2-D simulations of the self magnetic pinch diode

For many years AWE has used self magnetic (SM) pinch diodes on its lower voltage flash x-ray machines (MEVEX @0.8 MV and Mini-B @ 2 MV). The SM pinch diode has proved to be a reliable source for providing small diameter radiographic spot sizes (2.0 - 2.5 mm). With the recent emphasis on reduction of the x-ray spot size at higher voltages, one part of the diode research project has been to field SM pinch diodes at higher voltages. An electromagnetic PIC code, LSP, has been used to carry out 2-D simulations of the diode to support this project. Results of these code simulations will be presented. The simulations show good agreement with measured experimental machine voltage and current records. Good correlation is also achieved with old experimental data on diode performance. The simulations suggest further improvements in spot size reduction could be achieved with changes in the diode geometry.