Patent Number: 
Section: claims

1. A method of providing a neutron source, the method comprising:providing a nuclear reactor neutron source, the nuclear reactor neutron source comprising:an enclosure delimiting a chamber,a nuclear reactor core arranged inside the chamber,the nuclear reactor core is configured to produce neutrons from a nuclear fuel element inside the nuclear reactor core;installing a beam generator arranged to generate a beam directed into the chamber;wherein the beam generator forms part of a spallation neutron source for providing neutrons;removing the nuclear fuel element of the nuclear reactor core from the chamber,wherein removing the nuclear fuel element forms a void inside the chamber;andinstalling, inside the void, a target configured to eject neutrons upon impact of the beamwherein impact by the beam onto the target causes neutrons to be ejected from the target and emitted from the chamber through a neutron beam outlet arranged through the enclosure,wherein the neutron beam outlet provides a passage for neutrons to leave the enclosure. 2. The method according to claim 1, wherein the chamber of the provided nuclear reactor neutron source further comprises a moderator, and wherein the act of installing the target comprises arranging the target inside the moderator. 3. The method according to claim 2, wherein the moderator of the provided nuclear reactor neutron source comprises a material selected from the group consisting of H2O, D2O, liquid or solid hydrogen or deuterium, liquid or solid methane, mesithelene, and ice. 4. The method according to claim 1, wherein the chamber of the provided nuclear reactor neutron source further comprises a reflector, and wherein the act of installing the target comprises arranging the target inside the reflector. 5. The method according to claim 4, wherein the reflector of the provided nuclear reactor neutron source comprises a material selected from the group consisting of graphite, beryllium, steel, tungsten carbide nickel, tungsten, heavy water, lead, and alloys of these. 6. The method according to claim 1, wherein the provided nuclear reactor neutron source further comprises an additional neutron beam outlet arranged through the enclosure to provide an additional neutron passage for neutrons from the chamber, and wherein the act of installing of the beam generator comprises directing the beam into the chamber via the additional neutron passage onto the target. 7. The method according to claim 1, wherein the enclosure of the provided nuclear reactor neutron source further comprises a thermal column or an access shaft, and wherein the act of installing of the beam generator comprises directing the beam into the chamber via the thermal column or the access shaft onto the target. 8. The method according to claim 1, wherein the act of installing a beam generator comprises installing the beam generator or a portion of the beam generator inside the chamber. 9. The method according to claim 1, wherein the act of installing a target comprises installing a target comprising a material selected from the group consisting of mercury, tantalum, lead, liquid lead-bismuth alloy, tungsten, rhenium, alloys of these, or beryllium and lithium. 10. The method according to claim 1, wherein the installing a beam generator arranged to generate a beam directed into the chamber comprises installing the beam generator to form part of a spallation neutron source for providing neutrons. 11. The method according to claim 1, wherein the installing a beam generator arranged to generate a beam directed into the chamber comprises installing the beam generator to form part of a compact neutron source for providing neutrons. 12. The method according to claim 1, wherein the chamber of the provided nuclear reactor neutron source further comprises a hot or cold neutron source, and wherein the act of installing a target comprises arranging the target adjacent to the hot or cold neutron source.