an rpc-based technical trigger for the cms experiment
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An RPC-Based Technical Trigger for the CMS Experiment. Outline: Requirements Implementation Performance during CMS MTCC. Flavio Loddo I.N.F.N. Bari On behalf of the CMS RPC/Trigger Collaboration. Motivations and requirements. - PowerPoint PPT PresentationTRANSCRIPT
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
An RPC-Based Technical Trigger for the CMS
Experiment Outline:
Requirements Implementation Performance during CMS MTCC
Flavio Loddo
I.N.F.N. Bari
On behalf of the CMS RPC/Trigger Collaboration
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
Motivations and requirements
Goal of this project is to produce an RPC-based Cosmic Ray Trigger for: the Commissioning of RPCs, to test the detector efficiency the Magnet Test-Cosmic Challenge later running of CMS as Technical Trigger, to calibrate the
detectors in the off-beam periods
The main requirements are: Compact Inexpensive
Use existing infrastructures and services (electronics and cables in the experimental hall)
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
Block diagram of CMS RPC Electronics full chain
datacontrol (DCS)
DetectorDetector
Periphery
Trigger Crate (12)
LMUX
LINK BOARD (Slave)
FEC
FEB
LINK BOARD (Master)
FEC
FEB
electrical
LMUX
TRIGGER BOARD
PAC
PAC
GB&
SORTER
SPLITTER BOARD
FanOut
Rx
SORTER Backplane
SORTER
SORTER
SORTER
GB & SORTER BOARD
SORTER
SORTER
SORTER
DATACONCENTRATORCARD
EVENTCONCENT
electrical
Sorter Crate (1)
Counting Room
SORTER BOARD(on Backplane)
SORTER
SORTER
SORTER
Tx
electrical
TTc Rx
Diagnostics
108 12
2
1
3
144 links/crate1732/total
CONTROL BOARD
CCU
Link Box
optical
Tx
Tx
Rx
RxReadout
Concentr.
60
96 LB boxes
108 GOHlinks
"Vme" DCS
"Tracker type, DOH based " DCS
datacontrol (DCS)
DetectorDetector
Periphery
Trigger Crate (12)
LMUX
LINK BOARD (Slave)
FEC
FEB
LINK BOARD (Master)
FEC
FEB
electrical
LMUX
TRIGGER BOARD
PAC
PAC
GB&
SORTER
SPLITTER BOARD
FanOut
Rx
SORTER Backplane
SORTER
SORTER
SORTER
GB & SORTER BOARD
SORTER
SORTER
SORTER
DATACONCENTRATORCARD
EVENTCONCENT
electrical
Sorter Crate (1)
Counting Room
SORTER BOARD(on Backplane)
SORTER
SORTER
SORTER
Tx
electrical
TTc Rx
toDAQ3 Slinks
Diagnostics
108 12
2
1
3
144 links/crate1732/total
CONTROL BOARD
CCU
Link Box
optical
Tx
Tx
Rx
RxReadout
Concentr.
60
96 LB boxes
108 GOHlinks
"Vme" DCS
"Tracker type, DOH based " DCS
datacontrol (DCS)
DetectorDetector
Periphery
Trigger Crate (12)
LMUX
LINK BOARD (Slave)
FEC
FEB
LINK BOARD (Master)
FEC
FEB
electrical
LMUX
TRIGGER BOARD
PAC
PAC
GB&
SORTER
SPLITTER BOARD
FanOut
Rx
SORTER Backplane
SORTER
SORTER
SORTER
GB & SORTER BOARD
SORTER
SORTER
SORTER
DATACONCENTRATORCARD
EVENTCONCENT
electrical
Sorter Crate (1)
Counting Room
SORTER BOARD(on Backplane)
SORTER
SORTER
SORTER
Tx
electrical
TTc Rx
toGlobalMuonTrigger
Diagnostics
108 12
2
1
3
144 links/crate1732/total
CONTROL BOARD
CCU
Link Box
Tx
Tx
Rx
RxReadout
Concentr.
60
96 LB boxes
108 GOHlinks
"Vme" DCS
"Tracker type, DOH based " DCS
444 + 84 (HO) links
opticaloptical
The Resistive Plate Chambers are part of the CMS Muon Trigger System
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
Cosmic Trigger with RPC Trigger electronics?
