Speaker
Description
During the operation of LINAC4, up to 25% of the source beam current is routinely lost in the Radio Frequency Quadrupole (RFQ) at an energy between 0.045 and 3 MeV. These losses can cause surface modifications which in turn may lead, in areas of high electric field, to an increased vacuum breakdown rate. An experimental study has been made to identify materials with high electric field capability and robustness to low-energy irradiation. Seven materials have been tested using high pulsing voltage after and before being exposed to H- low voltage irradiation. Surface analysis was preformed after each test using advanced microscopic techniques such as Scanning Electron Microscope, Electron Back Scattered Diffraction, Energy-dispersive X-ray Spectroscopy and conventional optical microscopy. Carbon contamination in some of these materials is also explored with the aim of understanding the existence of a correlation between the presence of Carbon on the materials surface and the breakdown testing.
