SSD Status

1. SSD Status P. Christakoglou (NIKHEF-UU) for the SSD collaboration Thanks to: Marco vL, Enrico, Mino, Marek and Massimo

2. Status of the DA • Pedestal DA is in AliRoot since last November • Main program ITSSSDpedDa.cxx and three support classes: AliITSHandleSSD, AliITSModuleSSD and AliITSChannelSSD • Sasha Borysov was the main developer but now he moved back to Ukraine • We will identify the person to take over in the upcoming SSD meeting • The latest version was installed around mid-July and since then no upgrades were performed • This latest version uses the new calibration object scheme (see next slides) There is an ongoing discussion among the SSD collaborators about the necessity to have an additional DA that will run during the physics runs and will monitor the noisy-dead strips and update the bad channel list accordingly at the EOR. Sasha Borysov

3. Status of the calibration objects • We were asked to move to a new format of the calibration objects: • 1698 objects replaced by one single object • During this transition, backward compatibility was lost • This was fixed around mid-July by providing a new set of classes and an interface to convert the old calibration objects to the new ones (AliITSNoiseSSD  AliITSNoiseSSDv2) • Noise: • $ALICE_ROOT/ITS/Calib/NoiseSSD • alien:///alice/…/OCDB/ITS/Calib/NoiseSSD • Updated after every “PEDESTAL_RUN” • Bad channels: • $ALICE_ROOT/ITS/Calib/BadChannelsSSD • alien:///alice/…/OCDB/ITS/Calib/BadChannelsSSD • Updated after every “PEDESTAL_RUN” • Gain: • $ALICE_ROOT/ITS/Calib/GainSSD • alien:///alice/…/OCDB/ITS/Calib/GainSSD • Static map – Updated manually • Pedestal • $ALICE_ROOT/ITS/Ref/PedestalSSD • alien:///alice/…/Reference/ITS/Ref/PedestalSSD • Updated after every “PEDESTAL_RUN”

4. Status of the preprocessor • The last time the preprocessor was changed was also around mid-July in order to adopt the new calibration format. • Since then it is running stably without any problems.

5. Calibration strategy • Take advantage of the high statistics of cosmic data to start looking at the gain calibration for smaller segmentations: • Currently we apply different gain factors for P and N-side • Difference per DDL, per side, per layer, per ladder? • Starting to look offline on the energy loss coming from the two SSD layers (Marek Chojnacki) • For the two tasks above we need to access the ITS.RecPoints.root, the AliESDs.root and the AliESDfriend.root files offline. • If needed, only the gain calibration file will be modified. • Offline analysis of standalone noise runs to refine the bad channel list (Massimo Venaruzzo) • Include the treatment of strips with non-Gaussian noise

6. Status of survey and alignment • 2 types of measurement: • Modules on ladder • Ladder endpoint on cones Measurement tip AliITSSurveyToAlignSSD AliAlignObjParams: 1 per module 1 per ladder • The official offline approach was followed: • The survey report was put in EDMS and then in the DCDB • A class was committed in aliroot to convert the survey points into AliAlignObjParams • Merging with the SDD is an ongoing activity • We expect shifts up to 200 μm in R and z and rotations of up to 1 mrad in φ. Marco van Leeuwen

7. Status of the QA (I) • Online QA: • We used both MOOD and AMORE • MOOD is considered to be the SSD’s expert’s tool • AMORE is used by the standard shifter • We monitor the raw data but there is an ongoing discussion to include also the rec. points based on the implementation of the SDD colleagues (P. Cerello). • We defined ~1.5 K histograms which are structured in a hierarchical way. • For the offline shifter, we put the flag to the 4 most representing objects • Average data size per DDL and per LDC • Average module occupancy for layer 5 and 6 • We also monitor the calibration objects put in the OCDB (AliEn) Is it foreseen to publish somewhere the results of the prompt offline QA? It would be nice to have them available either in the e-logbook or somewhere else.

8. READY IN PROGRESS NOT STARTED Status of the QA (II) • Offline QA • Work in progress on the definition of the quality checks since we start to understand the behavior of the detector. • Checks based not on reference data but on on-the-fly calculations/fits

9. Status of the cluster finder • Ongoing activities • Raw & digits reconstruction: Uniform treatment of 1D-clusters reconstruction from raw data and from digits. • 5 seed: CF reconstructs clusters summing only adjacent signals above 3 noise sigma, with at least one strip above 5 (the 5 seed was requested only for single strip clusters before, noise correlation between neighboring strips was not considered). • CM pseudochannels: additional channels used to store common mode noise values are now considered by the CF. Results from the last cosmic runs • Still to come • Bad channels: Include the bad channels in the reconstruction (excluded for the time being). • New rec. points classification: geometrical matching between P and N-side, charge matching (based on the experience from cosmic data. • Benchmarking and fine tuning of the code Enrico Fragiacomo and Mino Contin

10. BACKUP

11. Definition of bad channels • Noisy strips • Noise after CM correction > 20 ADC • Dead strips • Noise before CM correction < 1 ADC • Pedestal out of range • |Pedestal value| > 512 ADC