Post on 07-Feb-2016
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Nikos Varelas
University of Illinois at Chicago
L2Cal Group at UIC:Mark Adams
Bob Hirosky
Rob Martin
Nikos Varelas
Marc Buehler (graduate student)
James Heinmiller (undergraduate)
Mike Klawitter (part time engineer)
1 2/6/99 L2 Review NV/UIC
2/6/99 L2 Review 2NV/UIC
L2Cal Crate and I/O
Status of L2Cal Algorithms:
Jets
Electrons
Missing ET
Timing of Algorithms
Summary
2/6/99 L2 Review 3NV/UIC
• From Calorimeter via FIC/MBT: 10 input cables with 304 Bytes/cable – Header
– L1 Seed Tower Bit Masks for EM and Total
– L1 Tower ET data for EM and Total
• From SCL via MBT:– L1 accept (3 Bytes)
– L1 Qualifiers (2 Bytes)• L2Jet Needed
• L2Em Needed
• L2Etmiss Needed
• 3 Spare Bits
• Unbiased Sample
• Forced Write
• Collect Status
– L2Global accepts
2/6/99 L2 Review 4NV/UIC
• To L3– For normal events send the L2Global output
– For UBS or Forced Write events the full L1 input and L2Cal output will be sent
• To L2Global– About 136 Bytes/event (including headers)
– Will be fine tuned when algorithms are finalized based on input from physics/Id groups
• Each worker will preface its data with a 12Byte header– Header will include information about the
processing status (i.e., format errors, timeouts etc) of the event
• Each worker will complete transmission with a 4 Byte trailer
2/6/99 L2 Review 5NV/UIC
All L2Cal algorithms will use a low-threshold reference set of L1 0.2x0.2 trigger towers as input for clustering.
L1 EM ET - Rounded in 0.25 GeV stepsL1 Tot ET - Sum of EM and HAD truncated in
0.5 GeV steps
L2Cal ProcessorsL2Cal Processors
jet
electron
neutrinoWhat are the efficiencies of these algorithms?
Can we reduce the trigger rate w/o significant cost
in efficiency?
Can we do all these stuff in less than 100 s???
2/6/99 L2 Review 6NV/UIC
• The algorithm:
• Event Samples used in simulations:– Data: WJJ triggers from Run 1C Global
Runs with Lum = 17E30– MC: UPG GEANT inclusive jet events w/
generated thresholds: (2,5,10,20,40,80 GeV) overlapped with: (1,3,5,7) additional MB
interactions (not overlapped with noise)
Start w/ list of jet seed towers from L1• For each seed tower, cluster ET of the surrounding 5x5 (or 3x3)
tower array • Add to Jet list all clusters whose ET sum exceeds a min threshold• ET order the Jet list (descending order) • Eliminate Jets failing overlap restriction
If ET(A) > ET(C) ; keep A,BIf ET(C) > ET(A) ; keep C,B
2/6/99 L2 Review 7NV/UIC
WJJ DataTower Seed Distributions
Threshold RMS
1.0 GeV 40 20
1.5 GeV 17 7
2.0 GeV 9 4
For a high-ET (>350GeV) jet data sample: = 20, RMS= 6 for L1(1,2)
2/6/99 L2 Review 8NV/UIC
WJJ DataL2 Jet Distributions
2/6/99 L2 Review 9NV/UIC
Measured w/ MC - UPG Geant sample
Pjet and Cal Jet matching methods:
1) Projection Method
2) Matching Method(run L2Jet algorithm)
PJet
calorimeter
Project PJet axis intocalorimeter.Does corresponding seed/cluster ET passimposed cuts?
PJet
calorimeter
R<0.5?
