A High-Voltage Piezoelectric Transformer for Active Interrogation

Detection of nuclear or fissile materials is made difficult due to thespeed, quantity, and variety of entrance points of transported goodsin a global market. Inspecting transported goods under these conditionsrequires a convenient and portable device that uses provenmethods. Active nuclear detection can be performed by using neutronsto induce a nuclear reaction in a radioactive material, whichcan then be detected by an appropriate sensor. The University ofMissouri is developing an ultra-compact deuterium ion acceleratorto induce D-D fusion as a source of neutrons for detection purposes.The accelerator utilizes a lithium niobate piezoelectric transformercapable of producing a 100 kV output when driven with alow radio frequency resonant voltage. The transformer is a Rosentypetransformer composed of a rotated y-cut polarized rectangularcrystal, with the primary voltage applied through the crystal’sthickness and the secondary developed along its length. The transformerwill be used to supply and accelerate deuterium ions byfield emission from a tip attached to the crystal’s output electrode.The deuterium ions then impact a deuterated target inducing aD + D —> 3He + n reaction. Advantages of this circuit include lowpower consumption, quick turn on, and compactness. The piezoelectrictransformer characteristics have been measured and are presentedalong with the design of the neutron source.