Straw electronics Straw Readout Board (SRB)

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

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

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

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) UDP packets/s/view1680 effective IP packet length (bytes)8962 number of IP packets/s/view12278 total data to tranfer (Mbit/s/view) total data to tranfer (Mbit/s/station)

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

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

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

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

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

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

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

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

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