Direct measurement of the bi-polar ion current and anode-cathode (A-K) voltage in a self-magnetic pinch (SMP) diode

Summary form only given. A self-magnetic pinch diode is currently under extensive study in the Sandia Laboratory advanced radiographic development facility. The SMP diode is utilized in conjunction with the RITS accelerator. RITS is a voltage adder adding the voltage pulse of six 1.5 MV inductively insulated cavities. A tapered MITL cathode stalk threads the cavities, adds the voltage pulses and feeds the SMP electron diode at the end of the MITL. The maximum voltage can reach 9 MV. The diode's anode is made of high Z metal in order to produce copious and energetic flash x-rays for radiographic imaging of heavy objects. In any high voltage inductive voltage adder (IVA) utilizing MITLs to transmit the power to the load, the measuring of the voltage is problematic because of the presence of vacuum electrons (sheath current). The accelerating voltage quoted in the literature is from estimates based on the anode and cathode currents of the MITL well away from the diode. We are investigating a method to measure the bi-polar ion current and the A-K gap voltage by collecting the emitted ions from the anode target utilizing filtered Faraday cups and also time of flight-techniques. The proposed design, simulations and possibly results will be presented and analyzed.