  Gamma sources with high flux and spectral densities are the main requirements
for new nuclear physics experiments to be performed in several worldwide
laboratories and envisaged in the ELI-NP (Extreme Light Infrastructure-Nuclear
Physics) project or in the IRIDE (Interdisciplinary Research Infrastructure
with Dual Electron Linacs) proposals. The paper is focalized on an experiment
of gamma photons production using Compton collisions between the DA\Phi NE
electron beam and a high average power laser pulse, amplified in a
Fabry-P\'erot optical resonator. The calculations show that the resulting gamma
beam source has extremely interesting properties in terms of spectral density,
energy spread and gamma flux comparable (and even better) with the last
generation gamma sources. The energy of the gamma beam depends on the adopted
laser wavelength and can be tuned changing the energy of the electron ring. In
particular we have analyzed the case of a gamma factory tunable in the 2-9 MeV
range. The main parameters of this new facility are presented and the
perturbation on the transverse and longitudinal electron beam dynamics is
discussed. A preliminary accelerator layout to allow experiments with the gamma
beam is presented with a first design of the accelerator optics.
