Acoustic particle detection Robert Lahmann HAP Workshop: The - PowerPoint PPT Presentation

Acoustic particle detection Robert Lahmann HAP Workshop: The Non-Thermal Universe 
 Erlangen, 21-Sept-2016

Outline ● Introduction: acoustic neutrino detection ● The “first generation” of acoustic neutrino test setups ● Lessons learned and future activities ● Conclusions HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann

Neutrino signatures in different media sensor density sounddisk Ο (100)/km 3 radio lobe Ο (10)/km 3 optical Ο (1000)/km 3 light cone Salt domes Permafrost 10 16 eV 10 17 eV 10 18 eV Water Ice adapted from: R. Nahnhauer, ARENA Conf. 2010 light ü ü Advatages of acoustic detection: radio • long attenuation length ü ü ü • simple, robust technology sound ü ü ü ü • multi purpose applications HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 3

Acoustic signals of neutrino interactions Thermo-acoustic effect: (Askariyan 1979) energy deposition ð local heating (~µK) ð expansion ð pressure signal Bipolar Hadronic cascade: Pressure ~10m length, few cm radius Signal Pressure [Pa] (BIP) ~1 o ν Time Pressure field: Characteristic “ pancake ” pattern f max = O(10kHz) HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 4

The bipolar pulse E 0 Analytical calculation of a p max ∝ γ G signal in the far field for a 2 σ ρ ν Gaussian energy density γ G = c 2 α ~1.12 cold ice ~0.15 Med. C P 2 p max ~0.015 Baikal σ ρ α = Volume expansion coefficient C P = specific heat capacity (at constant pressure) ∫ ( ε : energy density) E 0 = ε dV c = speed of sound (ca. 1500 m/s in water) HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 5

− − � − � Attenuation length � water IceCube site (SPATS) 4 8 Absorption Length [km] 10 weighted mean � (3.202 km − 1 ) (from: T. Karg, ARENA2012) width of weighted distribution (+/ − 0.574 km − 1 ) 7 Mediterranean 3 10 6 2000m 5 2 100m 10 4 � [km − 1 ] 1 3 10 ~5km NaCl ⇔ Na + Cl − fresh water 2 0 10 1 0 − 1 10 MgSO 4 ⇔ Mg 2 + SO 4 − 1 shallow deep 2 − − 2 − 2 10 0 1 2 3 C190 C250 C320 C400 B190 B250 B320 B400 A190 A250 A320 A400 D190 D250 D320 D400 D500 10 10 10 10 Frequency [kHz] module + 68 m λ = 312 − 47 shorter than expected, but no show stopper HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 6

Acoustic detection test setups “First generation” acoustic test setups for feasibility studies (background), developing techniques/algorithms Two approaches: ● Use of existing (military) arrays ● piggybacking on neutrino telescope infrastructure Technology: Hydrophones (in water) and glaciophones (in ice) using piezo ceramics Array size: O(10) sensors HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann

Test setups in ice and water ACORNE (M) AMADEUS KM3NeT-Italia/OnDE (ANTARES) Baikal SAUND (M) green: currently operational (M): military array salt water fresh water ice SPATS (IceCube) HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann

Limits on UHE neutrino flux SPATS ACORNE SPATS, ARENA 2012 SAUND2 R. Abbasi et al.,arXiv:astro-ph/1103.1216 HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann

OnDE ambient noise (ARENA 2008) Main source: Surface agitation and precipitation Average noise 2005-2006 Sea State 2 Average noise per file [mPa] 1 Sea State 0 f 2 ⎡ ⎤ 2 A ( , f f ) PSD ( ) f df = ∫ ⋅ p 1 2 ⎢ ⎥ ⎣ f ⎦ 1 The average noise in the [20:43] kHz astro/ph 0804.2913 band is 5.4 ± 2.2 stat ± 0.3 syst mPa HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann

AMADEUS transient background investigations • Sources: Very diverse; Shipping traffic, marine mammals, … ð Mostly originating from near surface • Suppression: • signal classification • Project reconstructed signals to surface, perform clustering HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann

Lessons learned and future experiments Mediterranean ( è KM3NeT): ● Ambient noise low and stable; reduction of SNR for signal detection crucial ● Transient background: High level of (mainly dolphins); Recognition of “acoustic pancake” crucial Lake Baikal ( è GVD): ● Good background conditions, easy deployment, but low signal amplitude due to low temperature in lake Ice ( è IceCube-Gen2 ?): ● Attenuation length shorter than expected, but no show stopper; combination optical/radio/acoustic provides unique potential HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann

