Abstract
An associated particle neutron generator (APNG) capable of 109 neutrons per second has been operated with an alpha particle detector made of a ZnO:Ga phosphor with decay time of approximately 1 ns. Fast 14.1 MeV neutrons and 3.5 MeV alpha particles are produced through deuterium-tritium (DT) fusion reactions and travel in opposite directions to conserve momentum. The neutron generator provides high rate capability, excellent subnanosecond time resolution (< 0.7 ns), and a large solid angle with acceptance of 8%. The alpha detector was found to have a detection efficiency of 88% using a Burle 8850 bialkali photocathode. The DT beam spot diameter was measured down to 2.1 mm with the possibility of achieving 1 mm if desired. An opaque aperture was placed on the alpha detector and the neutron beam was obstructed using various amounts of lead shielding in an effort to study the generator�s imaging contrast capability for neutron radiography. The alpha detector can be pixilated using a multianode photomultiplier tube to deliver imaging capability and to enhance the signal to noise ratio. Due to its ability to suppress background, the developed APNG is to be used to search cargo containers for illicit special nuclear materials, using as a trigger prompt fission gamma rays in coincidence with an alpha particle within a 10 ns gate.
