Focused ion beam production using a pyroelectric crystal and a resistive glass tube

We describe the use of a lithium tantalate (LiTaO₃) pyroelectric crystal and a resistive glass tube to generate a focused ion beam. A sharp tip was mounted on one surface of the LiTaO₃ crystal which ionized a low pressure deuterium gas. A resistive glass tube was mounted coaxially with the tip. The resultant ion beam produced an illuminated spot on a ZnS screen. Experimental results were compared with finite element modeling performed using COMSOL Multiphysics. It was found that the spot size increased as the distance between the screen and the end of the resistive glass tube increased, which agreed with the COMSOL model.