Fast burst and steady-state intense neutron source

Abstract

A first system for producing a high flux of neutrons for non-destructive testing includes a dense plasma focus device neutronically coupled to a subcritical or sub-prompt critical fission assembly. The dense plasma focus device is a source of initiating neutrons for the fission assembly, and the fission assembly is configured to multiply a number of the initiating neutrons via inducing fission. A second system for producing a high flux of neutrons includes a gas-target neutron generator neutronically coupled to a subcritical or sub-prompt critical fission assembly. The gas-target neutron generator is a source of initiating neutrons for the fission assembly, and the fission assembly is configured to multiply a number of the initiating neutrons via inducing fission.

What is claimed is: 
     
         1 . A system for producing a flux of neutrons, the system comprising:
 a dense plasma focus device having an input end and an output end;   a fission assembly neutronically coupled to the dense plasma focus device, the fission assembly is a subcritical or a sub-prompt critical fission assembly; and   a fast neutron multiplier layer configured to cover the output end of the dense plasma focus device,   wherein the dense plasma focus device is a source of initiating neutrons for the fission assembly, and the fission assembly is configured to multiply a number of the initiating neutrons via inducing fission.   
     
     
         2 . The system of  claim 1 , wherein the dense plasma focus device includes
 a cylindrical cathode;   a cylindrical anode disposed within and concentric to the cathode; and   a chamber bounded by the cathode and the anode, the chamber being pressurized with a fill gas.   
     
     
         3 . The system of  claim 2 , wherein the dense plasma focus device includes an insulator provided between the cathode and the anode, the insulator disposed proximate to the input end of the dense plasma focus device. 
     
     
         4 . The system of  claim 2 , wherein the fill gas comprises a deuterium-tritium gas mixture. 
     
     
         5 . The system of  claim 2 , wherein a pressure of the fill gas is static at 1-100 Torr. 
     
     
         6 . The system of  claim 2 , further comprising a supply line configured to introduce puffs of the fill gas at pre-determined time intervals at the input end of the dense plasma focus device, wherein a pressure of the fill gas is dynamically raised at a pinch formed at a center of an end of the anode proximate to the output end of the dense plasma focus device. 
     
     
         7 . The system of  claim 2 , wherein the anode has a radius of at least 20 cm and the cathode has a radius of at least 30 cm. 
     
     
         8 . The system of  claim 1 , further including an outer multiplier layer configured to cover a sidewall and the input end of the dense plasma focus device. 
     
     
         9 . The system of  claim 1 , wherein the outer multiplier layer is comprised of depleted uranium metal. 
     
     
         10 . The system of  claim 1 , wherein the fission assembly comprises a low enriched uranium blanket. 
     
     
         11 . The system of  claim 10 , wherein the fast neutron multiplier layer is positioned between the output end of the dense plasma focus device and the low enriched uranium blanket. 
     
     
         12 . The system of  claim 1 , wherein the low enriched uranium blanket is configured to bound a test cavity. 
     
     
         13 . The system of  claim 1 , wherein the dense plasma focus device further comprises a group of capacitor banks constructed in series. 
     
     
         14 . The system of  claim 13 , wherein each capacitor bank is configured to individually discharge, and individual discharges of each of the capacitor banks are timed such that a specific pulse is formed in order to control a current drive time and a magnitude of current delivered to a pinch formed at a center of an end of an anode proximate to the output end of the dense plasma focus device. 
     
     
         15 . The system of  claim 1 , wherein the fast neutron multiplier layer is comprised of an aluminum-beryllium alloy. 
     
     
         16 . The system of  claim 1 , wherein the fission assembly further comprises a neutron reflector configured to surround the dense plasma focus device, an outer multiplier layer, the fast neutron multiplier layer and a low enriched uranium blanket. 
     
     
         17 . The system of  claim 16 , wherein the neutron reflector is comprised of copper. 
     
     
         18 . The system of  claim 1 , wherein the fission assembly is a subcritical fission assembly. 
     
     
         19 . The system of  claim 1 , further including an outer multiplier layer configured to cover a sidewall and the input end of the dense plasma focus device; and wherein the fission assembly comprises a low enriched uranium blanket; the fast neutron multiplier layer is positioned between the output end of the dense plasma focus device and the low enriched uranium blanket. 
     
     
         20 . The system of  claim 1 , wherein the dense plasma focus device includes
 a cathode;   a anode disposed within the cathode;   an insulator provided between the cathode and the anode, the insulator disposed proximate to the input end of the dense plasma focus device; and   a chamber bounded by the cathode and the anode, the chamber being pressurized with a fill gas.