In CMS the RPC Trigger Boards are connected in vertex geometry, which is not adequate to cosmic trigger
It could be possible with additional optical splitters and TBs, but the new proposed architecture provides redundancy and an independent tool for calibration and debugging
Overall costs are similar to the solution with additional splitters and TBs
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
RPC Technical Trigger: Implementation
Phase I: Sector-based Trigger for testing RPC (and DT) during Commissioning and MTCC
Phase II: Wheel-based trigger (Technical trigger) to be used during CMS
RBC (RPC Balcony Collector), on the detector
RBC + TTU (Technical Trigger Unit), in the Counting Room
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
RPC Technical Trigger: Implementation
Experimental Hall
30
6 Fibers/wheel
To Global Trigger
LBBox
RBC
LBBox
LBBox
RBC
LBBox
LBBox
RBC
LBBox
LBBox
RBC
LBBox
LBBox
RBC
LBBox
LBBox
RBC
LBBox
TT
UT
TU
TT
UT
TU
TT
U
5 wheel Triggers
Counting RoomT
echn
ical Trig
ger L
og
ic
Tech. Trigger
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
RBC Implementation The RPC signal cables (LVDS) are connected to the Link Boards (LB)
for synchronization, data compression and optical conversion
Each LB reads 96 strips of one partition (1 roll = half/chamber) and can produce 1 OR to be used for our goal
On LB front-panel, the CSC connector is used only in the Forward region, to send synchronization signals from RPC to CSC. It can be used in the Barrel to send signals from LB to RBC
In the endcap, the cosmic muon rate is very low and not adequate for fast monitoring run with cosmics
↓Technical Trigger involves only the Barrel RPCs
Each LBBox (LBB) houses 13 or 15 LBs of 1 Barrel Sector The LBBs are distributed in the 30 periphery racks in groups of 2 We can house 1 RBC/rack 1RBC/2 sect 30 RBCs in total
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
•RBCs will be housed in slot #12 of LBBox of odd sectors. The ORs and LHC_Clock are collected by 2 FrontPlanes
•RBC_Fake (just a connector collecting the ORs to be sent to RBC) will be housed in slot #12 of LBB of even sectors
•I2C (from Control Board) and Power Supplies will be accessible on the backplane
RBC Implementation
LBB with RBC
LB FrontPlane 1 LB FrontPlane 2
LB
LB
LB
LB
LB
LB
LB
LB
LB
LB
LB
LB
LB
Co
ntr
ol
Bo
ard
Co
ntr
ol
Bo
ard
RB
C
RBC FP1 RBC FP2
7 ORs 6 Ors + CLK + RCO
OUT
7 ORs
1
LB FrontPlane 1 LB FrontPlane 2
LB
LB
LB
LB
LB
LB
LB
LB
LB
LB
LB
LB
LB
LB
LB
Co
ntr
ol
Bo
ard
Co
ntr
ol
Bo
ard
RBC FP1 RBC FP2
7 or 9 ORs 6 Ors
LBB without RBC (and with RBC_FAKE)
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
•Receive 2x13 (or 15) ORs from LB (LVDS)
(OR of 96 strips (1 bi-gap = half RPC))
•Mask noisy/dead Ors
•Produce Sector Trigger (LVDS) according to pre-loaded patterns, with selectable Majority level (16)
•Force selected ORs to be in the coincidence, to
increase trigger selectivity
• Introduce latency (step = 25 ns) for synchronization with other triggers
•I2C Interface
•Transmit input OR to Counting Room using the GOL optical transmitter for Wheel-based trigger
RB4
RB3
RB2_OUT
RB2_IN
RB1_OUT
RB1_IN
Generic Barrel Sector
RBC Main Features
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
RBC Main Features
Based on Xilinx Spartan-3 Configure with JTAG through Flash Prom Not inserted in the CCU chain controlling LBs
firmware upgrade only in situ This is not a major limitation, since all internal
parameters and muon patterns are configurable via I2C The ORs will be available also in the Counting Room,
where the TTU Boards might be upgraded “on line” through Slow Control
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
RBC Block diagram
LV
DS
Receiver
GOL
QPLL
Trigger #1 (LVDS)
I2C AgilentHFBR-5720
40 MHz LHC Clock
Pattern
C
om
parato
r
Reconf
Controller
LV
DS
Drive
r
FPGA (Spartan III)
Trigger #2 (LVDS)
to TDC
Config. PROM
Backup Flash
EpromD
elay u
nit
(25 ns T
aps)
TLK2501
Only for test
purpose
Input ORs
13+13(or 13+15)
JTAG
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
RBC SEU Strategy
On the detector periphery the environment is not critical:
•Total DOSE < 1 krad
•Neutron flux (E > 20 MeV) < 100 cm-2s-1 Fluence < 1010 cm-2
Optical transceiver: Agilent HFBR-5720L
Tested by E. Denes, T. Kiss et al. (ALICE)
• Fluence: 1011 n/cm2 at different energies: 10 MeV, 150 MeV, 180 MeV
Serializer
Rad-tolerant GOL chip developed at CERN
The most sensitive device is the SRAM – FPGA!
