The Real-Time waveform mask interlock system for the RF gun conditioning of the ELI-NP gamma beam system

he new Gamma Beam System (GBS) of the ELI-NPproject [1], currently under installation in Magurele (RO)by INFN, as part of EuroGammas consortium, can providegamma rays with characteristics that open new possibilitiesfor nuclear photonics and nuclear physics.ELI-NP gamma rays are produced by Compton back-scattering to get monochromaticity (0,1% bandwidth), highflux (1013photons), tunable direction and energy up to19.5 MeV. Such gamma beam is obtained when a high-intensity laser collides a high-brightness electron beam withenergies up to 740 MeV.The S-band RF-Gun, made with the novel clamping gaskettechnique [2], working inπ-mode at100 Hzwith a max-imum RF input of16 MW, RF peak field of 120MVmandfilling time of420 nswas fully tested and conditioned duringDecember 2015 in Bonn University at ELSA facility.This paper will describe the real-time fast-interlock system,based on waveform mask technique, used during RF Gunconditioning. Instead of relying only on vacuum pumps read-out, this system monitors on-line the reflected RF signalsfor a pulse-to-pulse breakdown detection, thus ensuring ahigher safety of the Gun and modulator system.