dcz status & results b a b ar trigger workshop, december 2004 jamie boyd university of bristol...

DCZ status & results

BABAR Trigger Workshop, December 2004

Jamie BoydUniversity of Bristol

for the Trigger Upgrade Group

December 2004 Jamie Boyd 2

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 pT, dip angle () and z0

Primary usage: Cut on |z0| to remove background

z0 of alltracksin L-1events

Physics

Background


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

BABARDrift

ChamberBLT

L1 Accept

PTDGLT

TSFTSF PTDNewTSF

ZPD


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 8th


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 prototypes @ 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 1-4,8-10

8 TSF-Y modules which deal with SL 5-7

TSF X crate = 16 boards


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


Z-Triggering BABAR

DCZ triggered BABAR 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


A Z-Triggered Event1Z

1Z

1Z

2Z

1Z’1Z

1Z’ 1Zt

2Zt

1Z1Z


DCZ Track Efficiency Use reco. tracks in DCZ’s

, pT acceptance

98% for isolated tracks 93-94% for tracks in

hadronic events Consistent with simulation

studies

# of reco. tracks with DCZ match

# of reco. tracks


DCZ Track Resolution

Compare the track params.measured by DCZ and reco Resolution consistent

with simulation z0 core resolution ~4.6 cm

NB: Background peaksaround ±20 cm


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


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


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 timingshows ZPD timing couldadjusted by ½ clk8


L1 Trigger Rate

DCZ does its job just as well as we hoped Finding tracks and measuring z0 and pT

How do we use this information? ZPD can count tracks with cuts on |z0| and |1/pT|

We’ve tried |z0| < 15(12)cm, |pT| > 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


What is sent to the GLT? 1x16-bit, 2x8-bit and 1x4-bit phi maps sent to GLT every clk4 (269ns)

Sent to GLT Dec. bit

Pt(MeV) Tan dip Z0 (cm) Z0err Nmiss hit cut

mask

16 bit phi map0 >200 -2 – 3 -15 – 15

(-12 -12)<15 N A10|A7 @ 1st sector

1 >200 -2 – 3 -15 – 15 (-12 - 12)

<15 N A10|A7 @ 2nd sector

8 bit phi map 2 >200 -2 – 3 -10 – 10 <15 Y A10|A7 either sector

8 bit phi map 3 >800 -2 – 3 -15 – 15 <15 N A10|A7 either sector

4 bit phi map 4 >350 -2 – 3 -10 – 10 <15 Y A10|A7 either sector

DAQ data only 5 >300 -2 – 3 -6 – 6 <15 Y A10|A7 either sector

DAQ data only 6 >250 -3 – 3 -10 – 10 <15 N A10 only

DAQ data only 7 >250 -3 – 3 -10 – 10 <15 N A7 only


Remaining (few) issues

Firmware Remove 80s 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


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

dcz status & results b a b ar trigger workshop, december 2004 jamie boyd university of bristol...

Documents

z slide

jamie boyd5 tsf modules

tsfx modules

jamie boyd12 tsf data

tsfy modules

background z

tsfblt data

glt tsf extenders