Acoustic transceivers for the KM3NeT positioning system Miguel Ardid KM3NeT General Meeting Marseille, January 29 – February 1, 2013

The acoustic positioning system is a mandatory subsystem for the detector providing: 1) Guide during the deployment of the telescope structures and infrastructures 2) Optical module position during the telescope operation for muon track reconstruction Requirements:  relative positioning accuracy: <20 cm (less than the PMT diameter)  absolute positioning accuracy: <1 m (to be able to have a good pointing in the sky)  no interference with the optical detectors  easy installation  data acquisition/transmission system compliant with the Detector electronics The acoustic positioning system is a mandatory subsystem for the detector providing: 1) Guide during the deployment of the telescope structures and infrastructures 2) Optical module position during the telescope operation for muon track reconstruction Requirements:  relative positioning accuracy: <20 cm (less than the PMT diameter)  absolute positioning accuracy: <1 m (to be able to have a good pointing in the sky)  no interference with the optical detectors  easy installation  data acquisition/transmission system compliant with the Detector electronics Measurement of time travel sound (i.e. distances if sound speed is known) between emitter and receivers give us the position of optical modules after applying triangulation method. At least 3 distances are needed to apply triangulation method. LBL transceivers Mechanical structures Hydrophone Key elements for the Acoustic Positioning System (APS) 1)Auto-calibrating Long Baseline of acoustic transceivers anchored in known and fixed positions. 2)Array of acoustic sensors (hydrophones) rigidly connected to the mechanical structure. 3)Auxiliary devices: compasses, CTD, sound celerimeters, current metres 4)Data analysis system on-shore  The acoustic data can be used to monitor ocean noise and to study the acoustic neutrino detection. Miguel Ardid KM3NeT meeting - Marseille January 2013

 Acoustic transducer: We have selected the commercial available SX30 Free Flooded Ring from Sensortech, Canada, since it fulfils all the requirements: It can operate as emitter and receiver with good efficiencies (20-40 kHz) It can stand high power signals and high pressures It can be affordable in the large number of units required by KM3NeT  Electronics (Sound Emission Board): Especially developed electronics to: Fulfill the special requirements of the system: low-power consumption, reliable, configurable from shore, high intensity for emission, arbitrary signals for emission and low intrinsic noise. Optimize to the transducer chosen Reduce costs  Acoustic transducer: We have selected the commercial available SX30 Free Flooded Ring from Sensortech, Canada, since it fulfils all the requirements: It can operate as emitter and receiver with good efficiencies (20-40 kHz) It can stand high power signals and high pressures It can be affordable in the large number of units required by KM3NeT  Electronics (Sound Emission Board): Especially developed electronics to: Fulfill the special requirements of the system: low-power consumption, reliable, configurable from shore, high intensity for emission, arbitrary signals for emission and low intrinsic noise. Optimize to the transducer chosen Reduce costs Acoustic Transceiver proposed TransducerTransducer + Sound Emission Board Miguel Ardid KM3NeT meeting - Marseille January 2013 M. Ardid et al., Sensors 12 (2012) 4113

FFRFFR Resonance Frequency30 kHz Transmit Voltage Response, TVR133 dB re 1m Receive Voltage Response, RVR-193 dB re m Useable Frequency range20 kHz – 40 kHz Beam patternRadial: Omni Axial: Toroidal (60°) Efficiency50% Input Power300 W (2% duty cycle) Operating Depth (Metres)Unlimited Transmitting Directivity Response RadialRadial AxialAxial Characteristics provided by Sensor Technology Inc., Canada Miguel Ardid KM3NeT meeting - Marseille January 2013

Diagram of the SEB Power consumption: 100 VDC 1 VDC  Designed and adapted to the FFR transducers and to the neutrino infrastructure in order to manage the emission and reception.  It uses power supplies of 12V and 5 V, respectively provided by the telescope. Power consumption <1W.  Configurable and controlled from shore using low speed port (RS232,RS485…) and is able to emit arbitrary intense short signals.  Emission is triggered by a LVDS signal with an accuracy better than 1μs.  Relay for using the transducer as receiver.  Designed for a life expectancy > 20 years. Blue: Communication and control Microcontroller DSPic Red: Emission part digital amplification (PWM) + transducer impedance matching V out range: 35 V pp ÷ 400 V pp Green: Reception part relay  Designed and adapted to the FFR transducers and to the neutrino infrastructure in order to manage the emission and reception.  It uses power supplies of 12V and 5 V, respectively provided by the telescope. Power consumption <1W.  Configurable and controlled from shore using low speed port (RS232,RS485…) and is able to emit arbitrary intense short signals.  Emission is triggered by a LVDS signal with an accuracy better than 1μs.  Relay for using the transducer as receiver.  Designed for a life expectancy > 20 years. Blue: Communication and control Microcontroller DSPic Red: Emission part digital amplification (PWM) + transducer impedance matching V out range: 35 V pp ÷ 400 V pp Green: Reception part relay 7.3x10.5 cm Sound Emission Board Miguel Ardid KM3NeT meeting - Marseille January 2013 C.D. Llorens et al., J. Instr. 7 (2012) C01001

