Piera Sapienza: Km3Net
The energy region spanned by neutrino sources from the cosmos is huge, so the sensitivity must be optimized for the different sources. The object of Km3Net is to build the most sensitive neutrino telescope to study this wide energy region.
The challenges and design of a large scale underwater neutrino telescope are multiple. Optical modules are pressure-resistant glass spheres containing the PMTs. These are deployed in strings. Each contains 31 3″ PMTs. All the electronics is inside, and there are 20 storeys, with 40 meter inter-storey distance. Data transmission is being performed at several Gb/second to shore.
The speaker discussed several of the sources that Km3Net can study, and the sensitivity that the detector could have to discover the emission of neutrinos from these sources. These include the so-called “Fermi bubbles, gamma emission mesured to up to hundreds of GeV by Fermi.
They are funding for about 40MEuros. This allows for the start-up of a first phase of the construction. An expansion of the infrastructures is going on in Capo Passero and Toulon, with construction and deployment of first units. There are three options for the site hosting the detector.
The Capo Passero site was characterized by the NEMO collaboration. Due to rigid time constraints on the spending profile of the regional fundings, a first batch of detection units will be built there.
The site near Toulon is a bit west of the Antares site. On the sea floor one must deploy a modular net. The first node will be operational at the end of this year.
In conclusion, Km3Net has a robust physics case with several galactic sources at reach in few years of operation. The technology has been developed. The funding allows to perform the first steps. An option for a smaller, denser detector (ORCA) for neutrino properties studies is also under evaluation.