On 10 April 2014, the 12 country delegates mandated by their governments to decide about the start of site negotiations for CTA met in Munich. They took note of the report of the international Site Selection Committee (SSC) and thanked the members of the SSC as well as the CTA consortium for their extensive inputs on the merits of the proposed sites.
The delegates representing Argentina, Austria, Brazil, France, Germany, Italy, Namibia, Poland, Spain, South Africa, Switzerland and the UK decided, based on the 75% majority required, to start the negotiations on the two sites in the southern hemisphere, namely Aar in Namibia and ESO* in Chile, keeping Leoncito in Argentina as a third option. After negotiations finally one site will be selected at the end of the year. With the selection of the potential telescope sites in the southern hemisphere an important step towards the realization of the international Cherenkov Telescope Array has been made.
As far as the northern site of the CTA Observatory is concerned – candidate sites are located in Mexico, Spain and the USA – further considerations are necessary. Therefore, the delegates decided to postpone their decision and to ask the CTA board of agency representatives – the Resource Board – to take this forward.The decision for the negotiations about the northern hemisphere site will be taken as soon as possible.
“We are very happy that this important step has been reached” said B. Vierkorn-Rudolph, chair of the CTA Resource Board. “CTA will be a unique large-scale infrastructure for astronomy – with this decision we now can start the negotiations with the potential site countries in the southern hemisphere and advance the implementation of CTA.” The spokesperson of the CTA Consortium, Professor Werner Hofmann said “The site choice is on the critical path towards implementing CTA; this decision represents a major step forward and we appreciate very much the engagement and support of the funding agencies and the country delegates involved in the decision”.
CTA – the Cherenkov Telescope Array – is a multinational, worldwide project to construct a unique instrument exploring the cosmos at the highest photon energies. Over 1000 scientists and engineers from 5 continents, 28 countries and over 170 research institutes participate in the CTA project. CTA will provide an order-of-magnitude jump in sensitivity over current instruments, providing novel insights into some of the most extreme processes in the Universe. CTA will consist of over 100 Cherenkov telescopes of 23-m, 12-m and 4-m dish size located at one site in the southern and a smaller site in the northern hemisphere. Potential candidate sites have been identified in the northern and southern hemisphere. Extensive studies of the environmental conditions, simulations of the science performance and assessments of costs of construction were conducted. The Site Selection Committee, composed of international experts in the evaluation of sites for astronomical observatories, has reviewed the studies and provided an independent assessment of the various candidate sites.
Please note, profiles of colleagues who registered as evaluators in FP7 are not automatically transferred to the new database. You must log in at the above website and confirm your profile again to be registered again as evaluator for Horizon 2020.
The discovery of cosmic high energy neutrinos with IceCube has been awarded by the PHYSICS WORLD magazine as the breakthrough of the year 2013. An interview with Maarten de Jong, Professor at NIKHEF and spokesperson of KM3NeT.
Maarten, the IceCube Collaboration has been awarded the PHYSICS WORLD breakthrough of the year 2013. What do you feel about this as (1) a neutrino physicist and (2) as the responsible project manager of KM3NeT?
Maarten de Jong: I appreciate this recognition for the important achievements of the IceCube collaboration. The latest results do not only consolidate the relatively new field of neutrino astronomy, they put neutrino astronomy at the heart of the wider astroparticle physics programme. While IceCube has shown that the detection of cosmic neutrinos is possible today, the foreseeable future may tell us the answers to many long-standing questions such as: what is the origin of cosmic rays and how do cosmic particle accelerators work?
The recent observations by IceCube represent a major boost to the KM3NeT project. I am delighted because it validates my firm believe that neutrino astronomy has a bright future and because KM3NeT is now in an ideal position to fulfil this future.
The neutrino window to the cosmos has now really been opened by IceCube?
Maarten de Jong: Yes, now it is time to look through the window and see what is behind.
How about the science case of KM3NeT, frozen in concrete by the Icecube results?
Maarten de Jong: IceCube demonstrates the requirements, in particular the size, for building a neutrino telescope capable to detect cosmic neutrinos. Compared to IceCube, an experiment in water offers a better angular resolution and can be easier expanded to a larger sensitive volume. KM3NeT will provide the capability for really doing neutrino astronomy.
