TOF offline and calibration A. De Caro (University and INFN of Salerno)
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Transcript of TOF offline and calibration A. De Caro (University and INFN of Salerno)
TOF offline and calibration
A. De Caro (University and INFN of Salerno)
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.
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 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.
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 3
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 ~1.6s (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.
CERN Building 29, March 24th 2010
A. De Caro 4 ALICE TOF General meeting
Offset in TOF time measurements
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 5
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.
CERN Building 29, March 24th 2010
ALICE TOF General meeting
6
Correction of TOF measurementsat reconstruction level Till the second-last reconstruction step
tTOFESD = tTOF
raw+
- tonlineCalibration +
+ BCTDC
where: tTOF
ESD, 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);
BCTDC, TDC bunch crossing ID (available in TOF raw data).
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 7
Correction of TOF measurementsat reconstruction level (cont.)
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 8
Correction of TOF measurementsat reconstruction level (cont.)
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 9
Correction of TOF measurementsat reconstruction level (cont.)
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 10
TOF channel hardware status
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 11
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.
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 12
TOF channel offline hardware statusKnown 2009 December TOF hardware configuration
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 13
~10% not active TOF channels
Thanks to Gilda, Silvia and Francesca
See A.Alici’s talk for current TOF configuration.
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).
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 14
Information not available at offline level during 2009 December runs
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 15
€
εmatching =NTOF
N reco
€
NTOF = TOF matched tracks(*)
N reco = reconstructed tracks(*) in |η |< 0.9(*)Track selection : standard cuts
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 16
~10% not active TOF channels
Real data: run 104852MC data: LHC09d9
ADC @ 2009 December PWG1 meeting
€
εmatching =NTOF
N reco
€
NTOF = TOF matched tracks(*)
N reco = reconstructed tracks(*) in |η |< 0.9(*)Track selection : standard cuts
CERN Building 29, March 24th 2010
ALICE TOF General meeting
A. De Caro 17
~10% not active TOF channels
Real data: run 104852MC data: LHC09d9
ADC @ 2009 December PWG1 meeting
R.Preghenella study
Tuned MC means that we removed the noisy or not active TOF channels (with HV or LV or RO problems) at analysis level.
€
εmatching =NTOF
N reco
€
NTOF = TOF matched tracks(*)
N reco = reconstructed tracks(*) in |η |< 0.9(*)Track selection : standard cuts
Thanks for your attention