 The electronic noise of the FFR hydrophone, as receivers, has been measured in the anechoic chamber of Gandia.  The power spectrum density (PSD) acquired is < -120 dB re V 2 /Hz.  The electronic noise of the FFR hydrophone, as receivers, has been measured in the anechoic chamber of Gandia.  The power spectrum density (PSD) acquired is < -120 dB re V 2 /Hz. Electronic noise of the FFR PSD < -120 dB re V 2 /Hz Anechoic chamber FFR Miguel Ardid KM3NeT meeting - Marseille January 2013

 The sensitivity of the transducers have been measured.  The TVR and RVR have been calculated as function of the frequency and of the angle (directivity pattern).  ITC-1042 (TVR 148 dB ref. 1 m) and RESON-TC4014 (RVR – 186dB ± 3 dB re 1V/μPa) have been used as reference emitter and receiver, respectively.  The sensitivity of the transducers have been measured.  The TVR and RVR have been calculated as function of the frequency and of the angle (directivity pattern).  ITC-1042 (TVR 148 dB ref. 1 m) and RESON-TC4014 (RVR – 186dB ± 3 dB re 1V/μPa) have been used as reference emitter and receiver, respectively. 10 cm Emitter Receiver -90º +90º Receivers Receiving Voltage Response (RVR) Transmitting Voltage Response (TVR) Position 1 Position 2 Position 1 ITC RESON FFR Direction of emission or reception Position 1 Direction of emission or reception Position 2 Miguel Ardid KM3NeT meeting - Marseille January 2013

Position 1 Position 2 Receiving Voltage Response of the transceivers (using Reson CCA 100 preamp with 0 dB gain) Transmitting Voltage Response of the transceivers Miguel Ardid KM3NeT meeting - Marseille January 2013

HyperbaricTank HyperbaricTank FFRFFR VelocImeter Hydrophone. ANTARES IFREMER (France) Pressure dependence study : tested up to 440 bar Tests performed at the large hyperbaric tank at IFREMER-Brest Capacitance FFR Resistance FFR Miguel Ardid KM3NeT meeting - Marseille January 2013

SEB FFR moulded Control PC NI USB CH0 CH1 trigger Emission Trigger Reson-TC4014 Amplifier Probe 100x RS232 port USB port Set up used to test the system  Different tone burst signals with ~ Vpp of amplitude, 250 µs length in the kHz frequency range were generated through the SEB and sent to the FFR emitter.  The pressure signal was detected by means of the RESON-TC4014 receiver.  The emitted and received signals were recorded through NI USB-5132 board managed with a control PC through USB port.  Different tone burst signals with ~ Vpp of amplitude, 250 µs length in the kHz frequency range were generated through the SEB and sent to the FFR emitter.  The pressure signal was detected by means of the RESON-TC4014 receiver.  The emitted and received signals were recorded through NI USB-5132 board managed with a control PC through USB port. Emitted signal amplitude through SEB Miguel Ardid KM3NeT meeting - Marseille January 2013

Nude FFR FFR over moulded To water block and facilitate its fixing in the mechanical structures of the telescope Polyurethane material Transmitting Voltage Response of the FFR over molded Transmitting Voltage Response of the nude FFR Miguel Ardid KM3NeT meeting - Marseille January 2013

+ Tank: 87.5 x 113 x 56.5 cm 3 FFR Calibrated hydrophone in agreement with the electronics design FFR over moulded Sound Emission Board Transmitting Power of the System Miguel Ardid KM3NeT meeting - Marseille January 2013

Pool: 6.30 x 3.60 x 1.30 m 3 10 cm 57 cm Water level 4.5 m 140 m 1 m Water level Configuration used for the measurements in the pool and in the Gandia Harbour  Test the system in water pool and in the shallow sea water to prove the system in different conditions from that of the laboratory (longer distance, noisy environment, etc.).  Study of different signals to calculate the sound travel time (i.e. the distance between emitter and receiver hydrophone) and to prove different signal processing techniques.  Test the system in water pool and in the shallow sea water to prove the system in different conditions from that of the laboratory (longer distance, noisy environment, etc.).  Study of different signals to calculate the sound travel time (i.e. the distance between emitter and receiver hydrophone) and to prove different signal processing techniques. Miguel Ardid KM3NeT meeting - Marseille January 2013

