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Design of Narrowband Emission Phosphors
Published in Ru-Shi Liu, Xiao-Jun Wang, Phosphor Handbook, 2022
The electron–lattice coupling strength is not only related to the emission bandwidth but also related to thermal stability. For the phosphors with lower electron–lattice coupling strength, the electron in the excited state will have a lower possibility of crossing the crosspoint of the ground state and the first excited state. Also, the small lower electron–lattice coupling strength give rise to the small Stokes shift, and the large thermal activation energy can be obtained. Therefore, good thermal stability can be expected. The weak electron–lattice coupling strength is beneficial to good thermal stability; however, one should notice that it is not the only parameter to determine thermal stability. The thermal ionization energy, which is the energy between the excited states to the conduction band, should be considered as well. That is to say, despite the weak electron–lattice coupling strength, the phosphors will still possess poor thermal stability if the ionization energy is too small. This effect will be discussed in detail in Section 5.3.2.3.
Analytical Methods
Published in S. Komar Kawatra, Advanced Coal Preparation and Beyond, 2020
High-temperature combustion methods are used by the various commercially available automated sulfur analyzers. They are very rapid and do not require a high level of operator skill to use; however, they are empirical and require careful calibration with an SRM before the results are meaningful. The SRMs used are coal samples that have had their sulfur content analyzed precisely by other means, such as the Eschka method. 2,5-Di(5-tertbutylbenzoxazol-2-yl)thiophene (BBOT) can also be used as a certified sulfur reference with a sulfur content of 7.47%. In recent years, research has also been carried out to produce SRMs using ion chromatography and isotope dilution thermal ionization mass spectrometry. Both methods can produce standards that have the sulfur determined to a high precision (Kelly et al., 1994; Thomas, 1995).
Measurement of Partial Pressure at Vacuum Conditions
Published in Igor Bello, Vacuum and Ultravacuum, 2017
There are many ion sources that have been used in MS. A variety of these ion sources operates on the principles of thermal ionization, chemical ionization, laser ionization, and electron impact ionization, and also on the principles employing desorption. The ionization is induced at both vacuum and atmospheric conditions. Electron impact ionization is the main ionization to induce unique ionic species with assistance of various electric discharges that allow us deeper studying of the properties of materials. The electric discharges used in MS comprise glow discharges, inductively coupled radio-frequency discharges, microwave discharges, and spark discharges. The combination of the different conditions and ionization methods indeed provides a large number of ion sources that have been used in MS. Discussion of these ionization methods is far beyond the scope of this publication.
Neutronic Characterization for a Pressurized Water Reactor Spent Fuel Assembly
Published in Nuclear Science and Engineering, 2023
Rowayda Fayez M Abou Alo, Amr Abdelhady, Mohamed K. Shaat
Ion chromatography in conjunction with inductively coupled plasma mass spectroscopy (ICP-MS) was used to characterize two different spent fuel samples: UO2 and MOX. FPs were determined using isotope dilution analysis with ion chromatographic separation (Rb, Sr, Cs, Ce, Nd, Sm, Eu, and Gd). For the determination of isotopic FPs and actinides, the standard additions method was used (Y, La, Pr, 147Pm, 237Np, 243Am, and 244Cm). Isotope Dilution-Thermal Ionization Mass Spectrometry (ID-TIMS) gamma spectrometry was used to calculate the total uranium and plutonium and to find the concentrations of Nd, Am, and Cm isotopes. Fuel burnup was calculated, and the total fuel inventory was calculated by the KORIGEN code.[3] SNF characteristics are provided by the FP and actinide buildup inside the fuel matrix along with the metallurgy of the cladding to resist fracture during fuel degradation.[4–9]
Behaviors of actinides in chromatographic separation by using TBP resin in nitric acid solution and hydrochloric acid solution
Published in Journal of Nuclear Science and Technology, 2023
Fauzia Hanum Ikhwan, Hiroyuki Kazama, Chikage Abe, Kenji Konashi, Tatsuya Suzuki
Precise and accurate isotope ratio measurements of radionuclides are necessary for various applications, e.g. for analysis of nuclear samples, radioactive waste, and environmental materials, such as biological samples, soils, dust, and water, especially for geological and medical samples. For isotope analysis of metals and metalloids, thermal ionization mass spectrometry (TIMS) has been mainly used in the domain of geochemistry and cosmochemistry. The introduction of inductively coupled plasma mass spectrometry (ICP-MS) had a huge impact on the field of isotopic analysis. The application of ICP-MS in elemental analysis and isotope analysis of actinides have been massively studied for natural thorium isotopes level in marine [1], plutonium isotopic composition [2] actinides determination in urine [3] isotope analyses in clinical samples [4], and radioactive waste characterization in nuclear application [5,6]. Recently in Japan, ICP-MS is used to detect nuclides and analyse isotope ratio of sample from debris for characterization for decommissioning of Fukushima-Daiichi Nuclear Power Plant [7].
Weapons Radiochemistry: Trinity and Beyond
Published in Nuclear Technology, 2021
Susan K. Hanson, Warren J. Oldham
Within just a few years, mass spectrometry emerged as a powerful technique to elucidate the isotopic composition of both uranium and plutonium. Actinide mass spectrometry measurements were originally performed as a specialized analysis at Argonne National Laboratory; the measurements moved to Los Alamos as the technique become more mature and widespread in the late 1960s (Ref. 4). More recent advances in mass spectrometry, including progress in thermal ionization mass spectrometry and the development of inductively coupled plasma mass spectrometry, have led to enhancements in the precision, sensitivity, and speed of analysis. At the same time, the sensitivity and resolution of alpha counting also improved greatly, particularly as a result of silicon semiconductor detectors becoming widely available. In the modern radioanalytical laboratory, both mass spectrometry and alpha spectrometry are routinely used to measure the concentrations and isotopic compositions of actinide elements.