Prospects for an optical re-triggering system for the LHC beam dumping system at CERN

The LHC (Large Hadron Collider) beam extraction kicker system, composed of 15 fast kicker magnets per beam, is used to extract the particles in one turn from the collider and to dispose of them, after dilution, on an external absorber. Each of the 15 magnets is powered by a separate pulse generator, all of which are simultaneously triggered when a beam extraction from the machine is requested. Spontaneous firing of a single generator will create beam oscillations that are likely to exceed the accelerator aperture, resulting in beam losses and potential damage to the machine. In order to protect against occurrence of such events, a Re-Triggering System (RTS) has been implemented to redistribute, as fast as possible, a trigger request issued from the spontaneous-firing generator to all 15 generators. A prospect for a RTS based on passively generated and transmitted optical power to all others generators has been studied as an alternative to existing re-triggering line solution. This can be accomplished by coupling light from a number of diode laser arrays at re-trigger sources of one generator to bundles of optical fibres subsequently dispatched to all 15 generators. At each generator control stage we foresee a re-triggering switch which ensures the conversion of the light signal into an isolated electrical triggering pulse.