Measurement of 14N(n,p)14C cross section for kT = 25.3 keV Maxwellian neutrons using gridded ionization chamber

Accelerator mass spectrometry measurements of theC13(n,γ)C14andWallner1, Bichler2, Buczak3 et al. 2016Phys. Rev. C281170View full textAdd to dashboardCite

“…At 25 keV there is perfect agreement with the work of Sanami et al [16]. Up to about 100 keV all data are well consistent with a 1/v shape of the cross section.…”

“…In this case the 13 C pocket is artificially included as in the other models, however, because the temperature in that region only reaches up to 70 MK before the onset of the following thermal instability, the 13 C(α,n) 16 O reaction is not activated until the 13 C nuclei are ingested in the following convective region [58]. In this case the impact of the 14 N(n,p) 14 C neutron poison reaction is even more crucial because the large amount of 14 N present in the H-burning ashes is ingested at the same time.…”

“…Much more work exists for 14 N(n,p) 14 C in the keV energy range [13][14][15][16], The measurements by Koehler and O'Brien [14] support a 1/v energy dependence almost up to 100 keV. Above that energy the cross section is determined by the tails of two resonances at 493 and 655 keV.…”

“…Nevertheless, they may constitute significant neutron poisons because a small capture cross section can be compensated by a very high abundance as in case of the 13 C and 14 N content of the pocket. While 12 C(n,γ ) 13 C reactions are also competing for neutrons, the produced 13 C will then act as a target for the 13 C(α,n) 16 O reaction so that the neutrons consumed by capture on 12 C are recycled, and thus recovered for the sprocess budget [10]. On the contrary, the 13 C(n,γ ) reaction hampers the production of neutrons not only in the manner of a usual poison, because the captured neutrons are lost for the s process, but also because primary 13 C target nuclei are transformed into long-lived 14 C. The second reaction studied, 14 N(n,p) 14 C, has a considerably higher cross section of ∼2 mb at keV energies because of the larger phase space in the exit channel.…”

Improved determination of thermal cross section of 14N(n,p)14C for the neutron lifetime measurement

“…Additionally, in boron neutron capture therapy, this is one of the main reactions that produce high linear energy transfer protons, when thermal neutrons are injected into the human body [41]. The cross section values at the cosmological temperatures can be used for estimating the amount of isotopes produced in the slow-neutron capture processes in asymptotic giant branch stars, which can be compared with the experimentally measured values [15,36,42,43,44]. The value of σ( 14 N) is often used for the analysis of other reactions and evaluating the neutron flux [45].…”