energy is described. Where and r]3 are the conversion efficiency from the laser energy to the kinetic energy of ions and from it to the electric energy respectively. 3.1.1. Experimental procedure. The experimental apparatus is shown in Fig. 3. Both carbon and cross-linked polyethylene (XLPE) are used as targets. The laser device is a TEA (Transversally Excited Atmospheric Pressure) CO2 laser with a wavelength of 10.6/zm. The laser output is about 8J/pulse at maximum and the fullwidth at half maximum of the laser pulse is about 150 nsec. At first, the method of measuring is explained. The laser energy is measured by a calorimeter. The ions' kinetic energy is measured by the Langmuir probe set at 1.5 m from the target surface. Firstly the voltage Vp is applied on the probe and the time variation of the probe current is measured. These waveforms of measured probe current for different applied voltage Vp are read and Vp-Ip characteristics at each time are obtained as shown in Fig. 4. The ion saturation current Isi at each time is obtained from the Vp-Ip curve and the ion density n is calculated by the following equation: where S is the area of the probe, e is the electric charge of an electron and v is the expansion velocity of ions, but the number of electric charges of an ion Z is assumed to
RkJQdWJsaXNoZXIy MTU5NjU0Mg==