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IceCube Dust Loggers. Kurt Woschnagg, Ryan Bay Physics Department, UC Berkeley Instrumentation Session IceCube Collaboration Meeting Bartol, March 2004. Borehole Dust-Logger. First-generation logger (mechanically drilled hole). Field Tested Pole-to-Pole. A dust logger in Greenland.
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IceCube Dust Loggers Kurt Woschnagg, Ryan Bay Physics Department, UC Berkeley Instrumentation Session IceCube Collaboration Meeting Bartol, March 2004
Borehole Dust-Logger First-generation logger (mechanically drilled hole)
Field Tested Pole-to-Pole A dust logger in Greenland A dust logger in Antarctica
Record of Northern climate variations at GISP2(Greenland Ice Sheet Project, 3054 meters) Dust logger data Dust in ice core Temperature record from ice core
Motivations for an optical dust logger in IceCube • Constrain horizontal variations • Improve depth resolution of ice model • Currently ~10 m using in situ OMs • Volcanic ash? • Bonus science (à la RICE, acoustic detectors, etc.) A hole in the ice is a valuable commodity fast crucial calibs hi-res
Dust layers dominate ice properties AMANDA: Variations in optical properties correlate with… …dust in ice cores.
Siple Dome, West AntarcticaOver 60 volcanic ash layers detected
Volcanic ash at South Pole • ~500 miles from SDM; altitude 3× as high • Known to exist Palais, J. M. et al., GRL (1992) Cole-Dai, J. et al., Ann. Glaciol. (1999)
Ash bands can improve simulations Thin, extremely absorbing ash bands introduced “Standard” ice description Zcog = depth (z) of center-of-gravity for reconstructed muon tracks Analysis by Marek Kowalski
Technicals • Continuous laser, signal integration: 10 ms – 1 s • Sampling rate: ~50 Hz • Located at bottom of string, between weights (TBD) • Centered in hole, unobstructed view • 4 service-wire pairs from lowest breakout (@DOM59) • Connectors TBD • Readout during deployment (only) → slipring connection • Stand-alone DAQ or Integrated into deployment/drill
Issues • Irregular walls will degrade data quality • Dust log requires real-time depth readout → Pick-off deployment pressure • Must not jeopardize deployment • Time limit • No retrieval once drop (lowering!) begins • Slower rate (factor 2) through instrumented ice? Normal drop speed (15m/min): ~1 hour
Plan for IceCube dust loggers • Total of 9 loggers - one in each of the six corners - three inside array (one of these at AMANDA center for cross- calibration with AMANDA dust profile) • First dust logger in first season (04/05, PY03) • Then two per season • Built & operated by UCB (at least first few)
Conclusion • Dust loggers are crucial calibration devices • Need to get one in early • Have experience, will travel