# Presentation: 487408

## Acoustic test setup at south pole

- IceCube Collaboration Meeting,
- Berkeley, March 2005

## Motivation

**Motivation**

**Absorption length**
- ≈ few km
- temperature dependant depth dependant
**Speed of sound / refraction**
*v**ice** **≫** v**water* larger signals ( *P**max** **∞ v**ice**2* )
- density dependant refraction of surface noise
**Noise level**
- determines energy threshold
**Background events**
- few signal events/year few transient events or good suppression

**Evalution of acoustic detection needs acoustic parameters of south polar ice**

## Setup

**Setup**

**Use IceCube**
- 3 distant holes
- down to 400 m
**7 levels per hole**
- sensors
- transmitters
- auxiliary
**Surface digitization**
- String PCs
- DAQ
- Power
- Fiber LAN

## Acoustic stage

**Acoustic stage**

**In all three holes**
- at the same height do measurement in same layer
- sensor **and** transmitter at each stage reduce systematic error in redundant setup
**Sensor module and transmitter module**
- close together  check with low signals
- standard pressure housing
- 10 cm diameter steel tube
- end caps with commercial penetrators
**String support**
- own steel cable
- avoid signal shielding by IceCube cable need spacer
**Auxiliary devices**
- temperature or pressure sensors
- commercial hydrophones

## Acoustic stage: sensor

**Acoustic stage: sensor**

**Sensor module**
- based on existing design
- PZT5 piezoceramics plus amplifier directly coupled to steel tube
- three channels per module local coincidences directional information
**Power supply**
- cable losses use larger supply voltage
-  ±5V generated in module

## Acoustic stage: transmitter

**Active element**
- piezoceramic transducer signals ≥ 1000 V possible
- no orientation possible ring-shaped ceramic
-  azimuthal symmetry
- broad resonance large pressure amplitude
- directly coupled to the ice calculable system
**HV Signals**
**Problem:** cable capacitance down in the ice
- use LC-circuits sine bursts and pulses

## Cables

**Option 1: flexible outdoor robot cable**
- 6×2, 8×2 ... 16×2 twisted pairs
- 0.51 mm2 (ATW24), 100 Ohmloss: < 2 dB/100m
- used for moving parts at -40 deg
****** ≈ ****6**** ****€ / m (8×2 ******** one cable)**

**Sensors**
- differential signals 3×2 (twisted pairs)
- power supply 1×2

**Option 2: use cheap ethernet cables**
- 4×2 twisted pairs
- 0.52 mm2 (ATW24), 100 Ohmloss: < 2 dB/100m
- two free pairs from transmitter use for auxiliary sensors
- tested for -20 deg test at lower temperatures
****** ≈ ****0.3 ****€ / m (4×2 ******** two cables)**

**Transmitters**
- signal 1×2
- power supply 1×2

## String PC

**Limitations**
- cable costs
- cable losses
****** ****DAQ at top of each string**
**String PC**
- DAQ board(s)
- Power supply
- Fiber LAN switch
- only used for data handling slow CPU, small disk
- buried in snow waterproof container

## String PC: DAQ

**DAQ requirements**
- Low sampling rates
- low data rates
****** ****use of the shelf DAQ**
**Proposal: NI-DAQ 6259**
- 16 differential inputs two cards per strings
- 1.25 MHz single channel
- 1.0 MHz multichannel 83.3 kHz per channel
- digital and analog triggering
- variable gain: ± 50 mV to ± 10 V large dynamic range
- 4 differential outputs transmitter signals

## String PC: Power supply

**String PC: Power supply**

**Power consumption**
- Wire resistance: AWG24 (0.5mm2), 500m 86 ohm / pair
**Sensor**
- ± 5V / 30mA per amplifier  ~ 1W / 100mA  per module
- cable loss (86ohm, 0.1A)  ΔU = 8.6V
**Transmitter**
- +5V / 200mA, ~ 1W per module
- cable loss (86ohm, 0.2A)  ΔU = 17.2V
****** ****Power Supply: TXL Series**
-  Uin  = 86V-264 VAC 50/60Hz
- size   99x82x35 mm fits into standard PC housing
- sensors: TXL 035-1515D Uout = ±15V / 1.3A
- transmitters: TXL Series, TXL 060-24S Uout = 24V / 2.5A
**Total: ~15 W per string**

