the atlas level-1 central trigger processor
DESCRIPTION
The ATLAS Level-1 Central Trigger Processor. On behalf of P. Borrego Amaral 1) , N. Ellis 1) , P. Farthouat 1) , P. Gallno 1) , J. Haller 1) , A. Krasznahorkay 1)2) , T. Maeno 1) , T. Pauly 1) , H. Pessoa Lima Jr. 3)4) , I. Resurreccion Arcas 1) , - PowerPoint PPT PresentationTRANSCRIPT
Thilo Pauly, CERN-PH 1
The ATLAS Level-1 Central Trigger Processor
On behalf of
P. Borrego Amaral1), N. Ellis1), P. Farthouat1), P. Gallno1), J. Haller1), A. Krasznahorkay1)2), T. Maeno1), T. Pauly1), H. Pessoa Lima Jr.3)4), I. Resurreccion Arcas1),
G. Schuler1), J. M. de Seixa3), R. Spiwoks1), R. Torga Teixeira1), T. Wengler1)
1) CERN, Switzerland2) University of Debrecen, Hungary3) Federal University of Rio de Janeiro, Brazil4) Brazilian Center for Physics Research, Brazil
Thilo Pauly, CERN-PH 2
The ATLAS Experiment
• General-purpose experiment at CERN’s Large Hadron Collider.• Watches collisions of two pulsed high energy and high intensity
proton beams.• Bunch-crossings every 25ns (40 MHz).• Trigger system: Reduce the rate, but keep interesting events
Thilo Pauly, CERN-PH 3
The Trigger-DAQ System
LVL1
DATAFLOW
H
L
T
Readout System(ROS)
LVL2
Calo MuTrChOther detectorsTrigger DAQ40 MHz
<2.5 s
Reg
ion
of
Inte
rest
Lvl2 acc = ~3 kHz
Event Building
Event Filter~ sec
EFacc = ~200 Hz
Storage
RoI requests
RoI data
Lvl1 acc = 75 kHz
~10 ms
event data
DETECTOR READOUT ELECTRONICS
custom hardware
event selection
in software
This Presentation
PipelineMemories
Thilo Pauly, CERN-PH 4
The Level-1 Trigger System
•Synchronous, pipelined processing at 40MHz
•LTP = Local Trigger Processor(Standard sub-detector interface to the CPT)
•TTC = Timing, Trigger & Control•Busy = Tree of Busy Modules•ATLAS has about 40 TTC
Partitions
Pre-processor
ClusterProcessor
(e/γ and τ/h)
Jet/EnergyProcessor
End-cap MuonTrigger
Barrel MuonTrigger
Muon-CTP-Interface
Central Trigger Processor
LTP
BusyTTC
TTC
Part
itio
n
Detector Front-Ends/Read-out
LTP
BusyTTC
TTC
Part
itio
n
...
Muon DetectorsCalorimeter Detectors
Thilo Pauly, CERN-PH 5
Central Trigger Processor - Functionality
• Trigger Inputs:– Multiplicities from Calorimeter and Muon
Triggers for e/γ, τ/hadron, jets, and muons– Energy flags from Calorimeter Trigger:
∑ET, ETmiss, ∑ET
jet
– Calibration requests from sub-detectors– Specialized triggers: Beam pick-ups, etc.– Up to a total number of 160 trigger inputs at
any one time• Internal triggers from CTP Core Module:
– Random triggers– Pre-scaled clock– Bunch crossing groups
Thilo Pauly, CERN-PH 6
CTP – Functionality (2)
• Level-1 Accept (L1A):– Derived from trigger inputs according to trigger
menu:• Up to 256 trigger items are made from combinations
of up to 256 conditions on the trigger inputs, e.g. 1EM10 = “At least one e/γ with ET≥10
GeV”XE20 = “Missing energy of at least 20
GeV”• Each trigger item has a mask, a priority and a pre-
scale factor• Example:
2EM10 AND XE20, mask=ON, priority=LOW, prescale=100
• L1A = OR of all trigger items
Thilo Pauly, CERN-PH 7
CTP – Functionality (3)
• Additional Functionality:– Trigger Type word (8 bits) accompanying every
L1A– Dead-time in order to prevent front-end buffers
from becoming full– Information for the Level-2 Trigger– Event data for the Read-out and Monitoring– Scalers for monitoring
• Constraints:– Trigger latency budget: 100ns (4 clock ticks)
from trigger input to L1A output– Trigger menu changes with
physics/beam/detector conditions.
Thilo Pauly, CERN-PH 8
CTP Design
BC/Orbit4xSPD [30..0]
4xSPD [30..0]
4xSPD [30..0]
L2/Read-out
5xLTP-Link
5xLTP-Link
5xLTP-Link
5xLTP-Link
Beam Pick-up/Other
CPT_MI
CTP_IN
CTP_IN
CTP_IN
CTP_MON
CTP_CORE
CTP_OUT
CTP_OUT
CTP_OUT
CTP_OUT
CTP_CAL
VME Bus
COM bus (common)
PIT bus
CAL bus
(patt
ern
-in-t
ime)
(Calib
rati
on
request
s)
Machine Interface
Input Modules: Trigger Inputs
Bunch-to-bunch monitoring
Trigger Menu and Read-out
Calibration Requests, Patch-Panel
Trigger fan-out/Busy fan-in
The CTP is in a single 9U VME64x crate+ custom backplanes.
