A 10 MHz beam and multiplicity counter system for experiment E864

The E864 experiment at the AGS is a high sensitivity search for strangelets and other novel forms of matter that are expected to be produced in heavy ion collisions. The experiment is designed to operate at an incident beam rate of 107 Au ions per spill. The authors describe the performance of the quartz-Cherenkov beam counter and scintillator -multiplicity-trigger system that were installed and tested during the Fall run of 1994. A special feature of the system is the low pulse height (60mV for the beam counter) operation necessary to maintain small PMT anode currents for high rates. The authors provide results for the time resolution and stability of the system at beam rates of 5x105 and 1x107 Au ions per spill