SVT Improvement (Track counting in GhostBuster board) Motivation: Processing time of L2 can be significantly reduced (2-3us level?) using # of good tracks counted by SVT GhostBuster(GB) board. (good track: Pt>2GeV/c, chisq<15, d0>100um) studied by Kristian Hahn, idea: Bill Ashmanskas Jonathan Lewis Number of good track(s) > 0 and >1 (2 bit assignment) in SVT End of Event (EoE) could be useful for the fast decision of L2 alpha program.

Track counting in SVT GB board (cont’) Changing GB firmware is not so hard, takes ~2 weeks including test. Therefore, only discussion for 2 bit assignment of EoE is needed 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 HD DS L2B L1T Error Flags PA Event Tag (BC) Essential for SVT and/or L2 Note: bit 9 : Parity error bit 10: Lost sync bit 11: FIFO overflow bit 12: Invalid data bit 13: Internal overflow bit 14: Truncated Output bit 15: G-link lost lock bit 16: Parity error to L2? Relatively low priority (1) There are almost no resources without overriding error bit. (Bit 16 is not used yet, but useful in future: tracklist overrides ) (2) bit 17, 18 are useful to check the data. (bit 17 may be used in diff Pt cut) (3) I proposed the overriding the bit 13(N>0) and 14(N>1). Bit 13 and 14 is not a real error condition.

Current situation for error bit bit 13 and 14 error is naturally occurred in SVT and indeed happened in almost every events. They are set so often and carries almost no information. bit 15 is never set (if this happens, SVT stopped processing). So, this bit is also OK to use. These can be checked by SPYMON until the GB though SVTD information for overridden error bits will be lost. (since SVTD readout is after the EE modification) GB timing SPY SVTD L2 track list GB track Proc. Candidate for EE modification

Summary Counting the number of good tracks inside GB could improve the L2 processing time significantly. (worth while trying) Firmware changing is not so hard. It takes a couple of weeks including the test, optimistically. I propose bit 13 and 14 overridden. (If there is no strong objections, this is the simplest and safest for current SVT configuration).