NEMO: a project for the construction of a km3scale high-energy neutrino telescope in Mediterranean Sea

Abstract

NEMO:apro jectfortheconstructionofkm3scalehigh-energyneutrinotelescop einMediterraneanSeaAntonio Cap oneaonb ehalf of NEMOCollab orationbaUniversityLa Sapienza,Roma, andINFN SezionediRoma, ItalybTheNEMOCollab oration list canb e foundat http://nemoweb.lns.infn.itABSTRACTThe NEMO (NEutrino Mediterranean Observatory) collab oration is conducting an intense activitytodeveloptechnicalsolutionsforthedeploymentofkm3scaleneutrinodetectorinMediterraneanSea.Thestudyofunderwater networks of electro optical cables andconnectors,mechanical layout and data transmission,isconductedtogetherwithleadingcompaniesinthe eldofsubmarineop erations.Thecollab oration hasalsoselected and characterised an optimal marine site in the region of Cap o Passero at 3300 m depth, near the SicilianCoasts.Inaddition,duringyear 2001, the collab oration has equipp edaTestSitefacility 28 km o shore thetown of Catania.The facility willbefundamental for prototyping mechanical structures and data transmissionsystems.Keywords:Highenergyneutrinoastronomy,DeepSeasitequali cation,Mechanicsfordetector,Electronics for Deep SeaCerenkov Detector1.AKM3SCALENEUTRINOTELESCOPEINTHEMEDITERRANEANSEAAt present, in the eld ofCerenkov neutrino telescop es, only two collab orations are in data taking:AMANDA,1that already deployed a small scale detector at the South Pole, and BAIKAL, the pioneer underwaterCerenkovdetector deployed in the Sib erian lakeBaikal.2The ICECUBE collab oration3is going to extend the dimensionsand capabilities of AMANDA aiming at a km3neutrino telescop e in the Southern hemisphere.The Mediter-ranean Sea o ers optimal conditions,over a worldwide scale, to lo cate the km3detector; three collab orationsare active there:NESTOR4; ANTARES5and the NEMO group of INFN. The ANTARES collab oration (whichincludes several researchers from NEMO) is going to deploya0.1 km2detector in the vicinityofToulon (France)at2400 m depth starting from year 2002.The contemp orary op eration of ICECUBE and a future Mediterranean km3detector will o er the optimalconditionsforneutrinoastronomyprovidingthefullcoverageofsky.Thetwodetectorswillalsohaecomplementary characteristics:thelong lightabsorption lengthofAntarcticicewillp ermitgo o d energyresolution, the long light scattering length of the Mediterranean abyssal seawater will p ermit excellent angularresolution.Thedevelopmentofdeep-sea technologies ismandatory fortheconstruction ofunderwater km3-scaledetector.In deep sea, indeed, the lifetime of most materials used for surface applications is strongly reduced; newmaterials and techniques are needed together with long term tests.The construction and op eration of ANTARES0.1 km2will provide the rst real test for such apparatuses.In the same time NEMO is acquiring technologiesand supp ort for the construction of the km3telescop e.After three years of activity the NEMO collab orationhas achieved several result:i) an optimal deep sea site for the deployment of the telescop e has b een selected andcharacterised as a function of seasonal variations;ii) a preliminary design of the detector mechanical structureandofsubmarine electro-optical connectionshas b eendevelop ed;iii)Montecarlo simulations ofthedetectoreciency as a function of the geometry and environmental parameters have b een carried-out;iv) a preliminarydesign of data and p ower transmission system to/from the shore is under study.This work has b een conducted(Send corresp ondence to Antonio Cap one)Antonio Cap one:E-mail:antonio.cap one@roma1.infn.it, Telephone:+39 06 49914415Address:Physics Department, University La Sapienza, P.le Aldo Moro 2, 00185 , Roma, Italy