Calibration team plans: T0a measurements at Pole

1
Calibration team plans T0/a measurements at Pole

• Plans for the next polar seasons

Elisa Bernardini AMANDA/IceCube Meeting Uppsala
October 2004
2
What is meant with laser calibration

• Surface YAG laser used to generate photons pulses
  at each OM and measure the delay due to the
  (output signal) cable transit time and the
  front-end electronics response and the slewing
  corrections.

• From measured hit
• times (wrt a reference
• channels) and hit
• amplitues we get a
• measurement of T0 and
• a for each OM.

3
what is meant with laser calibration

• Estimate of the 1pe peak position done off-line,
  from fits to the ADC spectra obtained from
  down-going muon data (amplitude-calibration,
  for the delayed-channels)
• were done by the laser-calibration teams data
  processing/filtering teams M.Walter
• will be repeated this year
• Laser data not appropriate for amplitude
  calibration
• how many photons injected?
• promt-channels enter the TWR-DAQ
• estimate of the 1pe peak were done by the TWR
  teams
• will be repeated this year
• X-talk maps and X-talk filter constants are
  extracted from fits to the laser calibration data
  collected for T0 and a measurements
• data was taken by the laser-calibration teams
  analysis by I.Taboada
• ? data will be taken this year analysis ?

4
Desired/required for the laser-calibration

• Before starting data taking
• The detector should be in its final state (HV,
  thresholds, front-end electronics modules,
  amplifiers gains )
• SWAMPs replacement, channel debugging,
  HV/amplifier gains/thresholds settings should
  occur prior to starting of laser measurements
• Data from down-going muons should be available in
  such a configuration (for cross-checks, an
  estimate of the new 1pe-peak values is also
  needed for analysis of laser data)
• A few hours of stable data taking needed and
  spectra to be analyzed
• Reference channel for TWR DAQ needs to be set
• Scripts from TWR team to check status of TWR data
  taking (e.g. ADC and TDC histograms of selected
  channel and reference channel) would be helpful

5
Time schedule and manpower

• SWAMP/VLF team 76 man-day
• Calibration team 116
• E.Bernardini, T.Castermans, S.Schlenstedt,
  M.Walter
• TWR team 182

• Overlap 1 and 2 2 persons for each team for 12
  days
• help fixing all gains
• check ADC spectra with down-going muon data
• start T0 calibration as soon as possible, on
  those channels already fixed
• Overlap 2 and 3 2 persons (cal.) and 1 person
  (TWR) for 9 days
• further gain adjustments?
• complete T0 calibration and calibrate eventual
  additional problematic channels with changed
  gains
• to pass knowledge to TWR team on data taking for
  calibration

6
Time constraints for laser calibration

• Minimum time needed for data-taking
• 30 min/OM
• for about 600 OMs makes 300 hours
• with two-teams (2 people) this requires 15
  days, at regime (team complete, 20 hours/day,
  detector stable)
• calibration team (4 people) is complete for 2
  weeks!
• room for further-adjustments available only in
  collaboration with the SWAMP and TWR teams
• Define now, which are the requirements for the
  gain adjustments and share the task between the
  three teams

This is the real minimum to allow in parallel
analysis of data to have immediate feed-back of
data quality and check which/if OMs should be
re-measured!!
7
Plan for calibration data taking at Pole

• Gain adjustments currently planned for strings
  5-10, 14-16,19
• all affected channels need T0/a calibration
• SWAMPs will be replaced on strings 1-10
• all affected channels on strings 1-4 need T0/a
  calibration (no major effect expected )
• Measurement of the reference channels on the
  other strings (10 OMs)
• cfr. http//www-zeuthen.desy.de/7Ebernardi/T0cal/
  Laser-T0-2003-2004.html
• and summary on calibration results _at_ Bartol
  Meeting 2004
• Data will be taken in a way to allow update of
  the X-talk filter constants (use multi-mode
  fibers/get high-amplitude hits when possible)

8
Following the measurements

• Preliminary calibration constants for the
  muon-DAQ will be immediately available (analysis
  done at Pole)
• Muon calibration done _at_ Penn State
• Comparison with laser data will be done
  immediately after (M.Walter?)
• TWR time-calibration analysis will be done by TWR
  team
• Future of the laser calibration?