Gamma Spectroscopy of $^{13}$B via Proton Transfer Reaction at 50~MeV/nucleon

We have investigated proton single particle states in $^{13}$B via a proton transfer reaction on $^{12}$Be at 50~MeV/nucleon. A candidate was found at the excitation energy of 4.8~MeV in $^{13}$B whose spin and parity was deduced to be 1/2$^{+}$ from a Distorted Wave Born Approximation (DWBA) analysis of the observed angular distribution of the differential cross sections. The experiment was performed in RIKEN Accelerator facility with RIKEN Projectile-fragment Separator (RIPS). A $^{12}$Be beam bombarded a liquid helium target of 120 mg/cm$^2$-thickness. Gamma rays from excited states on $^{13}$B were detected with six Germanium detectors, a part of Gamma-Ray detector Array with Position and Energy sensitivity (GRAPE) located at upstream of the target. The incident and outgoing particles were identified event-by-event by measuring their velocities and energies. In this talk, we report the detail of experiment and data analysis, and discuss about the single-particle nature of the observed state.