## String PC: Fiber LAN

**String PC: Fiber LAN**

**Data ****rates**
- 2 DAQs x 1.0 MS/s x 16 Bit ≤ 32 MBit/s per string
**Optical fiber LAN**
- 2- or 4-port (String-PC/Master-PC)
- 1 GBit/s standard
- 10 km Point-to-Pointon single mode fibers
- Cheap outdoor cable rated-50 degrees  test for large arrays

## Cost estimate

| Item | Quantity | Cost |  | Total |  |
| --- | --- | --- | --- | --- | --- |
| Sensor modules | 21 | 200 | ,- € | 4.200 € |  |
| Transmitter modules | 21 | 300 | ,- € | 6.300 € |  |
| Auxiliary sensors (temperature, pressure,...) | 21 | 10 | ,- € / ? | 210 € |  |
| Sensor cables | 4.440 m | ≈ 3 | ,- €/m | ≤ 15.000 € |  |
| Transmitter cables | 4.440 m | ≈ 3 | ,- €/m | ≤ 15.000 € |  |
| Master PC | 1 | 2.000 | ,- € | 2.000 € |  |
| String PC | 3 | 1.000 | ,- € | 3.000 € |  |
| DAQ card | 6 | 1.195 | ,- € | 7.170 € |  |
| Power supply | 6 | 50 | ,- € | 300 € |  |
| Fiber LAN switch (String PC) | 3 | 500 | ,- € | 500 € |  |
| Fiber LAN switch (Master PC) | 1 | 1.000 | ,- € | 1.000 € |  |
| Waterproof PC container | 3 | 500 | ,- € | 1.500 € |  |
| PC Power cable | ≤ 1000 m | 2 | ,- €/m | 2.000 € |  |
| Fibre LAN cable | ≤ 1000 m | 2 | ,7 €/m | 2.700 € |  |
| Total sum |  |  |  | 60.880 € |  |

## Project schedule 2005

|  | April |  |  | May |  |  |  | June |  |  |  |  | July |  |  |  | August |  |  |  |  | September |  |  |  | October |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| WK | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 |
|  |  |  |  | Sensor finalization |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  | Sensor and transmitter building |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |  | Sensor and transmitter calibration |  |  |  |  |  |  |  | Setup whole system |  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  | Build DAQ system |  |  |  |  |  |  |  |  |  |  |  |  |  | Test system in lake |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |  | DAQ software development |  |  |  |  |  |  |  |  | Software testing |  |  |  |  |  |  |  |  |  |
|  |  | Order parts |  |  |  |  |  | Parts arrive |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | Ship to pole |  |  |  |

## Constraints from IceCube

**Cargo**
- cables, PCs, DAQ
- Sensor and transmitter modules
****** ****total cargo need ≤ 5m****3**** **
**Manpower**
- deployment: trained person****** at the spot**
- commissioning: DAQ connection and setup, primary testing****** one person, two weeks**
**Deployment**
- separate deployment
- deployment with string possible only affecting the last 400 m
-  OMs are in safe depth
****** ****find best solution with IceCube deployment responsibles**

**Interference with IceCube**
- Acoustic signals 1 km above IceCube
-  < 10 mPa signal at OMs
- Electric signals low voltage (*±*5Vpp)
- High voltage generated locally low duty cycle (*≤ *1%).
- DAQ, power supply separate from IceCube
****** ****no interference expected**

## Summary

**all components are available and tested**
** ****reasonable cost and time scale**
**    ****major activities at all other neutrino telescopes**
** ****go for pole season 05/06**