1. pinger project 2008/09 Delia Tosi IceCube – Acoustic Neutrino Detection working group September 16 th, 2008 IceCube Collaboration Meeting Utrecht, Netherlands

2. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 2/9 Summary on pinger season 2007-08 + short distance: attenuation length still poorly constrained due to systematic effects  Different analysis done lead to 80 m < λ limit < ∞ Systematic effect Effect on λ estimate 1.Interference with reflections from hole back wallvarying 2.Strong polar / azimuthal sensitivity dependencedecreases 3.Shear wavesdecreases 4.Clock drift of ADC sample clocksneutral 5.Saturation, i.e. limited dynamic rangeincreases 6.Ice quality: possible hole ice inhomogeneities & cracks may affect pinger transmittivity and/or sensor sensitivity varying 7.Noise: if not subtractedincreases 8.Transmission coefficient (combination of position of pinger in hole, polar angle etc.) decreases

3. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 3/9 Improvements (1): larger distances Season 2008/2009: IceCube holes drilled at further distances from SPATS array  chance to constrain the attenuation length even with large error bars 4 strings optimized data taking underway  more sensors, higher statistic an illustration (not real data!)

4. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 4/9 Improvements (2): mechanical stabilization New mechanical stabilization system: Double system of stabilizers to center the pinger stage in the center of hole and minimize swinging back and forth Stiff tube holding the neck of the ITC 1001 to avoid pendulum oscillations of the piezo  will diminish the waveform instability due to interferences with the reflection from the back wall of the hole HV pulser ITC-1001 800 us s dt s rt s dt s rt

5. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 5/9 Improvements (3): higher repetition rate Higher repetition rate (was 1 Hz!): Pinging will be synchronized with the PPS signal from the GPS, but a new on-ice electronic module will be introduced to increase the repetition rate up to 100 Hz Two options under construction: FPGA or CMOS based Recording time fixed due to bandwidth limitation string PC master PC Higher number of ‘events’ for averaging  S/N will increase ~ sqrt(repRate) Under discussion: new data taking scheme with simultaneous multiple channels in triggered-mode

6. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 6/9 Adjustments (1): new piezoceramic ITC1001 Same type of last year but brand new: Tests will be done to see consistencies of the acoustic pulse emitted between the two Study of the differences on paper from calibrations done by company as far as: - directivity pattern - transmit voltage response Next: experimental comparison

7. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 7/9 Adjustments (2): can we hear the pinger at long distance? HV pulse height determined on the HV board inside the module by a jumper which fixes the steering voltage. From last year data the signal at the distances foreseen in the next season should fit in the range of our sensors after average  The steering voltage is foreseen to stay the same Adjustable eventually once the performances of the new ITC are verified Toy model! Noise level with no average Noise level with average Saturation level

8. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 8/9 pinger season 2008-2009 D A B C 3 holes: n° 37: 20 Dec 2008 n° 19: 26 Dec 2008 n° 5: 18 Jan 2009 Distances: From 125 m..  compare with last year data.. to ~ 1 km  all-holes, one sensor analysis possible for every sensor

9. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 9/9 Deployment activity Lot of experience acquired from pinger campaign last year Operational success thanks to IceCube support and help Equipment: ~ 40 kg weight, all in one box Time required: 1.5 hours in between drilling end / IceCube string deployment Personnel involved: holes 37 & 19: Freija + little help from 3 IceCube people hole 5: someone from Berkeley + 3 IceCube people

10. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 10/9 Back Up

11. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 11/9 pinger season 2008-2009 3 holes: n° 37: 20 Dec 2008 n° 19: 26 Dec 2008 n° 5: 18 Jan 2009 Distances: from 125 m to 1 km

12. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 12/9 Clock frequency multiplier (1) L. Gustafsson 1 PPS converter voltage to current RW cable

13. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 13/9 Clock frequency multiplier (2) Sulanke & Tosi 1 PPS converter voltage to current RW cable

14. Delia Tosi Utrecht – Sept. 16, 2008IceCube Coll. Meeting 14/9 Clock frequency multiplier (0) 1 PPS converter voltage to current RW cable Clock frequency multiplier