The following two-step isotope selective photoionization process has been studied for the separation of Ir isotope from natural Iridium irradiated in a medium flux reactor for 28 days.5d6sF9/240.0cm→247.5871nm5d6s6p40389.83cmJ=9/2→307.9nmIrDensity matrix formalism has been used for the investigation of laser isotope separation process. Optimum system parameters such as peak power densities of the excitation and ionization lasers, bandwidth of the excitation laser, angular divergence limit to the atomic ensemble have been derived. Effects of number density and ion travel distance prior to collection on charge exchange probability have also been studied. It has been shown that it is possible produce ∼98% enriched Ir at rate of 82 μg/h (27.9 GBq/h or 0.76 Ci/h) which can provide activity of 334 TBq/g or 9027 Ci/g. The enriched Ir can be used in both high-dose brachytherapy and high speed radiography. This is the first ever study on the laser based enrichment of Iridium isotopes.
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http://dx.doi.org/10.1016/j.apradiso.2023.110820 | DOI Listing |
Talanta
January 2025
Radioisotope Science and Technology Division, Oak Ridge National Laboratory, USA. Electronic address:
Single particle - inductively coupled plasma - mass spectrometry (SP-ICP-MS) is a powerful technique for characterization of the elemental and isotopic composition of individual particles. In this work, the capabilities of the newest generation of MC-ICP-MS with acquisition rates down to 50 ms were evaluated for single particle analysis, with a focus on isotopic precision achievable on a single-particle level. Nd (NdVO) nanoparticles (∼120 nm in diameter) were used as case study and were first characterized in terms of mass (respective size) and particle number concentration by SP-ICP-TOF-MS and then by SP-MC-ICP-MS for isotopic precision.
View Article and Find Full Text PDFAnal Chem
January 2025
Laboratory for Air Pollution/Environmental Technology, Empa, 8600 Dübendorf, Switzerland.
Mid-infrared laser absorption spectroscopy enables rapid and nondestructive analysis of methane clumped isotopes. However, current analytical methods require a sample size of 20 mL STP (0.82 mmol) of pure CH gas, which significantly limits its application to natural samples.
View Article and Find Full Text PDFAnal Chem
January 2025
Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China.
Detection of trace gases, such as radioactive carbon dioxide, clumped isotopes, and reactive radicals, is of great interest and poses significant challenges in various fields. Achieving both high selectivity and high sensitivity is essential in this context. We present a highly selective molecular spectroscopy method based on comb-locked, mid-infrared, cavity-enhanced, two-photon absorption.
View Article and Find Full Text PDFJ Phys Chem Lett
December 2024
Biomolecular Physics Department, Faculty of Physics, Babeş-Bolyai University, 1 M. Kogalniceanu Str., 400084 Cluj-Napoca, Romania.
Surface-enhanced Raman spectroscopy (SERS) has emerged as a powerful tool for analyzing nucleic acids due to its exceptional sensitivity and specificity. This study rigorously investigates not only the impact of polyA strands of different lengths (, 5, 10, 15, and 20 adenine bases) but also their distinct grafting strategy (SH at 5' and NH at 5' end) on the SERS signal of DNA strand using synthesized gold nanoparticles (AuNPs) on graphene oxide sheets (GO-AuNPs). By comparing the thiol vs amine bonding onto the GO-AuNP nanoplatform, we found a strong correlation between the adenine peak intensity at 732 cm and the strand length for both grafting methods (SH at 5' end or NH at 5' end).
View Article and Find Full Text PDFPhotochem Photobiol
December 2024
Institute of Chemistry, State University of Campinas, Campinas, São Paulo, Brazil.
Given that non-equilibrium molecular motion in thermal gradients is influenced by both solute and solvent, the application of spectroscopic methods that probe each component in a binary mixture can provide insights into the molecular mechanisms of thermal diffusion for a large class of systems. In the present work, we use an all-optical setup whereby near-infrared excitation of the solvent leads to a steady-state thermal gradient in solution, followed by characterization of the non-equilibrium system with electronic spectroscopy, imaging, and intensity. Using rhodamine B in water as a case study, we perform measurements as a function of solute concentration, temperature, wavelength, time, near-infrared laser power, visible excitation wavelength, and isotope effect.
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