ARIANNA - A New Concept for Neutrino Detection

Steve Barwick, UC Irvine Madison, Aug. 2006http://www.ps.uci.edu/~anita

ARIANNA Institutions: UCI, UCLA, UH, OSU,UCollege-London

The Energy Gap

There is a gap in the Energy response of current detectors between 1017-3x1018 eV

GA

P

ARIANNA is designed to span the gap

ARIANNA rates(6 month)

ESS Fe-only~40 few

(20,500 hrs)

Neutrino Cross-Section

] = 0.24 If Nev = 400If =0.5o

If =2GQRS

2 parameter fit:Normalizationcross-section

QuickTime™ and aTIFF (Uncompressed) decompressor

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ARIANNA - 10 years

GQRS

ARIANNA Concept100 x 100 station array, ~1/2 Teraton

~300m

Ross Ice Shelf, Antarctica

Satellite Image of Victoria Land and Ross Ice Shelf

Ross Island

2

Dry Valleys

ARIANNA

south

Minna Bluff

~150

km

30x30 km2

Ice Thickness ~500m

Reflected and Direct Events

ignore ice

Direct Reflected(much greater solid angle)

S. Barwick, 3rd NOVE Workshop (Venice, 2006)

Reflection loss: Ross Ice Shelf

150

Regions of smoother than normal ice-water interface

1 2

80

165180

77.8

2~0 dB

~0 dB1

C.S. Neal, J. Glaciology, 24(1979)295

south

Ross Ice Shelf

Reflection properties of the Ross Ice Shelf

150

12

80

165

180

77.8

2

~0 dB

1

1 2

south

Basal Smoothness of Ross Ice Shelffrom C.S. Neal, Ann. Glaciology 3(1982)216.

Location Surface RMS height (m)

77o25’S, 171o38’E

(good reflection coef)

84o24’S, 163o43’W

(known poor refl. coef)

0.03

0.10

60 MHz, 60ns radio echo pulse

Corroborating Evidence for Smooth Surfaces

from K. W. Nicholls, et al., Geophy. Res. Lett 33(2006)L08612.

<8mm!Flow trace

Sonar map of surface beneath Fimbul Ice Shelf

Conclusion: In regions outside of Flow Traces, surface variation is <8 mm!

Event Reconstruction

• Preliminary studies show that the radio path ambiguity (direct or reflected) is manageable.

– ~ 1 deg– E/E ~ 1

Detector Response• Simulations assume 100x100 square array, 300m separation, 500m

thick ice, all v-flavors(1:1:1), firn layer, 2 Quad-ridge horns per station, 3-station multiplicity, 2/4 channel@2.3Vrms, depth dependent attenuation, 3dB reflection loss, standard model

• Preliminary studies show that ARIANNA is sensitive over all angles.

Dir

ect

&

Reflect

ed

Reflectonly

ARIANNA Configurations

Configurations in Study1: 1-Quad, 1/2 chan2: 2-Quad, 2/4 chan3: 1-Quad, 1 dipole, 1/3 chan4: 5-Quad-closed, 2/10 chan5: 5-Quad-spread, 2/10 chan6: 5 -Quad-spread, 2/10 chan

1 station only

Base

line

Note: Channel threshold =2.3Vrms, 3 stations in Trig, unless otherwise stated

Ice Property Systematics

Index of refractionof firn ice

EffectiveAttenuationlength

Reflection Coef. Scattering fromIce-Water

ARIANNA Config. Systematics

Separation betweenstations Channel Threshold

Stations in Trigger

Channel Multiplicity

ARIANNA Advantages

• Near McMurdo, logistics manageable• Site likely has good reflection and absorption properties• Site protected from RF interference, and likely to stay that way• Borrow technologies from Auger, ANITA• Deployment straightforward and stations serviceable• Design relatively insensitive to many imprecisely known ice

properties (eg, localized patches of bad ice, strong scattering, reflection)

• Negligible environmental impact – stations removable when project ends

• 24/7/(365/2)

ProtostationBlock Diagram of Electronics

Outlook• With AMANDA-II, the requisite tools to

inaugurate multi-messenger astronomy are available -> IceCube continues this technique.

• To probe the neutrino fluxes and physics at highest energies, new techniques are being developed based on radio cherenkov detection.

• ANITA extends search volume to 106 km3

– McMurdo launch expected Dec 2006

• ARIANNA spans the impending energy gap – Awaiting further ice studies in Nov’ 06 (A-127M, if you want to

track our progress), and not the only contender (SALSA, superRICE, acoustic detection)

– Development continues at a feverish rate

ARIANNA Spec Sheet

• ~0.5 Teraton, 30km x 30km, 100x100 array• Resides on Ross Ice Shelf, near McMurdo• Angular Resolution <1 deg• 2 view of sky• Energy Resolution E/E ~ 1• Energy interval = 5x1017 eV -1020 eV• GZK Event Rate

~40 events/6 mo. (ESS)Few/6 mo if Fe only

Station Configurations

top

side2m

“2 Quad”

top

side

“5 Quad, Closed”

2m

5 Quad, Spread has 5m spacing

Block Diagram of ARIANNA Station Electronics

Ice Thickness Map for ARIANNA

McMurdo

ARIANNA

170 km50

km

50 k

m

1 2

south

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Antarctic Traverse Route

Use part of traverse infrastructure to access ARIANNA?

Hillary Route - ‘57

UCI/UCLA Simulation Comparison

UCLA UCI

Direct: N>3 direct raysReflect: N>3 reflected rays

Combo: N<3 for both direct and ref.Both: N>3 direct, N>3 reflect

PHOTONS: not deflected, but: reprocessed in sources, absorbed in IR (100 TeV), and CBR

PROTONS: deflection in magnetic fields, GZK cutoff

NEUTRINOS: not absorbed or deflected, hard to see

AN

ITA

-GZ

K

~100sm

For GZK E

CCsm

(Anchordoqui, et al, hep-ph/0307228)

EHE Neutrinos Explore Higher EHE Neutrinos Explore Higher DimensionsDimensions

Ice transparency

• Loss tangent a strong function of temperature

• For cold ice, UHF (0.1-1GHz) best

• Antarctic data approaches pure ice values

L = [n (’’/’)] –1 ~ 6 km at 300 MHz & -60C (pure ice, theory)

Matsuoka et al. 1996

The Energy Gap and ARIANNA

[ Antarctic Ross Iceshelf ANtenna Neutrino Array ]