C+C Fusion Cross Sections Measurements for Nuclear Astrophysics

Abstract

Abstract. Total fusion cross section of carbon isotopes were obtained using the newly developed MUSIC detector. MUSIC is a highly efficient, active target-detector system designed to measure fusion excitation functions with radioactive beams. The present measurements are relevant for understanding x-ray superbursts. The results of the first MUSIC campaign as well as the astrophysical implications are presented in this work.

Extracting dynamics in the fusion of neutron-rich light nuclei

“…Examination of the neutron density distributions reveals that with increasing neutron number, the tail of the neutron density Predicted fusion cross-sections with a TDHF model with a SLy4 interaction are indicated. The fusion excitation function for 13 C (not shown) is comparable to that of 14 C. Data taken from [16,17].…”

“…4. A linear behavior of the TDHF predicted cross-section on neutron ex-cess is observed indicating that neither any additional enhancement or supression of dynamics is predicted despite the extreme neutron-richness of 22 C. This linear behavior manifests the same slope as the dependence of σ I on neutron excess defined by 12,16,17,18,20 C indicating that for the TDHF model dynamics provides essentially a constant increase to the cross-section above the geometric size. The magnitude of this increase due to the dynamics in the TDHF model is ≈280 mb.…”

“…The dependence of σ I on neutron excess for 12≤A≤14 is weak as is the dependence for 16≤A≤18. Between 14 C and 16 C one observes a jump in σ I from a value of ∼850 mb to ∼1050 mb. This increase reflects the completion of the 1p 1 2 with N=8 and the population of the sd-shell indicating that the shell structure of the neutron-rich isotopes is observable through measurement of σ I for an isotopic chain.…”

“…Depicted in Fig. 3 are the cross-section data for 10,12,13,15 C that have been taken from [17] along with 14 C cross-sections measured using the same approach but at higher beam intensity beams [16]. While an improved analysis, primarily a reduction of background arising from scattered beam, resulted in publication of revised cross-sections for 10,15 C [17,20], systematic comparison of the neutron number dependence of the fusion cross-section for the isotopic chain has not been published.…”

Influence of halo single-neutron transfer on near barrier $$^{15}$$C + $$^{12}$$C total fusion

“…In a recent article deSouza et al [1] make a systematic comparison of measurements [2,3] of the fusion excitation functions for the 12−15 C + 12 C systems at energies just above the respective Coulomb barriers. They find that the average fusion cross section, σ F , shows a more rapid increase with increasing projectile neutron number than can be accounted for by static barrier penetration models using potentials based on calculated nuclear matter densities.…”