Compare L2Jets to PJetsLook for matches
2/6/99 L2 Review 10NV/UIC
Reference algorithm L1(1,2) L2(1,10)
Eff
s. f
or s
eed
/clu
ster
cu
ts a
nd
Alg
orit
hm
(see
d c
ut,
clu
ster
cu
t)L2Jet Efficiency for seeds/clusters
Central jets
2/6/99 L2 Review 11NV/UIC
L2Jet Rate Estimates
11
1
(weight) x ) samplein events(#
(weight) x ) thresholdpassing events(#Rate
• Method:– First weight MC events appropriately
1) use JETRAD to bridge all PJet Cross Section to central inclusive jet CS in data
2) estimate total MC event cross section for PJet ET>5 GeV; ~ 1/11 Min Bias cross section
– Calculate trigger rate as ~ fraction of MB events passing imposed threshold(s)
• Plot L2Jet Efficiency vs Rate for 20 and 100 GeV PJets.– Compare L2 3x3 jet algorithm to 5x5 version
– Measure Eff. vs Rate w/ and w/o L2 clustering
– Examine the effects of 0.5 GeV truncation to trigger-tower ETs
2/6/99 L2 Review 12NV/UIC
3 = 3x3 algorithm 5 = 5x5 algorithm
• ~ factor of 3 rate reduction w/ 20% eff. cost• no strong cluster size preference• need to tune the MC further so we can study/improve the algorithm for low-ET jets
L1(1,1.5)
L1(1,2)
L2 thresholds (1,10)(1,8)(1,6)(1,4)(none)
3x3
5x5
L1 only
Eff. vs Rate at 20 GeV
2/6/99 L2 Review 13NV/UIC
3 = 3x3 algorithm 5 = 5x5 algorithm
Eff. vs Rate at 100 GeV
L1(1,7)
L1(1,9)
• order of magnitude rate reduction easily attainable at L2 w/o loss in efficiency• no strong cluster size preference
L1 only
L2 thresholds (1,60)(1,50)(1,40)(1,30)(none)
2/6/99 L2 Review 14NV/UIC
Effects of L1 Total-ET Truncation for 20 GeV Jets
L2 (1,4)
L2 (1,6)
L2 (1,8)
L2 (1,10)
L2 (1,12)
L2 (1,15)
L1 (1,2)
the effect of L1 energy truncation can be accommodatedat L2 by choosing lower jet thresholds
0.25 GeV rounding
w/ 0.5 GeV truncation
2/6/99 L2 Review 15NV/UIC
An Example at Lum=1E32
Level-0
45 mb x 1E32 = 4.5 MHz
L1(1,9)
6.7 KHz
<L2(1,30)>
130 Hz
L3
L1(1,12)
Eff at 100 GeV
~ 96%
~ 92%
1800 Hzfor same Eff
2/6/99 L2 Review 16NV/UIC
• The algorithm:
• Event Samples used in simulations:– Single electrons uniformly distributed in in the forward
region: 1.9<||<2.3– ISAJET dijet events with various thresholds starting at
2 GeV
Events were processed through UPG_GEANT with two (onaverage) additional interactions (not overlapped with noise)
Start w/ list of EM seed towers from L1• For each seed tower, determine nearest neighbor w/ the largest ET • Calculate the following summed ET : quantities:
1) ET(EM) of seed tower + largest neighbor 2) ET(Total) of seed tower + largest neighbor 3) sum ET(Total) of 3x3 trigger towers centered on seed tower
• Order surviving candidates in descending ET(EM)
Apply cuts on ET(EM), EM fraction, andIsolation
2/6/99 L2 Review 17NV/UIC
• L1 Cuts:– FPS: 0.3 MIPs (upstream)
5 MIPs (downstream)
U view matching
V view matching
– CAL: EM trigger tower above threshold
– Match FPS with CAL L1 Tower in Quadrant
• L2 Cuts:– FPS: Require downstream U and V view
matching convert to , in 0.2 x 0.2 bins
– CAL: Find EM cluster using NN algorithm. Apply EM fraction and Isolation cuts.