Furthermore, IceCube and KM3NeT complement each other to cover the full sky. Scientifically very interesting, the field of view of KM3NeT includes the central region of our Galaxy, which hosts many potential sources of high-energy neutrinos. So, KM3NeT may well be the first to identify the sources of the observed high-energy neutrinos.
And let’s face it, as an underwater infrastructure KM3NeT offers a lot of opportunities that go far beyond neutrino astronomy. Antares demonstrates that there is synergy with Earth and sea sciences.
Can you explain what is KM3NeT phase-1.5?
Maarten de Jong: Following the design study and preparatory phase, the KM3NeT “phase-1” project was launched in January 2013 with an available budget of about 31M euro. The costs for the complete infrastructure, which we call “phase-2”, amount to about 220–250M euro. During a joint meeting with Antares, IceCube, KM3NeT and Lake Baikal in October 2013, the idea of an intermediate phase emerged. The main objective of “phase-1.5” is to be as sensitive as IceCube and measure the IceCube signal with different systematics, improved resolution, and complementary field of view.
IceCube’s technology has been developed in the 1990s/early 2000s, which is more than 10 years ago. Concerning KM3NeT, what major technology developments have been made since that time?
KM3NeT DOM at Nikhef
Maarten de Jong: In general, a neutrino telescope consists of a huge three-dimensional array of photosensors deployed in a transparent medium such as deep water or ice. Among many developments made to increase sensitivity and reduce costs I would like to emphasize that the last decade demonstrated that even the well-known photo-multiplier tube (PMT) technology could be advanced to substantially higher sensitivities. Compared to the traditionally used large PMTs of typically 10 inch size inside a glass sphere, KM3NeT developed an alternative based on incorporating many newly designed small PMTs of 3 inch size inside the same glass sphere. This design helped maximizing the total photo-cathode area, improving photon counting and directionality and reducing costs. The KM3NeT design has attracted interest from other scientific groups as well as industry for the implementation of the low-power high voltage. Following the demand of KM3NeT, the price of small PMTs is now competitive -if not better- compared to large PMTs. In addition to a price reduction, the segmentation of the photo-cathode brings in better data for science. This is like in your digital camera: more pixels yield a better picture!
The readout of the detector is based on the “All-data-to-shore” concept pioneered in Antares. In this, all analogue signals from the PMTs are digitized and all digital data are sent to shore for real-time processing by a farm of commodity PCs. Modern electronics and fiber-optics combined with state-of-the-art firmware and software provide for a flexible and cost-effective implementation of the readout system.
All in all, the costs for the KM3NeT detector are significantly less than those of previous detectors. In short, the KM3NeT telescope will be at least five times larger than IceCube for less than double of the price. In this respect, KM3NeT can be considered as the next generation neutrino telescope.
As a final question for today: In the global context, where do you place KM3NeT?
Maarten de Jong: In October 2013, the Antares, IceCube, KM3NeT and Lake Baikal collaborations signed the Memorandum of Understanding for a Global Neutrino Network (GNN). This step formalized the already active cooperation between the different groups. Once infrastructures of similar scale are operational on the three continents, the stated aim of the GNN is a worldwide Global Neutrino Observatory.
After signing the MoU on GNN: From left to right Christian Spiering (DESY, Zeuthen), Maarten de Jong (Nikhef, Amsterdam) Tyce deYoung (PennState Univ., University College), Zhan-Arys Dzhilkibaev (INR, Moscow), Juan-José Hernandez-Rey (Univ. Valencia), Paschal Coyle (CPPM, Marseille), Olga Botner (Univ. Uppsala), Uli Katz (Univ. Erlangen).
The idea to closer link the neutrino telescope projects underwater and in ice has been discussed in the international community of high-energy neutrino astrophysicists for several years. Finally, at October 15 of this year, representatives of the collaborations ANTARES, BAIKAL, IceCube and KM3NeT signed a Memorandum of Understanding on a Global Neutrino Network (GNN). The signature act (see picture) was part of the annual common meeting of all four collaborations, this time in Munich.
GNN aims for a closer collaboration and a more coherent strategy among the neutrino telescope communities and for exploitation of the resulting synergistic effects. It will serve as a forum for formalizing and further developing the present annual Mediterranean-Antarctic Neutrino Telescope Symposium (MANTS) meetings and biannual international workshop on Very Large Volume Neutrino Telescopes (VLVNT).
