[en] The study of a pulsed helicon discharge with a planar Langmuir probe is presented. An unexpected and unreported effect has been observed, i.e. a large current peak on the probe at the end of the pulse. The post-discharge has then been carefully studied and the temporal evolution of the plasma parameters during the pulsed discharge was obtained by analysing the probe characteristics. In the post-discharge, a relaxation of the plasma parameters (plasma density (n_e), plasma potential (V_p), electron temperature (T_e)) was observed. The difference between the decay times measured for each parameter enables one to explain the current peak on the probe at the beginning of the post-discharge