Characterization of high-voltage lithium niobate piezoelectric transformers

Piezoelectric transformers (PTs) are capable of generating the high accelerating potentials required for many charged-particle beam applications. However, the PTs need to be characterized during operation as an accelerator for such beam loads. PT characteristics such as internal stress, electric field, and electric potential can provide insight into the optimal operating conditions for a given application. Measurement of internal stress can be used to ensure that the single-crystal lithium niobate (LiNbO₃) PT does not exceed the fracture limit. Internal electric field and potential can be used to determine the accelerating potential created by the PT. Internal parameters such as these have been measured using an optical diagnostic that relies on the inherent photoelastic and electro-optic properties of lithium niobate. Beam currents have been determined using least-squares curve fitting with experimental and modeled results. Further characterization of the beam interactions with the PT was done by examining the direct bremsstrahlung x-ray spectra that were produced and the x-ray fluorescence peaks excited by the source. This paper presents a variety of PT characterization results under varied PT operating conditions.