Goal of GNN include the coordination of alert and multi-messenger policies, exchange and mutual checks of software, creation of a common software pool, establishing a common legacy of public documents, developing standards for data representation, cross-checks of results with different systematics, the organization of schools, and other forms of exchanging expertise, e.g. through mutual working visits of scientists and engineers or by forming ad-hoc advisory committees of members of the four participating collaborations.
No doubt, the recent evidence for extraterrestrial neutrinos by IceCube gave wings to GNN and encourages KM3NeT (Mediterranean Sea) and GVD (Lake Baikal) to focus their efforts towards a first Northern cubic kilometre detector and to ask for appropriate funding. At the same time, also IceCube considers extension of its present configuration. Once the Northern projects KM3NeT will have evolved to a comparable scale as IceCube, GNN might be even develop into a more formal consortium, tentatively christened GNO (Global Neutrino Observatory).
The APPEC Horizon 2020 Workshop on November 4/5, 2013 has put the magnifying glass on the coming EU Framework Programme for Research and Innovation
This time the big questions were not about fundamental research in astroparticle physics, but what to expect from the new Framework Programme for Research and Innovation (Horizon 2020). Very soon, with the adoption of the Horizon 2020 work programme on December 11, 2013 the first calls for proposal shall be published, the most recent draft documents can be found online. It is important to note that first deadlines will already be in April 2014.
More than 120 astroparticle physicists from 12 European countries followed the invitation to attend the APPEC workshop at DESY in Zeuthen. The aim of the workshop was to provide participants with firsthand information on funding opportunities for both, individual researchers as well as groups applying for collaborative projects.
Structure of Horizon 2020
Horizon 2020 is structured in three pillars: excellent science, industrial leadership, and societal challenges. While it is not excluded that there may be opportunities also in the last two pillars, excellent science is the main target for basic research and thus was put in the focus of the workshop.
On the first day, EU experts from National Contact Points (NCPs) presented the various funding instruments based on the currently available information. Together with the general conditions to apply for the European Research Council (ERC) grants and Marie Skłodowska Curie Actions (MSCA) the experts gave practical advice on competitive proposal writing and changes in comparison to the 7th Framework Programme (FP7).
Giorgio Rossi, the vice chair of the Physical Sciences and Engineering (PSE) strategy working group of ESFRI (European Strategy Forum on Research Infrastructures), was invited to present the ESFRI strategy and the relation to Horizon 2020. He reported on the European Commission’s goal to have 60% of the projects on the current ESFRI roadmap implemented in 2015. Therefore, ESFRI initiated an assessment of all projects (including the two astroparticle RIs CTA and KM3NeT) concerning the management, governance, and financial aspects. The results are summarized in the high level expert group report “Assessing the projects on the ESFRI roadmap”.
A fourth presentation took a detailed look at the topic Future Emerging Technologies (FET), a programme with several funding instruments to support R&D projects closely linked to application. For instance, the thematically open calls within FET-Open shall allow submitting proposals for exploring novel ideas almost anytime.
On the second day, the workshop continued with parallel working groups (conveners in parenthesis) thematically focusing on:
Cosmic Rays (A. Haungs)
Gamma Rays (J. Knapp)
Gravitational Waves (M. Punturo)
Underground Physics (L. Baudis)
Underwater Research (P. Coyle)
Neutrinos (M. Mezzetto)
Computing (G. Lamanna)
Theory (A. Masiero)
Technology (S. Katsanevas)
The individual groups were asked to develop ideas and strategies for collaborative projects and coordinate proposals for the upcoming calls in 2014 and 2015. The results have been presented to the full audience; the presentations can be accessed at the APPEC workshop website. In the final discussion of the workshop it has been agreed that APPEC shall continue to collect and prepare all relevant Horizon 2020 information for the community. The working groups shall act as the information hubs into the entire astroparticle physics community, so if you want to be part of any of these groups please fill in this formand/or please get in touch with the convener(s) of your preferred topic(s).
Ernie, high-energy neutrino observed with IceCube (picture: IceCube Coll.)
