ABSTRACT The electron density and temperature of the laser induced silicon plasma were measured using two different methods. The plasma was produced via the interaction of high peak power Nd-YAG laser at the fundamental wavelength of 1064 nm with a plane solid iron target contain small traces of silicon as an element of minor concentration. The lines from the Si I at 288.15 nm and Si II-ionic lines at 413.08 and 634.71 nm were utilized to evaluate the plasma parameters. The reference plasma parameters were measured utilizing the Hα-line at 656.27 nm appeared in the spectra under the same condition. The electron density was measured utilizing the Stark broadening of the silicon lines and the temperature from the standard Saha-Boltzmann plot method. The comparison between electron densities from different silicon lines to that from the Hα-line reveals that the Si I-line at 288.15 nm contain some optical thickness while the Si II-ionic lines were found to be free from this effect. The measurements were repeated at different delay times between the laser and the camera in the range from 1 - 5 μsec. The electron density was found decreases from 2 × 1018 down to 4 × 1017 cm–3. After correcting the spectral intensity at the Si I-line at 288.15 nm, the temperatures evaluated from the different methods were found in an excellent agreement and decreases from 1.25 down to 0.95 eV with delay time.
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A. Sherbini and A. Aamer, "Measurement of Plasma Parameters in Laser-Induced Breakdown Spectroscopy Using Si-Lines," World Journal of Nano Science and Engineering, Vol. 2 No. 4, 2012, pp. 206-212. doi: 10.4236/wjnse.2012.24028.
 S. Klein, J. Hildenhagen, K. Dickmann, T. Stratoudaki and V. Zafiropulos, “LIBS-Spectroscopy for Monitoring and Control of the Laser Cleaning Process of Stone and Medieval Glass,” Journal of Cultural Heritage, Vol. 1, 2000, pp. S287-S292.
 O. Samek, D. C. S. Beddows, H. H. Telle, J. Kaiser , M. L?ska, J. O. Cáceres and A. Gonzáles Ure?a, “Quantitative Laser-Induced Breakdown Spectroscopy Analysis of Calcified Tissue Samples,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 56, No. 6, 2001, pp. 865-875.
 M. Z. Martin, N. Labbé, T. G. Rials and S. D. Wullschleger, “Analysis of Preservative-Treated Wood by Multivariate Analysis of Laser-Induced Breakdown Spectroscopy Spectra,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 60, No. 7-8, 2005, pp. 1179-1185.
 N. Carmon, M. Oujj, E. Rebollar, H. R?mich and M. Castillejo, “Analysis of Corroded Glasses by Laser Induced Breakdown Spectroscopy,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 60, No. 7-8, 2005, pp. 1155-1162. doi:10.1016/j.sab.2005.05.016
 L. St-Onge, E. Kwong, M. Sabsabi and E. B. Vadas, “Rapid Analysis of Liquid Formulations Containing Sodium Chloride Using Laser-Induced Breakdown Spectroscopy,” Journal of Pharmaceutical and Biomedical Analysis, Vol. 36, No. 2, 2004, pp. 277-284.
 L. Barrette and S. Turmel, “On-Line Iron-Ore Slurry Monitoring for Real-Time Process Control of Pellet Making Processes Using Laser-Induced Breakdown Spectroscopy: Graphitic vs. Total Carbon Detection,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 56, No. 6, 2001, pp. 715-723.
 L. E. Garcya-Ayuso, J. Amador-Hernández, J. M. Fernán- dez-Romero and M. D. Luque de Castro, “Characterization of Jewellery Products by Laser-Induced Breakdown Spectroscopy,” Analytica Chimica Acta, Vol. 457, No. 2, 2002, pp. 247-256. doi:10.1016/S0003-2670(02)00054-5
 A. Jurado-López and M. D. Luque de Castro, “Laser- Induced Breakdown Spectrometry in Jewellery Industry.: Part II: Quantitative Characterisation of Goldfilled Interface,” Talanta, Vol. 59, No. 2, 2003, pp. 409-415.
 F. Capitelli, F. Colao, M. R. Provenzano, R. Fantoni, G. Brunetti and N. Senesi, “Determination of Heavy Metals in Soils by Laser Induced Breakdown Spectroscopy,” Geoderma, Vol. 106, No. 1-2, 2002, pp. 45-62.
