Mitigation of background EMI, mechanical and acoustic effects from the Gamble 11 pulsed power generator

The Gamble II accelerator can be used with several diode configurations to provide a diverse x-ray spectrum to different test packages. For example, in Bremsstrahlung mode, the Gamble II accelerator typically injects a 600-700 kA, 1.2-1.4 MV electron beam into a tantalum X-ray converter to produce X-ray Bremsstrahlung. However, along with the radiation flux, the test package may be subjected to unwanted electromagnetic interference (EMI) or mechanical and acoustic effects that can confuse the test results. Most of the EMI and mechanical effects are generated in the power conditioning sections of Gamble II. We have undertaken a series of measurements using calibrated RF antennas and accelerometers to find the sources of EMI and mechanical effects. These measurements are used to design upgrades to the pulsed power system that minimize any detrimental impact on the test packages.