M. Selen, 7/24/03 LEPP Lunch: Pg 1www.hep.uiuc.edu/cleo/trig3/
The CLEO-c TriggerThe CLEO-c Trigger System:System:More Than Just Blinking Lights !More Than Just Blinking Lights !
LEPP Lunch Talk
Mats Selen
Overview Tracking Calorimeter Timing Performance
M. Selen, 7/24/03 LEPP Lunch: Pg 2www.hep.uiuc.edu/cleo/trig3/
What the Trigger & DAQ DoesWhat the Trigger & DAQ Does
Suppose you want to keep only pink hexagonal widgets moving down a conveyor belt.
y/n
y yn n
Trigger
You are the trigger: You stamp “y” on the pink hexagonal widgets You stamp “n” on the others
n
y
trash
SAVE
DAQ
Your friend DAQsaves only widgetslabeled “y”
The problem is: Working fast means you make some mistakes !
M. Selen, 7/24/03 LEPP Lunch: Pg 3www.hep.uiuc.edu/cleo/trig3/
Requirements: Decision TimeRequirements: Decision Time
Each widget must get examined and stamped
y/n
y yn n
Trigger
- You need to decide on one before the next one comes along.
- Your decision can’t take longer than t = d/v.
- Taking more time means making less mistakes.
v
d
M. Selen, 7/24/03 LEPP Lunch: Pg 4www.hep.uiuc.edu/cleo/trig3/
Requirements: EfficiencyRequirements: Efficiency
You can’t stamp too many pink hexagonal widgets ”n”:
y/n
n nn n
Trigger
SAVE
DAQ
nn n
trash
?? ?
M. Selen, 7/24/03 LEPP Lunch: Pg 5www.hep.uiuc.edu/cleo/trig3/
Requirements: RejectionRequirements: Rejection
y/n
y yy y
Trigger
The rate of widgets stamped “y” can’t exceed the capacity of your friend (the DAQ) to save them.
y
trash
SAVE
DAQ
y
Whenever the DAQ is busy saving something it causes “dead-time” (he will miss the next few widgets). If he misses any marked “y”, thiscauses a loss of efficiency.
M. Selen, 7/24/03 LEPP Lunch: Pg 6www.hep.uiuc.edu/cleo/trig3/
y/n
Working in Steps: PipeliningWorking in Steps: Pipelining
Have more than one person working in series
- Each individually one takes less than t = d/v- Collectively, much more work is done- A smarter decision can be made – less mistakes
y yn n
Trigger
n
y
trash
SAVE
DAQ
v
d
M. Selen, 7/24/03 LEPP Lunch: Pg 7www.hep.uiuc.edu/cleo/trig3/
M. Selen, 7/24/03 LEPP Lunch: Pg 8www.hep.uiuc.edu/cleo/trig3/
14 feet
800 feet
d = 14 feet, v = 1 foot/ns
t = 14 ns
There are 183 RF buckets in CESR
M. Selen, 7/24/03 LEPP Lunch: Pg 9www.hep.uiuc.edu/cleo/trig3/
The trigger runs at1/3 the CESR RF freq
(i.e. each step is 42 ns)
This smears together 3 beam collisions every time we look. We can do this
since its very rare that anything happens during a collision.
In CESR/CLEO, beam collisions are
spaced a minimum of 14 ns apart.
This is not enough time to do any serious trigger processing
Only ~45 of thesebuckets contain beam ‘bunches’
M. Selen, 7/24/03 LEPP Lunch: Pg 10www.hep.uiuc.edu/cleo/trig3/
0 1 2 3 . . . . . . 58 59 60
0
1
2
3
60
59
58
M. Selen, 7/24/03 LEPP Lunch: Pg 11www.hep.uiuc.edu/cleo/trig3/
0 1 2 3 . . . . . . 58 59 60
0
1
2
3
60
59
58
M. Selen, 7/24/03 LEPP Lunch: Pg 12www.hep.uiuc.edu/cleo/trig3/
0 1 2 3 . . . . . . 58 59 60
More about thisin a few minutes
M. Selen, 7/24/03 LEPP Lunch: Pg 13www.hep.uiuc.edu/cleo/trig3/
Trigger Philosophy Use only drift chamber (DR) and calorimeter (CC) information. Make trigger decision every 42ns (i.e. trigger clock rate). Take enough time (number of pipelined steps) to make a sophisticated Level-1
trigger decision: About 2 s. The readout deadtime is about 20 s, so we need to keep the trigger rate < 1000
Hz.
RF bucket
Pipeline clk
Early DR
Late DR
Early CC
Late CC
look here for CC info
72 MHz
24 MHz
look here for DR infoSuppose eventhappens here
M. Selen, 7/24/03 LEPP Lunch: Pg 14www.hep.uiuc.edu/cleo/trig3/
TRCR
Mixer/ShaperBoards
TILE(8)
ASUM
QVME
TILE (16)
ASUM
AXTR(16) AXX(16)
DR3 - TQT
STTR(12)
TRCR
L1D
G / CAL
DFC
CLEO
An
alo
g
Gates
ctrl
.
