillation counter filled with either pure Xe or Ar-Xe mixtures is described for the 0.1-10 keV X-ray energy range. It is shown that the spectra tail distortion exhibited by Xe filled gaseous detectors for soft X-rays below 2 keV is reduced if Ar-Xe mixtures are used. The peak-to-valley ratio increases by a factor of about 2 or 3 as the Xe concentration is reduced from 1...
Monte Carlo calculations of drift velocities and diffusion coefficients of Ar+ ...
Barata, J. A. S.; Conde, C. A. N.Results are presented for the calculated drift velocities and diffusion coefficients for Ar+ ions in helium at atmospheric pressure, temperature T=300 K and for reduced electric fields E/N from about 1 Td up to about 150 Td, using Monte Carlo techniques. The drift velocities range from 5.94×103 to 559.0×103 cm s-1 for the Ar+ ions in the ground state 2P3/2 and from 5.85×103 to 545.0×103 cm s-1 for the Ar+ ions ...
A new experimental technique for positive ion drift velocity measurements in no...
Neves, P. N. B.; Conde, C. A. N.; Távora, L. M. N.A new technique is described for measuring the drift velocities and mobilities of noble gas ions in noble gases that makes use of a gaseous electron multiplier (GEM) and a UV flash lamp to produce the ions in a thin, well-defined, planar region. The drift velocities are determined from measurements of the transit time of the ions in crossing the drift space. We present experimental results for xenon ions in xen...
A simulation study of the effect of drift electric fields on the response of ra...
Távora, L. M. N.; Dias, T. H. V. T.; Conde, C. A. N.The effect of the presence of a drift electric field on the response of gaseous and semiconductor radiation detectors to energetic X-rays (energies from 20 to 200 keV) is investigated using the PENELOPE code to simulate the photo-absorption and the slow-down of the electrons produced in Si, Ge, and Xe gas at 1 atm. For typical drift fields, the energy deposited in the detection media is calculated taking into a...
Planar LAAPDs: temperature dependence, performance, and application in low-ener...
Ludhova, L.; Amaro, F. D.; Antognini, A.; Biraben, F.; Cardoso, J. M. R.; Conde, C. A. N.; Covita, D. S.; Dax, A.; Dhawan, S.; Fernandes, L. M. P.An experiment measuring the 2S Lamb shift in muonic hydrogen ([mu]-p) was performed at the Paul Scherrer Institute, Switzerland. It required small and compact detectors for 1.9 keV X-rays (2P-1S transition) with an energy resolution around 25% at 2 keV, a time resolution better than 100 ns, a large solid angle coverage, and insensitivity to a 5 T magnetic field. We chose Large Area Avalanche Photodiodes (LAAPDs...
X-ray spectrometry with Peltier-cooled large area avalanche photodiodes
Fernandes, L. M. P.; Lopes, J. A. M.; Santos, J. M. F. dos; Conde, C. A. N.Performance characteristics of the response of a Peltier-cooled large-area avalanche photodiode are investigated. Detector gain, energy linearity, energy resolution and minimum detectable energy are studied at different operation temperatures. Detector energy resolution and lowest detectable X-ray energy present a strong improvement as the operation temperature is reduced from 25 to 15 °C and slower improvement...
Calculation of elastic integral and differential collision cross-sections for l...
Barata, J. A. S.; Conde, C. A. N.http://www.sciencedirect.com/science/article/B6TVT-4CJV8FD-2/1/ca6fcda4998b56a276acc3c13ed660de
Monte Carlo calculations of drift velocities of Ne+ ions in helium
Barata, J. A. S.; Conde, C. A. N.http://www.sciencedirect.com/science/article/B6TVT-4CJV8FD-C/1/00202ca836fe62f957759a4e3ff18ae9
Intrinsic limitations in the energy resolution of drift-field based radiation d...
Távora, L. M. N.; Conde, C. A. N.; Santos, F. P.; Dias, T. H. V. T.; Rachinhas, P. J. B. M.http://www.sciencedirect.com/science/article/B6TVT-4CJV8FD-4/1/9b1ae9691329367fa8f13902d8fd318d
A curved-grid gas proportional scintillation counter instrumented with a 25-mm ...
Monteiro, C. M. B.; Morgado, R. E.; Santos, J. M. F. dos; Conde, C. A. N.The curved-grid technique provides a simple method to compensate for the variation in solid angle viewed by the PMT in large-area gas proportional scintillation counters (GPSC), improving their performance. The scintillation region is delimited by a planar grid and a curved one, whose shape is calculated to produce a radially increasing scintillation yield, compensating for the decrease in the solid angle. In t...
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