ted liu, july 5,00, idea on ztrigger l1 trigger strategy l1 trigger requirements and trigger lines...
DESCRIPTION
Ted Liu, July 5,00, idea on Ztrigger Trigger Lines for Hadronic Events B Physics Continuum Pure DCT Pure EMT DCT + EMT CP Channels: high eff. Non-CP channels: high + precise eff. Requirements: High & precise eff. for background sub. orthogonal lines redundant lines record all trigger DAQ data prescaled lines Strategy for eff. Measurements : run9304TRANSCRIPT
Ted Liu, July 5,00, idea on Ztrigger
L1 Trigger Strategy
• L1 Trigger Requirements and Trigger Lines• L1 Trigger performance• Background Study• Improving Performance: near-term strategy • Future Prospect: long-term strategy• summary
Ted Liu, Lawrence Berkeley Lab (for the trigger group)
Ted Liu, July 5,00, idea on Ztrigger
Trigger Line Definition/Convention
DCT Objects:
A: long track reaching SL10, Pt ~180 MeV
B: short track reaching SL5, Pt ~120 MeV
A’: high Pt track reaching SL10, Pt > 800 MeV
EMT Objects:M: minimal ionizing cluster, E >100 MeV
G: intermediate energy cluster, E >300 MeV
E: high energy cluster, E >700 MeV
Y: backward barrel cluster, E >1 GeV
IFT Objects:1U: 1 high P muon in backward endcap
B*,M*...* means back-to-back objects(>120 )D2 = 2B&1A, D2* = B*&1AD2*+ = B*&1A&1A’ , A+ = A&A’
o
Ted Liu, July 5,00, idea on Ztrigger
Trigger Lines for Hadronic Events
B Physics
Continuum
Pure DCT
Pure EMT
DCT + EMT
CP Channels: high eff.
Non-CP channels: high + precise eff.
Requirements:
High & precise eff.for background sub.
orthogonal linesredundant linesrecord all trigger DAQ dataprescaled lines
Strategy for eff. Measurements:
run9304
Ted Liu, July 5,00, idea on Ztrigger
Use orthogonal DCT-EMT lines to study eff.
Total eff for hadron skim: (EMT OR DCT) > 99.3%
From Su Dong
Ted Liu, July 5,00, idea on Ztrigger
Trigger Lines for non-physics Events
Luminosity, calibration:2-prong ee,High + precise eff.
Pure DCT
Pure EMT
DCT + EMT
Requirements:
Calibration, beam monitor:1-prong ee,
Background&Trigger studies
Background monitoring
only
run9304
Ted Liu, July 5,00, idea on Ztrigger
Trigger Lines for and 2 Events
Physics
Pure DCT
Pure EMT
DCT + EMT
Rare & Asy.: high eff.
Branch Ratios: precise eff.
Requirements:
precise eff.
All unprescaled lines have high Pt cut (800MeV) and with back-to-back requirement. No unprescaled orthogonal lines.All high eff. Lines have to be prescaled.
Shortcomings:
2 Physics
Expected @ high background rate, will try to improve…add 2BM+1AM, lower Pt cut?
Ted Liu, July 5,00, idea on Ztrigger
L1 Strategy to improve performance
Better Combination of trigger lines:
DCT+EMT phi matchingGive up some orthogonal lines
Improve trigger objects:
Short-term: PTD ---> DOCAD
Long-term: DOCAD --> DOCAZD?
Need good understanding of background --> next
...
Ted Liu, July 5,00, idea on Ztrigger
HERLER Single beam
L1 pass thr.events
Z distribution
LER
HER
From S. Petrak
Ted Liu, July 5,00, idea on Ztrigger
HERLER
Single beam
L1 pass thr. events
x-z view
Many tracks from beampipe: off Z --> off IP in x-y
LER
HER
Ted Liu, July 5,00, idea on Ztrigger
Trigger data
Fine position data forsegments found foraxial SLs
Drift Chamber
Track Segment Finder (x24)DOCAD
24 Gbits/sCoarse datafor all supercellhits
Binary Track Linker (BLT x1)
PT Discriminator
PTD (x8)
GLT
A, B
A’
16
16
DCT Trigger Hardware
New idea
(only firmware change)
Ted Liu, July 5,00, idea on Ztrigger
Drift Chamber Trigger ( DCT )
The heart of DCT is the Track Segment FinderTSF continuously live image processor
A novel method: using both occupancy and drift-time information, to find track segments continuously with:time resolution of ~ 100 ns, event-time jitter window ~ 100 nsspatial resolution ~ 1 mm used for track Pt Discrimination
Use 24 TSF modules
(2) send segment patterns to the DAQ system for use in Level 3 ...
