Pinger project 2008/09 Delia Tosi IceCube – Acoustic Neutrino Detection working group September 16...
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Transcript of Pinger project 2008/09 Delia Tosi IceCube – Acoustic Neutrino Detection working group September 16...
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