Low Level Radio-frequency Developments toward a Fault-tolerant Linac Scheme for an Accelerator Driven System

In view of the construction of the MYRRHA ADS demonstrator in Mol (Belgium), that requires a highly reliable MW-class proton driver, an analysis was carried out to evaluate the fault-tolerance capability of the superconducting linac in the particular case of a radiofrequency (RF) cavity failure. As a complement to past beam dynamics studies, extensive simulations on the RF behaviour of a 700 MHz superconducting cavity as well as its tuning and feedback loop systems have been performed in the case of fast fault-recovery procedures. A prototypical digital Low Level RF (LLRF) system suited to such scenarios is also proposed.