Simulation of the CSC Track Finder
D.Acosta, S.M.Wang
University of Florida
V.Golovstov, B.Razmyslovich
PNPI
CMS Week
June 1999
A
standalone version of the CSC Track Finder simulation (Endcap region only) is almost ready
Written in Fortran
Interface with the ntuple produced by CMSIM
Emulate as close as possible to the design of the hardware
CSC Muon Trigger Scheme
Sector Processor / Muon Track Finder
the track primitives (LCTs) in a 60 sector
link LCTs into tracks
Measure Pt, and Send 3 best track candidates to the Muon Sorter
handle
Sector Processor Block Diagram
3-4
TAU2
2(3x21)
EU3
2-3
2–3
(18 bits)
Track 4
2-4
2-3
- Downloading/
Readout Line
1(6x21)
1-2
EU2
1-3
1– 3
(36 bits)
TAU1
Track 3
Track 2
Track 1
STA
3 (3x21)
FSU
Track 5
1-3
3 (3x21)
Track 6
2 (3x21)
EU1
1-2
CLOCKED
FIFO
1(6x21)
VME BUS
2–4
(18 bits)
2-3
- Control Line
EU – Extrapolation Unit
TAU– Track Assembling Unit
FSU– Final Selection Unit
STA –Selected Track Address
LID– Look-Up Input Data
EU4
2-4
1–2
(36 bits)
Data
Extraction
LID
Pt
LUT
Output
Data
6x26
MUX
3x22=66
OUTPUT
CONNECTOR
- Data Line
2 (3x21)
Input Data
15x26=390
Control
4 (3x21)
INPUT DATA&
CONTROL
INTERFACE
9U CUSTOM
BACKPLANE
Data
3–4
(9 Extrapolations or
18 bits)
DOWNLOADING/
READOUT
INTERFACE
3 (3x21)
EU5
3 -4
8x3
4 (3x21)
Fig.1. Track Finding Processor. Block Diagram.
Extrapolation Unit (EU) : Links LCTs in two CSC
stations together
Track Assembler Unit (TAU) : Use the extrapolation
results to form tracks
Final Selection Unit (FSU) : Selects 3 best track candidates
Assignment Unit : Determines the Pt of the selected
track candidates
Extrapolation Unit
ME4
41
4
4
2
3
ME3
31
33
32
ME2
21
22
23
ME1
11
12
Perform all
1 $2 ,1
2 $4 ,3
no 1 $ 4
i
k
i
i
k
i
i
k
13
14
15
16
combinations of extrapolations :
$3 ,2 $3 ,
$4 ,
k
k
i
k
Extrapolation Unit in Detail
η1
6
SM
η2
6
η1−η2
7
LUT
128 x 1
η1
6
&
LUT
Match η
6
64 x 1
LUT
7
1
η2
6
LUT
6
64 x 1
CMP
128 x 7
7
LUT
128 x 7
7
CMP
7
1
η∗,∆φ
PRE
3-2
η∗∗,∆φ
LUT
2
16 x 2
2
&
2 Bits
Input Data
52 Bits
η1
6
6
LUT
128 x 7
10
SM
φ2
10
φ1−φ2
η∗∗∗,∆φ
7
1
φ1
CMP
7
11
3
LUT
Match φ
&
8x1
6
LUT
64 x 6
6
SM
∆φ−ψ1
ψ1
6
ψ2
6
6
SM
Q1
3
Q2
3
AMB1
1
AMB2
1
7
6
LUT
64 x 2
∆φ−ψ2
LUT
Match ψ1
128 x 1
6
7
LUT
Quality
2 Q
Match ψ2
128 x 1
2
NAND
Track primitives are matched in Coarse Pt is assigned based on the
angle of the two track primitives
FIG.2. EXTRAPOLATION UNIT. BLOCK DIAGRAM.