Lake Baikal Acoustic detector Integrated in GVD 450 м GVD: Gigaton Volume 625 м Recording acoustic Detector; Modules - 8 units Planned for 2020 With step 20m Main problem for 1300 м acoustic detection: low temperature GVD optical modules 1360 м 60 м (from: N.Budnev, ARENA2016) HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 13

KM3NeT design piezo sensor integrated into OM HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 14

Potential fiber hydrophone system for KM3NeT ● Erbium doped fibers with a grating ● Sensor oil filled hose or solid cable Convert pressure pulse to a mechanical deformation of the fiber: strain ● Interrogator on-shore system TNO (Dutch organization for applied scientific research) joined KM3NeT to pursue this technique HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 15

Acoustic Sensors for IceCube-Gen2 • IceCube-Gen2 is a planned extension of IceCube Neutrino Observatory • Increased detector volume (~ 10 km 3 ) in the Antarctic ice • Increased spacing between detector modules (~ 240 m – 300 m) → Optical geometry calibration (accuracy < 1m) is expected to deteriorate → Use acoustic signals, due to larger extinction length ( ~ 300m [SPATS]) for geometry calibration • Develop acoustic positioning concept for IceCube-Gen2 • Use sensors for acoustic neutrino detection Up to now: (master’s thesis S. Wickmann) • Modified existing acoustic sensor from the EnEx project • Two channels: Channel 1 for positioning, channel 2 for neutrino detection • Substantially reduced power consumption • Integrated modified sensor into an IceCube DOM • Tested the acoustic positioning concept in water Acoustic Sensors for IceCube-Gen2 16 [SPATS] : R. Abbasi, et al., Astropart. Phys. 34, 382–393 (2011). 21/09/16

Conclusions ● “First generation” acoustic arrays have been used to investigate neutrino detection methods and provide input for simulations ● Extension of investigations possible with KM3NeT, GVD and IceCube-Gen2 HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 17

Thank you for your attention!

Acoustic signals of neutrino interactions in water I Thermo-acoustic effect: (Askariyan 1979) energy deposition ð local heating (~µK) ð expansion ð pressure signal Wave equation for the pressure p for deposition of an energy density ε : 2 2 1 p ∂ α ∂ ε 2 p ∇ − = − 2 2 2 c t C t ∂ p ∂ α = Volume expansion coefficient C P = specific heat capacity (at constant pressure) c = speed of sound in water (ca. 1500 m/s) Solution (analytical/numerical) with assumption of an instantaneous energy deposition HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 19

Erbium doped fibers as hydrophones for KM3NeT? reflection 1530 wavelength [nm] 1570 ICHEP 2014, Valencia - July 05, 2014 - Robert Lahmann 20 20

Sound absorption length in water 4 Absorption Length [km] 10 3 10 Mediterranean 2000m 2 100m 10 1 10 ~5km NaCl ⇔ Na + Cl − fresh water 0 10 − 1 10 MgSO 4 ⇔ Mg 2 + SO 4 2 − − 2 10 0 1 2 3 10 10 10 10 Frequency [kHz] HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 21

Acoustic signals of neutrino interactions in water I Thermo-acoustic effect: (Askariyan 1979) energy deposition ð local heating (~µK) ð expansion ð pressure signal Wave equation for the pressure p for deposition of an energy density ε : 2 2 1 p ∂ α ∂ ε 2 p ∇ − = − 2 2 2 c t C t ∂ p ∂ α = Volume expansion coefficient C P = specific heat capacity (at constant pressure) c = speed of sound in water (ca. 1500 m/s) Solution (analytical/numerical) with assumption of an instantaneous energy deposition HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 22

Acoustic signals of neutrino interactions in water II 0.12 0.1 Hadronic cascade: Bipolar 0.08 ~10m length, few cm radius Pressure 0.06 Pressure [Pa] Pressure [Pa] (simulations by ACoRNE Coll.) Signal 0.04 (BIP) 0.02 0 -0.02 ~1 o ν -0.04 -0.06 10 11 GeV @ 1000m -0.08 -0.04 -0.02 0 0.02 0.04 Time [ms] Time [ms] Pressure field: Characteristic “ pancake ” pattern Long attenuation length (~5 km @ 10 kHz) HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 23

Temperature profile 0 0 Depth [m] Depth [m] − 500 − 1000 winter summer − 1000 − 2000 − 1500 − 3000 − 2000 − 4000 − 2500 − 5000 12 14 16 18 20 22 24 0 5 10 15 20 25 30 Temperature [C] Temperature [C] (a) (b) Tropical Ocean Mediterranean Sea 24 o 30’N and 72 o 30’W HAP Meeting Erlangen - 21-Sept-2016 - Robert Lahmann 24