Optimization of the aluminium target thickness on space charge measurement using the LIPP technique

In this paper, the influence of the Aluminium (Al) disc thickness on the acoustic reflection, spatial resolution of space charge measurements in 1.2mm and 2mm XLPE plaques using the LIPP system has been studied. Experimental results indicate that there exists a minimum thickness of Al for each sample, which requires eliminating the signal reflection. It is also revealed that the spatial resolution determinate with the thickness of Al. Using a optimal thickness of Al for the target, preliminary results obtained from 2mm as-received and degassed planar XLPE samples subjected to a dc electric stress of 30 kV/mm (at room temperature) for 24 hours are reported.