Plasma Atomization of Strontium Chloride Powder by a Supersonic Plasma Jet and Measurement of Its Efficiency Using Diode Laser Absorption Spectroscopy

Abstract

Direct elemental and isotope analyses of solid samples have attracted considerable interest due to their potential role in preventing serious accidents at nuclear facilities. We previously developed an analytical method for detecting radioactive isotopes, combining diode laser absorption spectroscopy with a supersonic plasma jet. Its basic performance, that is, the detection limit as well as the translational temperature upstream and downstream of the supersonic nozzle, was investigated using stable Xe isotopes. The developed apparatus could atomize a solid sample and reduce the translational temperature for isotope identification. For direct isotope analysis, translational temperature and atomization efficiency during powder feeding are remarkably important. In the present study, a novel approach for the atomization of Sr powder samples containing isotopes with highly radiotoxic radionuclides is described. We found that the temperature of Sr atoms in the supersonic plasma jet decreased to approximately 85 K, which is comparable with the slight isotope shift of 88 Sr– 90 Sr due to the difference in mass number. Moreover, based on the measured atomic number density and flow velocity, the atomization efficiency was found to be 10.4 ± 1.8%. The results of this study and further improvements in the efficiency can lead to the development of powerful tools for the rapid analysis of solid samples, particularly those contaminated with highly radioactive species, without the necessity for complex chemical separation.

Doppler splitting and expansion dynamics of laser-produced plasma plume under a high vacuum ambience

“…The suppression of the loss due to LPP expansion and plasma connement are required to apply differential pumping, such as an orice and supersonic nozzle. 24,25 In addition, the role of molecules in the LPP plume [54][55][56] and the inuence of direct ionisation by LAs can provide useful information to suppress the loss and improve the analysis accuracy.…”

“…column density of particles and gas temperature) owing to the use of narrowlinewidth (<100 kHz) tuneable lasers. [23][24][25][26] Miyabe et al investigated the expansion dynamics of atoms and ions in LPP in the range of 10 1 -10 3 Pa varying by He and Ar gas, 27 and Harilal et al have particularly extended the target to LPP induced by a femtosecond-pulsed laser. 28,29 These studies and many applications of laser-induced breakdown spectroscopy have concentrated on moderate-to-atmospheric pressures in the range of 10 2 -10 5 Pa.…”

Lamb-Dip Laser-Induced Fluorescence Spectroscopy in a Supersonic Plasma Jet for Isotope Identification

“…Details of the shape and dimensions of the nozzle were described in the authors' previous studies. [15][16][17] To detect the Sr atoms, an external cavity diode laser (Toptica, DL100) was used with the laser linewidth set to a frequency of approximately 100 kHz as the probe laser light source. The laser wavelength was scanned over an absorption profile by modulating the voltage of the piezoelectric element.…”

“…This exhibits both a high-temperature region for sample preparation and a low-temperature region for isotopic identification. [15][16][17] In the authors' previous studies, the temperature of Xe and Sr atoms were greatly reduced to approximately 180 and 86 K, respectively. 16,17) In particular, Sr was successfully detected directly from a solid sample.…”

“…[15][16][17] In the authors' previous studies, the temperature of Xe and Sr atoms were greatly reduced to approximately 180 and 86 K, respectively. 16,17) In particular, Sr was successfully detected directly from a solid sample. Although this method provided essential information for rapid analysis, complete removal of the Doppler broadening effect was not possible.…”