A new precision half-life measurement of 25 Al was conducted using the TwinSol β-counting station at the University of Notre Dame. The new measured value of t new 1/2 = 7.1657(24) s is in good agreement with the most recent measurement, while being 3 times more precise. Using these new measurements, an evaluation of the 25 Al half-life has been performed, leading to an average halflife of t world 1/2 = 7.1665(26) s, which is 5 times more precise than it's predecessor and has a more satisfactory Birge ratio of 1.1. To aid in future measurements of correlation parameters, a new Fermi to Gamow-Teller mixing ratio ρ and correlation parameters for this mixed transition have been calculated assuming Standard Model validity using the new world half-life.

The National Ignition Facility provides the opportunity to study nuclear reactions under controlled conditions at high temperatures and pressures at a level never before achieved. However, the time scale of the deuterium-tritium (DT) implosion is only a few nanoseconds, making data collection and diagnostics very challenging. One method that has been proposed for obtaining additional information about the conditions of the implosion is to activate a dopant material using the αparticles produced from the DT fuel as a diagnostic. The yield of the activated material can give a measure of the mixing that occurs in the capsule. One of the reactions that has been proposed is 10 B(α, n) 13 N, as it produces a radioactive reactant product with an convenient halflife of ≈10 minutes. While this reaction has several advantages for the application at hand, it has not seen much study in the present literature, resulting in large uncertainties in the cross section. Further, for the current application, the cross section must be well characterized. With this motivation, the 10 B(α, n) 13 N cross section has been remeasured from 2.2 < Eα < 4.9 MeV, with the angle integrated ground state cross section reported for the first time. The present results, combined with previous measurements, allow for a determination of the cross section to a significantly higher degree of accuracy and precision than obtained previously, and are shown to be consistent with thick-target measurements. Preliminary calculations are performed to test the feasibility of this reaction as a diagnostic for a NIF implosion.

No abstract

No abstract