pinger project pinger project 2008/09 2008/09

pinger project pinger project 2008/09 2008/09

Delia Tosi Delia Tosi

IceCube – Acoustic Neutrino Detection working groupIceCube – Acoustic Neutrino Detection working group

September 16September 16thth, 2008, 2008

IceCube Collaboration MeetingIceCube Collaboration Meeting

Utrecht, NetherlandsUtrecht, Netherlands

Delia Tosi Utrecht – Sept. 16, 2008 IceCube 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 < λlimit < ∞

Systematic effect Effect on λ estimate

1. Interference with reflections from hole back wall varying

2. Strong polar / azimuthal sensitivity dependence decreases

3. Shear waves decreases

4. Clock drift of ADC sample clocks neutral

5. Saturation, i.e. limited dynamic range increases

6. Ice quality: possible hole ice inhomogeneities & cracks may affect pinger transmittivity and/or sensor sensitivity

varying

7. Noise: if not subtracted increases

8. Transmission coefficient (combination of position of pinger in hole, polar angle etc.)

decreases

Delia Tosi Utrecht – Sept. 16, 2008 IceCube 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!)

Delia Tosi Utrecht – Sept. 16, 2008 IceCube 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-1001800 us

sdt srtsdt

srt

Delia Tosi Utrecht – Sept. 16, 2008 IceCube 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

Delia Tosi Utrecht – Sept. 16, 2008 IceCube 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

Delia Tosi Utrecht – Sept. 16, 2008 IceCube 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 averageNoise level with average

Saturation level

Delia Tosi Utrecht – Sept. 16, 2008 IceCube 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

Delia Tosi Utrecht – Sept. 16, 2008 IceCube 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

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

Back Up

Delia Tosi Utrecht – Sept. 16, 2008 IceCube 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

Delia Tosi Utrecht – Sept. 16, 2008 IceCube Coll. Meeting 12/9

Clock frequency multiplier (1)

L. Gustafsson

1 PPS

converter voltage to current

RW cable

Delia Tosi Utrecht – Sept. 16, 2008 IceCube Coll. Meeting 13/9

Clock frequency multiplier (2)

Sulanke & Tosi

1 PPS

converter voltage to current

RW cable

Delia Tosi Utrecht – Sept. 16, 2008 IceCube Coll. Meeting 14/9

Clock frequency multiplier (0)

1 PPS

converter voltage to current

RW cable

Clock frequency multiplier