Ice Cube Ice Top Serap Tilav Bartol Research

Ice. Cube / Ice. Top Serap Tilav Bartol Research Institute University of Delaware Aspen Cosmic Ray Workshop April 25 -30 2005

Ice. Cube Project Ice. Cube/Ice. Top AMANDA SPASE Ice. Cube Array Ice. Top Array The South Pole @ South Pole

Ice. Top • 1 km 2 Air Shower Array • 1 station on top of each Ice. Cube string • 2 ice tanks per station • 2 PMTs in each tank • Ice. Top will detect Air Showers of energies 3 x 1014 e. V to ~1018 e. V Ice. Cube • • 1400 m 1 km 3 High Energy Neutrino Telescope 4800 PMTs 80 Strings Ice. Cube is designed to detect neutrinos of all flavors at energies from 107 e. V to 1020 e. V 2400 m

Ice. Cube String Locations ~ 125 m apart

Ice. Top: The surface array of Ice. Cube Surface array is unique opportunity for n-telescope in deep ice • Calibration – Absolute Pointing – Angular resolution • Veto -Tagging background for study and rejection A 3 D air shower array for cosmic-ray physics Demonstrated by SPASE/AMANDA But, 5000 x larger acceptance wider energy range, better resolution

Ice. Top Design Ice Cherenkov Tank 0. 9 m clear ice Diffusely reflecting liner 2 m

Ice. Top Design • Single particles (low-energy e±, m, g for tank calibration) – Remnants of low energy interactions – ~ 2. 5 k. Hz for 30 Me. V threshold (10 pe) – Muons deposit 200 -300 Me. V (70 pe) • Small showers (few Te. V for tagging single m in deep-ice) – Typical source of m background in deep detector (Em ~ 0. 5 Te. V initially) – 10 -20 m footprint on ground • • Coincidence between two tanks at a station No signal in neighboring stations No Ice. Top trigger Check each in-ice event for such surface activity • Large showers (E > 300 Te. V for air showers and muon bundles in deep-ice) – Ice. Top trigger: 4 stations hit in ~300 ns window

Ice. Top Design Ice. Top Station • • • 2 Ice Tanks 10 m apart Local coincidence between 2 tanks 1 Low Gain, 1 High Gain PMT in each tank for dynamic range Ice. Cube Drill Hole 25 m Two DOMs : 10” PMT One high -gain; one low -gain in each tank Junction box LG HG HG 10 m LG

The Digital Optical Module (DOM) • 10” PMT in 13” Glass sphere • Mother Board: Ø 2 ASIC (ATWD) chips to digitize PMT signals in 3. 3 ns samples Ø FPGA for feature recognition Ø CPUs, disks for communication, calibration, buffering data • Incredible dynamic range: 1 pe to 25000 pe • Low photon counting background: in-ice rates of order 700 Hz • Complete, self-contained, reconfigurable digital data acquisition system • High-precision timing over vast network of 1000’s of sensors to nanosecond scale.

04/05 deployment season 4 Ice. Top Stations deployed in December 2004 1 st Ice. Cube string deployed on Jan 29 2005

1 st Ice. Cube String 60 DOMs 17 m apart

Ice. Cube string anchored between Ice. Top tanks

2 DOMs frozen in Ice. Top Tank Freeze control unit under ~75 cm clear ice

DOM clock stability (Ice. Top) Timing: Clock calibration: of order 2 ns rms

Ice. Top DOM Gain Calibration 1 x 107 gain, low threshold 5 x 106 gain, high threshold Single PE Single Muon ATWD Channel 0 Single Muon ATWD Channel 1 ATWD Channel 2

plane wave shower reconstruction

Run 463 Event 1694

Run 872 Event 5945

Ice. Top – In-Ice coincident events

Sample Event Waveforms High gain DOMs Y axis 0. 05 Volts per grid Low gain DOMs X axis 20 ns per grid

Sample Event Waveforms

Sample Event Waveforms

Ice. Top Timeline Austral Season # of stations 04/05 05/06 4 12 06/07 16 07/08 08/09 18 18 09/10 12 Successful engineering year All 76 (60 Ice. Cube + 16 Ice. Top) DOMs are working Excellent timing precision is achieved Detailed waveforms bring extra dimension to analysis