Askaryan(Radio(Array( (ARA)( Michael(DuVernois( - PowerPoint PPT Presentation

Askaryan(Radio(Array( (ARA)( Michael(DuVernois( Wisconsin(IceCube(Par<cle(Astrophysics( Center((WIPAC)( University(of(Wisconsin—Madison(

PHYSICS'

((Cosmic(Rays(and(Neutrino(Sources( T. Gaisser 2005 ' Cosmic(rays(exist(at(highest(energies:(( ' The'puzzle ( No(nearby((<50Mpc)(sources(observed.(( More(distant(sources(are(not(observable(in( cosmic(rays(due(to(collisions(with(microwave( background.(( ( Neutrinos(above(10 17P19 (eV,(GZK(or(cosmogenic( neutrinos(are(at(some(level(guaranteed.(( knee However,(fluxes(will(be(small,(requires( 1 part m -2 yr -1 very(large(detectors( ( ( Ankle 1 part km -2 yr -1 3(

T. Gaisser 2005 T. Gaisser 2005 Atmospheric(( neutrinos:( AMANDA,(IceCube( Waxman(–Bahcall(upper(bound( IceCube(E^P2(upper(limit( Cosmogenic( Galac<c(neutrino( neutrino(flux,(( flux(model:(( e.g.(ESS((blue((line)( e.g.,(Ingelman(&(Thunman(

Neutrinos(as(messengers( Study(of(the(highest(energy(processes(and(par<cles( throughout(the(universe(requires ! PeVPZeV(neutrino( detectors( ( To(“ guarantee” EeV(neutrino(detec<on,( design'for'the' GZK'neutrino'flux ( ( Existence(of(extragalac<c(neutrinos(inferred(from(CR( spectrum,(up(to(10 20( eV,(and(similarly,(Galac<c(up(to( 10 18( eV( ( Need(gigaton((km 3 )(mass((volume)(for(TeV(to(PeV( detec<on,(and(teraton(at(10 19 (eV( ( Neutrino(detec<on(associated(with(EM(sources(will(ID( the(UHECR(sources( ( “EM(Hidden”(sources(may(exist,(visible(only(in( neutrinos.( ( Neutrino(eyes(see(farther((z>1),(and(deeper((into( compact(objects),(than(gammaPphotons,(and(straighter( than(UHECRs,with(no(absorp<on(at((almost)(any(energy(

The(cosmic(energy(fron<er,(10 7 (to(10 11 (GeV( Cosmogenic(or( GZK (neutrinos( -2 10 ] -1 ν ν × 1) Honda + Sarcevic Atmos. × 3) Blazars Stecker 2005 3 2) Waxman Bahcall 1998 3/2 µ µ sr ν ν 4) ESS + , 2001 5) Ahlers et al. Best Fit 6) Ahlers et al. Maximal µ e -3 ν × ν 10 7) Baikal Cascade Limit 1038 d, non-contained 8) AMANDA-II Diffuse Limit 3 9) IC40 Atmos. Unfolding -1 µ µ ν × 10) IC40 Diffuse Limit 3 11) IC40 EHE All Flavor Limit 12) IC86 3 Year Est. Sensitivity s µ ν × 14) Auger Limit 3 13) RICE 2011 Diffuse Limit 15) ANITA-II 2010 τ -2 16) ARA 3 Year Est. Sensitivity -4 [GeV cm 10 (13) (15) -5 10 -6 10 ν (12) (11) /dE (14) (7) (8) -7 ν 10 dN (2) (16) (10) -8 2 ν 10 E -9 10 (6) (9) (3) (1) (4) (5) -10 10 3 5 6 8 9 10 4 7 11 12 10 10 10 10 10 10 10 10 10 10 E [GeV] ν 6(

