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!