Very High Energy Neutrinos

Beyond atmospheric neutrinos, produced by the interactions of cosmic rays in the upper atmosphere, it was soon anticipated that violent astrophysics phenomena like active galactic nuclei could produce very high energy neutrinos as well as high energy gamma rays.

First proposals

The first detectors of atmospheric neutrinos in 1965 were particle or nuclear physics types [Ach65a,Rei65b]. It was difficult to build huge detectors of this type. But, at the 1960 Rochester Conference, Moisei Markov had reported his brilliant and prescient idea of deep underwater neutrino detection: “we propose setting up apparatus in an underwater lake or deep in the Ocean to separate charge particle direction by Cherenkov radiation” [Mar60]. Indeed, water is very cheap and the target itself is not a limiting factor. The idea revived in 1973, at the ICRC Conference, where a small group discussed a deep-water detector to clarify puzzles in muon depth-intensity curves. The first DUMAND workshop in 1975 [Kot75] chose Hawaii as a possible site to welcome the proposed detector: a large volume of deep sea equipped with lines of photomultipliers. To observe neutrinos coming from astrophysical sources, it was mandatory to suppress the background due to the many atmospheric neutrinos which come downward. So the detection principle focused on upward-traveling muons coming from high-energy (> 1 GeV) muon-neutrino interactions. The photomultipliers record arrival time and amplitude of Cherenkov light emitted by muons or particle cascades. It has been followed by a long series of DUMAND workshops which are reviewed in the history paper by A. Roberts [Rob92].

The possible astrophysical sources identified in 1978 were neutron star binary systems, like Cygnus-X3 and TeV-gamma-rays sources, as well as “hidden” sources observables only in neutrinos, not in gammas. The calculations of the flux predictions for still uncertain sources made in any case necessary to build huge detectors.

From DUMAND to IceCube

After a first proposal DUMAND-I, the DUMAND-II detector (100 m diameter and 230 m high) was proposed in 1988. In the 80’s, similar activity was developed in USSR, exploring the possibilities of the Baikal Lake with the name NT 200 (about 200 optical modules). But 1988 was also the time of the first “International Venice Workshop on Neutrino Telescopes” where the crazy idea to use high depths of ice (as in the Antarctic) to observe neutrinos was discussed by Francis Halzen and John Learned.

In the 90’s, the first prototypes of DUMAND failed, showing that ocean is also a hostile environment, and the funding agencies did not give a second chance. Developments in ice were more lucky and the first AMANDA prototype (80 optical modules) was deployed at the South Pole in 1993-1994. In Russia, the Baikal NT 200 was completed only in 1998 [Bel97]. In the Mediterranean Sea, the NESTOR project was proposed in Greece in 1993 [Res94] but never reached a critical size, the ANTARES experiment (12 lines of photomultipliers) was launched in 1995 [Asl99] and the NEMO R&D in 1998.

        In the 90’s, new developments in astrophysics showed that detectors of the km3size were needed to observe sources like the active galactic nuclei. AMANDA [Hal96], ANTARES and NT-200 were then considered as prototypes for km3 size detectors: this gave rise to IceCube in Antarctica (5000 optical modules installed on 86 strings at depths of 1450 to 2450 m), the most advanced detector and Km3Net in Mediterranean Sea [Bag08]. In 2013, IceCube observed two events in the PeV (1018 eV) range, the first very high energy neutrino events coming from yet unknown cosmic accelerators [Aar13a]. A crowning has been the recent detection of a high-energy neutrino with an energy of approximately 290 TeV, arriving from a known gamma-ray blazar TXS 0506+056 [Ice18], announcing the birth of multi-messenger astronomy.
South Pole : IceCube detector, control room


