1. IceCube Meeting Berkeley1March, 23 2005 Alternative Detection Methods for Highest Energy Neutrinos Possibilities – Timescales - Competition Rolf Nahnhauer, DESY

2. IceCube Meeting Berkeley2March, 23 2005 Projects of the next decade: All Radiation EeV Neutrino detection Arrays  observe > 10 events/year from GZK flux  V eff ≥ 50 km 3  target material: water, ice, salt, rock?  profit from combination of different detections methods: optical-acoustic-radio in background reduction, cross calibration, detection sensitivity,…

3. IceCube Meeting Berkeley3March, 23 2005 The Water ARENA + Acoustic 1000 hydrophone array for Mediterranean 3 hydrophones per cluster ( sensor distance : 50 m ) 300 m grid spacing red line : incident neutrino (7.2*10 19 eV) red cube : deposited energy of - interaction yellow points : hydrophones green cubes : signal hits From L. Thompson, unpublished And U. Katz, ApPEC Workshop 2003

4. IceCube Meeting Berkeley4March, 23 2005 Water ARENA Sensor R&D Erlangen : cheap selfmade hydrophones sensitivity = 6x commercial S/N  10 pressure wave on fibre  modulation of cavity size, leading to modulation of laser wavelength detectable by interferometer spectral response to a 65 kHz loud-speaker modulation (Mach-Zender OPD = 150 m) commercial selfmade From: P. Kollmannsberger, DPG 2004 From: M.Morganti, Roma 2005 Pisa, Firenze: fibre acoustic sensors

5. IceCube Meeting Berkeley5March, 23 2005 A Water ARENA Test Site cable: 10 OF; 6 conductors A fully equipped facility to test and develop technologies for the Mediterranean km 3 From G. Riccobene for this workshop 2004-2006 Shore laboratory port of Catania Underwater test site: 25 km E offshore Catania 2000 m depth

6. IceCube Meeting Berkeley6March, 23 2005 NEMO “phase 1” frame Successfully deployed on 23 Jan 2005 4 hydrophones: 2 (10 Hz - 40 kHz) ; 2 (1 kHz - 40 kHz) Digitization (24 bits 96 kHz) and electro-optical translation Continuous monitoring from shore First tests: The NEMO - O DE (Ocean noise Detection Experiment) From G. Riccobene for this workshop Sperm whales clicks

7. IceCube Meeting Berkeley7March, 23 2005 The Water ARENA Preparation at Antares site in 2005 Spring deploy string-0,dummy+hydrophones check sensitivity, measure noise Summerrecover string-0 Autumn deploy string-1, string-2 each has five levels upper level 5x2 hydrophones 4 lower levels 5x3 PMT’s Two strong groups:Erlangen, Sheffield Money:~2x500k Euro Personpower (G):10 students (PhD+diploma) 9 talks at German DPG 2005 (1 talk from IC++) Personpower(UK)???

8. IceCube Meeting Berkeley8March, 23 2005 If LOPES R&D successful  add radio detectors to AUGER 4 km 1EeV air shower radio beam 2 km 50 km 1mV/m/Mhz 1 The Air ARENA AUGER + Radio vertical 10 17 eV air shower center +100m +250m data:Allan and Prah A. Horneffer et al., SPIE 2004

9. IceCube Meeting Berkeley9March, 23 2005 Iran, 7km diameter Canada 8x5 km 2 Many Gulf coast salt domes 3-4 km diameters, 5-10 km depths typical The Salt ARENA I many big salt domes around the world From M. Chiba, NANP-Dubna 2003 Typical salt dome: RF loss similar to ice at -40° C 2.5 times more dense  build radio detector array

10. IceCube Meeting Berkeley10March, 23 2005 Halite (rock salt) L a ( 500 m w.e. Depth to >10km Diameter: 3-8 km V eff ~ 100-200 km 3 w.e. No known background >2p steradians possible 1 2 3 4 5 6 7 Depth (km) Meeting at SLAC Feb/05 : SalSA Collaboration born U-Hawaii,UCLA, SLAC, … Basic array geometry simulated P. Gorham talk at SLAC meeting 2.5 km 3 array with 225 m spacing 12 2 =144 strings, 12 3 =1728 antenna nodes 12 antennas per node, dual polarization ~300 km 3 sr at 1 EeV threshold 10 17 eV, few 100s antennas hit at 1 EeV, >1000 hits at 10 EeV Rate: claim at least 10 events per year from rock-bottom minimal GZK predictions Phase 1: look for right location deploy test strings in a few holes study attenuation, noise etc in-situ The Salt ARENA I

