Tetheredballoonsforradiodetec1onofUHEneutrinosinAntarc1ca:theRITAproject

Presentedby:IlyaKravchenko

(UniversityofNebraska‐Lincoln)

Rustam Dagkesamanskii (Lebedev Physics Institute, Pushchino) Eugenia Kravchenko (Radio Astronomy Observatory)

Igor Zheleznykh (Institute for Nuclear Research, Moscow) Dave Besson (University of Kansas)

Introduc1onRussian/SovietradioworkinAntarc1ca,RAMAND– Pilotexperiments

– Knowledgeaccumulated

RITA:proposalfortetheredballoonexperiment– Design– Fluxsensi1vityprojec1ons

Talkoutline

Askaryan’s idea (1961-1965): detect coherent Cherenkov radio emission of E.M.

cascades produced by cores of EAS and muons

Antarctic ice (very low RF absorption at -50C) is a natural large-scale dielectric neutrino target – Gusev and Zheleznykh, 1983

Nearly 50 years of studies of radiowave neutrino detection and detection in ice

Introduc1on

•  Glaciology information -  transparency of ice for radio waves of 100 MHz – 1 GHz

for different temperatures •  1985-1986:first experimental investigations -  mean noise level, amplitude spectra of pulses in a single

radio detector module 250–1000 MHz (G. Gusev et al.) •  1986-1987: “Hydra” (3-channel installation) -  investigation of pulse BG sources (A. Provorov et al.)

•  1988 and 1990: “Hydra-7” (7 channels) -  RAMAND prototype

Russian(Soviet)radioνworkinAntarc1caRAMAND experiments at Vostok and Mirny

4 Antarctic expeditions in 1985-1990

Some results also see in (A. Provorov et al., Proc. ”Venice 1991, Neutrino telescopes”, 337-355)

Sta1onsinAntarc1ca

Iceabsorp1onvsfrequencyatdifferenttemperatures

Polariceproper1es

FirstbackgroundstudiesandHydraDrillingequipmentatVostok,‘80s

Deploymentofradiopinger

•  1985‐1986:– noisestudiesw/singlemodule

•  1986‐1987:Hydra– 3broadbandreceiverchannels– Pingerloca1onsreconstructed– Man‐madebackgroundsinves1gated(sourcescoincidewithsta1onobjects)

– Upperlimitonfluxofimpulsepulsesfromiceobtained

50m

Proc. 20th Inter. Cosmic Ray Conference. Moscow, “NAUKA”, 1987, vol. 6, pp. 472-275.

RadiowavedetectorofUHEνwithVeff≈10km3

– Hexagonalantennafield,shallowdeployment(15m)

– Approvedin1988bySovietauthori1es

RAMANDconcept

•  PrototypeHydra‐7•  7‐channelinstalla1on•  DeployedandtestedatVostokin1988and1990

RAMANDpilot:Hydra‐7

Unfortunately,thisworkhasbeenabruptlydiscon1nuedin1991

TEMhorn:– Broadbandantennawellsuitedforimpulsivefieldmeasurements

– PlannedforRAMAND,usedinHydra‐7:1m×1marcsineTEMhorn,recep1ontransferfunc1onRA=0.14V/(V/m)

– Total1280antennasintended

RAMANDantennas

TEMhornantennasmadeRussiancollaboratorsarealsopartoftheRICEexperiment

•  Broadbandradioreceiversmountedonaballoonatafewkmabovetheground

•  Tetheredaboveice,whichservesasνtarget

RITAconcept

•  Elevatedstrategyaffordslargerfieldofview

•  Tetheredscheme(comparetoANITA):– Highdutycycle– Cancarrypowertotheballoon(notlimitedtosolar)– Datatransferredinreal1me– Runincoincidencewithgroundantennas(ala’RAMAND)

Advantagesoftetheredballoons

•  Al1tude:–  Icecrystalforma1ononelectronicsfavors>1.5km

– Technologically,upto2.5‐3kmappearsfeasible– Higheral1tudeisbeher:largeraperture

•  Payload:– 500‐550kgcapacityforconsideredop1ons– Tether:~300kg(polystyrenerope+signalcable)

•  Fillant:– Helium– Heatedair(electric,w/solarbaharies,orgas‐jet)

Balloonspecs/opera1ngparameters

•  Size:– About20mdiameter,24mheight

•  Environmentalspecs:– Opera1ngtemperatures‐20to40C– Winds<7m/s

Specs,con1nued

•  Hornantennas(asinRAMANDorANITA)•  Planardipolegrid– Eachdipolereadoutindependently– 16(4x4)orthogonaldipolearray

•  Receivebothlinearpolariza1ons– Ac1vedipoles‐>amps‐>ADC‐>FPGA– Angularresolu1onofarray~23deg.– Eacharraycovers~90×90deg.– Total4‐5sucharrays,designedforλ=40cm

•  (haveexperiencewith16‐elementλ=1marrays)

Radioreceivers

•  UseRICEsimula1on,withtheaddi1ons:– Updatedlocaliceproper1es(atVostok,iceisdeeperandcolder)

– AssumedANITA‐likeantennaconfigura1onwithfull2πcoverageand200‐1200MHzbandwidth

– AddFresnelcoefficientsforsignaltransmissionthroughsurface

– Assumeperfecttrigger@5σ

•  NB:asZRxincreases,moreicevisible,but<R>tovertexalsoincreases,pushesthresholdsup

RITAsensi1vityes1mates

•  Compare:RICEvsRITAvsANITA(38km)Sensi1vevolumeprojec1ons

RITAvsANITA:x10lessVeff,BUTexposurecanbemuchlonger

RITA180dayexposure,assumesperfecttrigger@5σ

Neutrinofluxlimitprojec1ons

•  LonghistoryofRussianradiostudiesinAntarc1ca

•  Significantexper1sebuiltwithinHydra/RAMANDprojects

•  Proposedlowcost‐highsensi1vityRITAexperiment– Largeeffec1vevolume– Fluxlimitprojec1ons:promising

Summary