Neutron generator

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Neutron generators are neutron source devices which contain compact linear accelerators and that produce neutrons by fusing isotopes of hydrogen together. The fusion reactions take place in these devices by accelerating either deuterium, tritium, or a mixture of these two isotopes into a metal hydride target which also contains either deuterium, tritium or a mixture. Fusion of deuterium atoms (D + D) results in the formation of a He-3 ion and a neutron with a kinetic energy of approximately 2.5 MeV. Fusion of a deuterium and a tritium atom (D + T) results in the formation of a He-4 ion and a neutron with a kinetic energy of approximately 14.1 MeV.

Thousands of such small, relatively inexpensive systems have been built over the past five decades.

[edit] Alternative neutron generator technologies

Another type of innovative neutron generator is offered by a company in Germany: NSD-Fusion. This neutron generator differs from the conventional ion beam onto solid target types because it avoids using a solid target which will be eroded. Originally called a fusor, it was invented by Philo Farnsworth, the inventor of electronic television, and is often referred to as inertial electrostatic confinement fusion. The fusor remained largely ignored until the 1990s when its commercial potential was recognized and improvements made to enhance the characteristics as a neutron generator for industry.

In April of 2005 researchers at UCLA demonstrated the use of a thermally cycled pyroelectric crystal to generate high electric fields in a neutron generator application. In February of 2006 researchers at Rensselaer Polytechnic Institute demonstrated the use of two oppositely poled crystals for this application. Using these low-tech power supplies it is possible to generate a sufficiently high electric field gradient across an accelerating gap to accelerate deuterium ions into a deuterated target to produce the D + D fusion reaction. These devices are similar in their operating principle to conventional sealed-tube neutron generators which typically use Cockcroft-Walton type high voltage power supplies. The novelty of this approach is in the simplicity of the high voltage source. Unfortunately, the relatively low accelerating current that pyroelectric crystals can generate, together with the modest pulsing frequencies that can be achieved (a few cycles per minute) limits their near-term application in comparison with today's commercial products (see below). Also see pyroelectric fusion. [1]