Sine Sweep Signal: kHz – 1ms Pure Sinusoidal signal: 30 kHz – 0.25ms  Examples of emitted signals through SEB:  Pure Sinusoidal signal: 30 kHz, length 0.25 ms, 1 ms or 4 ms.  MLS signal: order 11, sampling frequency 200 kHz.  Sine sweep signal: kHz, length 1 ms or 4 ms.  Examples of emitted signals through SEB:  Pure Sinusoidal signal: 30 kHz, length 0.25 ms, 1 ms or 4 ms.  MLS signal: order 11, sampling frequency 200 kHz.  Sine sweep signal: kHz, length 1 ms or 4 ms. MLS 11 signal: 200kHz – 10.2ms Miguel Ardid KM3NeT meeting - Marseille January 2013

 The time travel sound calculated for the different signal are the distance between the 0 at the maximum value of the correlation.  Taking into consideration the delay due at the electronics components of the board, which is 5.4 µs. MLS: D E-R =(0.691 – )*(10 -3 )*1450m/s= 0.99m Reflexion on the surface MLS: D E-R =(1.01 – )*(10 -3 )*1450m/s= 1.46m Sweep: D E-R =(0.695– )*(10 -3 )*1450m/s=0.99m Sine: correlation method is not god due to the very broad peak obtained, we should use the classical method «filter+threshold». Time accuracy  1 µs.  The time travel sound calculated for the different signal are the distance between the 0 at the maximum value of the correlation.  Taking into consideration the delay due at the electronics components of the board, which is 5.4 µs. MLS: D E-R =(0.691 – )*(10 -3 )*1450m/s= 0.99m Reflexion on the surface MLS: D E-R =(1.01 – )*(10 -3 )*1450m/s= 1.46m Sweep: D E-R =(0.695– )*(10 -3 )*1450m/s=0.99m Sine: correlation method is not god due to the very broad peak obtained, we should use the classical method «filter+threshold». Time accuracy  1 µs. D=1m Pool: 6.30 x 3.60 x 1.30 m 3 Received signal MLS signal Sine sweep signal Pure sine signal Distance Emitter- Receiver MLS signal Sine sweep signal Pure sine signal Distance Emitter- Receiver Reflexion on the surface Distance Emitter- Receiver Electromagnetic signal Correlation between emitted and received signals Miguel Ardid KM3NeT meeting - Marseille January 2013

Received signal MLS signal Sine sweep signal Pure sine signal  Delay due at the electronics components of the board is 5.4 µs and of the external trigger is 8.25ms.  Considering this delay the time travel sound calculated for the different signal are: MLS: D E-R =( – )*(10 -3 )*1500m/s= 139,98 m Sweep: D E-R =( – )*(10 -3 )*1500m/s= 139,98 m Sine: correlation method is not god due to the very broad peak obtained, classical method «filter + threshold»not able to deal with it. Time accuracy better than 30 µs (accuracy of external synchronization)  Delay due at the electronics components of the board is 5.4 µs and of the external trigger is 8.25ms.  Considering this delay the time travel sound calculated for the different signal are: MLS: D E-R =( – )*(10 -3 )*1500m/s= 139,98 m Sweep: D E-R =( – )*(10 -3 )*1500m/s= 139,98 m Sine: correlation method is not god due to the very broad peak obtained, classical method «filter + threshold»not able to deal with it. Time accuracy better than 30 µs (accuracy of external synchronization) Distance Emitter- Receiver MLS signal Sine sweep signal Pure sine signal Distance Emitter- Receiver Correlation between emitted and received signals 140 m Miguel Ardid KM3NeT meeting - Marseille January 2013

