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 AntarcticaA dust logger in Greenland

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 hi-res crucial calibs

Dust layers dominate ice properties …dust in ice cores. …dust in ice cores. AMANDA: Variations in optical properties correlate with… AMANDA: Variations in optical properties correlate with…

Km-scale horizontal variations?

Siple Dome, West Antarctica Over 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 Analysis by Marek Kowalski Z cog = depth (z) of center-of-gravity for reconstructed muon tracks

Simulation of volcanic ash layers in bubbly ice MC Data

Strawman IceCube dust logger design

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 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

Simulation of volcanic ash layers in bubbly ice MC Data