We report on the development of a custom particle detection system that aims to improve the detection capabilities of the ROSPHERE array. The detector is designed specifically for lifetime measurements using the in-beam Fast-timing method for nuclear states in nuclides produced in nuclear transfer reactions. An 80 x 3.6 mm disc of BC400 plastic scintillator was coupled to a sparse SiPM array readout connected to a dedicated Front End Electronics board. The detector was tested versus a conical LaBr3(Ce) coupled to a Hamamatsu PMT readout. The timing measurements resulted in a resolution of 896(5) ps. The detector design, characteristics, and performances are presented in this paper along with future improvements.