K-shell X-ray spectroscopy of laser produced aluminum plasma

Optimization of a laser produced plasma (LPP) X-ray source has been performed by analyzing K-shell emission spectra of Al plasma at a laser intensity of 10¹³–10¹⁴ W/cm². The effect of varying the laser intensity on the emissivity of the K-shell resonance lines is studied and found to follow a power law, I_x=(I_L)^α with α=2.2, 2.3, 2.4 for He_β, He_γ, He_δ respectively. The emission of these resonance lines has been found to be heavily anisotropic. A Python language based code has been developed to generate an intensity profile of K-shell spectral lines from the raw data. In theoretical calculations, the temperature is estimated by taking the ratio of the Li-like satellite (1s²2p–1s2p3p) and the He_β (1s²–1s3p) resonance line and the ratio of the He-like satellite (1s2p–2p²) and the Ly_α (1s–2p) resonance line. To determine the plasma density, stark broadening of the Ly_β spectral line is used. Simulation was carried out using the FLYCHK code to generate a synthetic emission spectrum. The results obtained by FLYCHK are T_e=160 eV, T_h=1 keV, f=0.008, n_e=5×10²⁰ cm^-3 and the analytical model resulted T_e=260–419 eV and n_e=3x10²⁰ cm^-3.