– Match FPS track to EM cluster within x = 0.3 x 0.3
• No rounding/truncation applied to L1 tower energies
Courtesy Mrinmoy Bhattacharjee
2/6/99 L2 Review 18NV/UIC
Eff. vs Background Rate at 18 GeV
Forward electrons
L2 thresholds (1,15)(1,12)(1,10)(none)
L1 (1,7)
L1 (1,7)
preliminary
2/6/99 L2 Review 19NV/UIC
Eff. vs Background Rate at 18 GeV
Forward electrons
L2 thresholds (1,17)(1,15)(1,12)(none)
L1 (1,10)
L1 (1,10)
preliminary
2/6/99 L2 Review 20NV/UIC
Eff. vs Background Rate at 30 GeV
Forward electrons
L2 thresholds (1,15)(1,12)(1,10)(none)
L1 (1,7)
L1 (1,7)
preliminary
order of magnitude rate reduction attainable at L2 w/ small cost in efficiency
w/ FPS match
2/6/99 L2 Review 21NV/UIC
Eff. vs Background Rate at 30 GeV
Forward electrons
L2 thresholds (1,17)(1,15)(1,12)(none)
preliminary
L1 (1,10)
L1 (1,10)
order of magnitude rate reduction attainable at L2 w/ small cost in efficiency
w/ FPS match
2/6/99 L2 Review 22NV/UIC
• Candidates will be sorted in descending ET order
• Information per candidate– eta (1 Byte)
– phi (1 Byte)
– ET (2 Bytes)
– eta center (1 Byte)
– phi center (1 Byte)
– eta leading TT (1 Byte)
– phi leading TT (1 Byte)
– Spare (4 Bytes)
• Total 12 Bytes/object
2/6/99 L2 Review 23NV/UIC
• Candidates will be sorted in descending ET order
• Information per candidate– eta (1 Byte)
– phi (1 Byte)
– ET (2 Bytes)
– EM fraction (1 Byte)
– Isolation Fraction (1 Byte)
– eta leading TT (1 Byte)
– phi leading TT (1 Byte)
– eta other TT (1 Byte)
– phi other TT (1 Byte)
– Spare (2 Bytes)
• Total 12 Bytes/object
2/6/99 L2 Review 24NV/UIC
• Need input from physics groups
• Information per event– Missing ETX (2 Bytes)
– Missing ETY (2 Bytes)
– Scalar ET (2 Bytes)
– Spare (10 Bytes)
• Total 16 Bytes/event
2/6/99 L2 Review 25NV/UIC
• The algorithm:
• Possible Enhancements:– Calculate Scalar ET using the same cuts as for
Vector ET
– Calculate ET for more than one set of Tower cuts
– Calculate ET using different threshold for each Tower
Loops over all towers within prescribed range, calculating the vector ET sum of all towers with ET > Min_Tow_ET. It returns the X and Y components of the Missing ET.
2/6/99 L2 Review 26NV/UIC
• Code:– written in C
– compiled with C or C++ compiler on DEC Alpha workstation running UNIX (timing results
roughly the same)
– Executable down-loaded and run on UIC PC164 evaluation board containing DEC 21164 Alpha processor with 500MHz clock
• Event Sample:– MC Dijet data generated with ISAJET
– Data block Structure as planned for hardware• 10 “cable blocks” containing:
* EM Tower Seed Mask
* Total Tower Seed Mask
* EM Tower ET data
* Total Tower ET data
2/6/99 L2 Review 27NV/UIC
Jet proc time vs # seeds
0
5
10
15
20
25
30
35
0 5 10 15 20 25 30
# Level 1 seeds
Tim
e (u
s)
Time (s) ~ 2.5 + 1.12 x (# seeds)
Average seed range
2/6/99 L2 Review 28NV/UIC
Time (s) ~ 2 + 2.3 x (# seeds)
2/6/99 L2 Review 29NV/UIC
MET Mean Processing time
30
31
32
33
34
35
36
37
38
39
40
0 200 400 600 800 1000 1200 1400
Mean # Tow ers
Mea
n T
ime
(us)
The average time for 0.5 GeV Tower ET threshold is ~ 33 s
All Towers abovethreshold
2/6/99 L2 Review 30NV/UIC
• We have a fully designed L2Cal Preprocessor system which has sufficient CPU power to execute reasonable L2 algorithms with < few % deadtime– if more power needed, can add up to two
Workers for parallel processing
• We have working versions of Jets/Electron/Missing ET algorithms which offer acceptable rate reduction
• The data movement architecture is complete and the monitoring path has been established (see previous talks)
• We request TDR approval