Op#mizing ARIANNA Design (all-nu, nu-tau, cosmic ray) US, Sweden, Taiwan, Germany, Denmark S. Barwick, UC Irvine PoS(ICRC2017) 1042
Why go to Polar Regions? • Radio Quiet, but – Noisy near bases and/or experiments – Noise from satellites in case of ANITA-III • Thick cold, Radio transparent, (free) material • Ice provides a dense target for neutrinos • Surprisingly good infrastructure TeraTon detectors at modest cost
Science Mo#va#on • ARIANNA 5 year sensi#vi#es for 1296 sta#ons (including published live#mes and analysis efficiency) C Persichilli PoS(ICRC2017)977 Reach minimum all proton cosmogenic flux IC EHE ARIANNA baseline ARIANNA with wind IceCube
Science Mo#va#on • ARIANNA 5 year sensi#vi#es for 1296 sta#ons (including published live#mes and analysis efficiency) C Persichilli PoS(ICRC2017)977 Extend measurement of IceCube Flux IC EHE ARIANNA baseline ARIANNA with wind IceCube
Science Mo#va#on • ARIANNA 5 year sensi#vi#es for 1296 sta#ons (including published live#mes and analysis efficiency) C Persichilli PoS(ICRC2017)977 Improve search at 10 20 eV by order of magnitude IC EHE ARIANNA baseline ARIANNA with wind IceCube
Hexagonal Radio Array (HRA): 2012-present HCR A B CR 1 G C F 1 km CR E D 2 Deployed 2012 Deployed 2014 Moore’s Bay, 110 km from McMurdo Station
Current status of ARIANNA - HRA HRA 7 regular sta1ons “ Cosmic Ray ” sta1on 1 “ Cosmic Ray ” sta1on 2 All sta#ons run reliably since deployment - technology is ready 7
Event ID: Template Matching Observed CR Candidate Template Predicted waveforms confirmed by Cosmic Ray “calibra#on beam”
>200 Cosmic Ray Candidates Nelles PoS(ICRC2017)399 and Wang PoS(ICRC2017)358 2015-2016 2016-2017 Horizontal CR tower 2016-2017
Neutrino Search 2015-2017 CR candidate
Horizontal Propaga#on at ARIANNA site HCR A A B B CR 1 C G C F D 1 km CR E D X 2 Despite non-op#mal antenna Vpol Dipole pulser geometry, signals observed buried at depth of 20m on all sta#ons to 1.4 km
Horizontal Propaga#on also seen at South Pole S. Pole (D. Besson) ARIANNA site Ln(r*V) L ajen = 501 +-168 m L ajen = 508 m 0 1600 Distance(m) Antarc#c data compa#ble with simple model |E|~ (e -r/Lajen )/r
Modeling Horizontal Propaga#on-ray paths Idealis#c Firn Realis#c Firn ARIANNA ARIANNA No signals TRX TRX propagate to ARIANNA sta#on Large amplitudes in 100m studies suggests ~50% of signal is trapped; modeling consistent with this
Poten#al Improvement with Horizontal Propaga#on 5x increase No geometric reason to bury antennas at S. Pole Combina#on sta#on with both dipoles and LPDA gives best results with horizontal propaga#on 5x increase is possible! As few as 169 ARIANNA sta#ons at South Pole can reach science goal
Commentary • IceCube neutrinos, especially those above 10 15 eV provide strong incen#ve to probe to higher energies with larger detectors. • ARIANNA technology has operated robustly • Horizontal propaga#on has poten#al to improve sensi#vity. It is worth inves#ga#ng I believe the Antarc#c neutrino projects will coalesce around common technique within the next year to produce a “mature” proposal supported by the community.
Shown: (Left to right) Joulien Tatar, Chris Persichilli, James Walker, Corey Reed Thank You! Thank You
Backup Slides
Modeling Horizontal Propaga#on Signal vs Distance Signal vs depth (2-4m below surface) Rays emijed between L ajen =500m 38 o -40 o trapped within 5m ARIANNA of surface TRX ~50% signal trapped 500 2500 Range (m) 0 40 Depth (m)
Quote from the recent IceCube paper (arXiv:1607.05886): The detec(on of cosmogenic neutrinos from sources with weak or no evolu(on, and of heavy-composi(on UHE-CRs requires a larger scale detector. Cost effec(ve radio Askaryan neutrino detectors, such as ARA or ARIANNA, will therefore be an important future op(on.
