![Page 1: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/1.jpg)
Hydrophone based calibrator for seawater acoustic detection of
UHE neutrinos
Omar Veledar
ACoRNE collaboration – University of Sheffield
Sapienza Universitá Di Roma25 – 27 June 2008
![Page 2: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/2.jpg)
Outline
Rona array DAQ Calibration Pinger development Deployment Future work
![Page 3: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/3.jpg)
Rona hydrophone array
• North-West Scotland (ranging hydrophones)• Good test bed for future deep sea experiments
• Existing infrastructure √• Wideband hydrophones √• Omnidirectionality √• Unfiltered data √• All data to shore √• Control over DAQ √• No remote access X
![Page 4: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/4.jpg)
Rona hydrophone array
8 hydrophones Low noise preamplifiers 1200m x 200m at mid
depth in 230m deep sea Hydrophone positioning
off during data readout
![Page 5: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/5.jpg)
DAQ
Offshore acquisition of amplified unfiltered data (16bit ADC@140kHz, ±1.2 V, 1bit = 38.147μV = 3662.1μPa)
FLAC lossless compression (>50%)
8TB RAID interfacing to
16 tape autoloader LT03
tape robot (possible to
relocate) Offline signal processing
and analysis - unlimited data re-processing
Quantum Superloader 3
![Page 6: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/6.jpg)
Calibration - hydrophone
Acoustic detection of UHE neutrinos relies on ability to calibrate hydrophones - bipolar acoustic pulse from single omnidirectional source
Thermal energy resembling (shape and intensity) that of a neutrino induced shower should be deposited: array - interface pattern analogous to neutrino generated ‘pancake’
Other possibilities: Laser – interesting, but impractical Copper plate current discharge
![Page 7: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/7.jpg)
Calibrator development - progressionLaboratory tank
Swimming pool
Lake (Kelk)
Open sea (Rona)
Development
![Page 8: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/8.jpg)
Calibrator development - toolsTx – omnidirectional ± 1.8dB @ 10kHz Rx - flat frequency response
![Page 9: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/9.jpg)
Know system and desired output to deduce required excitation pulse
Convolution integral (t)y(t) = x(t) * h(t) - complicatedConvolution (s) - freq. domain
Y(s) = X(s) . H(s)
Inverse FFTy(t) = IFFT(Y(s))
Impulse response not practical use step response
Step response = time integral of impulse response
Signal generation - system
i
invixnvnx ][][][*][
dtgftgtf )()()(*)(
0,0
0,)(
x
xx
(hydrophone)input output
system & output => excitation pulse
Time domain
Discrete time signal
Impulse
xdttxH )()(
Step
![Page 10: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/10.jpg)
Signal generation - signal
d / dtstepHydro
system H(t)
o/pImp. resp.
Deconvolute i/p from sys. & o/pX(s) = Y(s) / H(s)
Transform to time domainx(t) = IFFT(X(s))
RECIPE Find step response (of the transmit hydrophone) Generate system TF (model transmit hydrophone) Find excitation signal by deconvoluting required o/p and system TF
![Page 11: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/11.jpg)
Pool – hydrophone modelling
Hydrophone step response is recorded at various distances and dejittered
![Page 12: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/12.jpg)
Hydrophone data fitting
5th order TF used to model hydrophone
TF:Mathematical representation of the relationship between the i/p and o/p of a LTI system
![Page 13: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/13.jpg)
Technique verification
![Page 14: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/14.jpg)
Excitation signal
Desired acoustic pulse and the estimated hydrophone driving electrical signal
Generates10 Pa @ 1m
![Page 15: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/15.jpg)
Pool - bipolar acoustic pulse
Measured at various distances
![Page 16: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/16.jpg)
Rona - field trip
The joys of British “Summer”
![Page 17: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/17.jpg)
Future work
Repeat Rona deployment at different sea state and over different hydrophones using new excitation pulses
An array development using 8 hydrophones Line array – acoustic pancake
Fully autonomous for great depths Surface deployment => Power Amplifier, easy DAQ,
(linearity?)
Field data analysis
![Page 18: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/18.jpg)
New excitation signal
Restrictive by the hydrophone linearitypotentially, can generate up to
approximately 60 Pa @ 1m
See Bevan et al. – parameterisation:more energy at core of the shower
![Page 19: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/19.jpg)
Array hydrophone count2 hydrophones
4 hydrophones
8 hydrophones
3 hydrophones
6 hydrophones
10 hydrophones
![Page 20: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/20.jpg)
Array development
Acquired RESON hydrophones
Developed PIC based hydrophone control
Array construction under way
![Page 21: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/21.jpg)
Conclusions
Understood and mathematically modelled hydrophone system
Successfully generated bipolar acoustic pulses in laboratory and pool conditions
Ongoing Rona data analysis Array development Pancake detection
![Page 22: Hydrophone based calibrator for seawater acoustic detection of UHE neutrinos](https://reader035.vdocuments.net/reader035/viewer/2022062518/5681479b550346895db4ced4/html5/thumbnails/22.jpg)
Thank you
Questions ?
http://pppa.group.shef.ac.uk/acorne.php