status of 1.5.3 detector characterization a.k.a. calibration & monitoring
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Status of
1.5.3 Detector Characterization
a.k.a. Calibration & Monitoring
• Project Year 2 objectives (→ Mar ‘04)1. Calibration plan (first draft in March ‘03 – still circulating…)2. Define contents of calibration DB3. Define algorithms4. Monitoring interface for TestDAQ5. Monitoring plan (new L4 for monitoring: Rodin Porrata)
• Manpower1 FTE (UCB) + 0.5 FTE (UW) + 0.2 FTE (UD) + δ
Kurt Woschnagg, UC Berkeley
Calibration Tasks
Low-level calibrations:• Timing 7 ns• Geometry 1 m• Charge, OM gain (lab, ice)• Angular OM acceptance (lab)• Optical ice properties
High-level calibrations:• Energy (cascades)• Vertex resolution• Pointing accuracy and angular resolution
DOM lab calibrations not included here
Timing calibrationAutomatic, part of normal DAQ ops
1. Every waveform time-stamped (coarse, fine) locally in DOM
2. Clock calibration (RAPcal) to relate local times to global (master) time
3. PMT transit time measurement (in lab, in-situ with onboard LED)
Testing (post-deployment):- with flasher data- with muons (req. reconstruction)
Development and testing underway @LBL
Calibration devices
• Standard candles (lasers) vertex, energy• Flasher boards geometry, timing, vertex,
energy, ice• Dust loggers ice properties• On-board LEDs charge, timing (transit time)
• Pressure sensors geometry, deployment
• Payout, drill, GPS geometry• Acoustic televiewer drilling
So far: physics requirements, cable issues
Geometry calibration in 3 stages
►Stage 1 (~days)Combine deployment data: surface survey, drill log, pressure data, payout etc. One shot!
►Stage 2 (~weeks→days?)Interstring calibration with flasher dataRequires: timing calib.
►Stage 3 (~months→weeks→days?)Muon surveyRequires: timing calib., reconstruction
Geometry calibration – Stage 1
Initial geometry from deployment data:
• GPS survey of surface locations
• Pressure sensors• Drill log• Well depth• Cable payout
+ Hole diameter from acoustic televiewer
→ Absolute OM positions within ~1 m
Time scale: days → day?
Geometry calibration – Stage 2
→ Relative string positions within ~0.5 m Time scale: weeks → days?
Global interstring fit to flasher timing data
Does it work in IceCube?
Measuring ice flow with cosmic-ray muons
Rigid down to 2000 m
Stuck atbedrock
Lagging
1. Reconstruct downgoing muon tracks2. Find location for each OM that minimizes
its contribution to the reconstruction likelihood
Geometry calibration – Stage 3
Survey with downgoing muons
→ OM positions within ~0.3 m
Time scale: month(s) → weeks → days?
Test: finds artificial shifts
Development and testing on AMANDAdata underway @ UCB (Jeff Allen, Dima)
Optical properties of ice
So what is left to do…
From in-situ light sources in AMANDA we get (after some analysis):
Optical properties in IceCube
1. Are the dust bands horizontal over km-scale?
2. What happens below 2100 m?
3. Can we measure hole ice prop.?
Calibration hardware
Flasher boards• Requirements document (ERD) finalized
• Each board has 12 LEDs (405 nm)6 horizontal for geometry6 at ~45° for cascade simulationAll 12 can be fired independentlyAdjustable light output
• Cascade energies up to 10 TeV (at least)
Calibration hardware
Dust loggers
Conceptual design stage,but:• Experience at UCB• Proven method
Optimal placement: in IceCube corners andat AMANDA center
Deploy first season?
Record of Northern climate variations at GISP2(Greenland Ice Sheet Project, 3054 meters)
Dust in ice core
Temperature record from ice core
Dust logger data
A dust logger in actionRyan Bay,
UCB
DOM gain (charge) calibrationRelate measured charge to number of photoelectrons
• In lab (pre-deployment): measured for all DOMs → database- SPE peak- linearity- dynamic range- saturation- dependence on HV, temperature
• In situ (post-deployment): on-board LED, min-bias muon data- SPE peak- linearity? saturation?
Calibration hardware
On-board LEDsHardware:
Separate UV LED on DOM main board
Purpose:Charge calibration: SPE peakTiming calibration: PMT transit time
Work in progress (@LBL):Light outputPulse widthOptical couplingPlacement
Cascade energy calibration
~105 photons/GeV
In-situ light sources:
1. Flashers; up to 10 TeV2. Lasers; 1 TeV and up
Standard candles: absolute calibration in labRealistic cascade simulation (light distribution, timing)
• Overlay events to reach higher energies- saturation (database with lab measurements)- software
Getting ready for the first strings
The first IceCube string is deployed in Dec ’04…then what?
Mainly calibrations in ’05
• Timing calibration• Reconstruction• Deployment daqAMANDA/IceCube cross calibrations:
- Common reconstruction- Coordinate system
Dependencies by WBS element
• Reconstruction• Deployment• DAQ• AMANDA-IceCube integration• Software• Simulation• In-ice devices (in-situ light sources)
• Monitoring, database, …
help!
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