1. on behalf of Barrel RPC Collaboration
RPC Technical Trigger
Flavio Loddo
I.N.F.N. Bari
on behalf of Barrel RPC Collaboration
CMS Week March F. Loddo INFN-Bari

2. CMS Week 14-16 March 2005 F. Loddo INFN-Bari
RPC Technical Trigger
Phase I: Sector Trigger for testing RPC (and DT) during Commissioning
RBC (RPC Balcony Collector)
RPC Cosmic trigger
Phase II: Technical trigger to be used during off-beam periods for RPC (and other detectors) calibration
RBC + TTU (Technical Trigger Unit)
CMS Week March F. Loddo INFN-Bari

3. Block Diagram of RPC DAQ
CMS Week March F. Loddo INFN-Bari

4. RPC LBBox In Barrel LBBox it is unused
It can provide the OR of 96 strips (half RPC)
CMS Week March F. Loddo INFN-Bari

5. Phase I: RBC (RPC Balcony Collector) Main Features
Generic Barrel Sector
Receive 2x13 (or 15) ORs from LB (LVDS)
(OR of 96 strips (1 bi-gap = half RPC))
Produce Sector Trigger
Mask noisy/dead Ors
Force selected ORs to be in the coincidence to
increase trigger selectivity
Majority level selectable between 1 and 6
I2C Interface
Re-Transmit input OR electrically (LVDS) to TDC
Transmit input OR optically to Counting Room (GOL)
RB4
RB3
RB2_OUT
RB2_IN
RB1_OUT
RB1_IN
CMS Week March F. Loddo INFN-Bari

6. CMS Week 14-16 March 2005 F. Loddo INFN-Bari
RBC Block Diagram
CMOS-LVDS
Driver
FPGA (Spartan IIE)
to TDC
LVDS-CMOS
converter
13 (15) ORs
Programmable
Majority Logic
From 2 LBBoxes
Trigger 1
(2 sectors)
13 (15) ORs
Trigger 2
Controller
GOL
Reconf
HFE4383
( Reconfigure FPGA every ~ 5 mins to recover eventual SEU loss of configuration)
to Optical PP
QPLL
Deskewed HF clock
I2C (from CB)
1 RBC per 2 sectors
6 RBC/Wheel
30 RBC/Barrel
40 MHz LHC Clock (from LB)
CMS Week March F. Loddo INFN-Bari

7. CMS Week 14-16 March 2005 F. Loddo INFN-Bari
RBC Status
FPGA design is under development.
What was done:
I2C Interface
Masking and Forcing feature
Trigger generation (but I’m waiting for further input/suggestions from Users)
Still to do:
GOL management
Board design …………….
…………….
Open issues:
Board location
Fibers routing and patch panels
INFN Financial approval
…….
CMS Week March F. Loddo INFN-Bari

8. Phase !!: RPC Technical Trigger Implementation
USC area
UXC area
TTU
VME Crate
LBBox
RBC
LBBox
RBC
1 RBC/ 2 sectors
Fiber
Receiving panel
Barrel Wheel
10 Optical Ribbons
1 Optical Ribbon/Half wheel
CMS Week March F. Loddo INFN-Bari

9. TTU (Technical Trigger Unit) Block Diagram (Preliminary)
Receive optical link from RBCs
Combine ORs from 1 Wheel (or from Half Wheel)
……………………..
Programmable
Majority Unit
TLK2501
TLK2501
Trigger
TLK2501
TLK2501
6x16 bit data
TLK2501
HFBR782
6x16 bit data
6 Fibers
Deskewed HF clock
VME Interface
QPLL
TTCrx
Comm. line
LHC Clock
CMS Week March F. Loddo INFN-Bari

10. CMS Week 14-16 March 2005 F. Loddo INFN-Bari
Cost Estimation
RBC: QPLL+GOL+VCSEL ~ 100,00 €
FPGA ~ 100,00 €
PCB ~ 300,00 €
Various ~ 100,00 €
NRE ~1000,00 €
Tot (30 RBC) ~20.000,00 €
Fibers (6000 m) ~ 6000,00 €
5 TTU: ~ ,00 €
1 VME crate: ~ 5000,00 €
1 VME controller (V2728): ~3000,00 €
CMS Week March F. Loddo INFN-Bari