 The Acoustic Transceiver already tested in laboratory, in pool and in harbour have been integrated in the instrumentation line of ANTARES and in the NEMO phase-II tower in order to test it in real conditions and study its behaviour in situ.  Some changes in the SEB were done to simplify the system and to deal with the particular limitations of the ANTARES instrumentation line and NEMO infrastructures. It was installed inside a titanium container (Laser Container)  For simplicity and due to limitations to both infrastructures, it was decided to test the transceiver only as emitter. The receiver functionality will be tested in other in situ KM3NeT tests.  The changes performed in the transceiver, particularly in the SEB, show the capacity to adapt the electronic parts to the situation and available conditions.  The Acoustic Transceiver already tested in laboratory, in pool and in harbour have been integrated in the instrumentation line of ANTARES and in the NEMO phase-II tower in order to test it in real conditions and study its behaviour in situ.  Some changes in the SEB were done to simplify the system and to deal with the particular limitations of the ANTARES instrumentation line and NEMO infrastructures. It was installed inside a titanium container (Laser Container)  For simplicity and due to limitations to both infrastructures, it was decided to test the transceiver only as emitter. The receiver functionality will be tested in other in situ KM3NeT tests.  The changes performed in the transceiver, particularly in the SEB, show the capacity to adapt the electronic parts to the situation and available conditions. Acoustic Transceiver + INTEGRATED ANTARES NEMO Miguel Ardid KM3NeT meeting - Marseille January 2013

 On June 2011 the transceiver was deployed at 2475 m depth. The connection of the Line to the Junction Box was not possible due to lack of free connections in the junction Box and ROV availability. The line was taken out in 2012 for PPM-DOM test upgrade, and the transceiver was working without problem. Now, the line is ready for deployment again and the transceiver will be tested soon.  On June 2011 the transceiver was deployed at 2475 m depth. The connection of the Line to the Junction Box was not possible due to lack of free connections in the junction Box and ROV availability. The line was taken out in 2012 for PPM-DOM test upgrade, and the transceiver was working without problem. Now, the line is ready for deployment again and the transceiver will be tested soon. SEB integrated inside of the titanium vessel of the Laser calibrator. FFR hydrophone with the support and the titanium laser container m 2.80 m 1.40 m 50cm ANTARES hydrophone FFR hydrophone 83 cm 6.5 cm Anchor of the IL11 of ANTARES Miguel Ardid KM3NeT meeting - Marseille January 2013

 Changes done in SEB:  Use the transceiver only as emitter.  The reception part was eliminated.  The standard RS232 was adapted to standard RS485.  A new functionality for the microcontroller to control the laser emission and the instructions to select the kind of signals to emit matching the procedures of the ANTARES DAQ system through the MODBUS communication protocol was implemented.  Changes done in SEB:  Use the transceiver only as emitter.  The reception part was eliminated.  The standard RS232 was adapted to standard RS485.  A new functionality for the microcontroller to control the laser emission and the instructions to select the kind of signals to emit matching the procedures of the ANTARES DAQ system through the MODBUS communication protocol was implemented. Diagram of the SEB 7.3x10.5 cm Sound Emission Board Graphic interface for the MODBUS commands Miguel Ardid KM3NeT meeting - Marseille January 2013 RS485 adapter

 Using the values of the Transmitting Power measured previously the received pressure variation as a function of the distances at 30 kHz and 44 kHz is calculated for the vertical direction (along the IL11) with the following equation: [µPa], Where P r is the pressure calculated at distance r, P 0 is the received pressure at 1 m and α is the absorption coefficient calculated using the parameterisation of François et Garrison: [Np/m]  Using the values of the Transmitting Power measured previously the received pressure variation as a function of the distances at 30 kHz and 44 kHz is calculated for the vertical direction (along the IL11) with the following equation: [µPa], Where P r is the pressure calculated at distance r, P 0 is the received pressure at 1 m and α is the absorption coefficient calculated using the parameterisation of François et Garrison: [Np/m] Received pressure variation as a function of the distance Miguel Ardid KM3NeT meeting - Marseille January 2013

 Knowing the sensitivity of the ANTARES (-196 dB re 1V/µPa at 44kHz) and AMADEUS ( dB re 1V/µPa at 30 kHz) hydrophones and the ΔP calculated before, the received electric signal amplitude can be calculated. Received amplitude with the AMADEUS hydrophones Received amplitude with the ANTARES hydrophones 44 kHz 30 kHz ΔP for the distances of the Line 12 Floor 21 Floor 22 Floor 23 Received amplitude with the AMADEUS hydrophones of Line 12 Floor 21 Floor 22 Floor 23 Miguel Ardid KM3NeT meeting - Marseille January 2013

 The transceiver prototype is going to be integrated at the end of July in the anchor of the NEMO phase-II detector. Anchor of the tower FFR hydrophone and SEB integrated inside of the titanium vessel of the Laser calibrator. FFR SEB Drawing of the integration in the Anchor of the tower Diagram of the SEB Sound Emission Board Changes in the SEB:  The reception part was eliminated.  A new functionality for the microcontroller to control also the laser emission has been implemented. Changes in the SEB:  The reception part was eliminated.  A new functionality for the microcontroller to control also the laser emission has been implemented. 7.3x10.5 cm Miguel Ardid KM3NeT meeting - Marseille January 2013

