A perspective view of the ESS reference design is shown in this figure. It consists of a proton linear accelerator (Linac), that accelerates negatively charged Hydrogen ions to 91% of the speed of light. When this beam of high energy particles exit the linear accelerator it is either directed straight at the long pulse target station and converted into a long pulsed of neutrons (2 millisecond) or send through a set of compressor rings. Click here and you will see how it works:The ESS facility

These compressor rings form extremely short proton pulses (1,4 microseconds). Eventually these compressed proton pulses are led to the short pulse target station where they are converted into short pulses of neutron beams.

Either on of the two targets consist of 1200 litres of liquid mercury, encased in special a steel container, ready to take the full 5 MW blast of beam power. And it is here, in the mercury target shielded by thick layers of steel and concrete, that the spallation process take place and neutrons are released.

These neutrons still need some treatment before they can be used for experiments. Moderators - consisting on hydrogenous materials such as water or hydrogen itself - rapidly slow down the speed of the spallation neutrons to a value that is required for the study of materials.

Neutron beam channels - the openings in the shielding of the target - enable the neutrons to travel to the instruments where the experiments are being carried out. The instruments, typically 24 for each target, are arranged around each target station.