The Laser-Induced Breakdown Spectroscopy (LIBS) plasma characteristics are known to strongly dependent on the surrounding pressure. Six different samples (C, Ni, Cu, Sn, Al, Zn) are used to support the existence of a `soft spot' in the vicinity of 1 torr where the maxima in plasma lifetime is observed. With pressure decrease, the elemental lifetimes of samples except for carbon increased until 1 torr and started to decline with continued pressure drop. The boiling point and electronegativity of the samples are amongst the physicochemical properties that are used to explain this peculiarity.
Isomeric states in 59,61 Ti have been populated in the projectile fragmentation of a 345 AMeV 238 U beam at the Radioactive Isotope Beam Factory. The decay lifetimes and delayed γ-ray transitions were measured with the EURICA array. Besides the known isomeric state in 59 Ti, two isomeric states in 61 Ti are observed for the first time. Based on the measured lifetimes, transition multipolarities as well as tentative spins and parities are assigned. Large-scale shell model calculations based on the modified LNPS interaction show that both 59 Ti and 61 Ti belong to the Island of Inversion at N = 40 with ground state configurations dominated by particle-hole excitations to the g 9/2 and d 5/2 orbits.
Categorized certified reference materials simulating metal, rock, soils, or dusts are used to demonstrate the standoff detection capability of laser-induced breakdown spectroscopy (LIBS) at severely low pressure conditions. A Q-switched Nd:YAG laser operating at 1064 nm with 17.2-50 mJ energy per pulse was used to obtain sample signals from a distance of 5.5 m; the detection sensitivity at pressures down to 0.01 torr was also analyzed. The signal intensity response to pressure changes is explained by the ionization energy and electronegativity of elements, and from the estimated full width half-maximum (FWHM) and electron density, the decrease in both background noise and line broadening makes it suitable for low pressure detection using the current standoff LIBS configuration. The univariate analyses further showed high correlation coefficients for geological samples. Therefore, the present work has extended the current state-of-the-art of standoff LIBS aimed at harsh environment detection.
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