Livetime and sensitivity of the ARIANNA Hexagonal Array

Background emission

Operations

Department of Physics and Astronomy, University of California Irvine, CA, USA

Cosmic Rays

υ

Date, time (UTC)20-00h 20-12h 21-00h 21-12h 22-00h 22-12h

Freq

uenc

y [G

Hz]

00.10.20.30.40.50.60.70.80.9

Reco

rded

Am

plitu

de [m

V]

102030405060708090

DateDec 18 Jan 01 Jan 15 Jan 29 Feb 12 Feb 26 Mar 11 Mar 25 Apr 08 Apr 22

Frac

tion

of D

ay

00.10.20.30.40.50.60.70.80.9

1

Stn Livetime

Above 0 Deg

Above 2.5 Deg

Above 5 Deg

Above 7.5 Deg

Above 10 Deg

Above 12.5 Deg

Site B

DateDec 18 Jan 01 Jan 15 Jan 29 Feb 12 Feb 26 Mar 11 Mar 25 Apr 08 Apr 22

Frac

tion

of D

ay

00.10.20.30.40.50.60.70.80.9

1

Stn Livetime

Above 0 Deg

Above 2.5 Deg

Above 5 Deg

Above 7.5 Deg

Above 10 Deg

Above 12.5 Deg

Site C

Strong solar burst of December 2014 visible in ARIANNA antennas

Burst caused Aurorae that are also visble

Antenna detects different areas of Galactic emission during one day

Variation a result of folding the Galactic emission pattern with antenna sensitivty

Array status and hardware

7 stations with four downward point-ing antennas operational since 2014

1 station with two upward pointing antennas for background studies of lower frequencies (site X)

Communication via long-range wifi and/or Iridium sattelites

Next-generation boards for data-acquisition, SST

4 channels of 256 samples2 Giga-samples per secondBand of 0.1 - 1 GHz 32 GB of solid state memoryRemotely programmable 12 bits of dynamic rangePower consumption less than 6 Watts per station1 mV RMS trigger sensitivity at > 600 MHz trigger band

Power and Communication Tower for one ARINNA station on the Ross

Ice-Shelf

Ultra-high energy cosmic protons will generate neutrinos in interaction with the Cosmic Microwave Background

ARIANNA is designed to detect neutrinos at these energies (> 107 GeV) [1,2]

ARIANNA is also sensitive to radio emis-sion of air showers

Important/only background at site on the Ross Ice Shelf

Extensive Monte Carlo study underway to determine thresholds for air shower detection

Threshold depends on energy and the distance to the shower maximum

Upward facing antennas as additional veto for air showers installed

First cosmic ray candidates identified

CoREAS simulation

Storm at the ARIANNA siteRepeated failure to establish wifi communication

Rare hardware issue inter-rupted running of stations, fixed remotely in February No sunlight after

April 21st

Plans for next seasonInstall batteries and newest boards at all stations inside the electronics boxesRun solely on Iridium communication to study prospects of low power operationImprove on cosmic ray identification, study antenna sensitivity in iceExplore potential of lower frequencies (> 50 MHz)

Future plansBuild the full ARIANNA: extend array to 1000 stationsEvery station will be an autonomous and independent neutrino detector

[1] S.W. Barwick et al., Astro.Part.Phys. 70 (2015) 12-26[2] C. Reed for the ARIANNA Collaboration, PoS(ICRC2015)1149, Board: 279[3] S.W. Barwick et al., IEEE Trans. on Nucl. Sc. (in press) (2015)[4] S.A. Kleinfelder et al., Proc. IEEE Nucl. Sc. Symp. Seattle, WA (2014)

Simulations:CORSIKA 7.4005, QGSJET-II-04, FLUKA

ARIANN

AAnna Nelles and Chris Persichilli for the ARIANNA Collaboration

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7 e

V-1

sr

-1 s

-2 J

(E) [

m⋅

2.7

E

1510

1610

1710

1810

1910

2010

2110

2210

2310 Pierre Auger Coll. (2013)HiRes I (2007)HiRes II (2007)KASCADE Grande (2012)KASCADE (2005)IceTop (2013)TA (2012)

Livetime with battery

Livetime without battery

Livetime > 90%, limited by communication windows

Enourmous gain in live-time by using a backup battery

Details in [3,4]

Sunlight at ARIANNA site

Downward pointing antennas see no fluctiation due to position and back-lobe suppression