The HELL platform includes two main sections: electron acceleration and laser beam transport and monitoring , both of which have been designed and developed in house. A three-dimensional overview of the HELL platform setup in E5 in the first implementation phase is shown in the figure above. Before entering an auxiliary chamber, a portion of the L3 beam can be used for its characterization in a dedicated laser diagnostic optical table. The L4 (small aperture) laser beam is directly connected to the auxiliary chamber.

The HELL platform is designed to accommodate various experimental schemes proposed by the users according to the scientific case that is exhaustively described in the ELI Whitebook . For this reason HELL has been planned to be a flexible platform where different advanced user experiments can be accommodated. It is important to highlight that some of these schemes will need a temporal synchronization below 10 fs, which in the first phase of ELI-Beamlines' implementation will not be available if different laser beams are used in the same experiment. However, this limitation can be overcome in the HELL platform by splitting the L3 beam into two or three auxiliary beams (intrinsic synchronization).