Development of exploding wire ion source for intense pulsed heavy ion beam accelerator

A Novel exploding wire type ion source device is proposed as a metallic ion source of intense pulsed heavy ion beam (PHIB) accelerator. In the device, multiple shot operations are realized without breaking the vacuum. The basic characteristics of the device are evaluated experimentally with an aluminum wire of diameter 0.2 mm and length 25 mm. A capacitor bank of capacitance 3 μF and a charging voltage of 30 kV was used, and the wire was successfully exploded by a discharge current of 15 kA with a rise time of 5.3 μs. Plasma flux of ion current density around 70 A/cm2 was obtained at 150 mm downstream from the device. The drift velocity of ions evaluated by a time-of-flight method was 2.7×104 m/ s, which corresponds to the kinetic energy of 100 eV for aluminum ions. From the measurement of the ion current density distribution, the ion flow is found to be concentrated toward the direction where the ion acceleration gap is placed. From the experiment, the device is found to be acceptable for applying the PHIB accelerator.