Mixer/Shaper Crates (24)
QVME
TPRO(2)
TCTL
TIM
DM/CTL
TIM
DM/CTL
TIM
DM/CTL
TPRO(4) TIM
DM/CTL
TIM
DM/CTL
AXPR
CCGL
SURF
SURF
Drift Chamber Crates
Axi
al t
rack
erS
tere
o t
rack
er
Bar
rel C
CE
nd
cap
CC
CC
Dig
ital
Lev
el 1
dec
isio
nF
low
co
ntr
ol &
Gat
ing
DAQ
CLEO-III/cTriggerSystem
Overview
M. Selen, 7/24/03 LEPP Lunch: Pg 15www.hep.uiuc.edu/cleo/trig3/
What it Looks LikeWhat it Looks Like (all more or less alike to untrained (all more or less alike to untrained
eye)eye)
M. Selen, 7/24/03 LEPP Lunch: Pg 16www.hep.uiuc.edu/cleo/trig3/
Common FeatureCommon Feature
FPGA based Logic
DAQ/VME
CircularBuffer
Inputs Outputs
TDITMSTCK
TDO JTAG
M. Selen, 7/24/03 LEPP Lunch: Pg 17www.hep.uiuc.edu/cleo/trig3/
16 AXTRtrigger boards
backplane(single ended)
16 AXX receiver boards
LVDS fromDR3 preampstrack info to
TRCR
106 x 2Repeatingunit (x 8)
7
Axial Tracking TriggerAxial Tracking Trigger
M. Selen, 7/24/03 LEPP Lunch: Pg 18www.hep.uiuc.edu/cleo/trig3/
Layer 9 = “key”
InnerLookup
OuterLookup
Inner/Outer track correlator
M. Selen, 7/24/03 LEPP Lunch: Pg 19www.hep.uiuc.edu/cleo/trig3/
Stereo Stereo Tracking Tracking TriggerTrigger
There are too many wires to form allcombinations in LUT
- Combine these into 4x4 blocks
M. Selen, 7/24/03 LEPP Lunch: Pg 20www.hep.uiuc.edu/cleo/trig3/
r
TQT
48
TQT
48
8
8
8
stereo trigger hardware
8
1 superlayer
M. Selen, 7/24/03 LEPP Lunch: Pg 21www.hep.uiuc.edu/cleo/trig3/
= Hit wire location at z = 0
Track trajectory:Pperp = 350 MeV/c = 35o
= 15o
-shifted curve, Pperp = 350 MeV/c = 35o
= 17o
Track in U and V IndependentlyTrack in U and V Independently
M. Selen, 7/24/03 LEPP Lunch: Pg 22www.hep.uiuc.edu/cleo/trig3/
Axial – Axial – Stereo Stereo
CorrelationCorrelation
M. Selen, 7/24/03 LEPP Lunch: Pg 23www.hep.uiuc.edu/cleo/trig3/
Axial – Axial – Stereo Stereo
CorrelationCorrelation
M. Selen, 7/24/03 LEPP Lunch: Pg 24www.hep.uiuc.edu/cleo/trig3/
Axial112
112
48
Raw key wires
Clustered key wires
Axial matching cells
48 high
48 low
Stereo - U
48 high
48 low
Stereo - V
Axial - Stereo CorrelationAxial - Stereo Correlation
high highlow
M. Selen, 7/24/03 LEPP Lunch: Pg 25www.hep.uiuc.edu/cleo/trig3/
Calorimeter TriggerCalorimeter Trigger
Energy sharing between boardscan result in a loss of efficiency:
Present summing = Tile summing =
Sim
ula
ted
E
ffic
ien
cy
containedshower
Threshold = 500 MeV
M. Selen, 7/24/03 LEPP Lunch: Pg 26www.hep.uiuc.edu/cleo/trig3/
Wrinkle – We need to work fast!Wrinkle – We need to work fast!
Preamp out
Mixer/shaper out
Trigger signal
Discriminator out
2 s/div
Calorimeter trigger informationcomes ~ 1.8 us after crossing.
twicedifferentiated
M. Selen, 7/24/03 LEPP Lunch: Pg 27www.hep.uiuc.edu/cleo/trig3/
1 m/s crate
1 m/s card
lowmed
high
“Tiling” sets too many bits Must Sparsify
M. Selen, 7/24/03 LEPP Lunch: Pg 28www.hep.uiuc.edu/cleo/trig3/
H M L proj
01
11
11
10
11
H
M
L
proj 11
11
10
01
H
M
L
011
001
001
lowmed
highAvailable
to decisionboards
M. Selen, 7/24/03 LEPP Lunch: Pg 29www.hep.uiuc.edu/cleo/trig3/
10
Key
Wir
e
Time Bucket
20
30
40
50
60
70
80
90
100
110
5 10 15 20
#trackEv-time
Timing IssuesLOW
MED
HIGH
CC time – TR time
M. Selen, 7/24/03 LEPP Lunch: Pg 30www.hep.uiuc.edu/cleo/trig3/
0 1 2 3 . . . . . . 58 59 60
That’s how thisplot is made !
