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Nuclear Reaction Analysis
Published in Zeev B. Alfassi, Max Peisach, Elemental Analysis by Particle Accelerators, 2020
Like nitrogen, the common proton-induced reactions on the major oxygen isotope, 16O, are endoergic, the highest Q-value being for the (p,α) reaction, - 5218 keV. Oxygen analysis and tracing is thus restricted to the determination of the heavy isotope, 18O, with a natural abundance of only 0.205 at%. The only proton-induced reaction that has been used for its analysis is O18(p, α)Ν15Q=3980keV
Neutrons and Other Important Particles of Reactor Physics
Published in Robert E. Masterson, Introduction to Nuclear Reactor Physics, 2017
Another element that is frequently encountered in the study of nuclear science and engineering is the element Plutonium. Plutonium is heavier than Uranium, and it does not exist naturally because it tends to decay too quickly to be present in measureable quantities in nature. However, Plutonium is produced in nuclear reactors in significant amounts, and in some reactors, about 1/3rd of the power is generated from it. The amount of an element that appears in nature is called its natural abundance. The most common isotopes (or varieties) of Plutonium are Pu-238, Pu-239, Pu-240, and Pu-241. Pu-238 is used as a power source in interplanetary space probes. The number of protons inside a nucleus defines an element, and the number of neutrons inside the same nucleus defines an isotope of that element. Because of this, Uranium has 92 protons in the nucleus, and Plutonium has 94. The number of protons and neutrons then determines the isotope of a particular element (i.e., U-238, Pu-239, or Pu-241). Isotopes are discussed in more detail in Chapter 6.
Understanding the Atom and the Nucleus
Published in Robert E. Masterson, Nuclear Engineering Fundamentals, 2017
Another element that is frequently encountered in the study of nuclear engineering is the element plutonium. Plutonium is heavier than uranium, and it does not exist naturally because it tends to decay too rapidly to occur in measureable quantities in nature. However, plutonium is produced in reactors in significant quantities, and in some reactors, about 1/3 of the power is generated from it. The amount of an element that appears in nature is called its natural abundance. The most common isotopes (or varieties) of plutonium are Pu-239, Pu-240, and Pu-241. The number of protons inside a nucleus defines an element, and the number of neutrons inside of the same nucleus defines an isotope of that element. Because of this, uranium has 92 protons in the nucleus and plutonium has 94. The number of protons and neutrons then determines the isotope (i.e., U-238, Pu-239, Pu-241). Isotopes are discussed in more detail in Chapter 9.
Corrections to the Raman fundamental band of N2 and O2 due to molecular non-rigidity: computations and experiment
Published in Molecular Physics, 2020
Jacek Borysow, Tyler Capek, Claudio Mazzoleni, Massimo Moraldi
Roto-vibrational lines in oxygen spectra are reasonably well isolated, unlike nitrogen, therefore we do not anticipate any interference to integrated intensities from neighbouring spectral lines. We expected that the main contribution to errors is due to counting errors equal to the square root of numbers of photons (shot-noise) and cosmic rays. The data in Figure 11 (blue circles) are an average of 11, 60 s runs. Error bars are smaller than the data symbols, except for which overlaps with the signal from atmospheric carbon dioxide. The spread in the experimental data from all runs is larger than one would expect due to shot-noise, particularly for largest rotational states. We attributed this to the contribution to spectra from cosmic rays. The data runs were not long enough to obtain a uniform distribution of intensities due to cosmic rays throughout the entire spectral region of interest. Cosmic rays affect weak spectral lines more significantly than intense lines. As for nitrogen, in addition to errors of statistical nature, we also have systematic errors. These come primarily from the overlapping Raman signal from oxygen isotopologue OO. The Q branch of OO can be clearly seen in Figure 3. O and S branches are also hidden under the O spectrum. The natural abundance of OO in the atmosphere is 0.0038 with respect to O. We neglected the presence of O here, because of its small abundance. We computed the roto-vibrational Raman spectrum of OO and show it in Figure 13. We used molecular constants from Reference [22]. A comparison of the two spectra shows how OO affects the integrated intensities of O lines. For example, there are two roto-vibrational OO lines under the O(15) line of O and only one OO line under the O(17) line of O.