Overview of AMADEUS and Positioning for KM3NeT Outline Overview of AMADEUS and Positioning for KM3NeT Technical implementation of AMADEUS Positioning with AMADEUS Conclusions 1 1

Overview of AMADEUS and Positioning for KM3NeT 2

Goals of the AMADEUS Project Feasibility study for future large scale acoustic detector Background investigations (rate of neutrino-like signals, localisation of sources) Investigation of signal correlations on different length scales Tests of different hydrophones and sensing methods Development and tests of filter and reconstruction algorithms Studies of hybrid detection methods 3 3

The AMADEUS System Taking data since 5-Dec-2007 Completely installed since 30-May-2008 “Pingers“ (acoustic RxTx) on each Anchor 4

Overview of Acoustic Sensors 19 commercial hydrophones: all working 11 self-made hydrophones: 9/11 working 3 Acoustic Modules (6 acoustic sensors): all working 34/36 sensors working in total Typical sensitivity of hydrophones: -145 dB re. 1V/Pa 5 5

Piezo sensors + preamplifiers Acoustic Modules Piezo sensors + preamplifiers Design allows for integration of acoustic sensors into pressure housing of photo sensors  No need for additional mechanical structures 6 6 6 6 6 6

Positioning Option for KM3NeT AMADEUS-like acoustic sensors have the potential to combine: positioning investigation of acoustic neutrino detection techniques marine science The Acoustic Modules (AMs) allow for an integration of acoustic sensors into Optical Modules. Are piezo elements within a PMT housing an inexpensive option for a multi purpose acoustic system for KM3NeT? Most answers can be given by investigating AM performance! This presentation: A look at positioning with AMADEUS

Technical Implementation of AMADEUS 8

Full detector capabilities (time synchronisation, DAQ,…) Features of AMADEUS Full detector capabilities (time synchronisation, DAQ,…) Combines local clusters of acoustic sensors with large cluster spacing Designed to make use of standard ANTARES hard- and software as much as possible All data to shore (but off-shore pre-trigger possible) Triggered data (on-shore) ~10 GByte/day Continuous data taking with (currently) ~80% uptime 9 9

Setup of Acoustic Storey with Hydrophones Hydrophone: Piezo sensor with pre-amplifier and band pass filter in PU coating ~10cm Titanium cylinder with electronics 3 custom designed Acoustic ADC boards 10 10

Characteristics of the Acoustic ADC boards 3 Acoustic ADC boards (AcouADC boards) used per storey, each processing 2 sensors 16 bit digitisation (-2V to +2V) Bandwidth up to ~125 kHz Adjustable digitisation rate, max. 500 kSamples/s (Currently using downsampling 2: 250 kSamples/s transmitted to shore, i.e. 3MByte/s for 6 hydrophones) System extremely flexible due to use of FPGA off-shore (downsampling, adjustable gain 1 to 562, off-shore firmware updates possible) 11 11

The Acoustic DAQ System 12

Postioning with AMADEUS 13 13

Pinger Signals for Reconstruction of Hydrophones and AMs Hydros 14 14 14

Methods for Position Reconstruction goal: positioning at cm-level (4s sampling ≙ 6mm) Main Method – using database info about emission time of pinger signals positioning of individual sensors use absolute time for the 14 pingers: cs  (treception – temission) Trigger on first negative peak,… Stockwerkbild austauschen gegen das von Anneli …Zero crossing defines treception

Position Reconstruction for Hydrophones Hydrophone Storey L12Fl22

First Look: Resolution of Hydro Reconstruction 

Resolution of Hydrophone Reconstruction: Interpretation of Observations Why better resolution in z-direction? Each pinger reconstructs a slightly different position: Hydrophones are not pointlike: (less pronounced in z-direction) Uncertainty in position of ANTARES pingers (similar for all directions?) Hydrophones move during pinger cycle (10~15s) Piezo diameter ≈25mm In general, only a sub-set of the ANTARES pingers is used due to shadowing: This subset varies for each hydrophone and each pinger cycle Only a first look (further studies required) but looks extremely promising Expect error on positioning to be dominated by systematic effects

Position Reconstruction for Acoustic Modules AM Storey L12Fl21 ch0 ch1 AM0 ch1 AM1 ch0 AM2 ch0 ch1

First Look: Resolution of AM Reconstruction

Resolution of Acoustic Module Reconstruction: Interpretation of Observations Reconstruction more difficult with AMs : Signals guided inside glass shere: (Signal interference, trigger point more difficult to define) Acoustic sensors show stronger differences in individual behaviour Stronger shadowing effect Reconstruction with AMADEUS AMs can be improved but will not reach precision of hydrophones Option for KM3NeT: Principle Design is applicable and easily adaptable. Some optimization needed (more sensors, study different piezos…)

Conclusions AMADEUS performance is excellent The AMADEUS system has all features of an acoustic neutrino telescope (except size) Can be used as a multi purpose device (studies of neutrino detection, marine science, positioning,…) “Acoustic Modules” are an option for acoustic measurements without additional mechanical structures for KM3Net AMADEUS design flexible: adaptable to KM3NeT design and DAQ hardware As option for KM3NeT: More studies with AMADEUS and in laboratory required Funded by: 22 22 22