An experiment aimed to investigate the two-proton(2p) decay of the previously unknown nucleus ~(30)Ar was performed at GSI. By tracking the decay products in-flight with silicon micro-strip detectors, the 2p decays of ~(30)Ar were observed for the first time. For the calibration purpose, 2p decays of ~(19)Mg were also remeasured by tracking the coincident ~(17)Ne+p+p trajectories. By comparing the measured angular p-17 Ne correlations with those obtained from the corresponding Monte Carlo simulations,the simultaneous 2p decay of ~(19)Mg ground state and the sequential 2p emission of several known excited states of ~(19)Mg were confirmed. One new excited state in ~(19)Mg and two new excited states in ~(18)Na were observed. An experiment aimed to investigate the two-proton (2p) decay of the previously unknown nucleus ~ (30) Ar was performed at GSI. By tracking the decay products in-flight with silicon micro-strip detectors, the 2p decays of ~ For the calibration purpose, 2p decays of ~ (19) Mg were also remeasured by tracking the coincident ~ (17) Ne + p + p trajectories. By comparing the measured angular p-17 Ne correlations (19) Mg ground state and the sequential 2p emission of several known excited states of ~ (19) Mg were confirmed. One new excited state in ~ (19) Mg and two new excited states in ~ (18) Na were observed.