ABSTRACT
In nuclear reactors that use molten fluoride salts, either as coolants or as the medium for the fuel, the purity of the salts is critical for controlling salt chemistry and mitigating corrosion. Water is a particularly important contaminant in this regard, as it participates in a number of important corrosion reactions, so the careful measurement of oxygen, which is principally present in the salts due to water contamination, is a critical step in salt characterization. Here, we present an analytical method for quantifying oxygen contamination in Li2BeF4 (FLiBe), a technologically important and suitably representative fluoride salt, with a detection limit of 22 µg of oxygen, or 110 ppm in a 200 mg sample. To test the method, four FLiBe samples from different batches were tested. Two of these showed oxygen concentrations below the method detection limit, while two showed concentrations above it. In particular, the difference in the oxygen concentration between purified and un-purified batches of material from Kairos Power showed the efficacy of this method in characterizing the degree of oxygen removal obtained from purification methods.
ABSTRACT
In this paper, we experimentally demonstrate a strong correlation between the frequencies of the Raman pump and the Raman probe inside an optically pumped Raman laser. We show that the correlation is due to rapid adjustment of the phase of the dipoles that produce the Raman gain, following a sudden jump in the phase of the Raman pump. A detailed numerical model validates this interpretation of the phase correlation. The width of the spectrum of the beat between the Raman pump and the Raman laser is significantly narrowed due to this correlation. As a result, the minimum measurable change in the cavity length, for a given linewidth of the Raman pump laser, is substantially reduced. Therefore, this finding is expected to enhance the sensitivity of such a laser in various metrological applications (e.g., accelerometry).
ABSTRACT
For the first time, optical cooling has been observed in the (4)I(13/2) excited state of erbium(III), using the low phonon energy host materal, potassium lead chloride (KPb(2)Cl(2)). Cooling was observed when samples were pumped at wavelengths longer than 1557 nm, 17 nm longer than the mean fluorescence wavelength of 1540 nm, which implies a nonradiative heat load of 1.1% for the (4)I(13/2)-->(4)I(15/2) transition. When pumped at 1568 nm, the total cooling efficiency was 0.38% of the absorbed power. These results highlight the potential of Er(3+):KPb(2)Cl(5) as a material for lasers operating in an eye safe spectral region.
Subject(s)
Erbium/chemistry , Lasers , Cold Temperature , Computer-Aided Design , Equipment Design , Equipment Failure Analysis , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
Doubly vibrationally enhanced (DOVE) resonances have been observed in the infrared four-wave mixing (IRFWM) spectra of crotononitrile. The 2D DOVE-FWM spectra of the cis and trans isomers of crotononitrile showed cross peaks between the CN stretching fundamental and the CN + C=C stretch and the CN + C-C stretch combination bands for each of the two isomers that were observed, demonstrating the isomer selectivity of DOVE-IRFWM. Frequency-domain simulations were able to reproduce the features of the observed spectra, so the values for the nonlinearity and dephasing rates of all of the nonlinear processes could be measured. The results are compared to the calculations of the third-order susceptibility based on the transition moments, line positions, and line widths observed in the infrared absorption and the Raman spectra of crotononitrile.
