Ion Source Development and Operation

A new vacuum arc type ion source (VARIS) has been developed and tested for high current uranium operation. Figure 1 shows a cross sectional view of the ion source. The discharge arrangement has a tubular anode opposite to the cathode mount carrying 17 cathodes (each one is 5.7mm in diameter and 17mm in length). The anode, made of stainless steel, is placed 15mm apart from the cathode. Its aperture is 15mm respectively. The magnetic field configuration for charge state enhancement is created by a solenoid, which is placed near the front face of the anode. A second solenoid, which is placed in the back part of the tubular anode, is additionally installed for plasma confinement. To avoid vacuum problems both coils are entirely located outside the plasma chamber. For ion extraction an accel-decel system has been used. Its screening electrode is encapsulated for reasons of length reduction of the extraction system. Most important improvements compared to the MEVVA IV ion source are: