The mass-separator MASHA built to identify Super Heavy Elements by their mass-to-charge ratios is described. The results of the off- and on-line measurements of its separation efficiency are presented. In the former case four calibrated leaks of noble gases were used. In the latter the efficiency was measured via 284 MeV {Mathematical expression}Ar beam and with using the hot catcher. The ECR ion source was used in both cases. The {Mathematical expression}-radioactive isotopes of mercury produced in the complete fusion reaction {Mathematical expression}Ar+ {Mathematical expression}Sm {Mathematical expression}Hg+xn were detected at the mass-separator focal plane. The half-lives and the separation efficiency for the short-lived mercury isotopes were measured. Potentialities of the MEDIPIX detector system have been demonstrated for future use at the mass-separator MASHA.