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 DAPhi NE electron beam and a high average power laser pulse, amplified in a Fabry-Perot 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.
