Mémoire de Maîtrise
DOI
https://doi.org/10.11606/D.85.2010.tde-10082011-102711
Document
Auteur
Nom complet
Iara Batista de Lima
Adresse Mail
Unité de l'USP
Domain de Connaissance
Date de Soutenance
Editeur
São Paulo, 2010
Directeur
Jury
Tobias, Carmen Cecília Bueno (Président)
Gonçalves, Josemary Angélica Corrêa
Martins, Marcos Nogueira
Titre en portugais
Medidas do coeficiente de multiplicação gasosa no isobutano puro
Mots-clés en portugais
coeficiente de multiplicação
isobutano
parâmetros de transporte em gases
Resumé en portugais
Neste trabalho so apresentadas as medidas do coeficiente de multiplicao gasosa (α) no isobutano puro obtidas com uma cmara de placas paralelas protegida contra descargas por um eletrodo de vidro (anodo) de elevada resistividade (ρ = 2 x 1012.cm). O mtodo empregado foi o de Townsend pulsado, onde a ionizao primria produzida pela incidncia de um feixe de laser de nitrognio em um eletrodo metlico (catodo). As correntes eltricas medidas com a cmara operando em regime de ionizao e de avalanche foram utilizadas para o clculo do coeficiente de multiplicao gasosa pela soluo da equao de Townsend para campos eltricos uniformes. A tcnica utilizada foi validada pelas medidas do coeficiente de multiplicao gasosa no nitrognio, um gs amplamente estudado, e para o qual se tem dados bem estabelecidos na literatura. Os coeficientes de multiplicao gasosa do isobutano foram medidos em funo do campo eltrico reduzido no intervalo de 139Td a 208Td. Os valores obtidos foram comparados com os simulados pelo programa Imonte (verso 4.5) e com os nicos dados existentes na literatura, recentemente obtidos pelo nosso grupo. Esta comparao demonstrou que os resultados so concordantes dentro dos erros experimentais.
Titre en anglais
Measurements of gaseous multiplication coefficient in pure isobutane
Mots-clés en anglais
isobutane
multiplication coefficient
Resumé en anglais
In this work it is presented measurements of gaseous multiplication coefficient (α) in pure isobutane obtained with a parallel plate chamber, protected against discharges by one electrode (anode) of high resistivity glass (ρ = 2 x 1012.cm). The method applied was the Pulsed Townsend, where the primary ionization is produced through the incidence of a nitrogen laser beam onto a metallic electrode (cathode). The electric currents measured with the chamber operating in both ionization and avalanche regimes were used to calculate the gaseous multiplication coefficient by the solution of the Townsend equation for uniform electric fields. The validation of the technique was provided by the measurements of gaseous multiplication coefficient in pure nitrogen, a widely studied gas, which has well-established data in literature. The coefficients in isobutane were measured as a function of the reduced electric field in the range of 139Td up to 208Td. The obtained values were compared with those simulated by Imonte software (version 4.5) and the only experimental results available in the literature, recently obtained in our group. This comparison showed that the results are concordant within the experimental errors.
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Date de Publication
2011-08-15
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