1. Calibrating ALICE

2. Basics All ALICE detectors need calibration
Calibration parameters must be available on the flight for the first pass reconstruction following shortly data taking
Calibration parameters can be fine tuned offline for the second pass reconstruction
Calibration parameters, which are dependent on statistics can be improved continuously
Responsibilities
The calibration strategy and algorithms are under responsibility of the detector experts
The calibration framework is the responsibility of DAQ, HLT and Offline groups
The coordination is the responsibility of the Commissioning Task Force

3. Status 1
All detectors have a well defined calibration strategy; they know how :
to convert raw data into calibrated data
to reconstruct with dead/noisy channels
to calculate the calibration parameters and collect dead/nosy channels
the size of the raw and final calibration data sets
the running condition to acquire calibration data
to store and access offline the calibration parameters
Most of the detectors have implemented 1. and 6. in the offline framework
It is presently used in the simulation and reconstruction of the PDC

4. Status 2 The Offline framework is operational (see FCA at Bologna):
It provides access to calibration parameters: OCDB
It provides the mechanism to collect the calibration parameters and to store them into OCDB (Shuttle)
Attention: OCDB contains pointer to the data (root files), the files are stored on the GRID

5. Status 3 http://cern.ch/alice-daq/DA-framework/
The DAQ Online framework is ready, it provides:
the rules to process calibration data: LDC, GDC, monitoring cluster
tools to store result files from 1. in the DAQ File Exchange Server
tools to read/write detector-specific config files in the DAQ db
example code for both use-cases (LDC/GDC files & monitoring), including a small "support" library to package the algorithm (rpm)
documentation
Guinea pigs: SPD and TOF
Reference document at

6. Status 4
User requirements & progress monitoring have been collected from all detectors :
Calibration and reference data format and size in OCDB
Source of data: physics run, calibration run, DAQ, HLT, DCS monitored parameters
Running conditions: update frequency, run/trigger type, statistics
Online -> Offline
Accessibility, implementation of algorithms

7. Parameters from MCS available in DCS archive + B field data
Name
Description
Type
Solenoid
Emergency Shutdown
Fast Dump or Slow Dump
Boolean
Steady State
Current Setting = Current Read
Ramping
Ramping up and down
Polarity
Positive = TRUE, Negative = FALSE
Current
[A]
Analog
Set Current
Temperature IN
Temperature of water in [C]
Temperature OUT
Temperature of water out [C]
Dipole

8. ! Facts Calibration data size OCDB query during reconstruction
Per data set (update every run, 400 runs/year) for all ALICE
In OCDB (final calibration data): > 228 GB – very high
Raw calibration data > 6610 GB
Anticipated in the Computing Model: GB/year
We might need to review the UR
OCDB query during reconstruction
1 Hz catalogue access frequency (the catalogue is centrally located at CERN)
The calibration files will are replicated at several locations around the world !

9. To do list Detectors SHUTTLE File Exchange Server
Complete and revise the requirement document
Data size in FES, OCDB and reference
Implement the online algorithms (not yet started, except SPD and T0-TOF combined time zero calibration)
SHUTTLE
Framework (Offline) done
Pre-processor: detector calibration algorithms and ROOTification (detectors) not started
File Exchange Server
File system definition (DAQ done, DCS & HLT started)
Online framework (DAQ in progress, DCS & HLT started)
Parameters evaluation (detectors) not started
HLT access to condition parameters
Discussion started

10. Milestones Monitor progress of detector readiness in Summer 2007
Raw data format (Cvetan)
Calibration issues (Alberto)
Alignment issues (Raffaele)