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Impact of laser energy and gate delay on self-absorption of emission lines in laser induced plasma spectroscopy

Laser-induced plasma spectroscopy (LIPS) is a spectroscopy that utilizes laser induced plasma as an emission source. The most challenging part in dealing with emission lines is the self-absorption (SA) which distorts the profile and reduces emission intensity of the spectrum. Resonant lines are most...

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Main Author: Mohd. Sabri, Nursalwanie
Format: Thesis
Language:English
Published: 2018
Subjects:
QC Physics
Online Access:http://eprints.utm.my/id/eprint/81476/1/NursalwanieMohdSabriMFS2018.pdf
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spelling my.utm.814762019-08-23T05:19:01Z http://eprints.utm.my/id/eprint/81476/ Impact of laser energy and gate delay on self-absorption of emission lines in laser induced plasma spectroscopy Mohd. Sabri, Nursalwanie QC Physics Laser-induced plasma spectroscopy (LIPS) is a spectroscopy that utilizes laser induced plasma as an emission source. The most challenging part in dealing with emission lines is the self-absorption (SA) which distorts the profile and reduces emission intensity of the spectrum. Resonant lines are most prominent lines of an element in the spectrum and at the same time most prone to SA. This project focuses on the impact of experimental parameters; laser energy and gate delay on the SA coefficient of emission lines which depends on two plasma parameter namely electron temperature, Te and electron density, Ne. A sample made of Al, Mn and Zn embedded in KBr matrix was irradiated with Nd:YAG laser and the plasma signals were recorded using optical spectrometer attached to a delay unit. The atomic and ionic spectral lines of Al, Mn and Zn were observed in the spectra. The lines were verified using references and National Institute of Standards and Technology (NIST) database. Resonant lines are Al I 256.4 nm, Al I 265.6 nm, Al I 308.2 nm, Mn I 403.3 nm, Mn II 259.4 nm and Mn II 260.1 nm. The laser energy was varied from 5 to 650 mJ at a fixed gate delay of 3.75 µs, meanwhile, the gate delay was varied from 0 to 23.75 µs at a fixed laser energy of 650 mJ. The intensity of the emission lines was found increasing in response to higher laser energy. The emission lines of Al, Mn and Zn was found initially increased in intensity within first 1 µs, but then it decreased as the increasing delay time. Te was calculated using the intensity ratio method applied on Mn I 257.6 nm and Mn I 422.5 nm emission lines and Ne was determined using Stark broadening method of Ha-line 656.3 nm. The SA coefficient was calculated for both experimental parameters, by using resonant lines Al I 308.2 nm and Mn II 259.4 nm, and non-resonant lines; Al I 309.1 nm and Mn I 257.6 nm. SA coefficient has variation from 0 to 1. The maximum value of the coefficient indicates that the emission lines is free from SA. The SA coefficient was found to increase from 0.3 to 0.9 as the laser energy increased resulting from rise in Te and Ne of the plasma. Meanwhile, the increasing gate delay caused the SA coefficient to decrease from 0.9 to 0.1, where the emission lines are more prone to SA. This is due to the decreasing of Te and Ne. This work has emphasized on implementation of higher laser energy and shorter gate delay of LIPS experimental parameters as response to SA coefficient. It will save time and effort and lead to reliable plasma diagnostics, as well as pioneers in studying plasma opacity. 2018 Thesis NonPeerReviewed application/pdf en http://eprints.utm.my/id/eprint/81476/1/NursalwanieMohdSabriMFS2018.pdf Mohd. Sabri, Nursalwanie (2018) Impact of laser energy and gate delay on self-absorption of emission lines in laser induced plasma spectroscopy. Masters thesis, Universiti Teknologi Malaysia. http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:124966
institution Universiti Teknologi Malaysia
building UTM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Teknologi Malaysia
content_source UTM Institutional Repository
url_provider http://eprints.utm.my/
language English
topic QC Physics
spellingShingle QC Physics
Mohd. Sabri, Nursalwanie
Impact of laser energy and gate delay on self-absorption of emission lines in laser induced plasma spectroscopy
description Laser-induced plasma spectroscopy (LIPS) is a spectroscopy that utilizes laser induced plasma as an emission source. The most challenging part in dealing with emission lines is the self-absorption (SA) which distorts the profile and reduces emission intensity of the spectrum. Resonant lines are most prominent lines of an element in the spectrum and at the same time most prone to SA. This project focuses on the impact of experimental parameters; laser energy and gate delay on the SA coefficient of emission lines which depends on two plasma parameter namely electron temperature, Te and electron density, Ne. A sample made of Al, Mn and Zn embedded in KBr matrix was irradiated with Nd:YAG laser and the plasma signals were recorded using optical spectrometer attached to a delay unit. The atomic and ionic spectral lines of Al, Mn and Zn were observed in the spectra. The lines were verified using references and National Institute of Standards and Technology (NIST) database. Resonant lines are Al I 256.4 nm, Al I 265.6 nm, Al I 308.2 nm, Mn I 403.3 nm, Mn II 259.4 nm and Mn II 260.1 nm. The laser energy was varied from 5 to 650 mJ at a fixed gate delay of 3.75 µs, meanwhile, the gate delay was varied from 0 to 23.75 µs at a fixed laser energy of 650 mJ. The intensity of the emission lines was found increasing in response to higher laser energy. The emission lines of Al, Mn and Zn was found initially increased in intensity within first 1 µs, but then it decreased as the increasing delay time. Te was calculated using the intensity ratio method applied on Mn I 257.6 nm and Mn I 422.5 nm emission lines and Ne was determined using Stark broadening method of Ha-line 656.3 nm. The SA coefficient was calculated for both experimental parameters, by using resonant lines Al I 308.2 nm and Mn II 259.4 nm, and non-resonant lines; Al I 309.1 nm and Mn I 257.6 nm. SA coefficient has variation from 0 to 1. The maximum value of the coefficient indicates that the emission lines is free from SA. The SA coefficient was found to increase from 0.3 to 0.9 as the laser energy increased resulting from rise in Te and Ne of the plasma. Meanwhile, the increasing gate delay caused the SA coefficient to decrease from 0.9 to 0.1, where the emission lines are more prone to SA. This is due to the decreasing of Te and Ne. This work has emphasized on implementation of higher laser energy and shorter gate delay of LIPS experimental parameters as response to SA coefficient. It will save time and effort and lead to reliable plasma diagnostics, as well as pioneers in studying plasma opacity.
format Thesis
author Mohd. Sabri, Nursalwanie
author_facet Mohd. Sabri, Nursalwanie
author_sort Mohd. Sabri, Nursalwanie
title Impact of laser energy and gate delay on self-absorption of emission lines in laser induced plasma spectroscopy
title_short Impact of laser energy and gate delay on self-absorption of emission lines in laser induced plasma spectroscopy
title_full Impact of laser energy and gate delay on self-absorption of emission lines in laser induced plasma spectroscopy
title_fullStr Impact of laser energy and gate delay on self-absorption of emission lines in laser induced plasma spectroscopy
title_full_unstemmed Impact of laser energy and gate delay on self-absorption of emission lines in laser induced plasma spectroscopy
title_sort impact of laser energy and gate delay on self-absorption of emission lines in laser induced plasma spectroscopy
publishDate 2018
url http://eprints.utm.my/id/eprint/81476/1/NursalwanieMohdSabriMFS2018.pdf
http://eprints.utm.my/id/eprint/81476/
http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:124966
_version_ 1643658721885159424
score 13.211869

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