(1) send segment patterns downstream forL1 trigger decision making
Upon a L1 accept:
Track Segment Finder
Ted Liu, July 5,00, idea on Ztrigger
Ted Liu, July 5,00, idea on Ztrigger
Ted Liu, July 5,00, idea on Ztrigger
x
x A10 seed
IP
SL7
SL4
SL1
Pt threshold (800MeV)
Current PTD algorithm
x
x
SL7
SL4
SL1
IP
New DOCAD algorithm
Tracks (above threshold) coming from IP should leave all the hits in one of the slices Tracks not coming from IP will most likelyleave hits in different slices
4 hits on one track with ~1mm,should be able to tell whether the track is from IP
(baseline design: simple algo.)
800MeV850MeV900MeV1 GeV
Ted Liu, July 5,00, idea on Ztrigger
Apply DOCAD algorithm to TSF data Hadron skim: signal
LER single beam run: background
PTD on
DOCAD on
PTD on
DOCAD on
Background rejection: 40%
Effect on Signal:
Effect on Background:
Use hadron skim (~10% bkg)
~ 4% loss at turn on
Use single beam runL1 pass thr events
40% rejection on A’ linewith simple algorithm
Max Pt in the event
The goal here is not to find thebest algorithm possible, but onewhich is easy to be implementedand with good performance
Ted Liu, July 5,00, idea on Ztrigger
DOCAD algorithm: possible improvement Require 3/3 in ALL slices
70% bkg rejection!
But 20% signal lossDue to cell ineff.
TSF can determine segment location with 1 mm resolutiononly for 4/4 patternsThe resolution is degraded for 3/4 patterns:
=xxx
xxx
x
xx
xx
3/4 4/4 4/4
1 2
1 < < 2
calibrating 3/4 patterns should help
Currently 3/4 pattern LUT is derived from 4/4 patterns
+
using the information should help(baseline design ignored )
Ted Liu, July 5,00, idea on Ztrigger
The Drift Chamber ( DCH )
10 superlayers of 4 layers each
Axial and stereo alternate
Cell size: 1.2 cm x 1.8 cm
L1 Long term strategy: cut in Z using TSF fine position info from stereo superlayers?
Ted Liu, July 5,00, idea on Ztrigger
L1 long-term strategy:
Can we cut in Z using TSF position info from stereo SLs?
Stereo SLs --> Z Axial SLs --> DOCA DOCAZD
Cosmic ray events
Close to IP in z
Off IP in z
In other words:move some L3 DCH algorithmupstream to L1 (cut in doca&z)
Tough but possible !
What to expect? The answer is in the TSF data we already have
Ted Liu, July 5,00, idea on Ztrigger
B1B1
Track z distributionfor L1 passthroughevents
LERHER
Lost particle interact with beampipe flange
due to a step in the synchrotron mask
real collision
Ted Liu, July 5,00, idea on Ztrigger
40~50 or so slices in theta
~ 2 cm in z for SL2
TSF phi resolution ~ 1 mm Z resolution ~ 2 cm
Off Z trackBasic idea (~16 new DOCAZ boards in phi)
Ted Liu, July 5,00, idea on Ztrigger
L1 long-term strategy:
Can we cut in Z using TSF position info from stereo SLs?
Stereo SLs --> Z Axial SLs --> DOCA DOCAZD
What to expect? The answer is in the TSF data we already have!
Current“triggervolume”
Possible improved “trigger volume”??
Ted Liu, July 5,00, idea on Ztrigger
Trigger dataDAQ
Fine position info for segments found for allsuperlayers
Drift ChamberDAQ
Level 3 Filter
Track Segment Finder (x24)
Upon a L1 Accept ...Using segments found by TSFs as seeds, fast algorithm applied to DCH data to further reject background...reduce the rate from 2 kHz to 100 hz.
Currently TSF provides fine position infofor all SuperLayers to L3, only axial SLsinfo passed to PTD.
24 Gbits/s
Ted Liu, July 5,00, idea on Ztrigger
Trigger dataDAQAll track
segments found
Drift ChamberDAQ
Level 3 Filter
Track Segment Finder (x24)
24 Gbits/s
DOCAZD ??
GLT
A,B
DZ?Fine phi infofor all(?) SLs
Supercellhits
One possible scenario
Ted Liu, July 5,00, idea on Ztrigger HER
LER
Ted Liu, July 5,00, idea on Ztrigger
Ted Liu, July 5,00, idea on Ztrigger
Ted Liu, July 5,00, idea on Ztrigger
The Drift Chamber ( DCH )
10 superlayers of 4 layers each
Axial and stereo alternate