The(cosmic(energy(fron<er,(10 7 (to(10 11 (GeV( Cosmogenic(or( GZK (neutrinos( -2 10 ] -1 ν ν × 1) Honda + Sarcevic Atmos. × 3) Blazars Stecker 2005 3 2) Waxman Bahcall 1998 3/2 µ µ sr ν ν 4) ESS + , 2001 5) Ahlers et al. Best Fit 6) Ahlers et al. Maximal µ e -3 ν × ν 10 7) Baikal Cascade Limit 1038 d, non-contained 8) AMANDA-II Diffuse Limit 3 9) IC40 Atmos. Unfolding -1 µ µ ν × 10) IC40 Diffuse Limit 3 11) IC40 EHE All Flavor Limit 12) IC86 3 Year Est. Sensitivity s µ ν × 14) Auger Limit 3 13) RICE 2011 Diffuse Limit 15) ANITA-II 2010 τ -2 16) ARA 3 Year Est. Sensitivity -4 [GeV cm 10 (13) (15) -5 10 -6 10 ν (12) (11) /dE (14) (7) (8) -7 ν 10 dN (2) (16) (10) -8 2 ν 10 E Sensi<vity(of(3(years(( of(ARA(37( -9 10 (6) (9) (3) (1) (4) (5) -10 10 3 5 6 8 9 10 4 7 11 12 10 10 10 10 10 10 10 10 10 10 E [GeV] ν 7(

ASKARYAN'EFFECT'

Detec<on(mechanism(proposed(by(G.(Askaryan((1962):(( Measure(the(coherent(RF(signal(generated(by(neutrino(interac<on(in( dielectric(media((such(as(ice)(( moves as a wavelengths shorter than the charge asymmetry in particle compact bunch, a bunch length suffer from shower development results in a few cm wide and destructive interference 20% excess of electrons over ~1cm thick ! Moving net positrons in a particle shower charge in a dielectric nucleus( L is the ν length of the bunch Par<cle(cascade( E(>(10 17 eV( electric field strength proportional to the square of the shower energy λ >>  Add coherently!

Askaryan(Effect( In(electronPgamma(shower(in(maker,(there(will( be(~20%(more(electrons(than(positrons.( Compton(scakering:(( γ (+(e P(at(rest) (( → ( γ (+(e P( ( Positron(annihila<on:(e +( +(e P(at(rest) ( → ( γ (+( γ ( (( In(dense(material(R Moliere ~(10cm. ! ( λ <<R Moliere( (op<cal(case),(random(phases ⇒ ( P ∝ 'N ' ((((((((((( λ >>R Moliere( (microwaves),(coherent( ⇒ ( P ∝ 'N 2' dP CR d ν ∝ ν d ν

Valida<on(at(SLAC( ANITA(I(beamtest(at(SLAC((June06):(proof(of( Askaryan(effect(in(ice( " ((Coherent((Power(~(E 2 )( " ((Linearly(Polarized( “Likle(Antarc<ca”( April(2010(

Natural(target(material?( • Lunar(regolith((20m(akenua<on(length) ( (Parkes(Telescope;(GLUE;(WSRT;(…( • Ice((100P1500m(akenua<on(lengths) ( ( ( (Forte((satellensaltedite);(ANITA((balloon);(ARA(( • Salt((100P500m(akenua<on(lengths)( ( ( (SalSA((proposed,)( • Air(is(too(thin( • Water(is(RF(lossy,(natural,(outdoor,(sand((as( opposed(to(pure(silica)(is(also(lossy(

INSTRUMENTATION'

10 7 (to(10 11 (GeV:(Radio(ice(Cherenkov(detec<on( Askaryan Radio Array (ARA) heritage: Existing and previous instruments using radio in Polar ice Members of all three efforts are currently involved with ARA ANITA Special radio detectors RICE and pulsers in IceCube • array of single dipole antennas deployed between 100 and 300m near the Pole • balloon payload of horn antennas • surveys the ice cap from high altitude • much of the instrumentation was for RF refracted out of the ice deployed in AMANDA holes • ! high fidelity data acquisition system >Gs/sec waveform capture • Pioneered technique in the ice 14(

ARAP(Collabora<on( • ARA(is(an(interna<onal( Collabora<on( – 14(ins<tu<ons( – ~50(authors( (( .((

