On 20 and 21 April, the first beam was accelerated through the 4 drift tube linac installed in the tunnel of the European Spallation Source (ESS) in Lund, Sweden. The intensity of the current and the energy of the beam correspond to what was foreseen by the calculations, without the need for correction of the trajectory. Accurate measurements on the properties of the beam will be made in the coming weeks; INFN LNL staff will also be present in this crucial phase. The first accelerated beam is the ultimate proof of the quality of INFN long and tenacious work, carried out between Legnaro and Turin, and in Lund too.