dierence in the
(classied as either : Low Pt, Medium Pt, High Pt)
Accelerator Muon bits are used to reject halo muons
Results of the extrapolation are in the form of Quality
codes
Stream
Paths
Data Streams Data
to Track
Assembler
Units
2 best
33 – 4
33
2 best
2 – 33
1 – 3, 2 – 3, 3 – 4
Extrapolations
3 best
1 – 33
2 best
32 – 4
32
2 best
2 – 32
3 best
1 – 32
TAU2
Track Assembler Unit
(TAU2)
Str eam 2
STREAM 2
Track types:
2 best
31 – 4
31
2 best
2 – 31
1–3
2–3
3–4
3 best
1 – 31
1–3–4
2–3–4
Extrapolation
Units
STREAM 1
2 best
21 – 3
2 best
21 – 4
Track Assembler Unit
(TAU1)
3 best
1 – 21
21
Stream 1
Track types:
1–2
2–4
1–2–3
1–2–4
1–2–3–4
2 best
22 – 3
1 – 2, 2 – 3, 2 – 4
Extrapolations
TAU1
2 best
22– 4
22
3 best
1 – 22
2 best
23 – 3
D. Acosta, University of Florida
Results
Streams
3/27/99
2 best
23 – 4
23
3 best
1 – 23
from extrapolations are sent to TAUs in 2
{ Stream 1 : 1
{ Stream 2 : 1
$ 2, 2 $ 3, 2 $ 4
$ 3, 2 $ 3, 3 $ 4
) TAU 1
) TAU 2
21 – 1
21 – 3
21 – 4
22 – 1
22 – 3
22 – 4
23 – 1
23 – 3
23 – 4
6
6
12
6
6
3 best
extrapolations
4 (2+2) best
extrapolations
3 best
extrapolations
4(2+2) best
extrapolations
15
9
3bits + 3bits + 3bits
according to the order of
priority (PCB Layout)
8
4
9
4
8
2bits + 2bits
according to the order of
priority (PCB Layout)
15
9
9
8
4
8
4
15
9
8
4
8
4
9
Multiplexer
4
12
6
6
3 best
extrapolations
4(2+2) best
extrapolations
4
Sel1
Sel2
Sel3
4
4⇒5
4⇒5
4⇒5
5
5
5
36
6
4
21 – 1
21 – 3
21 – 4
6
4
4
4
LUT
32Kx16
Link
21
6
4
4
Link
22
6
4
4
Extrapolations Quality
Link
23
4
A3
4
A2
4
A1
4
B3
4
B2
4
B1
4
C3
4
C2
4
C1
4
Selection
Unit
Track Absolute Quality
4
4
(3 Best
Tracks)
Track Local Quality
Track Assembler Unit (TAU1)
To Final Selection Unit
(Extrapolation Quality Part)
8 ([2bits Quality + 2bits Number] x 2)
12
To Final Selection Unit
(Hit Number Part)
7 bits:
Hit number (1st chamber) – 3 bits
Hit number (2nd chamber) – 2 bits
Hit number (3rd chamber) – 2 bits
Hit number (4th chamber) – 2 bits
2bits + 2bits:
2 bits select 21, 22 or 23 stream
2bits select h., m. or l. priority track.
Track Assembler Unit (TAU 1)
15 ([2bits Quality + 3bits Number] x 3)
Quality
of the extrapolations are sent to LINK units
Each LINK unit handles all the extrapolations to a
single LCT in Station 2 (Station 3 for TAU 2)
LINK unit
1
Q24
3
Q
1
1
1
LINK
1
2
21
1
1
2
Q23
2
1
1
2
Q23
12
4
Q24
3
4
2
2
Q12
3
Q12
3
unit is programmed to select extrapolations
with highest qualities to form tracks
Example for the above case :
Q112 > Q212 , Q312
Q123 > Q223
Q124 > Q224
) form a track using LCTs 11, 21, 31 and 41
In this simulation each LINK unit will form one track
Final Selection Unit (FSU)
8 bits:
1st track segment number – 4 bits;
2nd track segment number – 4 bits.