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
RBC SEU Strategy
Since also LBs are based on Spartan-3 devices, the same strategy is adopted to mitigate the SEU effects on FPGA:
•periodical re-load configuration SRAM from Flash EPROM (extremely robust against our level of irradiation)
•upon the receipt of the Reconf signal from LB, the time to load the bitstream is ~ 200 ms
•backup Flash Memory to store internal registers for fast reload
Test on Spartan-3•Performed by Fabula et al. (Xilinx) and presented at MAPLD 2004
•Test facility: Los Alamos Neutron Science Center
bit ~ 3.0x10-14 cm2/bit ~ 2.9x10-8 cm2 (E > 10 MeV)
Time to Configuration upset = 1/(*Flux) ~ 95 Hours/device
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
RBC prototype
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
Backplane connector:•3.3 V•2.5 V•GND•I2C
Front side
RBC prototype
•10 Layers PCB 14x14 cm2
to be housed on Mother Board, fitting LBBox dimensions
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
Since last June, 2 RBC prototypes + 1 RBC_fake are providing two Cosmic Triggers to the
detectors involved in the CMS Magnet Test Cosmic Challenge
W+2: Sect. 10 Sect. 11
Sect.10-11 patternsOR
RBC2
W+1: Sect. 10 RBC1
RBC Trigger in MTCC
(but only Sect.10 equipped with LBs during MTCC phase I)
RPC-TB pointing to the tracker
RBC LVDS-LVPECL Transceiv.
LVPECL Receiv.
LVDS Driver
LTC or
PSB
150 m (shielded twisted cable)
The RBC triggers were well synchronized with RPC-TB trigger and with other muon triggers (DT and CSC)
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
RBC Trigger rate in MTCC: rate plateau
Some measurements to find the working point of the RBC1 and RBC2 triggers vs. variation of the RPCs HV set points
Majority 5/6 - trigger rate ~30 Hz per wheelMajority 6/6 - trigger rate ~13 Hz per wheel
W1/S10 RB1in
0,00
2,00
4,00
6,00
8,00
10,00
12,00
14,00
16,00
8,4 8,6 8,8 9 9,2 9,4 9,6 9,8
HV(kV)
Tri
g R
ate
(Hz)
Majority: 6/6
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
RBC in MTCC: Iguana Event Display
Combined offline RPC (green) and DT digis
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
Examples of DQM plots: RPC Barrel Wheel +2 Sector 10
Station 4
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
Examples of Drift Tube occupancy plots triggered by
RBC
Z
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
•Receive optical link from RBCs
•Combine ORs from 1 Wheel and produce Wheel Cosmic Trigger Global Trigger as Technical Trigger
Wheel Trigger OpticalTransceiver
TLK2501Pattern
Recognition Processor
TTCrxQPLLVME InterfaceVME Interface
Comm. line
Deskewed HF clock
LHC Clock
6 Fibers
Phase II: Wheel-Based Cosmic TriggerPhase II: Wheel-Based Cosmic Trigger
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
The required functions are performed by the RPC Trigger Board (designed by Warsaw RPC Trigger Group):
• TTU needs:
1. 30 signals from detector: 1.6 GHz GOL drive multimode fiber;
2. each fiber transfers 26 or 28 bits @ 40 MHz;
3. signals must be synchronized;
4. pattern logic to make cosmic trigger
• RPC Trigger Board offers:
1. 18 inputs: 1.6 GHz GOL driven multimode fiber;
2. Opto-synch FPGA/3 optical inputs and maximum 72 bits @ 40 MHz;
3. Up to 4 PAC mezzanine boards for pattern recognition algorithm
RPC Trigger Board as TTU
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
TB as Technical Trigger UnitTLK2501 Max. 72 bit/synch
OP
TO
B
RD
OP
TO
B
RD
OP
TO
B
RD
OP
TO
B
RD
OP
TO
B
RD
OP
TO
B
RD
OP
TO
B
RD
OP
TO
B
RD
OP
TO
B
RD
SY
NC
HS
YN
CH
SY
NC
HS
YN
CH
SY
NC
HS
YN
CH
Pattern Comparator
Pattern Comparator
Pattern Comparator
Pattern Comparator
DAQ Concentrator
VME Interface
VME Connector
Custom Backplane Connector
Ghostbuster Sorter
• 3 Trigger Boards can be used to cover the whole Barrel, using 12 links per TB
• The Stratix2 PAC mezzanine board have huge amount of logic cells, enough to implement cosmic pattern recognition: 1 or 2 PACs should be enough
• VHDL code for data transmission and Internal Interface (VME driven internal bus) developed by Warsaw Group can be used
• Warsaw software for FPGA upload and diagnostic tools can be used
• TTU custom backplane (for TTCrx and to send out the Trigger) must be designed, but can be derived from the design of TB backplane
12th Workshop on Electronics for LHC and Future Experiments Valencia 25-29 Sept. 2006 F. Loddo I.N.F.N. Bari
Conclusions
The RPC Technical Trigger project is under progress: 2 RPC Balcony Collector (RBC) prototypes are in
use for MTCC to provide 2 Sector-based triggers The full production is expected to be available
before the end of 2006 The design of the new firmware and the backplane
for the Trigger Board-TTU will start in few weeks