M. Selen, 7/24/03 LEPP Lunch: Pg 31www.hep.uiuc.edu/cleo/trig3/
Compare to Simulation
(1995)
Mean = 17.5RMS = 0.73
Mean = 16.9RMS = 0.51
Mean = 16.7RMS = 0.41
Mean = 16.6RMS = 0.37
1 track events 4 track events
7 track events 10 track events
Trigger Time (42ns bucket) Trigger Time (42ns bucket)
Trigger Time (42ns bucket) Trigger Time (42ns bucket)
M. Selen, 7/24/03 LEPP Lunch: Pg 32www.hep.uiuc.edu/cleo/trig3/
Pipe-delay
Fro
m A
XT
R
MAKE 48MATCHINGCELLS
Bac
k-pl
ane
Pipe-delay
FINDEVENTTIME
Pipe-delay
AXIALCELLCOUNT
CB & DAQ
Typical Trigger Board
For timealignment
M. Selen, 7/24/03 LEPP Lunch: Pg 33www.hep.uiuc.edu/cleo/trig3/
AXPR
TRCR-1
TRCR-2
CCGL
L1D
From AXTRCrate
From STTRCrate
From TPROCrate
To DAQ
L1D Trigger Crate
LUMI
M. Selen, 7/24/03 LEPP Lunch: Pg 34www.hep.uiuc.edu/cleo/trig3/
LUT
8 FPGAs
Timing (3)
Info (185)
Timing (TR, CB or CE)
Info (valid at timing edge)
Route48 Prescale24 Bunch24
Scaler
L1-accept
Bac
kpla
ne
Trigger Decision Boards (L1D)Trigger Decision Boards (L1D)
M. Selen, 7/24/03 LEPP Lunch: Pg 35www.hep.uiuc.edu/cleo/trig3/
How To Define How To Define a CLEO-c a CLEO-c
Trigger LineTrigger Line
% Generic Hadron Line, Barrel Timing%SUBDESIGN line0(
in[117..0] : INPUT;out : OUTPUT;
)
Variable1cblow : SOFT;3tracks : SOFT;evtime : SOFT;
Begin-- trigger bit mappings:
tr_time[1..0] = in[1..0];cb_time[1..0] = in[3..2];ce_time[1..0] = in[5..4];cc_time[1..0] = in[7..6];
tr_n_hi[3..0] = in[11..8];tr_n_lo[3..0] = in[15..12];tr_n_ax[3..0] = in[19..16];tr_lowpos[1..0] = in[21..20];
cb_l_phi[7..0] = in[29..22];cb_h_phi[7..0] = in[37..30];
cb_low_old[1..0] = in[39..38];cb_med_old[1..0] = in[41..40];cb_high_old[1..0] = in[43..42];ce_low_old[1..0] = in[45..44];ce_med_old[1..0] = in[47..46];ce_high_old[1..0] = in[49..48];
cb_n_low[2..0] = in[52..50];cb_n_med[2..0] = in[55..53];cb_n_high[2..0] = in[58..56];ce_n_low[2..0] = in[61..59];ce_n_med[2..0] = in[64..62];ce_n_high[2..0] = in[67..65];
bha_theta[7..0] = in[75..68];
cc_spare[15..0] = in[91..76];
cpu_trig[1..0] = in[93..92];
control[23..0] = in[117..94];
------------------------------------------------ trigger line definition
1cblow = cb_n_low[] > 0;
3tracks = (tr_n_hi[]>2) # ((tr_n_hi[]>1)&(tr_n_lo[]>0)) #((tr_n_hi[]>0)&(tr_n_lo[]>1)) ;
evtime = cb_time[0];
out = 1cblow & 3tracks & evtime;
End;
M. Selen, 7/24/03 LEPP Lunch: Pg 36www.hep.uiuc.edu/cleo/trig3/
1/PT 1/PT
1/PT 1/PT
“Non-IsolatedTracks”
InHadronEvents
All TracksNo Trigger
- hardware
No Trigger
-missing hits
PT
Total Efficiency
200 MeV
Axial Trigger
Performance
M. Selen, 7/24/03 LEPP Lunch: Pg 37www.hep.uiuc.edu/cleo/trig3/
1/PT
“IsolatedElectronTracks”
All Tracks
No Trigger
Total Efficiency
210 MeV
Stereo Trigger
Performance(with axial)
B = 1.5 T
M. Selen, 7/24/03 LEPP Lunch: Pg 38www.hep.uiuc.edu/cleo/trig3/
1/PT
“IsolatedElectronTracks”
All Tracks
No Trigger
Total Efficiency
140 MeV
Stereo Trigger
Performance(with axial)
B = 1.0 T
M. Selen, 7/24/03 LEPP Lunch: Pg 39www.hep.uiuc.edu/cleo/trig3/
CC Trigger Performance
.8
.6
.4
.2
1.0
Needsmorestudy
M. Selen, 7/24/03 LEPP Lunch: Pg 40www.hep.uiuc.edu/cleo/trig3/
For Lots More InfoFor Lots More Info
http://www.hep.uiuc.edu/cleo/trig3/
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