9
Track 5
9
Track 4
9
MUX
8
Track 3
9
Track 2
9
Track 1
9
STREAM 1
8
Sel1 Sel2 Sel3
We should compare:
Track1-Track4; Track1-Track5;
Track1-Track6; Track2-Track4;
Track2-Track5; Track2-Track6;
Track3-Track4; Track3-Track5;
Track3-Track6 (9 bits as total)
10
10
10
9
9
9
9
9
Hit Number
Comparators
(9 Units)
9
9
Final
Decision
Unit
LUT
256Kx32
Track 6
Track 5
Track 4
Track 3
Track 2
Track 1
5
5
5
5
5
5
Extrapolations
Quality Comparators
(9 Units)
Stream1 Stream 2
From Track Assemling Unit
(Extrapolations Quality Part)
LCT ID Comparator
9
Final
Decision
Unit
LCT Quality Comparator
Final Selection Unit
To Data Extraction Multiplexer
Stream 2
Track 6
(if we need only 2 track segments
for Pt calculation)
8
Stream 1
From Track Assemling Unit
(Hit Number Part)
STREAM 2
Each track consists of 4 track
segments as maximum
⇓
6 Tracks has 24 track
segments
⇓
We need 10 (5+5)bits to
describe all possible
combinations
LCT Quality Comparator : compares the qualities of
the tracks found in STREAM 1 to the tracks found
in STREAM 2
LCT ID Comparator : compares the LCT IDs of the
tracks found in STREAM 1 to the tracks found in
STREAM 2
4i
Stream 1
3i
2i
1
Stream 2
i
4j
3j
2j
1j
ID Comparator is programmed to consider two tracks
are \identical" if both tracks share at least one
common LCT
Results from the comparators are sent to
Final Decision Unit to select 3 unique tracks of highest
quality. (These 3 track candidates should then be
forwarded to the Muon Sorter)
Results from the Simulation
Y x10 (m)
Y x10 (m)
Extrapolation Units
0.45
0.4
0.35
0.45
0.4
0.35
0.3
0.3
0.25
0.25
0.2
0.2
0.15
0.1
0.15
0.2
0.3
X x10 (m)
0.8
1
Z x10 (m)
(Example: Two muons which are relatively close together. Light
green line show the successful extrapolations)
Extrapolation Eciency for Single Muon Events
Pt = 3 GeV
%
ME1-ME2 ME1-ME3
successful extrapolation
= 93.4
81.3
Low Pt
= 77.1
58.1
Medium Pt
= 14.5
19.5
High Pt
= 1.8
3.7
Pt = 5 GeV
successful extrapolation
Low Pt
Medium Pt
High Pt
Pt = 50 GeV
successful extrapolation
Low Pt
Medium Pt
High Pt
%
ME1-ME2 ME1-ME3
= 99.1
98.1
= 44.8
46.4
= 53.2
46.8
= 1.2
4.9
%
ME1-ME2 ME1-ME3
= 99.4
99.4
= 0.02
0.01
= 0.9
1.1
= 98.4
98.2
Extrapolation Eciency of Single halo- events :
%
P = 100 GeV (Total # Evts = 9142)
successful extrapolation
= 0.01
Low Pt
= 0.00
Medium Pt
= 0.00
High Pt
= 0.01
Y x10 (m)
Y x10 (m)
Final Selection Unit
0.45
0.4
0.35
0.45
0.4
0.35
0.3
0.3
0.25
0.25
0.2
0.2
0.15
0.1
0.15
0.2
0.3
0.8
1
X x10 (m)
Z x10 (m)
(The dashed line are the tracks found by FSU)
Eciency of FSU on single muon events
High eciency for high Pt muons ( 100%)
< 1% of events FSU found > 1 track.
bremsstrahlung,
delta rays
0.35
Y x10 (m)
{ Extra LCTs due to
0.3
0.25
0.2
0.15
0.1
0.1
0.15
0.2
0.25
0.3
X x10 (m)
Y x10 (m)
sector boundary,
failed extrapolation
0.065
0.06
0.055
0.05
0.045
0.04
0.035
0.03
0.025
0.02
0.08
0.1
0.12
0.14
0.16
0.18
0.2
0.22
X x10 (m)
Y x10 (m)
{ Broken track due to
0.28
0.26
0.24
0.22
0.2
0.18
0.16
0.14
0.12
0.5
0.6
0.7
0.8
0.9
1
1.1
Z x10 (m)
Eff
Single Muon Track Finding Efficiency
1
0.75
Pt = 3 GeV/c
0.5
0.25
Eff
0
1
1.2
1.4
1.6
1.8
2
2.2
1.4
1.6
1.8
2
2.2
1.4
1.6
1.8
2
2.2
2.4
ηgen
1
0.75
Pt = 5 GeV/c
0.5
0.25
Eff
0
1
1.2
2.4
ηgen
1
0.75
Pt = 50 GeV/c
0.5
0.25
0
1
1.2
2.4
ηgen
Test Track Finder on Physics Events
Physics process :
H0 ! ZZ ! 2+2,
, MH = 300 GeV
Pre-select events that have at least one muon in the
endcap region (1:2 <j j< 2:4), and Pt > 3 GeV/c
Generated
FSU found
# Muons
# Evts
# Muons
# Evts
0
0
0
12
1
672
1
654
2
478
2
477
3
185
3
184
4
21
4
29
(Total number of events = 1356)
Excess events in the case FSU found 4 tracks are
mainly due to :
{ Extra LCTs (bremsstrahlung, delta rays)
{ broken tracks
{ punch throughs
Summary/Plans
A preliminary version of the Endcap muon Track Finder
is almost nished
The Pt assignment unit will be implemented soon
Dierent algorithms used in the Track Assembler Unit
and Final Selection Unit will be tested so as to reduce
the double counting due to fake tracks
Apply the Track Finder on Minimum Bias events to
estimate trigger rates, and to study issues on ghost/fake
tracks
Move to C++