S-Space College of Natural Sciences (자연과학대학) Dept. of Physics and Astronomy (물리·천문학부) Physics (물리학전공) Theses (Ph.D. / Sc.D._물리학전공)
Study of 19C by One-Neutron Knockout Reaction with a Carbon Target
탄소 표적과 중성자 탈락 반응을 이용한 탄소-19 핵종에 대한 연구
- Jongwon Hwang
- Issue Date
- 서울대학교 대학원
- RI physics, neutron-rich nuclei, 19C, one-neutron knockout, invariant mass, unbound state, shell model
- 학위논문(박사)--서울대학교 대학원 :자연과학대학 물리·천문학부,2015. 8. 최선호.
- The level structure of a neutron-rich nucleus 19C, which is known as a one-neutron halo, was studied via one-neutron (1n) knockout reaction with a 20C beam and a carbon target at 280 MeV/nucleon. Three prominent resonances were observed at E rel = 0.036(1), 0.84(4), and 2.31(3) MeV in the invariant
mass spectrum constructed from momentum vectors of decay products of the knockout residue, a 18C isotope and a neutron. The resonances correspond
to the neutron-unbound states in 19C at excitation energies of E x = 0.62(9), 1.42(10), and 2.89(10) MeV. The spin-parities of the 0.62-MeV and 2.89-MeV states were determined to be 5/2+1 and 1/2-1, respectively, by comparing the data with eikonal model calculations employing shell-model spectroscopic factors in terms of the 1n knockout cross section and the parallel momentum distribution.
We have clarified that the 0.62-MeV state is unbound and assigned its spin-parity with the direct evidence. The 1.42-MeV state is consistent with the 5/2+2 state, which is located at 1.46 MeV by the proton inelastic scattering measurement. The state at 2.89 MeV in 19C with a negative parity was observed for the first time, and its spin-parity was clearly determined. In addition, the shell structure involving the neutron 1s 1/2 and 0d 5/2 orbitals is discussed.