Hi Flemming, On Thu, 6 Sep 2001 22:05:38 -0400 "Flemming Videbaek" <videbaek@sgs1.hirg.bnl.gov> wrote concerning "trigger words": > I have had some question recently, I it might be useful to iterate > some of the fact of how the triggers latches are setup. > > The trigger system has 8 inputs, labelled trigger 1-8; 7/8 are > non-beam related i.e. pulsers+sync events; > A latch is made 3 times for each event > a) once before the scaledown -> bit 0-7 > b) after scaledown bit 8-15 > c) once before the enable setting bit 16-23 > > Thus the second 8 bit tells what trigger started the gates , while > the first 8 tells what triggers were set by the hardware for a given > event. It is important to beware this difference when evaluating > cross sections. Thus for scaledown events one should not test the > 16bits, but only the eight to decide what kins of trigger it is, but > use the second set for evaluating rates/ratios and cross sections. Let me get this straight: * For scaledown events, one should look at bits 8-15 (this is what is done in BrTriggerFilter). * For evaluating rates/ratios and x-sections, one should look at all 16 bites from 0-15. Is this correct? What can the upper 8 bites (from 16-23) be used for? Should we perhaps extend the functionality of BrTriggerFilter (or perhaps a new filter) for evaluating rates/ratios and x-sections? I think I put in some of this info in some document, class description, or something like that, but I just can't remember where, and I can't seem to find it again. Perhaps it was some email to one of the lists, but I'm in no mood to go through some 1000+ emails to figure out where it was (that search engine would be a really REALLY great thing indeed). Perhaps this information should be added to BrTriggerFilter or The Guide. Yours, Christian Holm Christensen ------------------------------------------- Address: Sankt Hansgade 23, 1. th. Phone: (+45) 35 35 96 91 DK-2200 Copenhagen N Cell: (+45) 28 82 16 23 Denmark Office: (+45) 353 25 305 Email: cholm@nbi.dk Web: www.nbi.dk/~cholm
This archive was generated by hypermail 2b30 : Fri Sep 07 2001 - 09:37:18 EDT