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J. Vandenbroucke
N. Bramall, M.D’Agostino, A. Morey, P. Sandstrom, M.Solarz, I.Taboada
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Calibration of the Standard Candle:How Standard Is It?
IceCube Collaboration Meeting, Baton Rouge, April 10, 2006
J. Vandenbroucke Baton Rouge April 10, 2006
Motivation
• An IceCube calibration source whose absolute intensity is known precisely for each pulse
• Extend the flasher energy range to cover IceCube’s high end
• Simulate high energy cascades to test cascade energy and direction reconstruction
• Combine with Golden DOM’s for a complete well-calibrated chain
J. Vandenbroucke Baton Rouge April 10, 2006
Components
Pressure VesselOptics
Laser
Electronics
J. Vandenbroucke Baton Rouge April 10, 2006
Laser
Heating Tape
Nitrogen Laser 337 nm 4 ns pulse 30 Hz internal power meter adjustable filter wheel
J. Vandenbroucke Baton Rouge April 10, 2006
Optics Design
Optics Implementation
Cherenkov-Sculpting ConeCerenkov-Sculpting Cone
J. Vandenbroucke Baton Rouge April 10, 2006
Software
Data Stream:•pulse number•mSec timestamp: pmt•mSec timestamp: laser•internal power•pmt DAQ dark current•pmt DAQ actual current•pmt DAQ temperature
J. Vandenbroucke Baton Rouge April 10, 2006
The First Standard Candle
Deployed on String 40Between 40-22 and 40-23
J. Vandenbroucke Baton Rouge April 10, 2006
The First Standard Candle
Deployed on String 40Between 40-22 and 40-23
J. Vandenbroucke Baton Rouge April 10, 2006
Calibration Specifics: Optics
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ηcone = 8.0 ±1.0%
We can “bypass” the extinctionin the optics by using an absolutecalibration of the PMT and thelaser’s internal power meter
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ηwindow ≈ 8% (prelim.)
Extinction due to cone:
Extinction due to window:
J. Vandenbroucke Baton Rouge April 10, 2006
Calibration Specifics: Obstructions
1) main cable
2) support vanesfor cone
3) steel supportcables
obstructions not aligned sum extinctions
J. Vandenbroucke Baton Rouge April 10, 2006
Calibration Specifics: Obstructions1) main cable
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ηbent = 5.5%
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ηstraight = 5.0%
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∴ηmain cable = 5.25−0.25+0.25%combine two cases
Extinction due to main cable:
J. Vandenbroucke Baton Rouge April 10, 2006
Calibration Specifics: Obstructions2) cone support vanes
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ηvanes = 4.34%Extinction due to vanes:
J. Vandenbroucke Baton Rouge April 10, 2006
Calibration Specifics: Obstructions3) steel support cables
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ηsteel cables = 2.4%Extinction due to steel cables:
J. Vandenbroucke Baton Rouge April 10, 2006
Two independent, calibrated internal energy measurements: PMT & power meter
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ELASER = rEpower meter
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EPMT
• Plot not available (en route from Pole)• PMT calibrated for filter wheel settings 50% and 5% (calibration to +/- 10%)
(1)
(2)
J. Vandenbroucke Baton Rouge April 10, 2006
Calibration Conclusions
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χ =(1−η cone) * (1−η window ) * (1−η vanes −ηmain cable −η steel cables)
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E = χEPMT
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E = χELASERand
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χ =0.74−.01+.06
E@50% ≈1.67−.03+.11 μJ
NMIN ≈ 4.75−.03+.40 *1010
NMAX ≈ 5.26−.15+.36 *1012
Preliminary Calibration:
Total extinction:
Per-pulse Energy:
For details, see Standard Candle Calibration and other SC documents:http://docushare.icecube.wisc.edu/docushare/dsweb/View/Collection-1152
The Future: Burning Brightly
More to come from the Standard Candleshop• Next year: point down (between DOM’s 12 and 13), 20x brighter
• Later: point sideways (with cone removed?)