The neutron source SINQ, which has been in operation since 1996, was the first, and is still the strongest, of its kind. It delivers a continuous neutron flux of 1014 n cm−2s−1. In SINQ the protons from the large particle accelerator strike a lead target and knock the neutrons out of the lead nuclei, making them available for experiments. In addition to thermal neutrons, a moderator made of liquid deuterium also enables the production of slow neutrons, which have a lower energy spectrum.