1. Development of combined sensors for UHE neutrino detection Alexander Enzenhöfer ARENA 2010 Nantes, 29.06. - 02.07 2010

2. Outline Basic considerations Concept of an Opto-Acoustical Module Prototype and Test Conclusion Work in progress Alexander Enzenhöfer, ARENA 2010, 02.07.2010 1

3. Basic considerations to deep-sea neutrino detection Mechanics Feedthrough problematic, possible source of errors → Use combined module to reduce feedthrough and electronics, e.g. DAQ, positioning Methods Large number of sensors/volumes needed → Combination of complementary detection techniques Calibration Dynamic environment requires monitoring of sensor position → Combine positioning of the sensor module with acoustic particle detection Alexander Enzenhöfer, ARENA 2010, 02.07.2010 2

4. Work at the ECAP Alexander Enzenhöfer, ARENA 2010, 02.07.2010 3 ANTARES optical neutrino telescope AMADEUS acoustic particle detection test setup acoustic techniques KM3NeT optical sensors acoustics calibration Combine optical/acoustical sensors with acoustics for: calibration (primary) marine science acoustic detection

5. Concept of a combined Opto-Acoustical Module Alexander Enzenhöfer, ARENA 2010, 02.07.2010 4 Optical Module: PMT integrated into pressure resistant housing Acoustic Module: Acoustic sensors integrated into pressure resistant housing Opto-Acoustical Module (OAM): PMT and acoustic sensor integrated into pressure resistant housing

6. Developed at the ECAP 3 Acoustic Modules integrated in AMADEUS Acoustic sensor glued to the inside of a pressure resistant housing Acoustic sensor protected against environmental influences No additional mechanical structures No additional feedthrough Show good results for storey positioning Acoustic Module Alexander Enzenhöfer, ARENA 2010, 02.07.2010 5

7. Possible disadvantage resulting from combination Design dependent angular acceptance Electronic interference Module power supply (supply/generation of different voltages inside the module) PMT HV supply PMT operation and piezo operation Interface water–glass–piezo complex signal path through the glass sphere coupling of the piezo to the glass Alexander Enzenhöfer, ARENA 2010, 02.07.2010 6

8. Prototype of an OAM Combine: High voltage power supply (ANTARES) Piezo-ceramic and preamplifier equivalent to Acoustic Module to build prototype: Additional acoustic sensor in Optical Module (totally unshielded) Number/Position of the acoustic sensor depending on module design Alexander Enzenhöfer, ARENA 2010, 02.07.2010 7

9. Acoustic Module: Angular acceptance Alexander Enzenhöfer, ARENA 2010, 02.07.2010 8 emitter water surface crane sensor (coupled) steel frame lead weight Distance 0.5 m steel rods “equator” glass sphere

10. Acoustic Module: Angular acceptance Alexander Enzenhöfer, ARENA 2010, 02.07.2010 9 ch0 Angular acceptance: ~ ± 70 deg  = 0 o φ

11. Recorded noise spectra (sensor totally unshielded) Alexander Enzenhöfer, ARENA 2010, 02.07.2010 10

12. Recorded noise spectra (sensor totally unshielded) Alexander Enzenhöfer, ARENA 2010, 02.07.2010 11 Integrated PMT influence RMS noise ≈ 5 x RMS typ. sea-state

13. Conclusion Ideally installation of more than one Acoustic sensor per module Influence of HV generation is limited to the frequency range (f > 90 kHz) not relevant for acoustic particle detection Significant influence of PMT signal generation on acoustic sensor Influence only local in frequency domain In current design (worst case with no electromagnetic shielding) no real drawback for positioning but for acoustic detection the design has to be improved Alexander Enzenhöfer, ARENA 2010, 02.07.2010 12

14. Frequency [Hz] Input admittance Work in progress Simulations Simulations of different sensor geometries to improve sensitivity increase angular acceptance Sound propagation and signal generation Alexander Enzenhöfer, ARENA 2010, 02.07.2010 13

15. Work in progress Design Design of an adapted preamplifier Improvement of electromagnetic shielding Tests Study influence of acoustic sensor on PMT operation Tests under real conditions Alexander Enzenhöfer, ARENA 2010, 02.07.2010 14

16. Alexander Enzenhöfer, ARENA 2010, 02.07.2010 15

17. Alexander Enzenhöfer, ARENA 2010, 02.07.2010 16