1. Preliminary Results on Hydrophones Energy Calibration with a Proton Beam Results at an intense low-energy proton beam in ITEP (Moscow), special thanks to Vladimir Lyashuk and Andrei Rostovstev group N protons ~ 10 10 E protons = 100 MeV, 200 MeV International ARENA Workshop May 17-19, 2005 DESY, Zeuthen Giulia De Bonis University “La Sapienza” Rome, ITALY

2. Overview Hydrophones Characterization (Frequency Response) Hydrophones Calibration on Proton Beam Future Developments

3. BENTHOS (prototipe) L = 15.5 cm d = 2 cm RESON 4042 (modified) Piezo-Electric HYDROPHONES previously used for 6 months at 2000 m depth. Both hydrophones are pre-amplified (~ 30 dB)

4. Frequency Response - the Hydrophones Sensitivity Test at IDAC (CNR – Roma) Data Analysis Results

5. CALIBRATION - Frequency Response IDAC – Institute of Acoustics “O. M. Corbino” – Rome (Italy) http://www.idac.rm.cnr.it/  UAL - Underwater Acoustics Laboratory remotely-operated transducer positioning system capable of handling weights up to 100 kg on two independent carriages water tank (fresh water) with dimensions: 6.0 m (length 4.0 m (width) 5.5 m (depth)

6. Experimental Set-Up Hydrophone Spherical Transducer (Model ITC 1007) d=1 m (distance) L=2.8 m (depth) The signal source (Reson ACS 9060) produces a 5KHz to 25 KHz sine wave (frequency sweep with a step of 0.5 KHz). 1.5 ms

7. CALIBRATION - Frequency Response RESULTS Benthos Reson Hydrophones sensitivity is measured in dB re 1V/1  Pa -173 dB re 1V/1  Pa -183 dB re 1V/1  Pa

8. Protons Interaction in Water - the Acoustic Signal -Test at ITEP (Moscow) Proton beam - Preliminary Data Analysis Results N protons /spill ~ 10 10 E protons = 100 MeV, 200 MeV up to 10 18 eV deposited per spill

9. Particles Interaction in Water: the Acoustic Signal “ instantaneous ” & localized energy deposition local heating of the medium Local density variation PRESSURE WAVE

10. The Bragg Peak If the proton energy is in the range 100-200 MeV, the most of the primary proton energy is deposited at the Bragg Peak. The Bragg Peak is a good approximation of a localized high- density energy deposition in water. Considering the Bragg Peak one can simulate an acoustic source.

11. ITEP Experimental Set-up June 2004 Dimensions 50.8 cm × 52.3 cm × 94.5 cm The 90% of the basin's volume is filled with fresh water. NO control on temperature. Beam Output Transducer Positioning System Data Acquisition with 3 different hydrophones B  -173 dB re 1V/1  Pa T  -133 dB re 1V/1  Pa R  -183 dB re 1V/1  Pa V.Lyashuk and A.Rostovstev group, G. De Bonis, G. Riccobene, R. Masullo and A. Capone B T R p Injection Tube Beam Output BENTHOS RESON ITEP Collimator

12. X [ cm ] Z [ cm ] BENTHOS RESON Hydrophones Configuration BENTHOS ITEP RESON p (Monte Carlo Simulation)

13. TTX Data BENTHOS RESON ITEP BCT Beam Current Transformer Hydrophones

14. Hydrophones Data - a Zoom View  ~ 50  s A ~ 45 mV Acoustic Pulse related to protons interaction Bipolar Shape Electro-magnetic induced pulse Typical pulse collected with 10 10 protons @ 200 MeV

15. Hydrophones Data Analysis FIT Operation BENTHOS RESON ITEP

16. Results - LINEARITY BENTHOS Hydrophone E beam = 200 MeV E beam = 100 MeV N protons = 2. 5·10 10 Linear Fit Total deposited energy = 10 8 [eV] 2. 5·10 10 =2.5 ·10 18 eV Proton Intensity Bipolar Amplitude

17. Results - LINEARITY E = 200 MeV E = 100 MeV RESON Hydrophone Linear Fit

18. Results - LINEARITY E = 200 MeV E = 100 MeV ITEP Hydrophone Linear Fit

19. Collimator Diameter Dependance BEFORE The BCT gives a measure of the number of protons BEFORE the collimator BENTHOS Data – E=100 MeV Results show a collimator diameter dependance Beam Intensity [N protons ] 0.5·10 10 0 1.5·10 10 1.0·10 10 2.5·10 10 2.0·10 10

20. Number of entering protons protons interacting in water. More over, collimators, located downstream the BCT, are used to modify the number of protons interacting in water. We considered collimator with diameter  = 2, 3, 5 cm). protons in the emitted bunch The voltage signal measured at the BCT channel is proportional to the number of protons in the emitted bunch. One can calculate N proton using the formula: N proton = A BCT [ V ] · 2 · C ·10 8 where C is a parameter depending on machine settings; the C-value is given by machine technicians.

21. N protons ENTERING THE BASIN Results (taking into accounts the effect of collimators…) E beam = 100 MeV 0.5·10 10 0 1.5·10 10 1.0·10 10 2.5·10 10 2.0·10 10

22. Future Plans Simulation (Geant4) of proton beam energy deposition in water Simulation of acoustic signal formation Development of a tool for open sea hydrophone calibration (controlled sparker) Simulation of acoustic signal from UHE neutrino induced showers in sea water