Quantitative Hydrogen Analysis of Zircaloy-4 Using Low-Pressure Laser Plasma Technique

Abstract

It is found in this work that variation of laser power density in low-pressure plasma spectrochemical analysis of hydrogen affects sensitively the hydrogen emission intensity from the unwanted and yet ubiquitous presence of ambient water. A special experimental setup has been devised to allow the simple condition of focusing/defocusing the laser beam on the sample surface. When applied to zircaloy-4 samples prepared with various hydrogen impurity concentrations using low-pressure helium surrounding gas, good-quality hydrogen emission lines of very high signal to background ratios were obtained with high reproducibility under weakly focused or largely defocused laser irradiation. These measurements resulted in a linear calibration line with nonzero intercept representing the residual contribution from the recalcitrant water molecules. It was further shown that this can be evaluated and taken into account by means of the measured intensity ratio between the oxygen and zirconium emission lines. We have demonstrated the applicability of this experimental approach for quantitative determination of hydrogen impurity concentrations in the samples considered.

Investigation of helium addition for laser-induced plasma spectroscopy of pure gas phase systems: Analyte interactions and signal enhancement

“…The recent work by Kurniawan and co-workers has specifically addressed this issue for hydrogen analysis via LIBS [20][21][22][23][24]. Similar to the current results, they observed an increase in hydrogen emission intensities combined with a decrease in hydrogen line broadening with helium addition, in which the latter may be interpreted as a decrease in electron density although no direct electron density calculations were reported.…”

“…Helium was found to produce the optimal signal-to-noise ratio in comparison to air and argon, and resulted in reduced line broadening. Contemporary studies by Kurniawan and co-workers have specifically addressed the role of helium for enhancement of hydrogen analysis in solid samples, including zircaloy-4 alloys, via the LIBS technique [20][21][22][23][24]. In their studies, hydrogen emission intensities were enhanced while Stark broadening was reduced through the use of helium breakdown, using both single and double-laser LIBS methodologies.…”

Spatial distribution of hydrogen and other emitters in aluminum laser-induced plasma in air and consequences on spatially integrated Laser-Induced Breakdown Spectroscopy measurements

“…6 confirms that the H I species is located in the same zone of Al I at any delay times investigated in the present work. These results suggest that the LIP H I content is mainly due to the ablation of the aluminum target, on whose surface water from background air adsorbs, and in a much lesser amount to the air breakdown [20]. This is reasonable considering the high adsorption coefficients on Al (as well as Al 2 O 3 ) and the lower breakdown thresholds of metals with respect to gases.…”

Deuterium analysis in zircaloy using ps laser-induced low pressure plasma

“…[13][14][15] Subsequently, research interest along this line was revived and intensified in response to the need of hydrogen analysis in some important materials, such as zircaloy used for fuel vessels in light water nuclear power plants, the widely used titanium alloys in industry, and the non-alloyed Ti used for medical purposes. 16,17 The excessive penetration of hydrogen into these materials is known to deteriorate the mechanical strength and other useful properties of the materials, thereby jeopardizing their functional reliability. Unfortunately, the usual LIBS method does not deliver its standard excellent performance to the sensitive detection of hydrogen.…”