Pixel Upgrade Plans

ROD/BOC PRRJuly 17, 2013

T. FlickUniversity of Wuppertal

Back-end Electronics Status and Services 2

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).

Oct. 3, 2012

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:

Oct. 3, 2012Back-end Electronics Status and Services 3

µ B-Layer Layer 1 Layer 2 Disks50 ns 37 39% 34% 52% 30%

25 35% 31% 48% 27%51 53% 59% 66% 39%76 71% 73% 111% 64%

Link occupancy at 75 kHz L1 Trigger

25 ns; 13 TeV

Back-end Electronics Status and Services 4

Observations: Layer 2 limitations at L=7x1033

Higher number of desynchronized modules in Layer 2

Oct. 3, 2012

Back-end Electronics Status and Services 5

Layer 2• Bandwidth limitations (@ 40 Mb/s) show up earlier as

expected getting worse with increased luminosity

• Increase link bandwidth to 80 Mb/so For this we need new readout cards, as the Pixel cards can only operate at 40 Mb/s

internally.

o IBL ROD and BOC can easily handle 80 Mb/s

o 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

o The firmware of the IBL ROD has to be modified to handle Pixel front end electronics

o IBL BOC: Tx path unchanged, Rx path has to be adopted to handle NRZ input signals (modified Rx Plugin fitting to SNAP12 socket)

o 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

Oct. 3, 2012

BOCMCC

TX

RX

BOCMCC

TX

RX

Now: Upgrade:

40 Mb/s

80 Mb/s

Back-end Electronics Status and Services 6

BOC

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.

Oct. 3, 2012

MCCTX

RX

BOCMCC

TX

RX

Now: Upgrade:

80 Mb/s

2x 80 Mb/s

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.

Back-end Electronics Status and Services 8

Bandwidth limitations MCC->

ROD

Number of pile-up events m

Lin

k o

ccu

pan

cy

Oct. 3, 2012

Back-end Electronics Status and Services 9

Further Benefits• We are short of spares for the present “old” BOCs

o 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 anyhowo 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:o Common spares for the 4-Layers Pixelo Same Tx Plugins over the whole Pixel Detector

Oct. 3, 2012