TPC status - Offline Q&A Marain Ivanov

Geometry are any changes in the geometry and material descriptions expected/foreseen? No Non orthogonal transformation as a small correction is the current situation satisfactory? Yes full/survey misalignment: is it possible to introduce full or survey misalignment without creating overlaps? I am no aware

Material budget * is the current step size good for the calculation of material budget and for energy loss correction? TPC step size – distance between pad-rows (0.75,1 and 1.5 cm) – Geo manager not used (homogeneous material)‏ The dEdx correction formula to be repeated with the MC information (Propagation for outer to inner track reference) Last time few years ago Test class (derived from the AliAnalysisTask) to be created (for all detectors) – currently just macros

Simulation (0)‏ Time information in simulation (needed for pileup sim and more realistic detector response - this item is new, we never asked them before!)‏ Is step manager correctly storing the time of the hits - Yes Does the digitization take into account the time of the hits - Yes Does the digitization simulates correctly the time response of the readout (binning, time windows etc.)‏ Yes

Missing - Simulation – Time (1)‏ LHC clock phase (offset)‏ Event by event – to be stored in raw data For merging to be read from background event - (to be used in Sdigitization)‏ For calibration – preferred to store it in the ESD Only way how to access it in Analysis framework Trigger time offset Experience from the the cosmic 2008 data – all trigger had different time offsets We calibrate it (TPC) but we do not know where to store it

Missing - Simulation – Time (2)‏ Some critical variables – V drift, gain depends on time with granularity smaller than Run Event time stamp to be simulated Drift velocity and gain corresponding to given time stamp to be used. For merging the same time stamp to be used

Offline Is the memory and CPU consumption under control at each simulation step: hits, sdigits, digits? Yes Labels: are the labels from the kinematics tree correctly propagated to hits, sdigits, digits? Track references: are the track references needed and if yes, are they correctly implemented in the step manager? Yes – We need more- Currently only at entrance of sector Event merging: is the event merging correctly working for the detector? Yes. Not tested currently. Embedding: is the track embedding foreseen in your detector? If yes, is it working correctly? Yes. Not tested currently

Raw data Is the raw data format already fixed, or additional changes are needed? Altro trailer - not in the simulation Critical - Altro – LHC phase

OCDB Are the gains stored in OCDB correctly used both in the simulation and reconstruction Yes New data member to be added Gas gain normalization factor for 3 pad types Transformation – MC to real data LHC machine parameters to go to GRP Critical – Temperature, pressure – to be used for all TPC run types

Reconstruction Are all the necessary reco params in OCDB (including params for cosmic reco) + Are reco params fully used in the reco Yes Shift in the reconstructed Pt: is the problem understood and is the current situation satisfactory? Current pt shift ~ 0.2-0.3% Doubly found tracks: is the reported increase confirmed and is the origin understood? My standard test did not indicate the increase Is the propagation status correctly taken into account? If the propagation fails, are the track parameters left unchanged? To be done verified on level of AliExternalTrackParam Propagate and also CorrectForMaterial Is the time information taken into account (needed for pileup)‏

PID Eta dependency of PID efficiency: is it understood? TPC dEdx part - Yes. The z,phi, theta calibration not yet used in the official ESD. PID part – dEdx (function of p) crossing point – fixing pt, theta defines the holes in the PID efficiency PID efficiency at the relativistic rise: is the comparison data vs MC OK? Is the results understood Study not yet finished