Levels inN12via theN14(

K. A. Chipps

¹

,

S. D. Pain

²

,

U. Greife

³

et al.

Particle decay of proton-unbound levels in N12

“…[1]. In the current work, reaction products and decays from excited, particle-unbound levels populated in 14 N(p,t) 12 N * →p+ 11 C are serendipitously detected in the same detectors, with improved resolution due to improved target purity.…”

“…[1]. In brief, a jet of 300 psig (∼5×10 18 atoms/cm 2 ) nat N was produced with the Jet Experiments in Nuclear Structure and Astrophysics (JENSA) gas jet target system [27] and bombarded by a 38 MeV proton beam of ∼1-4 enA from the Holifield Radioactive Ion Beam (HRIBF) 25…”

“…Using the external (alpha source) and internal (known 12 N levels) calibrations [1] for each detector gives the approximate energies of the observed decay-proton peaks 5 , listed in Table 2 II. Not all allowed decays are discernible in the spectra due to the high thresholds, low statistics, and worsened energy resolution.…”

“…Excited levels in 12 N have been the focus of many studies over the years [1,3,[12][13][14][15][16][17][18][19][20][21][22][23][24][25], but without much (if any) focus on the decay of those levels. The breakup of excited states in 12 N has been examined previously [25], as has the reverse reaction ( 11 C+p resonant scattering [21]), but with the explicit goal of informing the astrophysical 11 C(p,γ) 12 N reaction rate relevant for potential 3α reaction bypass paths and hence focusing on the first two excited states in 12 N. The current study extends to higher excitation energies (a level diagram for 12 N is shown in Figure 1).…”

“…[1], particles which fell within a timing gate of roughly 6 µs from the initial triton hit, but not in the same detector as the triton hit, were considered to be coincident Due to the thresholds set in the data acquisition hardware and firmware for the original measurement, coincidences were only detectable down to a decay proton energy of about 750 keV, or above the second excited state in 12 N if the p0 decay channel (to the 11 C ground state) is considered 3 . This also means that the "turn on" energy for each decay channel as detected is a convolution of both the particle decay threshold and the experimental threshold, though the experimental threshold is roughly constant, and the level spacing of the first three states in 11 C is also reasonably constant (∼2 MeV).…”