The LHCb DAQ and Trigger Systems: recent updates Ricardo Graciani XXXIV International Meeting on Fundamental Physics.

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates2 Overview LHCb The Original Design Trigger Rate: –From 200 Hz to 2000 Hz Level 1 suppression: –1 MHz Readout Outlook

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates3 LHCb LHC: –40 MHz crossing rate –30 MHz with bunches from both directions Luminosity: 2·10 32 cm -2 s -1 –10 to 50 times lower ATLAS, CMS One Arm Forward Spectrometer LHCb rates: (for visible events  at least 2 tracks in acceptance) –Total rate (minimum bias): 10 MHz –bb: ~100kHz Whole decay of one B in acceptance: 15kHz –cc: ~600kHz pp interactions/crossing  B (rad) Production angle Of B vs B

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates4 The Spectrometer p p 250 mrad 10 mrad Muon system Vertex Locator RICH detectors Tracking systemDipole magnet Calorimeters

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates5 LHCb Physics Program B s oscillation frequency, phase and ΔΓ s –B s  D s , J/ ΨΦ, J/ Ψη, η c Φ  from B d  0  –  +  with B d  J/  K S as a proof of principle –And  from b  s penguin  in various channels, differing sensitivity to new physics: –Time-dependent CP asymmetry of B s  D s  K  and D s  K  –Time dependent CP asymmetries of B d     and B s  K  K  –Comparison of decay rates in the B d  D 0 (K + π -,K - π +,K + K - )K * 0 system –Comparison of decay rates in the B -  D 0 (K + π -,K + π - π + π - )K - system –Dalitz analysis of B -  D 0 (K S π - π + )K - and B d  D 0 (K S π - π + )K *0 Rare decays –Radiative penguin B d  K* , B s  Φ , B d   –Electroweak penguin B d  K * 0      –Gluonic penguin B s  ΦΦ, B d  Φ K s –Rare box diagram B s      B c, b-baryon physics + unexpected !

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates6 The LHCb TP HLT

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates7 From 200 to 2000 Hz Initial Design: –200 Hz of partial or fully reconstructed B final States. –Exclusive B Trigger. Limitations: –Strong MC dependence: Efficiency determination Detector Performance (vertex, proper time, PID) Backgrounds –Huge MC samples are necessary. Conclusion: –Review strategy Use real Data for the above studies –Re-evaluation of Computing needs Factor 10 reduction on MC needs Factor 10 increase on Trigger rate

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates8 2 kHz Trigger Output Best guess at present (split between streams still to be determined) Exclusive reconstruction is kept Large inclusive streams to be used to control calibration and systematics (trigger, tracking, PID, tagging,…) 10-15% acceptance for any channel on inclusive samples. Output rateTrigger TypePhysics Use 200 HzExclusive B candidatesSpecific final states 600 HzHigh Mass di-muons J/ , b  J/  X 300 HzD* CandidatesCharm, calibrations 900 Hz Inclusive b (e.g. b  ) B data mining

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates9 Cost Estimate 200Hz2000Hz Hoffman 2007 Now 2008 CERN CPU(MSI2k) Disk(PB) Tape(PB) Tier-1’s CPU(MSI2k) Disk(PB) Tape(PB) Tier-2’s CPU(MSI2k)-7.6 Disk(PB)-0.02 Relative Cost

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates10 DAQ Architecture Storage System TIER0 Scalable in depth: more CPUs (<2200) Scalable in width: more detectors in Level-1 Multiplexing Layer FE Switch Level-1 Traffic HLT Traffic 1000 kHz 5.5 GB/s 40 kHz 1.6 GB/s 94 SFCs Front-end Electronics 7.1 GB/s TRM Sorter L1-Decision Readout Network Switch SFC Switch CPU SFC Switch CPU SFC Switch CPU SFC Switch CPU SFC Switch CPU CPU Farm ~1600 CPUs ~ 250 MB/s total TFC System ECS

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates11 The “old” System Detector L0 boards: –talk Gb Ethernet –implement buffer to allow for Level 1 latency Two Data Streams: –Level-1 trigger with latency limit of ~58 MHz 3.8 kB/event  ~4.3 GB/sec –HLT traffic without latency 40 kHz ~30 kB/event  ~1.2 GB/s

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates12 1 MHz DAQ

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates13 Advantages Major simplification of the DAQ system –Only one data flow through the system –Elimination of the SFCs; –Event-Building in each CPU node –Elimination of the Level-1 decision sorter –No latency limitations for event processing –Well suited for multi-core CPU architectures For the Trigger software –ALL information available at all times in full precision and full granularity Better trigger efficiency Required Switching power: ~ 60 GB/s

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates14 The Hardware Candidate Force10 equipment  Port densities –Biggest switch has 14 slots for line-cards –Biggest port density is 90 Gb Ethernet ports per line-card (90/48 over-committed) ➔ 14*90 = 1260 GbEthernet ports  Switching Fabric ➣ Switching capacity is raw ~ 1.6 Tb/sec, usable ~ 1.2 Tb/sec (150 GB/s)

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates15 Reviewed HLT Strategy

XXXIV IMFPThe LHCb DAQ and Trigger Systems: recent updates16 Outlook LHCb had a very scalable and flexible DAQ schema. LHCb Trigger includes inclusive samples –HLT rate from 200 to 2000 Hz. High-mass di-muon D* Inclusive b Full L0 rate (1 MHz) sent to Online Filter Farm for a full software High Level Trigger. Review Vertical Trigger strategy for HLT.