Measurements of gaseous multiplication coefficient in pure isobutane

Author(s)

Iara Batista de Lima

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Pesquisas Energéticas e Nucleares (IPEN/BT)
• Defense date: 2010-03-15

Examining board members

Carmen Cecília Bueno Tobias; Josemary Angélica Corrêa Gonçalves; Marcos Nogueira Martins

• Advisor: Carmen Cecília Bueno Tobias

Abstract

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. (AU)

• FAPESP's process: 07/06773-0 - Measurements of Gaseous Multiplication Coefficient of Pure Isobuthane
• Grantee: Iara Batista de Lima
• Support Opportunities: Scholarships in Brazil - Master