Patent Number: 
Section: claims

1. A secondary startup neutron source comprising an enclosure having an ampule therein, the ampule having a housing wherein the antimony and beryllium are contained in a coaxial arrangement with the antimony in a central enclosure located in a central portion of the ampule, and the beryllium is in powdered form located in an annular space between the housing and the central enclosure. 2. The secondary startup neutron source according to claim 1, wherein the housing of the ampule is made of an alloy, which does not interact with antimony during filling and operation. 3. The secondary startup neutron source according to claim 2, wherein the housing of the ampule is made of a niobium-based alloy. 4. The secondary startup neutron source according to claim 2, wherein the housing of the ampule is made of a material weakly interactive with beryllium. 5. The secondary startup neutron source according to claim 4, wherein the ampule enclosure is made of ferritic-martensitic steel. 6. The secondary startup neutron source according to claim 1, wherein the powdered beryllium has a particle size from 60 to 200 micron, and a porosity of 45%. 7. The secondary startup neutron source according to claim 1, wherein the ampule is installed in the enclosure of the secondary startup neutron source with a 0.1 mm clearance. 8. The secondary startup neutron source according to claim 1, wherein the enclosure further comprises an upper gas collector above the ampule. 9. The secondary startup neutron source according to claim 1, further comprising an upper gas collector, wherein the upper gas collector is pressed against the ampule through washers by a spring. 10. The secondary startup neutron source according to claim 1, wherein at the ampule is located above a reflector and a lower gas collector within the enclosure. 11. The secondary startup neutron source according to claim 1, wherein an inner cavity of the enclosure is filled with helium. 12. The secondary startup neutron source according to claim 1, wherein the enclosure is leak-proof. 13. The secondary startup neutron source according to claim 12, wherein the enclosure is sealed with an upper shank and a lower shank. 14. The secondary startup neutron source according to claim 12, wherein the enclosure is sealed by argon-arc welding. 15. The secondary startup neutron source according to claim 1, wherein the enclosure has four spaced apart spiral ribs. 16. The secondary startup neutron source according to claim 1, further comprising a gas collector, a reflector, washers and a spring, and wherein the enclosure, gas collector, spring, reflector and washers are made of ferritic-martensitic steel.