1. HLT & Calibration

2. HLT as Calibration Data Source
Among the main tasks of HLT (especially in the first years)
Monitoring of the detector performance
Analysing calibration data (real events and calibration triggers)
Calculation of a (first) set of calibration parameters
Applying calibration to online event reconstruction
Storing parameters in relevant databases
Procedures are being developed in collaboration with TPC, TRD, PHOS, and Dimuon detector
HLT is open for calibration tasks for all participating detectors
Compatibility w. Computing Power / Financial Budget

3. HLT & Databases
The HLT will have contact to different databases, which are for different purposes as well as under different administration.
For now, it is foreseen to have contact to three different DBs:
Configuration DB (DCS)
Condition DB (DCS)
Calibration DB (Detector Specific)

4. HLT DB Remarks Use of dedicated HLT portal nodes to contact DBs
Redundancy of these nodes to avoid single-point-of-failures
Data of the DBs is cached (where possible) and distributed to the appropriate places inside the HLT cluster (using its publisher- subscriber framework)
Output data to DBs will be written from the global layer of the HLT cluster.
Contact to the databases will be performed via ODBC or similar techniques.

5. TPC Calibration Example (1)
Pedestal run analysis and download
Pulser runs
Accumulation of pulser events
Gain calibration and timing alignment
Map hot/dead pads
Laser runs
Online reconstruction of laser tracks
Drift velocity map
ExB map
static E-field distortion map
Electron attachment / gas contamination
Online reconstruction of particle tracks / laser tracks
Cluster charge loss per drift length

6. TPC Calibration Example (2)
Drift velocity map
Nuclear collisions
Accumulate charge per timebin
Calculate charge step at central electrode
E.g. NA49 data
NA49
charge step

7. TPC Calibration Example (3)
Space charge effects
Online reconstruction of tracks
Histogram of track impact parameters
E.g. STAR TPC – fluctuations on second timescale

8. TPC Calibration Example (4)
Histogram of track residuals
E.g. STAR TPC – grid leak distortions
Ion leakage at gating grid gap

9. PHOS Calibration Example
Pedestal run analysis and download
LED runs
Accumulation of pulser events
Gain calibration and timing alignment
Map hot/dead channels
Gain/energy calibration
Nuclear collisions
Online pulse shape analysis
Timing alignment (using fastest particles)
Online reconstruction and accumulating of showers
Relative gain calibration by equalizing channels
Absolute energy calibration by monitoring pi0-peak

10. HLT Questions/Open Points
To plan connections from HLT to DBs, HLT needs to know:
At which places (processing steps) in the HLT cluster is DB data needed?
What is the estimated processing budget for online calibration?
What data for or/and from which databases?
Which detector needs what data?
How large is which data?
(different for different data -> detailed list wanted)
How often is data updated? (once (caching)  regular requests to DB)
Output data
General
e.g. Drift Velocity:
Type of measurement (once, continuous spectrum, every X sec., average, ...)
Write to DB (continously, at end of run, ...)
Who has access to data (online, offline)?