Fine structure in proton emission from ¹⁴⁵Tm discovered with digital signal processing

Fine structure in proton emission with the branching ratio I_p=9.6±1.5% was discovered during the reinvestigation of the 3.1 μs activity of ¹⁴⁵Tm. This observation was made possible by the development of the new technology of digital processing of detector signals. The slightly deformed shape of the ¹⁴⁴Er potential tunneled by the emitted protons was inferred from the measured energy of 0.33 MeV for the 2⁺ state. The structure of the wave function of ¹⁴⁵Tm and proton emission rates were analyzed within the models accounting for particle-core vibration coupling. The wave function was found to be dominated by the π0h_11/2 orbital coupled to the 0⁺ ground state of the ¹⁴⁴Er core and 2⁺ excited state of the core. The origin of the 1.40 MeV proton transition to the 2⁺ state was found in the small 3% π1f_7/2⊕2⁺ component in the wave function.