Measurement of the B10(α,n0)13N cross section

Abstract

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.

Low-energy cross-section measurement of the B10(α,n)N13 reaction and its impact on ne

“…Further, as is shown below, the main contributors to the reaction rate are from the previously observed strong resonance at E α = 1.51 MeV and from the newly proposed strong low energy resonance. Angular distribution measurements are available from Van der Zwan and Geiger [13] and Liu et al [46] for this resonance and they are in good agreement with R-matrix fit as shown in Fig. 11.…”

“…Alpha particle energies are in units of MeV, cross sections are in b/sr. Cross sections are from the present work except those at Eα = 1.5 MeV, which were measured as part of the experiment reported in Liu et al [46]. The data have common systematic uncertainty of 12% as discussed in Sec.…”

“…To explore the impact of the 10 B(α, n) 13 N reaction on the primordial reaction chains and the associated release of neutrons in an early star environment, we have performed experiments studying the strength of α-induced reactions on 10 B at very low energies at the Nuclear Science Laboratory (NSL) of the University of Notre Dame. The low energy measurements presented here have been followed up by the higher energy measurement of Liu et al [46]. In Sec.…”

“…Only a single angular distribution measurement for the 10 B(α, n) 13 N reaction is available from Van der Zwan and Geiger [13] for the strong resonance at E α = 1.51 MeV. An angular distribution measurement of this same resonance was also made in the experiment of Liu et al [46], but was not reported in that work as it was below the energy range of interest. In addition, three angular distribution measurements were made as part of this work at E α = 1.16, 1.57, and 1.65 MeV.…”