Two-proton radioactivity of $^{48}$Ni

In experiment performed at NSCL facility we studied the decay of extremely neutron deficient isotope of $^{48}$Ni. Ions were implanted into a gaseuos detector, the Optical Time Projection Chamber which allows to record tracks of charged particles. Six events of $^{48}$Ni were observed, the two-proton radioactivity (four events) and the $\beta$--decay (two events) channels were clearly indentified. The half--life of $^{48}$Ni is determined to be $T_{1/2}$ = 2.1$^{+1.4}_{-0.4}$ ms. The results of three--dimensional events reconstruction as well as comparison of results with theoretical models will be presented.