1. LANSCE Timing Requirements LA-UR-03-3376 Eric Bjorklund

2. Basic Characteristics “Gate” rather than “Event” driven system. 96 independent timing gates  82 gates in use. 8.3 millisecond machine cycle (120 Hz). 1 second super-cycle. Clock synchronized with ring RF. –2.7951389 MHz.

3. Resolution, Accuracy, Stability Resolution = 1 microsecond Accuracy =  180 nanoseconds Stability (jitter) = ± 30 nanoseconds

4. Neutron Chopper and AC Line Coupling Maximum Slew Rate = 0.3 Hz/second Maximum Drift =  100 microseconds Accelerator Tracking Sigma = 25 microseconds Chopper Tracking Sigma = 330 nanoseconds

5. Current Architecture Star configuration 4 redundant gate generator sets in 2 CAMAC crates. Gate generators are loaded by Master Timer computer, then run independently. Master Timer computer checks the output of the gate generators and automatically switches to another set when a discrepancy is seen. Master Timer MUX Timing Distribution Timing Gates Timing Gate Generators

6. Additional Requirements For Upgraded (Distributed) System Front-end IOCs need some way to know which cycle they are currently in and when a cycle starts Front-end IOCs need some way to know the “Flavor” of the current cycle.