Thilo Pauly, CERN-PH 9
CTP – Trigger Path
CPT_MI
CTP_IN
CTP_IN
CTP_IN
CTP_MON
CTP_CORE
CTP_OUT
CTP_OUT
CTP_OUT
CTP_OUT
CTP_CAL
VME Bus
COM bus (common)
PIT bus
(patt
ern
-in-t
ime)
CAL bus
(Calib
rati
on
request
s)
Tri
gger
Inputs
L1A
CTP_IN modules receive, synchronize and align1) the trigger inputs, and route them to the PIT bus
CTP_CORE: receives the PIT signals, compares trigger menu and generates Level-1 Accept, and sends L1A to the COM bus
CTP_Out: Receives the L1A from the COM bus and fans it out to sub-detector LTPs (common solution for all sub-detectors)
1) See Poster #1010 presented by Ralf Spiwoks“The ATLAS Level-1 Trigger Timing Setup”
Thilo Pauly, CERN-PH 10
The CTP at the Combined Testbeam
Combined test-beam in 2004 with periods of 25ns structured beam in order to test prototypes and final modules of all ATLAS sub-detectors with full trigger and data acquisition chain.
Particle
Beam
Thilo Pauly, CERN-PH 11
The CTP at the Combined Testbeam
IN
CORE
OUT
MI
MON
Trigger Inputs:Calorimeter Trigger: 4x3 bit e/γ
4x3 bit jet multiplicities1 bit total ET
Muon Trigger: 6x3 bit muon multiplicitiesScintillators: 3x1 bit
Calorimeter TriggerCommon Merger Modules
Muon-CTP-Interface
Barrel Muon TriggerSector Logic
End-cap Muon TriggerSector Logic
Test-beamspecificscintillators
LTP(fan-out to sub-detectors)
CTP
Thilo Pauly, CERN-PH 12
The CTP at the Combined Testbeam
CTP_MI
CTP_IN
CTP_CORE
CTP_MON
CTP_OUT
Thilo Pauly, CERN-PH 13
Some Results
• Trigger Generation:– 46 signals from the PIT bus were used to form 18 trigger
items– Prescaling and masking tested to work correctly– L1A used as trigger for read-out of the combined sub-
detectors
• Latency Measurements:– Measured latency between reference scintillator and L1A
as it arrives at the Muon Trigger read-out. Projection (cable length + time-of-flight corrections) for final ATLAS latency:
2.13μs (budget is 2.5μs)
– CTP Latency (budget 100ns):• 125ns at testbeam (non-optimized timing)• 95ns in lab after further optimisation
Thilo Pauly, CERN-PH 14
Conclusions
• The CTP has been successfully tested during the test-beam to generate triggers using 46 trigger inputs and 18 trigger items
• The CTP latency is measured to be 95ns• Work is continuing in the laboratory
(read-out, additional firmware, software, monitoring, GPS-based time-stamp)
• The CTP will be available for ATLAS commissioning in September 2005.
Thilo Pauly, CERN-PH 15
Backup - Slides
Thilo Pauly, CERN-PH 16
CTP – Timing & Control Signal Path
CPT_MI
CTP_IN
CTP_IN
CTP_IN
CTP_MON
CTP_CORE
CTP_OUT
CTP_OUT
CTP_OUT
CTP_OUT
CTP_CAL
VME Bus
COM bus (common)
PIT bus
(patt
ern
-in-t
ime)
CAL bus
(Calib
rati
on
request
s)
CTP_MI module receives timing signals from LHC, generates additional timing signals and sends all to the COM bus
CTP_Out module receives busy signals from sub-detector LTPs and send them to the COM bus.It receives clock signal from the COM bus and fans it out to the sub-detectors.
All CTP modules receive timing signals from the COM bus.
Bunch Clock, Orbit
Busy fromsub-detectors/Bunch Clockto sub-det.
Thilo Pauly, CERN-PH 17
CTP – Read-out and Monitoring
CPT_MI
CTP_IN
CTP_IN
CTP_IN
CTP_MON
CTP_CORE
CTP_OUT
CTP_OUT
CTP_OUT
CTP_OUT
CTP_CAL
VME Bus
COM bus (common)
PIT bus
CAL bus
(patt
ern
-in-t
ime)
(Calib
rati
on
request
s)
CPT_CORE sends Region-of-Interest (RoI) information to the Level-2 Trigger and event data to the Read-out System
CTP_MON produces bunch-by-bunch histograms of signals on the PIT bus
All CTP modules provide monitoring data to the VME bus.
RoI toLevel-2
Event datato Read-out
Thilo Pauly, CERN-PH 18
CTP – Calibration Requests
CPT_MI
CTP_IN
CTP_IN
CTP_IN
CTP_MON
CTP_CORE
CTP_OUT
CTP_OUT
CTP_OUT
CTP_OUT
CTP_CAL
VME Bus
COM bus (common)
PIT bus
CAL bus
(patt
ern
-in-t
ime)
(Calib
rati
on
request
s)
AdditionalTrigger Inputs(e.g. Beam-Pick-up)
CTP_OUT receive calibration requests from sub-detector LTPs and send them to the CAL bus
CTP_CAL:• Time-multiplexes calibration
requests• Receives additional trigger inputs
and sends them to a CTP_IN module