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Pixel Upgrade Plans. ROD/BOC PRR July 17, 2013 T . Flick University of Wuppertal. Pixel Readout Extension. With the restart of LHC we expect a higher luminosity, which will increase even more in the next years.
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Pixel Upgrade Plans ROD/BOC PRR July 17, 2013 T. Flick University of Wuppertal
Pixel Readout Extension • With the restart of LHC we expect a higher luminosity, which will increase even more in the next years. • The link occupancy for the Pixel readout link will suffer from bandwidth limitations. • For Layer2 this could be observed already in the last run period. • Module and link occupancy have been extrapolated using the experience gained from the last year(s). Back-end Electronics Status and Services
Occupancy extrapolation • The extrapolated pixel occupancies can be used to determine the occupancy per CP and BC: • This translates into an estimated MCCROD link occupancy at 75 and 100 kHz LVL1 rate: Back-end Electronics Status and Services
Observations: Layer 2 limitations at L=7x1033 Higher number of desynchronized modules in Layer 2 Back-end Electronics Status and Services
Layer 2 • Bandwidth limitations (@ 40 Mb/s) show up earlier as expected getting worse with increased luminosity • Increase link bandwidth to 80 Mb/s • For this we need new readout cards, as the Pixel cards can only operate at 40 Mb/s internally. • IBL ROD and BOC can easily handle 80 Mb/s • The doubled data input rate has to be sent out via the S-Link as well, which can also be handle by the sufficient number of S-Links on the IBL BOC card • The firmware of the IBL ROD has to be modified to handle Pixel front end electronics • IBL BOC: Tx path unchanged, Rx path has to be adopted to handle NRZ input signals (modified Rx Plugin fitting to SNAP12 socket) • That will allow the minimal or no change for the connectivity and fibre routing: 4 PP0s of Layer 2 to a single (more powerful) ROD/BOC pair BOC BOC Now: Upgrade: TX TX MCC MCC RX RX 40 Mb/s 80 Mb/s Back-end Electronics Status and Services
Layer 1 • Layer 1 will hit a brick wall later, at ~2x1034 luminosity • Layer 1 is already read out at 80 Mb/s • Double the links per module and upgrade the bandwidth to 2x 80 Mb/s, this is prepared by installing additional fibres now. • The IBL BOC then receives 2 links per module back, same as for the B-Layer right now. • Again, the IBL ROD/BOC can handle the 80 Mb/s throughput, only the NRZ input needs to be adapted with the modified RX-plugin. BOC BOC Now: Upgrade: TX TX MCC MCC RX RX 80 Mb/s 2x 80 Mb/s Back-end Electronics Status and Services
The way out • Therefore we plan to use the presented IBL ROD and BOC cards also for the Pixel upgrade to overcome the bandwidth limitations. • Firmware of the ROD need modification to handle the Pixel module data. • The Rx plugin has to be modified to receive the NRZ signals correctly. • We need another 26 card pairs for Layer2 and 38 card pairs for Layer1. • Ideally the cards are all produced in one go to save money and have the manpower and tests setups at hand in the institutes. • Layer2 needs action now, this means the first batch of cards have to be installed until mid of next year.
Bandwidth limitations MCC-> ROD Link occupancy Number of pile-up events m Back-end Electronics Status and Services
Further Benefits • We are short of spares for the present “old” BOCs • Exchanged Pixel BOC will deliver enough spares. • No further development (apart from the small redesign of Rx plugin) is needed as the ROD and BOC are there for the IBL anyhow • Firmware adaptation to Pixel needs • For our annoying Tx saga, the IBL BOC operate commercial plugins. These plugins we want to use also for the remaining Pixel BOCs interfaced with a small adaptor board. • This will uniform our readout system: • Common spares for the 4-Layers Pixel • Same Tx Plugins over the whole Pixel Detector Back-end Electronics Status and Services