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T0 offline status

Alla Maevskaya INR RAS ALICE offline week 20 October 2008. T0 offline status. Trigger timing (before alignment) versus bunch number single shot for SPD, V0, beam-pickup BPTX, T0 triggers. OCDB the status of conditions objects final I. run type PHYSICS event type PHYSICS.

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T0 offline status

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  1. Alla Maevskaya INR RAS ALICE offline week 20 October 2008 T0 offline status

  2. Trigger timing (before alignment) versus bunch number single shot for SPD, V0, beam-pickup BPTX, T0 triggers

  3. OCDB the status of conditions objects final I run type PHYSICS event type PHYSICS During physics run, T0physda collects the difference between time on the PMT1 and all others on each side event by event. Using mean of these histograms, collected during 1st 20000 events as equalizing shift between channels calculate 1st particle for both sides and vertex position as c*(TAbest-TCbest)/2 and write vertex position in histogram for events 20000-50000 The preprocessor gets the mean and RMS of these histograms (24 time and 1 vertex)‏ and writes it into OCDB to be used in reconstruction - as the value of the shift between the channels for equalizing - as shift in vertex position

  4. OCDB - the status of conditions objects final II run type LASER event type CALIBRATION Online during special multi-MIPs Laser calibrations runs Stored in OCDB 4 x 24 TGraphs • time-amplitude dependence (QTC amplitude)‏ • time-amplitude dependence (LED-CFD amplitude)‏ • amplitude #channel vs MIPs (QTC)‏ • amplitude #channel vs MIPs (LED-CFD)‏

  5. T0 DPs • DPs stored to Reference DB • t00_ac_scaler_sec[0..31] and scaler_sec[0..31] – T0 scalers: • counts from 12 A-side and 12 C-side PMT • counts from OR, TVDC, MPD, Mean timer and Reference point generator • t00_.._hv.. - HV on T0 PMTs • t00_.._lv.. - LV on T0 shoeboxes • t00_.._cfd.. - threshold and walk on CFDs • t00_ac_trm and t00_ac_drm – temperature of TRM and DRM • t00_ac_atten – setting of T0 LCS attenuator, recent request of T0 detector experts • Usage of DPs - product of long discussions within T0 collaboration: • Scaler DPs primarily used for Luminosity study • part of ALICE luminosity project • included in DCS distributed project • cross-check of scaler performance from Reference DB • all other DPs used for cross-check, monitoring and understanding the performance of T0

  6. % fluct. No. of channels DCS alias Data type Unit Value Update Frequency (s)‏ t00_a_hv_imon_[00..11] 12 float uA 83 0.9 3000 12 float V 1325 0.85 3000 t00_a_hv_vmon_[00..11] t00_a_lv_imon_[00..01] 2 float uA 83 0.9 3000 t00_a_lv_vmon_[00..01] 2 float V 6 0.15 3000 t00_c_hv_imon_[00..11] 12 float uA 83 0.9 3000 t00_c_hv_vmon_[00..11] 12 float V 1325 0.85 3000 t00_c_lv_imon_[00..01] 2 float uA 83 0.9 3000 t00_c_lv_vmon_[00..01] 2 float V 6 0.15 3000 t00_a_cfd_thre_[00..11] 12 float V 0.5 10 3000 t00_a_cfd_walk_[00..11] 12 float V -0.1 10 3000 t00_c_cfd_thre_[00..11] 12 float V 0.5 10 3000 12 float V -0.1 10 3000 t00_c_cfd_walk_[00..11] t00_ac_scaler_[00..31] 32 1/s 3*10^8 50 120 unsigned int t00_ac_trm_[00..09] 10 float Co 35 3 run start & stop and if changed t00_ac_drm_[00..04] 5 float Co 35 3 run start & stop and if changed t00_ac_scaler_sec[0..31] 32 1/s 80 50 120 unsigned int t00_ac_atten 1 int 5 50 run start & stop and if changed MIP DCS part of preprocessor All retrieved • Updated list of T0 DPs • SOR and EOR scripts tested • all 184 DP retrieved from Amanda server • AliT0Preprocessor - storing results to Reference DB: • local tests of new version AliT0DataDCS – to be ported to the coming AliRoot release and tested at P2

  7. Preprocessor and DA - are these complete, do you foresee a major change in the procedures? Yes, they are complete. Only number of events necessary for vertex calculations could be changed with beam energyWhat are the most common failures in thepreprocessors/DA operation since December 2007?T0 does not register cosmic data, so we can do all calibration which will use physic data during data taking with laser data. Most problem is switch DA on/off….. Yes ,

  8. Do you foresee to add new object and if yes what would be the increase in size? no • Location of objects OCDB/reference • Input data - do you still miss any of the input data for the Shuttle preprocessor from DCS (data points), DAQ, HLT? Now all DCS and DAQ data are retrieved • Run types - do you foresee new run types to be handled by the preprocessor? No, only “PHYSICS” and “LASER” as now • GRP/reco params - do you have implementation for the three defined types of reco params (low/high flux, calibration)? For no one now

  9. Second order calibration - what are the condition objects, methods and input data necessary for the second order (refined) calibration?Will the second order calibration run during the first pass reconstruction or elsewhere? How many of the conditions object will be modified for the second pass reconstruction and with what frequency?Now we are not planning 2nd order of calibration and 2nd pass of reconstruction. But if QA RecPoints will show that mean reconstructed time is different for each PMT we will need repeat calibration. And if mean vertex position will reconstruct in different Z than ITS vertex we will need redo calibration and reconstruction.   T

  10. No T0 overlaps in the ideal, residual and fully misaligned geometry • Survey data into alignment object (AliT0Align class)‏ • new version to be committed this week • T0-C – last survey: 05.04.2007, available and tested • problems with “VZERO”-”V0” mismatch on the grid • T0-A – last survey 05.06.2008, but soon invalid • survey must be redone once T0-A mounted back • data available and tested (not yet to be put to OCDB)‏ Alignment

  11. RAW QA During data taking laser calibration with given amplitude will take place in big gaps between bunches to check electronics AliT0QAMakerRec::MakeRAW collects 2 sets of histograms: for event type PHYSICS ( only for monitoring) for event type CALIBRATION (for QA ) expert histograms

  12. QA RecPoints RecPoints QA checks • difference between online (apparatus) and offline mean time after calibration should be stable. • the difference between reconstructed time on the PMT1 and all others on each side : mean should be 0 • for pp runscheck that amplitude measured by 2 methods (QTC and LED-CFD) has the same value

  13. QA ESD ESD QA : T0 writes in ESD • T0 signal (T0A+T0C)/2 • Vertex position (T0A-T0C)/2 AliT0QAChecker looks at RMS of these histograms and alarms if it is more then 3 channels (75 ps)

  14. Reconstruction resultsrun47696

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