First Protons in the ESS LINAC

The European Spallation Source (ESS), currently under construction in Lund, Sweden, will be the world’s brightest neutron source, driven by a linear accelerator (LINAC) with an average beam power of 5 MW at 2.0 GeV beam energy. The LINAC accelerates a proton beam of 62.5 mA peak current at 4% duty cycle (2.86 ms at 14 Hz). The accelerator uses a normal conducting front-end bringing the beam energy to 90 MeV, beyond that the acceleration up to 2 GeV is performed using superconducting structures. The first protons were extracted at the ESS site during the commissioning of the ion source and low energy beam transport that started earlier this year and will continue to the next stage of the commissioning up to 21 MeV early next year. This paper gives an overview of the status of the ESS accelerator and the commissioning of the ion source and the low energy beam transport.