10 7 (to(10 11 (GeV:(Radio(ice(Cherenkov(detec<on( Askaryan'Radio'Array'(ARA) ( P(a(very(large(radio(neutrino(detector(at(the(South(Pole( ( Ref:(Allison(et(al.,(Astropart.Phys.(35((2012)(457P477,(( arXiv:1105.2854(((Design(and(performance(paper)( Scien<fic(Goal:( Discover(and(determine(the(flux(of( • highest(energy(cosmic(neutrinos.(( Understanding(of(highest(energy( • cosmic(rays,(other(phenomena(at( highest(energies.(( Method:( (Monitor(the(ice(for(radio(pulses( generated(by(interac<ons(of( cosmic(neutrinos(with(nuclei(of( the(2.8km(thick(ice(sheet(at(the( Areal(coverage:(~150km^2( South(Pole( 16(

10 7 (to(10 11 (GeV:(Radio(ice(Cherenkov(detec<on( ARA(sta<on(geometry( Design(goals(and(choices:(( Every(sta<on(is(a(fully( • func<oning(detector.( ! (Lower(energy(threshold:(( nearby(events((300m)(can( be((reconstructed.(( Background(rejec<on:(( ! Embedded(strings:(Allow( good(vertex(resolu<on( and(high(ver<cal( resolu<on(for(background( rejec<on( 17(

Why strings? (rather than surface antennas) Ray'traces'200m' ( 0( Acceptance:(x2( • Depth([km]( Receiver( – Embedded(detectors(have(larger( 1( Transmiker( acceptance(due(to(shadowing( caused(by(gradual(change(of(index( 2( of(refrac<on(in(the(upper(200m(of( ice.(( 3( – Gain(at(200m(depth(compared(to( 0( 1( 2( 3( 4( Distance([km]( surface:(>(x2(event(rate( Horizon''for'3'different'receiver'depths'' Background(rejec<on:( 0( • 1 0 0 0 m ( – Transient(backgrounds,(man(made( Depth([km]( 200m( and(natural(come(from(surface!( 0.6( – Neutrino(events(generate(vertex(in( the(ice(and(the(signal(can(be( 1.2( uniquely(separated(by(basic(event( reconstruc<on.(( 1.8( 0( 0.5( 1( 1.5( 2( 2.5( Horizon([km]( 18(

~15m( ~15m(

Signal(Chain( • Physics:(Neutrino(interacts(in(the(ice,(charged(par<cles( generate(shower,(Askaryan(radio(pulse( • Antennas:(Radio(pulse(wavePfront(arrives,(superimposed( on(thermal((background)(noise( • LNA:(Amplify(the(delicate(signal(with(minimum(addi<onal( noise,(close(to(the(antenna( • RFoF((transmiker(&(receiver):(Transmit(signal(to(the( surface(without(cable(distor<ons,(and(then(return(op<cal( to(electrical(signal( • Trigger:(Diode(detectors((“square(law”)(followed(by( combinatorial(logic((e.g.,(5/16(or(in(the(future(something( more(complex)( • Readout:(Analog(capacitor(storage,(triggered(readout,( digi<za<on,(transfer(to(sta<on(computer,(fiber(to(IceCube( Lab(building,(hard(drive(storage,(&(satellite(to(North(

RECENT'WORK'

ARA37' Deployed(ARA( Sta<on( Rev'2/4/15' Planned(ARA( Sta<on(16/17( IceCube( Test(Bed( South( 3' 1' Pole( Sta<on( Deployed( WT3' Cabling( 7' 6' 2' Planned(16/17( Cabling( Skiway( 5' 4' 2(km(

ARA(field(ac<vi<es(on(the(ice(

ARA(field(ac<vi<es(on(the(ice( Status:(( 2010P11:(Test(detector((TestBed,(shallow)(deployed( ( (Deep(calibra<on(pulsers(deployed(with(IceCube( 2011P12:(ARA1(prototype(deployed:(~70m(due(to(drill(limita<ons(( 2012P13:(Drill(upgrade,(( ( (Built(and(Deployed(two(more(sta<ons,(now(at(200m(depth( 3'staYons'Comparable'to'sensiYvity'of'IceCube'at'10 18 eV' 2013P14:(Calibra<on(ac<vi<es( 2014P15:(Calibra<on(ac<vi<es,(repairs(on(ARA1( 2015P16:(Calibra<on(ac<vi<es,(another(repair(on(ARA1(