UIUC - BTeV Muon Trigger S. Davis, M. Haney, M. Selen, Use FPGA hardware + DSP algorithms to find tracks in muon detector subsystem. –Must provide adequate rejection of tracks due to random hits (lots of these in BTeV). –Must be efficient. –Must be fast Preliminary studies are very encouraging…

R view U & V views In this study we assume 3 stations with 3 views each (r,u,v)

Algorithm used in this study: Sparsify hits in each view. –Adjacent multi-hits “clustered” to a single tube. –Simple to do in hardware. Find {R,U,V} space-points in each station by exploiting the geometric constraint: U + V – Rcos(  ) = 65.5 –Gets rid of most random {R,U,V} combinations. –Efficient to do in software. –Can exploit correlations between stations to do this even more efficiently in the end.

R0R0 R2R2 R1R1 R N is the radial tube in station N. (numbering is out  in) 3D Scatter plot in {R 0,R 1,R 2 } space for a sample of good muon candidates (all octants). Points are very highly correlated (see rotated plot…) Similar planar correlation exists for U, V, (U-V)

R0R0 R2R2 R1R1 Points are very well fit by a simple plane. Very tight cuts can be made in this space. This is equivalent to a  2 lookup table for a bend-plane fit.

uds events (i.e. crap) good muon tracks For uds events, only the {R 1,R 2,R 3 } combination closest to the “good muon plane” is shown for each event.

How to exploit this: Rotate {x,y,x} coordinate system such that the “good event plane” lies at {x’,y’,0}: z’ y’ x’

z’ x’ y’ Create a lookup table in {x’,y’} plane Cut directly on narrow z’ distribution

muon efficiency uds rejection 1 track 2 tracks  tot cut 1 track (any uds event) 2 tracks 1 track when no muons are present in uds event Denominator: muons that satisfy - all views hit - R of track < 300 in all stations

Speed Running DSK on data from one event –2 muon tracks –lots of junk hits –no R cut (i.e. all 384 tubes looped over): clock cycles –About 0.8 ms at 133 MHz. Code size OK –“triggerdsktest.out” is 226 KB. –Of this, about 50KB is the “hit tube” data for one event. Pretty good for a first try –Will investigate several ideas for speeding things up. –Need to look at lots more events.

What's next: Lots more timing studies (Scott). Optimize algorithm for speed (Mike, Scott) Use realistic 4-view Muon Detector MC (Mats) Write TDR (Mike, Mats Scott) Mike is a key player in the overall BTeV trigger effort. –PI on the funded RTES Proposal (NSF). –Mr. WBS (not by choice). –(Mikes RTES talk here…)