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TOF offline and calibration
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  1. TOF offline and calibration A. De Caro (University and INFN of Salerno)

  2. Status of the TOF code • Updated: • Calibration parameters (P.Antonioli, S.Arcelli, ADC, R.Preghenella, C.Zampolli); • TOF channel hardware status definition (A.Alici, P.Antonioli, ADC); • Data Quality Monitoring histograms definition (F.Bellini); • Alignment task (B.Guerzoni). • To be updated: • Calculate alignment parameters on new reconstruction data; • Check the currently used TOF calibration parameters with the aligned detector; • TOF trigger description (A.Silenzi); • Event time calculation in case of incomplete information coming from T0 detector (see D.Caffarri’s talk); • TOF cluster finder algorithm (D.De Gruttola); • Quality assurance histograms definition; • TOF-track matching: associate all matchable TOF clusters to each reconstructed track, together the only one matched according to DCA. ALICE TOF General meeting

  3. Status of the TOF code • Updated: • Calibration parameters (P.Antonioli, S.Arcelli, ADC, R.Preghenella, C.Zampolli); • TOF channel hardware status definition (A.Alici, P.Antonioli, ADC); • Data Quality Monitoring histograms definition (F.Bellini); • Alignment task (B.Guerzoni). • To be updated: • Calculate alignment parameters on new reconstruction data; • Check the currently used TOF calibration parameters with the aligned detector; • TOF trigger description (A.Silenzi); • Event time calculation in case of incomplete information coming from T0 detector (see D.Caffarri’s talk); • TOF cluster finder algorithm (D.De Gruttola); • Quality assurance histograms definition; • TOF-track matching: associate all matchable TOF clusters to each reconstructed track, together the only one matched according to DCA. ALICE TOF General meeting

  4. What did we change in the TOF code… …from the first ALICE p-p collision data (December 2009) till now? • As a first look of p-p collision data, it was to be checked: • Offset(s) of TOF time measurements ~1.6ms (to be noted that the expected time-of-flight for a primary particle to reach the ALICE-TOF detector at ~378cm from the interaction point is ~16ns); • TOF channel hardware status: description to be completed. ALICE TOF General meeting

  5. Offset in TOF time measurements ALICE TOF General meeting

  6. Correction of TOF measurementsat analysis level • A couple of TOF analysis classes tuned on 2009 December p-p collision data (prepared by F.Noferini) have been published. • With these classes at analysis level, all ALICE components can: • recalculate the TOF time measurement associated to a reconstructed track, • estimate the event-time with the combinatorial algorithm of the TOF measurements, • recalculate the TOF particle identification (PID) probabilities, useful for PID with bayesian approach. ALICE TOF General meeting

  7. Correction of TOF measurementsat reconstruction level • Till the second-last reconstruction step tTOFESD = tTOFraw+ - tonlineCalibration + + DBCTDC where: • tTOFESD, TOF time associated to each reconstructed track matched to a TOF sensitive element; • tTOFraw, measured TOF time (available in TOF raw data); • tonlineCalibration, TOF calibration offset extrapolated from the calibration parameters calculated on cosmic and 2009 December p-p collisions data (available in the offline database, called OCDB); • DBCTDC, TDC bunch crossing ID (available in TOF raw data). ALICE TOF General meeting

  8. Correction of TOF measurementsat reconstruction level (cont.) • Last reconstruction step tTOFESD =tTOFraw+ - Sn=0,…,5(an*(qTOFraw)n) + - ( DBCTDC - DBCoffset)+ + tL0L1latency+ + tCTPlatency+ - tlatencyWindow+ - t0fill ALICE TOF General meeting

  9. Correction of TOF measurementsat reconstruction level (cont.) • Last reconstruction step tTOFESD =tTOFraw+ - Sn=0,…,5(an*(qTOFraw)n) + - ( DBCTDC - DBCoffset)+ + tL0L1latency+ + tCTPlatency+ - tlatencyWindow+ - t0fill where: • an, calibration parameters - cosmic and 2009 December p-p collisions data (OCDB); • qTOFraw, measured TOF time-over-threshold (available in TOF raw data); • DBCoffset, offset of the TDC bunch crossing ID (OCDB); • tL0L1latency, latency between L0 and L1 clocks (TOF raw data); • tCTPlatency, Central Trigger Processor latency (OCDB); • tlatencyWindow, latency window of TOF TDCs(OCDB); • t0fill, event time (estimated at online level and written in OCDB). ALICE TOF General meeting

  10. Correction of TOF measurementsat reconstruction level (cont.) • Last reconstruction step tTOFESD =tTOFraw+ - Sn=0,…,5(an*(qTOFraw)n) + - ( DBCTDC - DBCoffset)+ + tL0L1latency+ + tCTPlatency+ - tlatencyWindow+ - t0fill where: • an, calibration parameters - cosmic and 2009 December p-p collisions data (OCDB); • qTOFraw, measured TOF time-over-threshold (available in TOF raw data); • DBCoffset, offset of the TDC bunch crossing ID (OCDB); • tL0L1latency, latency between L0 and L1 clocks (TOF raw data); • tCTPlatency, Central Trigger Processor latency (OCDB); • tlatencyWindow, latency window of TOF TDCs(OCDB); • t0fill, event time (estimated at online level and written in OCDB). Well managed ALICE TOF General meeting

  11. TOF channel hardware status ALICE TOF General meeting

  12. TOF channel hardware status • A TOF channel can be off for three reasons: • its read-out channel is disabled (RO status); • its associated FEA is not powered (LV status); • its associated MRPC strip is not powered (HV status). • Per each of these cases, the Detector Control System sends bit maps to the offline: • RO.and.LV status map read at start of run-SOR: ready to propagate it in the OCDB; • LV and HV status maps read at SOR, end of run-EOR-, every 10minutes and when there are changes: almost ready; • fixed technical problem in the code; • numbering conversion from online to offline to be controlled: work in progress. ALICE TOF General meeting

  13. TOF channel offline hardware statusKnown 2009 December TOF hardware configuration Thanks to Gilda, Silvia and Francesca ~10% not active TOF channels See A.Alici’s talk for current TOF configuration. ALICE TOF General meeting

  14. Let me remind TOF-track matching definition • To be taken into account: • Material budget; • Particle decays; • TOF acceptance (PHOS hole, mechanical holes between TOF elements); • Noisy channels and active readout channels; • High voltage status for TOF detector elements (~1600 MRPC strips); • Low voltage status for TOF front-end electronics (~570 FEAC cards). Information not available at offline level during 2009 December runs ALICE TOF General meeting

  15. ALICE TOF General meeting

  16. Real data: run 104852 MC data: LHC09d9 ADC @ 2009 December PWG1 meeting ~10% not active TOF channels ALICE TOF General meeting

  17. Real data: run 104852 MC data: LHC09d9 ADC @ 2009 December PWG1 meeting R.Preghenella study ~10% not active TOF channels Tuned MC means that we removed the noisy or not active TOF channels (with HV or LV or RO problems) at analysis level. ALICE TOF General meeting

  18. Thanks for your attention