Lifetime testing of Airix accelerating units

Airix is a linear accelerator producing a 60ns, 2kA, 19MeV electron beam. It has been operated in a single shot mode by the “Commissariat à l'Energie Atomique et aux Energies Alternatives” (CEA) for flash X-ray radiography purposes for nearly 12 years [1, 3]. Usually each accelerating unit (a cell and its driver) delivers a 100ns pulse of 250kV amplitude to the beam. The test bench is used to determine the behaviour over time of the cells, the driver (high voltage generator) and the links between them (high voltage cables). We try different configurations and deal with ensuing problems. In this paper, we describe the test-bed in use, the problems we have met and how we dealt with them, and we establish the reliability performances we now expect from the accelerating units for the next decades.