THE EMITTANCE-METER Preliminary studies of the SPARC RF-Gun are planned to obtain an accurate analysis and optimization of the emittance compensation scheme, measuring the beam emittance evolution downstream the RF-Gun with an appropriate diagnostic system. Since in a space charge dominated beam the use of the quad-scan method is not applicable a 1D pepper-pot method will be used instead. A metallic mask with narrow slits will be installed on a longitudinally movable support, spanning a 1.5 m long region, to measure the emittance in several positions and reconstruct its evolution in the post gun section. Numerical simulations of the measurement, mainly based on PARMELA, have been used to estimate the achievable accuracy and to optimize the experimental setup. Wake field effects induced by the beam propagation through the long bellows have been also investigated with HOMDYN. Based on these simulations the design of the apparatus, called emittance-meter, has been realized and is under construction at LNF.