 I. B. Gornushkin, A.Ya. Kazakov, N. Omenetto, B. W. Smith and J. D. Winefordner, “Experimental Verification of a Radiative Model of Laser-Induced Plasma Expanding into Vacuum,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 60, No. 2, 2005, pp. 215-230.
 H. R. Griem, “Plasma Spectroscopy,” McGraw-Hill, Inc., New York, 1964.
 W. Lochte-Holtgreven, “Plasma Diagnostics,” North-Holland, Amsterdam, 1968.
 H. R. Griem, “Principles of Plasma Spectroscopy,” Cambridge University Press, Cambridge, 1997.
 A. M. El Sherbini, H. Hegazy and Th. M. El Sherbini, “Measurement of Electron Density Utilizing the Hα-Line from Laser Produced Plasma in Air,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 61, No. 5, 2006, pp. 532-539. doi:10.1016/j.sab.2006.03.014
 A. M. El Sherbini, Th. M. El Sherbini, H. Hegazy, G. Cristoforetti, S. Legnaioli, V. Palleschi, L. Pardini, A. Salvetti and E. Tognoni, “Evaluation of Self-Absorption Coefficients of Aluminum Emission Lines in Laser-Induced Breakdown Spectroscopy Measurements,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 60, No. 12, 2005, pp. 1573-1579.
 N. Konjevic, “Plasma Broadening and Shifting of Non- Hydrogenic Spectral Lines: Present Status and Applications,” Physics Reports, Vol. 316, No. 6, 1999, pp. 339- 401. doi:10.1016/S0370-1573(98)00132-X
 N. Konjevic, A. Lesage, J. R. Fuhr and W. L. Wiese, “Experimental Stark Widths and Shifts for Spectral Lines of Neutral and Ionized Atoms,” Journal of Physical and Chemical Reference Data, Vol. 31, No. 3, 2003, pp. 819- 927.
 A. Hssaine, B. Andre, F. Belkacem, R. Roland, R. Bruno and M. Pascal, “Correction of Self-Absorption Spectral Line and Ratios of Transition Probabilities for Homogeneous and LTE Plasma,” Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 75, No. 6, 2002, pp. 747-763. doi:10.1016/S0022-4073(02)00040-7
 P. Kepple and H. R. Griem, “Improved Stark Profile Calculations for the Hydrogen Lines Hα, Hβ, Hγ, and Hδ,” Physical Review Online Archive, Vol. 173, No. 1, 1968, pp. 317-325. doi:10.1103/PhysRev.173.317
 L. St-Onge, V. Detalle and M. Sabsabi, “Enhanced Laser-Induced Breakdown Spectroscopy Using the Combination of Fourth-Harmonic and Fundamental Nd:YAG Laser Pulses,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 57, No. 1, 2002, pp. 121-135.
 V. Narayanan and R. K. Thareja, “Emission Spectroscopy of Laser-Ablated Si Plasma Related to Nanoparticle Formation,” Applied Surface Science, Vol. 222, No. 1-4, 2004, pp. 382-393. doi:10.1016/j.apsusc.2003.09.038
 J. S. Cowpe, J. S. Astin, R. D. Pilkington and A. E. Hill, “Temporally Resolved Laser Induced Plasma Diagnostics of Single Crystal Silicon—Effects of Ambient Pressure,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 63, No. 10, 2008, pp. 1066-1071.
 L. M. Milán and J. J. Laserna, “Diagnostics of Silicon Plasmas Produced by Visible Nanosecond Laser Ablation,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 56, No. 3, 2001, pp. 275-288.
 H. C. Liu, X. L. Mao, J. H. Yoo and R. E. Russo, “Early Phase Laser Induced Plasma Diagnostics and Mass Removal during Single-Pulse Laser Ablation of Silicon,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 54, No. 11, 1999, pp. 1607-1624.
 A. M. EL Sherbini, A. M. Aboulfotouh, S. H. Allam and Th. M. EL Sherbini, “Diode Laser Absorption Measurements at the Hα-Transition in Laser Induced Plasmas on Different Targets,” Spectrochimica Acta Part B: Atomic Spectroscopy, Vol. 65, No. 12, 2010, pp. 1041-1046.