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Doctoral Thesis
DOI
10.11606/T.54.1984.tde-14102009-112032
Document
Author
Full name
Roberto Mendonça Faria
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 1984
Supervisor
Title in Portuguese
Medidas de absorção dielétrica e condutividade induzida por radiação ionizante em polifluoreto de vinilideno
Keywords in Portuguese
Absorção dielétrica
Armadilhamento
Condutividade induzida
Radiação ionizante
Abstract in Portuguese
Neste trabalho reportamos numerosas medidas de correntes devido á condutividade induzida por raios-x, durante e após a irradiação em amostras de filme de PVF2. Uma série de paramêtros de medidas foram variados, tais como: o campo elétrico, a taxa de radiação, o tipo de eletrodo, as condições atmosféricas das medidas e a espessura das atmosferas. Foram também feitas medidas de correntes de cargas e descarga de Absorção Dielétrica em ar úmido, em ar seco, em argônio e no vácuo. Curvas de correntes termo-estimuladas em amostras irradiadas e não-irradiadas permitiram verificar a presença de armadilhas no material, e também obter parâmetros dessas armadilhas. Finalmente desenvolveu-se modelo teórico e calculou-se curvas características para as correntes induzidas que concordaram com as curvas experimentais. O ajuste das curvas permitiu a determinação de valores numéricos para parâmetros de material.
Title in English
Dielectric abosrption and induced conductivity by ionizing radiation in PVDF
Keywords in English
Dielectric absorption
Induced conductivity
Ionization radiation
Trapping-detrapping
Abstract in English
We measured the radiation induced conductivity (RIC), prompt and delayed, in PVDF films under varied conditions, such as: electric fields, dose rate, electrode material, atmospheric environment and sample thickness. Polarization and depolarization absorption currents were also measured in dry and wet air, in argon and vacuum. Thermostimulated current measurements were carried out in irradiate samples showing that excited charges maybe captured by traps. Analysis of these currents led to the evaluation of the trap parameters. A model was developed in order interpret the transient RIC, assuming trapping, detrapping, recombination centers and also taking into account the extraction time.
 
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Publishing Date
2009-12-04
 
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