First Tests of the Full SIDDHARTA-2 Experimental Apparatus with a ⁴He Gaseous Target

In this paper, we present the first tests performed after full installation of SIDDHARTA-2 experimental apparatus on Interaction Region DA{\Phi}NE collider at INFN National Laboratories Frascati. Before starting measurement kaonic deuterium 2p{\rightarrow}1s transition, accurate evaluation background rejection. mainly achieved with Kaon Trigger system, was required. This run, in period 04-26/05/2022 a 4 He gaseous target, confirmed 10^5 rejection factor obtained reduced version setup and different machine conditions 2021. important outcome motivated filling target cell campaign transition.