The cross section of the ^{13}C(α,n)^{16}O reaction is needed for nuclear astrophysics and applications to a precision of 10% or better, yet inconsistencies among 50 years of experimental studies currently lead to an uncertainty of ≈15%. Using a state-of-the-art neutron detection array, we have performed a high resolution differential cross section study covering a broad energy range. These measurements result in a dramatic improvement in the extrapolation of the cross section to stellar energies potentially reducing the uncertainty to ≈5% and resolving long standing discrepancies in higher energy data.
View Article and Find Full Text PDFBenjamin Franklin was a preeminent proponent of the new colonial and Continental paper monetary system in 18th-century America. He established a network of printers, designing and printing money notes at the same time. Franklin recognized the necessity of paper money in breaking American dependence on the British trading system, and he helped print Continental money to finance the American War of Independence.
View Article and Find Full Text PDFThe ^{18}O(α,γ)^{22}Ne reaction is critical for AGB star nucleosynthesis due to its connection to the abundances of several key isotopes, such as ^{21}Ne and ^{22}Ne. However, the ambiguous resonance energy and spin-parity of the dominant 470 keV resonance leads to substantial uncertainty in the ^{18}O(α,γ)^{22}Ne reaction rate for the temperature of interest. We have measured the resonance energies and strengths of the low-energy resonances in ^{18}O(α,γ)^{22}Ne at the Jinping Underground Nuclear Astrophysics experimental facility (JUNA) with improved precision.
View Article and Find Full Text PDFToday, we take international collaborations as a necessity, but 150 years ago, when travel was not so convenient, it involved an enduring and time-consuming challenge. This paper presents letters and reports written by German physicist Julius Plücker to his wife, Antonie née Altstädten describing his travels to Great Britain and France between 1853 and 1866. These letters provide a view into how international collaboration and communication were developed and maintained as well as how friendships were built within the scientific community during the early industrial age, prior to telegraph, telephone, email, and internet.
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