A trigger card for event rejection in the RMC experiment at TRIUMF

A trigger card has been designed and constructed to improve the trigger efficiency of a large solid angle pair spectrometer to be used for the measurement of radiative muon capture at TRIUMF. A number of these trigger cards are connected to FASTBUS pipeline TDCs (time-to-digital converter) via the FASTBUS auxiliary connector to provide coarse information on the tracks of charged particles in a drift chamber. The trigger cards produce a majority OR of groups of six signals from the chamber, allowing very fast online event rejection. The performance of the cards and other relevant technical issues is discussed