Transmitting Power of the System + FFR over moulded Transmitting Power of the System Sound Emission Board Position 1 Position 2 Miguel Ardid KM3NeT meeting - Marseille January 2013

 Knowing the Transmitting Power of the transceiver, the received pressure variation (ΔP) as a function of the distance for a 30 kHz short tone burst emitted signal have been calculated. The received amplitude that will be recorded by a NEMO hydrophone with sensitivity of -172 dB re 1V/µPa is calculated as well. Received pressure variation as a function of the distance 30 kHz Received amplitude with the NEMO hydrophones Miguel Ardid KM3NeT meeting - Marseille January 2013

 In May 2010 in Gandia the functionality and compatibility between the NEMO acquisition electronic chain and the transceiver (FFR-SX30 + SEB) were successfully tested (Simeone et al., NIMA 662 (2012) S246-S248). Stability of the system better than 1µs.  In December 2011, in fresh water pool at IDASC (Istituto di Acustica e Sensoristica “Orso Mario Corbino”) Rome, tests were performed to evaluate and compare the performance in water of the SMID and FFR-SX30 hydrophones and of the transceiver prototype for the integration in NEMO Phase II tower and to check the compatibility and functionality of systems  In May 2010 in Gandia the functionality and compatibility between the NEMO acquisition electronic chain and the transceiver (FFR-SX30 + SEB) were successfully tested (Simeone et al., NIMA 662 (2012) S246-S248). Stability of the system better than 1µs.  In December 2011, in fresh water pool at IDASC (Istituto di Acustica e Sensoristica “Orso Mario Corbino”) Rome, tests were performed to evaluate and compare the performance in water of the SMID and FFR-SX30 hydrophones and of the transceiver prototype for the integration in NEMO Phase II tower and to check the compatibility and functionality of systems 4 m 6 m Fresh water pool at IDASC 4 x 6 x 5.30 m 3 FFR-SX30 with SMID preamplifier moulded by SEACON SMID hydrophone and SMID preamplifier moulded by SEACON Miguel Ardid KM3NeT meeting - Marseille January 2013

 The system developed at IGIC-UPV has been tested in the laboratory, in the pool and in the harbour accomplishing the requirements imposed by KM3NeT: − a system with reduced cost, low power consumption, high intensity for emission, low intrinsic noise and arbitrary signals for emission. − able to obtain a transmitting power of  170 dB ref. 1 1m in agreement with the electronic design and specification needed. − the use of wideband signals, Maximum Length Sequence (MLS) signals and sine sweep signals, results in an improvement of the signal-to-noise ratio, and therefore resulting in an increase in the detection efficiency and in the detection time accuracy. − the system is very stable and precise in time (better than 1µs).  The system (as emitter) has been integrated in ANTARES IL and NEMO- Phase II successfully. Now ready for deployment and connection for in situ tests.  The transceiver proposed is compatible with the different options for the receiver hydrophones proposed for KM3NeT. It is versatile, so in addition to the positioning functionality, it can be used for other calibration tasks or for acoustic detection of neutrinos and acoustic monitoring studies in deep-sea.  As next steps: a new prototype of the SEB is being designed and developed in order to reach transmitting powers of  180 dB ref. 1 1m. We are also setting a new lab and new protocols for testing acoustic sensors in Gandia.  The system developed at IGIC-UPV has been tested in the laboratory, in the pool and in the harbour accomplishing the requirements imposed by KM3NeT: − a system with reduced cost, low power consumption, high intensity for emission, low intrinsic noise and arbitrary signals for emission. − able to obtain a transmitting power of  170 dB ref. 1 1m in agreement with the electronic design and specification needed. − the use of wideband signals, Maximum Length Sequence (MLS) signals and sine sweep signals, results in an improvement of the signal-to-noise ratio, and therefore resulting in an increase in the detection efficiency and in the detection time accuracy. − the system is very stable and precise in time (better than 1µs).  The system (as emitter) has been integrated in ANTARES IL and NEMO- Phase II successfully. Now ready for deployment and connection for in situ tests.  The transceiver proposed is compatible with the different options for the receiver hydrophones proposed for KM3NeT. It is versatile, so in addition to the positioning functionality, it can be used for other calibration tasks or for acoustic detection of neutrinos and acoustic monitoring studies in deep-sea.  As next steps: a new prototype of the SEB is being designed and developed in order to reach transmitting powers of  180 dB ref. 1 1m. We are also setting a new lab and new protocols for testing acoustic sensors in Gandia. Miguel Ardid KM3NeT meeting - Marseille January 2013