LHCB-RICH-Upgrade. TORCH electronics 10 June 2010 Johan Fopma, University of Oxford. A T ime O f Flight detector using R I CH technology. Design by Roger Forty Possible replacement for RICH 1 • Tracks emit Cherenkov photons in the quartz block.
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10 June 2010
Johan Fopma, University of Oxford
1cm-thick quartz plate at z=12m
THE FRONT END
•We want overall time resolution of 20-30 ps from MCP-PMT.
•We will for sure need to sample full 25ns range per BX.
If we use 9-bit time index:
• sample window = 25ns / 512 = 49 ps
• contribution to resolution = window / √12 = 14 ps
If we use 10-bit time index:
• sample window = 25ns / 1024 = 24 ps
• contribution to resolution = window / √12 = 7 ps
•The sustained rate for min-bias.
• 7.7×106 hits per PMT per second for lumi2
• 7.5×107 hits per PMT per second for lumi20
• Assuming 20 bits per hit (10 for channel, 10 for time),
we get per PMT a sustained rate of 0.15 Gb/s for lumi2, 1.5 Gb/s for lumi20.
10, June 2010
Choose a more pedestrian MCP-PMT
8 X 8: XP85012, 25 micron pore size
HPTDCx2 in very high resolution mode,
Medium size Spartan3A/ Small Spartan-6,
Separate JTAGs for HPTDC through FPGA,
40Mhz external clock from motherboard via clock buffer,
Xilinx configuration flash (not needed for Spartan 3AN
Unified readout boards to simplify PCB and firmware design,
Each board uses a small – medium size FPGA and has it own Ethernet connection.
PC side need multiple NIC to cope with multiple readout cards from one MCP,
Possibility of using commercial network switch to collect multiple ethernet port in to one is to be investigated.
HPTDC readout control,
HPTDC JTAG control,
Ethernet readout control and readout protocol implementation,
Two TDC devices,
FPGA as readout controller,
Shared 32-bit parallel data bus,
Individual control bus for each HPTDC.
Based on Xilinx Spartan 3A Evaluation board with on-board 10/100Mbps Ethernet PHY,
MAC stack implemented with Xilinx IP core (xps_ethernet_lite)
PC using windows data socket for TCP/IP, wincap package for raw MAC packet capture.
MAC and Lightweight IP stack with Microblaze processor: 12Mbps
MAC stack only with no embedded processor: 60Mbps
Conclusion: Raw MAC protocol provides adequate performance but losing the neatness of TCP/IP connection.