1. Straw electronics Straw Readout Board (SRB)

2. Full SRB - IO Handling 16 covers – Input 16*2 links 400(320eff) Mbits/s Control – TTC – LEMO – VME Output – to PC farm – 2*1Gb/s ethernet – VME to SBC – L0 trigger – Choke/error

3. Straw detector output data flow Straw detector – 4 chambers 4 views each (x,y,u,v) ½ view is served by SRB (Straw Readout Board) – 2 SRBs/view – 8 SRBs/chamber – 32 SRBs/detector 2 x 1Gbit/s ethernet interfaces per SRB 1 chamber connected through 10Gbit link (+1 spare) to pc-farm – 16 Gbit links merged in a switch

4. Data rates Single straw rate 60kHz (average) – 48 bits/event (24 bits leading, 24 bits trailing) – Coarse time in header L0 1MHz rate with time window 250ns – Total data rate per SRB with protocol (UDP,IP,..) 440 Mbit/s – Total data rate per chamber with protocol 3.6 Gbit/s – Full detector ~16Gbit/s Without L0 and without protocol – 600->800 Mbit/s per SRB – Full data 4.8->6.4 Gbit/s per chamber

5. Details UDP header (bytes)12 max UDP length (bytes)65500 MEP header (bytes)8 event header (bytes)8 max IP length (bytes)9000 IP header (bytes)38 edge hit size (bytes)3 Event rate (Hz)1.00E+06 Hits per view6 Time window (s)2.50E-07 Rate (tracks) per View (Hz)1.80E+07 events in time window1.40E+01 event data (bytes)102 event size header+dati (bytes)110 max number of events in UDP packet595 data rate (bytes/s/view)110000000 UDP packets/s/view1680 effective IP packet length (bytes)8962 number of IP packets/s/view12278 total data to tranfer (Mbit/s/view)884.016 total data to tranfer (Mbit/s/station)3536.064

6. SRB – components TTC LEMO L0 OUT ETH COVERS TTCRx COVER CONTROL, DATA, SYNCH EVENT PROCESSOR 2(4)GB DDR3 DATA TO PC FARM TIME REMAP L0 PROCESSOR VME INTF ON-LINE MONITOR L0 LOOK_UP TABLE L0 OUT SRB

7. SRB – control flow Selectable control -TTC -LEMO -VME Clock delay to compensate time of flight, Group of 4 covers VME to - Setup - Control, - On-line monitoring - Data

8. SRB – data flow 16x2x320Mbit/s ~10Gbit/s 2.5Gbit/s 2x Gbit ethernet VME Alternative path

9. SRB – trigger data flow 16x2x320Mbit/s ~10Gbit/s 2.5Gbit/s 2x Gbit ethernet VME L0 PRIMITIVES Alternative path

10. Trigger First mentioned in TD Possibility to use Straw detector for L0 if proved to be useful Tracks or hit multiplicity Tracks – View is split to corridors 6 straws – Corridors overlap on each side by 2 straws – 2 or more trailing edges in a corridor in a defined time window qualify a track – Can be already used as a coarse position ~13mm

11. Trigger Position can be improved using leading edges Leading edges from 6 straws put into the time pipeline corresponding to the full drift time in straw, step 25ns Trailing edge track signal starts pattern recognition Leading edges are run though look-up table and output position code Time-corresponding position codes from all views are combined To look- up table 6 straws leading edges

12. Trigger 1 SRB with modified firmware collects primitives from 8 SRBs serving 1 chamber OR 1 SRB with modified firmware collects primitives from 16 SRBs serving 2 chambers Chambers 1,2 and 3,4 can either contribute alone or can be combined L0 SRB send L0 primitives to L0 processor Time estimate – Event to Cover to SRB – <500ns – Time-reordering of hits - 10us – Track finding - <1us – Collection of hits and combination < 10us – Sending L0 primitives in < 22us

13. Choke/error Use user-defined VME P2 line Open collector output from every SRB Wire-OR to combine all outputs Simple VME board to convert choke/error wire-OR signals to RJ45 standard Use 1 calorimeter choke/error collection board to combine outputs from all chambers and send to L0 processor Monitoring via VME

14. SRB conclusions Design started – Schematics – Big part of prototype board firmware could be reused – New parts Time reordering Event buffer management data format for pc-farm Online monitoring L0 trigger Ready for PCB layout in November Prototype January/February 2014 Price estimate – Components < 1 kCHF – PCB + assembly < 1 kCHF – Total < 2 kCHF Integration/dry-run between April-June 2014