DCZ status & results B A B AR Trigger Workshop, December 2004 Jamie Boyd University of Bristol for the Trigger Upgrade Group

December 2004Jamie Boyd2 Intro Goal: reduce the L1 trigger rate due to beam-related background by cutting on track z0 ZPD is a 3-D enhanced version of the PTD Finds tracks and fit them to helix (SL7 & SL10 seeds used) Measures p T, dip angle ( ) and z 0 Primary usage: Cut on |z 0 | to remove background z 0 of all tracks in L-1 events Physics Background

December 2004Jamie Boyd3 DCZ Project Outline ZPD (replacing PTD) does the 3-dim. tracking Replace TSF to send full stereo segment data New interconnects (cards and cables) New online software + simulation BABAR Drift Chamber BLT L1 Accept PTD GLT TSF PTD New TSF ZPD

December 2004Jamie Boyd4 ZPD Modules Designed and produced at Harvard 8 modules in the system +3 good spares Operated and debugged in IR2 for the entire Run 4 Firmware is final Each module covers 3/8 phi span – but only looks for tracks with SL7 / SL10 seeds in central 8 th

December 2004Jamie Boyd5 TSF Modules Designed and produced in the UK (Manchester, Bristol, RAL) Arrived in Summer ’04 24 modules in the system 25 production modules, plus 4 SLAC Firmware is final Job is to find track segments as 8 wire Pivot cells using 16bit LUT 16 TSF-X modules which deal with SL 1-4, TSF-Y modules which deal with SL 5-7 TSF X crate = 16 boards

December 2004Jamie Boyd6 Recent History Ran with DCZ triggering BaBar for last few days of run4 Slightly incomplete test TSF firmware either worked for TSF DAQ data or for TSF->BLT data (but not both) System configuration not done using the proper method (config objects not in DB) L3 being driven by Old TSF segments Since then took some magnet off COSMICs with DCZ triggering BaBar Fixed TSF firmware Optimised timing of signals to GLT TSF extenders fitted / recabled the DCZ crates

December 2004Jamie Boyd7 Z-Triggering B A B AR DCZ triggered B A B AR for the first time on July 29 Nothing fell over… Modest L1T rate reduction seen with conservative GLT setting Luminosity Deadtime L1T rate HER LER Run 50636, July 31, 2004

December 2004Jamie Boyd8 A Z-Triggered Event 1Z 2Z 1Z’ 1Z 1Z’1Zt 2Zt 1Z

December 2004Jamie Boyd9 DCZ Track Efficiency Use reco. tracks in DCZ’s , p T acceptance 98% for isolated tracks 93-94% for tracks in hadronic events Consistent with simulation studies

December 2004Jamie Boyd10 DCZ Track Resolution Compare the track params. measured by DCZ and reco Resolution consistent with simulation z 0 core resolution ~4.6 cm NB: Background peaks around ±20 cm

December 2004Jamie Boyd11 IP Correction Effect of IP not being at (0,0) in x-y can be corrected (remaining wave from no x correction so far) A small charge asymmetry effect seen in the bias after correction – to be understood

December 2004Jamie Boyd12 TSF Data (from COSMIC run) Comparing Old and New TSF DAQ data for same events

December 2004Jamie Boyd13 Timing to GLT Signals line up as well as (or better) than with old dct Signal stretch is same as before DCZ latency is ~5.5us which is in spec. GLT input mask timing shows ZPD timing could adjusted by ½ clk8

December 2004Jamie Boyd14 L1 Trigger Rate DCZ does its job just as well as we hoped Finding tracks and measuring z 0 and p T How do we use this information? ZPD can count tracks with cuts on |z 0 | and |1/p T | We’ve tried |z 0 | 200(800) MeV GLT can combine “Z tracks” with other trigger objects We’ve added “&1Z” to a few lines for the test runs It’s a delicate balancing act Physics efficiency (which physics?) and robustness Maximum reduction of L1 trigger rate Su Dong will discuss the trigger lines configuration in his talk

December 2004Jamie Boyd15 What is sent to the GLT? 1x16-bit, 2x8-bit and 1x4-bit phi maps sent to GLT every clk4 (269ns) Sent to GLTDec. bit Pt(MeV)Tan dipZ0 (cm)Z0errNmiss hit cut mask 16 bit phi map 0>200-2 – 3-15 – 15 ( ) 1 st sector 1>200-2 – 3-15 – 15 ( ) 2nd sector 8 bit phi map2>200-2 – 3-10 – 10<15YA10|A7 either sector 8 bit phi map3>800-2 – 3-15 – 15<15NA10|A7 either sector 4 bit phi map4>350-2 – 3-10 – 10<15YA10|A7 either sector DAQ data only5>300-2 – 3-6 – 6<15YA10|A7 either sector DAQ data only6>250-3 – 3-10 – 10<15NA10 only DAQ data only7>250-3 – 3-10 – 10<15NA7 only

December 2004Jamie Boyd16 Remaining (few) issues Firmware Remove 80  s DAQ delay (being worked on) Fix a broken register that controls the EZ* phi span Online Make DCZ configuration from DB (underway) Feed L3 from New TSF (should work but not attempted yet) Offline Complete and Validate DCZ simulation Wont be able to do physics with DCZ data until we have simulated data Monitoring in OPR

December 2004Jamie Boyd17 Summary DCZ working as planned Triggered BaBar for first time (end of run4) Resolution and efficiency as expected Since then have cleaned up a few problems (TSF firmware, timing, mechanical issues) DCZ will be production trigger when we start taking data again Need to start thinking about the best way to use its capabilities to best suit BaBar (L1 rate versus physics efficiency) A few small software tasks to finish before then