with bunched primary beam (bunching frequency 1.94070 MHz) we have strong PMT (mid) and particle detector signal. Time between both detectors was measured (in 3.3ns bins)

Particle Det ;  PMT (rising edge)
305 ; 256
227 ; 179
150 ; 102
73 ; 24


PD and PMT signal is second plot. Laser timing was not adjusted jet since it will change with Th beam.