Laser-produced copper ion energy spectrum employing Thomson scattering technique

Investigations were performed on laser-assisted ion emission when a copper target was irradiated with a Nd:YAG laser (1.064 μm 10 mJ and 1.1 MW). Charge states present in the ion core emitted from plasma were determined employing Faraday cup arrangement using a four-channel 500 MHz Digital Storage Oscilloscope YOKOGAWA DL 1740. The Thomson parabola scattering (TPS) technique was used to measure the energy of ions emitted from plasma. Singly charged positive ions were found to be in excessive amount. For the energy analysis, the ion beam was collimated using a pinhole arrangement. The collimated beam was then made to pass through a uniform magnetic field of 0.4 T. A solid-state nuclear track detector PM-355 was used to register the ion tracks. The energy of ions, found to be in the range of 9-50 keV. The ion energy spectra d ² N/d²N/dEdΩ show a decreasing trend with increasing ion energy. The empirical relation dN/dE ∞ E ^-n fits well with the experimental data at higher values of energy, i.e., greater than 20 keV.