11. IceCube Meeting Berkeley11March, 23 2005 The Salt ARENA I Add acoustic detector array to SalSA? Theoretical expectations : WaterIceSalt ρ [g/cm3]1.92.1 Vs [m/s]145038004500 P/Pwater11025 f/fwater1~3~6 eff. abs~km  7? km noiselargesmall ? From B.Price at SLAC meeting 02/05 Need measurements : learn from geophysicists f = 1 – 100 kHz, f res = 150 kHz Signal attenuation λ att = 1/α S = Ae -αr /r n n = 2 used λ att ≈ 170 m ! Signal location < 1 m T. Spies, J. Eisenblätter, J.Manthei, Z. f. angewandte Geologie, H2, 2002, 30 and references therein 1 crack seen by 12 detectors pressure waves + shear waves

12. IceCube Meeting Berkeley12March, 23 2005 The Salt ARENA II http://www.lofar.org interferometer in frequency range of 10 - 200 MHz array of 100 stations of 100 dipole antennas baselines of 10 m to 400 km All-Sky monitor: transient events LOFAR salt pillars Zechstein salt Detect UHE ’s using rock salt in Northern Europe (Groningen) Monitor UHE CR’s with LOFAR Develop: radar techniques for salt domes techniques to install antennas in salt domes LOFAR + ZESANA Zuidwending Onstwedde Zuidwending  7,5 km  A. M. van den Berg, SLAC meeting 02/05 From A. M. van den Berg, SLAC meeting 02/05

13. IceCube Meeting Berkeley13March, 23 2005 The Ice ARENA IceCube Collaboration: Study a hybrid optical-radio-acoustic array Idea behind: try to cross calibrate the detector, if discovery is made with one technique, confirmation with different technique necessary IC++ : o radio +acoustic  optical (IceCube)  o+r+a (IceCube+) example: 0.5 km spacing 1.5 km strings 91 strings V eff = 58 km 3 λ abs min N ch GZK (H+S)events/year 1 km4min0.5 1km4max1.5 6 km4min18 6 km4max54 acoustic array alone: acoustic noise : From J. Vandenbroucke, IceCube meeting Uppsala 10/04

14. IceCube Meeting Berkeley14March, 23 2005 The Ice ARENA Radio antennas for ice available and tested (RICE) Acoustic glaciophones under development : iron ball glass ball Calibration (until now only in water) reference hydrophone: Sensortech SQ03: -163.3±0.3 dB re 1V/μPa Improvement (S/N) ib = 50 (S/N) gb = 15 From S. Böser et al., to be published Testrun at proton beam: E tot = 5.6 PeV – 1.7 EeV E min (1m)  10 PeV P min : ~10 mPa

15. IceCube Meeting Berkeley15March, 23 2005 The Ice ARENA Ice properties for propagation of light measured (AMANDA) Ice properties for propagation of radio signals measured (RICE) Ice properties for propagation of sound waves still to be measured urgent requirement:  study ambient noise  measure absorption length test foreseen for season 05/06 x Proposal: use 3 holes diameter: ≥ 6” depth: 400 m 7 sensors per hole large variation of ice properties at the surface  non-equal spacing 7 transmitters per hole no possibility for transmitter allingment  azimuthal symmetry

16. IceCube Meeting Berkeley16March, 23 2005 Timescale and Competition ProjectR&D timeR&D fundingRealizationProblems KM3Net + acoustic2004-2008~1 Mio E> 2012deployment, cost AUGER + Radio2004-2008???> 2008AUGER Nord SalSA + (acoustic)2005-20083-5 Mio $> 2008location, acoustic, cost ZESANA + LOFAR2005-2008???> 2010cost IC++ opt./rad./acou.2003-20070.1 Mio E> 2010location,acoustic A hybrid extension could make IceCube the pre-eminent neutrino telescope at all cosmic energies But other projects near to take over

17. IceCube Meeting Berkeley17March, 23 2005 International ARENA Workshop May, 17 – 19 2005 DESY, Zeuthen, GERMANY http://www-zeuthen.desy.de/arena

18. IceCube Meeting Berkeley18March, 23 2005 Summary + Conclusions For the observation of the tiny neutrino fluxes above 10 18 eV  Optical detection techniques seem to reach their limits  Radio detectors start to become sensitive  Acoustic detectors have a big revival but still need R&D Further progress would profit from  Combination of different detection techniques in one project  Dedicated experiments at large scales  Network of worldwide cooperation