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Confinement Effect in TEA CO2 Laser-Induced Plasma on Solid Organic Samples
Nasrullah Idris,Yong-Inn Lee,Hendrik Kurniawan,Kiichiro Kagawa,Maria Margaretha Suliyanti,Takao Kobayashi,Tjung Jie Lie 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.47 No.1
A Transversely Excited Atmospheric (TEA) CO2 laser beam (500 mJ, 200 ns) was focused on soft solid organic compounds under a low-pressure surrounding gas at around 2 Torr. We found that in order to induce a laser plasma from solid organic sample, such as plastics, the ablated atoms must be confined in a small hole (diameter of about 1 mm and depth of around 1 − 2 mm). Using our unique technique of density jump measurement (Rainbow Interferometer), we proved that the plasma is excited by a shock wave and that the confining hole works to induce and enhance a strong shock wave. The plasma has favorable characteristics for spectrochemical analysis due to its low spectral background and sharp emission lines; hence, the spectra can be taken using optical multichannel analyzer (OMA) without gated mode. By using the confinement effect, we detected chlorine ionic lines (Cl II at 479.4 nm, Cl II at 481.0 nm, and Cl II at 481.9 nm) with relatively strong emission intensities in the plastic sample containing chlorine.
Nasrullah IDRIS,Yong Inn LEE,Kiichiro KAGAWA,Koo Hendrik KURNIAWAN 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.51 No.2I
An electromagnetic phenomenon in terms of the induced current in a laser ablation process has been studied, and its potential application has been demonstrated. A new electrode configuration for measuring the induced current emerged due to the interaction between the electric lines of force and the laser-produced plasma has been devised. In this new electrode configuration, the induced current is detected by employing a circuit of electrodes, supplied with several hundred DC volts and placed above the sample surface in parallel, which is called the parallel configuration. This parallel configuration provides a far higher flexibility in comparison with the sandwiched configuration developed in our previous work. The induced current signal can be detected from various samples of any size, including metals and nonmetals. We found that the source of the induced current was the outer electrons in the plasma. This induced current is very useful as a unique monitoring method and promises many applications in laser microprocessing. In this work, this induced current method was applied for several monitoring purposes in laser material processing, such as for estimating the ablated amount, monitoring the penetration of a laser beam into processed materials, and determining the precise tight focusing position of the lens, in real time.
Sub-target effect in film analysis using TEA CO2 laser-induced plasma
Yong-Inn Lee,Nasrullah Idris,Koo Hendrik Kurniawan,Tjung Jie Lie,Kenichiro Tsuyuki,Satoru Miura,Kiichiro Kagawa 한국물리학회 2007 Current Applied Physics Vol.7 No.5
A bioactive and biodegradable composite material consisting of hydroxyapatite (HA) and polyhydroxybutyrate (PHB) was investi-PHB composite which contained up to 40% by volume of particulate HA. The processing parameters for composite manufacture wereoptimized through thermal analyses of HA/PHB composite produced and production trials. The microstructure and properties of thecomposite were evaluated using various techniques. Form the results obtained, it is shown that good quality HA/PHB composite prod-ucts could be manufactured via the established production route.