In one of the episodes of the “Sesame Street”, the protagonists Ernie and Bert debate on Ernie’s frozen ice cubes which miraculously had disappeared. The story makers could not have guessed that some forty years later, members of a 270M dollar endeavour called IceCube would debate on the miraculous appearance of two events, and that these events would be nicknamed “Ernie” and “Bert” by some imaginative PhD students. Moreover, it would have gone beyond the imagination of the Sesame Street people that these two events would be interpreted as a first hint to something what scientists call “high-energy extraterrestrial neutrinos”.
IceCube is a cubic kilometre neutrino telescope installed in the deep Antarctic ice at the South Pole. The detector consists of 86 strings each equipped with 60 light sensors. The sensors record the faint light emitted by relativistic charged particles – including those which have been generated in neutrino interactions. IceCube construction was started in December 2004 and completed in December 2010, but data have been taken already before completion, year by year, with the strings already installed.
The ultimate goal of IceCube is to identify individual sources of extraterrestrial energetic neutrinos. These are neutrinos which have not been generated in cosmic-ray collisions in the Earth’s atmosphere (IceCube has recorded more than 105 of such “atmospheric neutrinos”), but which have reached us directly from distant cosmic objects like supernova remnants or active galactic nuclei. A neutrino signal would provide a watertight proof that the corresponding object is also a source of charged cosmic rays. Although IceCube has improved the sensitivity to energetic neutrinos by a factor 1000 over the last twelve years, it could not yet pinpoint any individual source. Neutrinos from such “point-like” sources would appear as an accumulation of events from a certain direction of the sky. Instead, the IceCube scientists collected growing evidence, that there is a tiny excess of events at the very highest energies which seem to arrive as a diffuse flux from many sources, or even from all directions.
High-energy tails in the energy spectrum had been observed repeatedly in analyses of data taken with the 40-string and 59-string configurations of IceCube. These deviations exceeded the predicted spectrum for atmospheric neutrinos by roughly two standard deviations (~2s). The first step clearly beyond 2s was made with an analysis of data taken in 2010 and 2011 with the 79-string and 86-string configurations. This analysis focused to energies larger than ~500 TeV and provided two events with reconstructed energies of 1.04 and 1.14 PeV (1 PeV = 103 TeV = 106 GeV): “Ernie” and “Bert” (see the figure). Ernie and Bert represent a 2.8s excess over the expectation for atmospheric neutrinos 1.
Motivated by this result, an alternative analysis of the same data was performed. It constrains the event to start in the inner volume of IceCube (using the outer part as veto layer), and at the same time considerably lowers the threshold compared to the first analysis (down to some tens of TeV).
Bert, high-energy neutrino observed with IceCube (picture: IceCube Coll.)
Results of this analysis have been firstly presented at May 14, 2013 at a conference in Madison/USA. It provides 28 events with energies deposited in the detector ranging from ~30 TeV to 1.14 PeV. “Ernie” and “Bert” stoically defend their top position in energy. Notably also the events at somewhat lower energies (~30 TeV – ~250 TeV) can hardly be explained alone by atmospheric neutrinos or by muons sneaking unrecognized from above into the detector. The calculated contribution of such “trivial” sources to the total of 28 events is estimated to only 12 events 2.
Does that mean that extraterrestrial high-energy neutrinos have incontrovertibly been detected? Certainly not! With a statistical significance of 4.1s, the excess has not yet reached the magical benchmark of 5s. Moreover one cannot exclude that estimates of the background from atmospheric neutrinos are still somewhat too low. This particularly applies to the so-called prompt neutrinos which emerge from the decay of short-lived charm particles high in the atmosphere. Such an underestimate would lead to an overestimation of the extraterrestrial contribution. However, the IceCube collaboration will have analyzed about twice the amount of data in autumn. The doubling of the statistics will go hand in hand with steadily improving understanding of systematic effects.
Summing up: we see light at the end of the tunnel – 40 years after the first detector of this kind was conceived3)! We are reluctant to open the bottles right now, but the Champagne is already in the fridge. With some luck we may pass the 5s benchmark within a few months…
1) M. Aartsen et al. (IceCube Coll.), First observation of PeV-energy neutrinos with IceCube, accepted for publication in PRL, arXiv:1304.5356
2) M. Aartsen et al. (IceCube Coll.), Evidence for High-Energy Extraterrestrial Neutrinos at the IceCube Detector, paper submitted for publication.
3) C. Spiering: Towards High-Energy Neutrino Astronomy. A Historical Review, EPJ-H 37 (2012) 515, arXiv:1207.4952
