A model for the formation of defects in RPC bakelite plates at high radiation levels

This study analyzes in detail the defects in bakelite observed in Resistive Plate Counters (RPC) after exposure to high-radiation environment and fluxed with humidified gas mixture at 9 kV voltage. Objective of this study was to identify the nature of defects and their formation mechanism. The defects were observed firstly on the whole RPC inner surface, and their localization mapped. The defected areas have been analyzed with optical and electron microscopy (SEM), and chemically by EDS (Energy Dispersion Spectroscopy) techniques. An area particularly defect-rich also analysed by x-ray diffraction (XRD). Samples of new and fluxed bakelite have been chemically analyzed by ICP-Plasma (via sample total digestion) in order to determine trace elements variations in composition. model is proposed to explain the chemistry of the formation process.