The fast linear Z-pinch was experimentally investigated using a high-current pulse generator (10·8 μF, 5-10 kJ, 150-250 kA) and pulse injection of argon and neon. Measured electrical characteristics of the discharge (current shape and risetime, inductance) and calculated dynamic parameters of plasma implosion (accelerated mass, radial plasma velocity) are presented. X-ray diagnostics with temporal resolution (vacuum X-ray diodes, semiconductor detectors) were utilized. The temperature and the density of pinch plasma (Te ≈50 eV, ne ≈1·4 × 1026 m-3) as well as its other parameters (size, lifetime) were estimated. Total energy emitted by the pinch in ultra-soft X-ray region (hv<1 keV) during ≈200 ns pulse achieves 125 J/4π. © 1990 Academia, Publishing House of the Czechoslovak Academy of Sciences.