  In this letter we present the primary continuum parameters, the photon index
Gamma and the high energy cut-off Ec, of 41 type-1 Seyfert galaxies extracted
from the INTEGRAL complete sample of AGN. We performed a broad band (0.3-100
keV) spectral analysis by fitting simultaneously the soft and hard X-ray
spectra obtained by XMM and INTEGRAL/IBIS-Swift/BAT respectively in order to
investigate the general properties of these parameters in particular their
distribution and mean values. We find a mean photon index for the whole sample
of 1.73 with a standard deviation of 0.17 and a mean high energy cut-off of 128
keV with a standard deviation of 46 keV. This is the first time that the
cut-off energy is constrained in a such large number of AGN. We have 26
measurements of the cut-off, which corresponds to 63% of the entire sample,
distributed between 50 and 200 keV. There are a further 11 lower limits mostly
below 300 keV. Using the main parameters of the primary continuum, we have been
able to obtain the actual physical parameters of the Comptonizing region i.e.
the plasma temperature kT_e from 20 to 100 keV and the optical depth tau <4.
Finally, with the high S/N spectra starting to come from NuSTAR it will soon be
possible to better constrain the cut-off values in many AGN, allowing the
determination of more physical models and so to better understand the continuum
emission and geometry of the region surrounding black holes.