Acoustic and radio-detection technics

If the Cherenkov technique has been largely developed since the 90’s, one needs much more sensitive detectors to detect the feeble fluxes at energies above 100 PeV (ultra high-energy neutrinos). Three techniques have been studied: acoustic detection, radio detection and detection via air showers. Acoustic detection [1]is reviewed by Nahnhauer [Nah10]. The original idea is from Gurgen Askaryan in 1957 [Ask57] and the technique was studied by the DUMAND collaboration, Igor Zheleznykh and others, but did not yet reach the critical stage. G. Askaryan is also at the origin of the radio detection [Ask62]. In 1983, Gusev and Zheleznykh proposed the Radio Antarctic Muon and Neutrino Detector (RAMAND) with radio antennas listening to the ice (electromagnetic cascades emit coherent Cherenkov radiation at radio frequencies. It has never been built, but the RICE and ANITA projects, deployed in Antarctic, gave limits on neutrino fluxes. Air-shower arrays like Pierre Auger Observatory or Telescope Array have been built to measure very high energy cosmic rays. They are also looking for showers induced by high energy neutrino interactions deep in the atmosphere.

[1] The neutrino interacting with a nucleon of the target material produces an outgoing lepton and a hadronic particle cascade. In this process a large amount of energy is nearly instantaneously produced in a small volume of cascading particles. The overheating of that volume leads to a corresponding pressure pulse, which develops in a disk transverse to the incoming neutrino direction. The pressure amplitude is directly proportional to the cascade energy.

Further information

A complete and lively historical review “Towards High-Energy Neutrino Astronomy” has been written by Christian Spiering [Spi12].

The online Symmetry Magazine published in April 2013 an article on IceCube’s highest-energy neutrino ever found.

During the conference on the History of the Neutrino (Sept. 5-7, 2018 in Paris) the history of High Energy Neutrinos was reviewed by :


Aar13aM.G. Aartsen et al., IceCube coll. First Observation of PeV-energy neutrinos with IceCubePhys. Rev. Lett. 111 (2013) 021103; arXiv:1304.5356
Ask57G. Askaryan Hydrodynamic radiation from the tracks of ionizing particles in stable liquids Sov. J. Atom. Energy 3 (1957) 921
Ask62G. Askaryan Excess negative charge of an electron-photon shower and its coherent radio emissionSov. Phys. JETP 14 (1962) 441
Asl99E. Aslanides et al., ANTARES collaborationA deep sea telescope for high energy neutrinosarXiv:astro-ph/9907432
Bag08P. Bagley et al.KM3NeT: Conceptual Design Report
Bel97I.A. Belolaptikov et al.The Baikal underwater neutrino telescope: design, performances and first resultsAstroparticle Physics 7 (1997) 263
Hal96F. Halzen Status of the AMANDA South Pole detectorarXiv:hep-ex/9611014
Ice18Ice Cube, Fermi-LAT, Magic, Agile, HESS, … collaborationsMulti-messenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922Science 361 (2018) 1378 ; arXiv:1807.08816
Mar60M.A. Markov On high energy neutrino physics Proc. 10th Int. Conf. on High-Energy Physics, Rochester, 1960, p. 579
Nah10R. Nahnhauer Acoustic particle detection – from early ideas to future benefits Nucl. Instr. and Methods A662 (2012) S20; arXiv:1010.3082
Rei65bF. Reines, M.F. Crouch, T.L. Jenkins, W.R. Kropp, H.S. Gurr, G.R. Schmid, J.P.F. Sellschop, B. MeyerEvidence for high energy cosmic ray neutrino interactions Phys. Rev. Lett. 15 (1965) 429
Res94L. Resvanis et al., NESTOR collaborationNESTOR: A neutrino particle astrophysics underwater laboratory for the MediterraneanNucl. Phys. B (Proc. Suppl.) 35 (1995) 294
Rob76A. Roberts, ed.DUMAND-76Proc. 1976 DUMAND Summer Workshop, September 1976, Hawaii
Rob92Arthur Roberts The birth of high energy neutrino astronomy : a personal history of the Dumand project Rev. Mod. Phys. 64 (1992) 259
Spi12Christian Spiering Towards High Energy Neutrino Astronomy – A Historical Review European Physical Journal H 37 (2012) 515; arXiv:1207.4952

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