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Description
The Linear IFMIF Prototype Accelerator (LIPAc) is a validation and test facility for the injector and the initial low-energy part of the IFMIF accelerator, designed to study a 125 mA-CW deuteron beam driver of the neutron source for the fusion materials examination. The RF section of the accelerator comprises three elements: a 9.8 m-long RFQ designed to extract a 5 MeV bunched beam accelerated from a 100 keV coasting beam, two re-buncher cavities, and eight superconducting half-wave resonators, which accelerate the beam up to 9 MeV. The beam commissioning has been conducted by incrementally increasing the duty cycle from the chopped to the raw extracted pulses. To date, in the intermediate construction phase of the design model, where the superconducting cryomodule has been replaced with a quadrupole beam transport line, we reached a duty cycle of 8.75 % for the 116 mA deuteron beam. This work presents an overview of the RF system, including a discussion of the challenges encountered during the commissioning periods. In particular, it will address the following points: the stability of the tetrode amplifier system, the impact of dissipation in the circulators, and the impact of beam cavity interaction in the RFQ as a resonator driven by eight RF stations.
