Beta-delayed neutron and gamma-ray spectroscopy of 17C utilizing spin-polarized 17B

TL;DR

This study investigates excited states in 17C via beta-delayed neutron and gamma-ray spectroscopy of spin-polarized 17B, revealing new state assignments and decay schemes using a novel combined experimental technique.

Contribution

It introduces a new method combining fibeta-NMR with beta-delayed particle measurements to determine spin-parity of states in neutron-rich nuclei.

Findings

Identified three negative-parity states in 17C above neutron threshold.

Mapped the beta-decay scheme of 17B including gamma-ray emissions.

Assigned spin-parity values to excited states at specific energies in 17C.

Abstract

Excited states in 17C were investigated through the measurement of beta?-delayed neutrons and gamma rays emitted in the ? decay of 17B. In the measurement, three negative-parity states and two inconclusive states, were identified in 17C above the neutron threshold energy, and seven gamma-lines were identified in a beta?-delayed multiple neutron emission of the 17B ? decay. From these transitions, the beta?-decay scheme of 17B was determined. In the present work, the fibeta-NMR technique is combined with the ?-delayed particle measurements using a fragmentation-induced spin-polarized 17B beam. This new scheme allows us to determine the spin parity of beta?-decay feeding excited states based on the difference in the discrete fibeta-decay asymmetry parameters, provided the states are connected through the Gamow-Teller transition. In this work, 1/2-, 3/2-, and (5/2-) are assigned to the observed states at Ex = 2.71(2), 3.93(2), and 4.05(2) MeV in 17C, respectively.