Positive-polarity rod-pinch experiments on the RITS-6 accelerator

RITS-6 is an inductive voltage adder based accelerator used for radiographic diode research and development. A recent experiment was conducted to demonstrate that a negative polarity induction voltage adder could operate in positive polarity, at reduced voltage, with minimal reconfiguration and maintenance. Circuit simulations, 2-D electrostatic field calculations, and particle-in-cell simulations were used to evaluate operation of RITS-6 in positive polarity and design hardware modifications. Changes to the RITS-6 accelerator during the conversion from negative-polarity high voltage (5-11 MV) output to positive-polarity low voltage (2-3 MV) output are discussed. The first positive polarity rod-pinch experiment generated 3.5 rad from a 1-mm spot size, comparable to previously published rod-pinch experiments on positive polarity accelerators.