The four beams within each quad are synchronized to arrive simultaneously at TCC. The separate quads are synchronized with respect to each other using a separate fiducial pulse as a cross-timing reference. The beams are synchronized at nominal T0 to within 30 ps rms, but multiple quads may be synchronized at a fixed delay if accurate relative beam timing is required at a large delay.
The arrival times of pulses at the TCC on NIF can be independently adjusted on a per-quad basis. The desired pulse delays are requested by the user through the shot setup in CMT. For delays that contain the start and stop of the pulse within a 0–35 ns absolute time window, the NIF system can handle the timing changes automatically. Timing changes that result in the end of the pulse occurring after a 35 ns window require a delay fiber to be installed in the respective quad(s) to achieve the requested delay. The maximum allowable time delay could be up to 1 μs, but the nonlinear effects within the fiber delay beyond a few hundred nanoseconds have not yet been evaluated. Negative delays are not allowed.
Two quads within a common bundle must have a relative delay that is less than ~80 ns due to mechanical and electrical constraints in the Plasma Electrode Pockels Cell (PEPC). The exact allowable delays will be different for each bundle, as the individual beamlines within the bundle may be more restrictive than the PEPC time window listed above.