EHE ν detectors: Comments EHE neutrino detectors: Contribute to ongoing quest to understand EHE CRs • Neutrino measurements provide independent confirma#on of GZK • mechanism Combined with CR and photon measurements, can help to constrain • source class, evolu#on, E max , and composi#on of CR Direct measurements of CR • Search for new physics • Beam of EeV neutrinos can uncover new physics at ~5-10 x E cm of LHC • through cross-sec#on and spectral modifica#ons Search for new sources: • EeV neutrinos must point back to sources and direc#on can be measured • with good precision ( and current procedures can be improved).
ARIANNA CR summary Between December 2015 and mid-March 2016 42 Cosmic Ray candidates 3 involved a coincidence between 2 sta#ons 1 involved a coincidence between 3 sta#ons 1 involved a coincidence between 5 sta#ons Candidates 1. Isolated in #me and similar characteris#cs 2. Have smooth and con#nuous power in FFT 3. More power in upward than downward LPDA 4. Correlate with CR template
Capabili#es Angular resolution σ θ ~2.8 o Down horizon cos( θ ) K. Dookayka, UCI PhD dissertation, 2011
No evidence of dispersion by horizontal propaga#on for d= 100m Dipole to Dipole, air vs 100m of firn Excellent shape agreement between air In shadow zone! to air studies in park and 100m through snow Dipole (20m) to LPDA Air vs firn Large intrinsic dispersion due to X-pol
Capabili#es Angular resolution σ θ ~2.8 o Down horizon cos( θ ) K. Dookayka, UCI PhD dissertation, 2011
ARIANNA can find new hard spectrum source if 0.1 Φ WB
SAVANT Wind Generator: 2016 Data 2016 Expecta#on 2016 Expecta#on 2017 HRA power requirement ARIANNA Site H. Bernhoff et al., Uppsala, Department of Engineering Sciences, 2016
SAVANT Wind Generator: 2016 Produced power consistent with design es#mate. Will it survive the Antarc#c winter? Does it produce RF noise? (anechoic chamber tests say no) Can Bajery management cope with Wind Gen and solar? ARIANNA Site H. Bernhoff et al., Uppsala, Department of Engineering Sciences, 2016
Radio Pulses by Cosmic Rays in Atmosphere But primary effect in dense media
Annual Rate of CRs in ARIANNA (~3x10 5 /year triggered with upward antenna) Look for anisotropies Energy spectrum with radio technique E cr ~ 10 20 eV ~ 1/year Auger Spectrum S.Barwick, et al. , arXiv:1612.04473v1 Majority of CR at highest energies arrive from direc#ons within 30 deg of horizon
Raw electric field spectrum Raw electric field pulse Cosmic Rays COREAS 0 MHz 500 MHz Antenna/amp response 80 ns • Air shower signals through front-lobe of LPDA have a unique characteris1c Gain and group-delay • High frequency chirping 300 mV Signal through front Signal through back 30 mV followed by lower frequencies • Due to short broadband pulses and group delay of antenna 30 150 ns 200 ns
A few words on Dispersive LPDA Dispersion is beneficial to help iden#fy short (few ns) pulses. Chirping + envelope is unique, and efficient. No RF BG close at ARIANNA site. There is not much downside to dispersion since most of the voltage amplitude in #me domain is derived from lowest frequencies (50 to 200 MHz). Dispersion is small enough so components add almost coherently. Small inefficiency at trigger level compensated by improved analysis efficiency. In addi#on, LPDA gain is 4-6 over the en#re frequency band, so signals are large compared to e.g, dipole. LPDA are inexpensive ~ $100 US in bulk purchase – other electronic components dominate budget LPDA are direc#onal and excellent in Xpol rejec#on. ARIANNA LPDA very good at polariza#on measurement.
Nu-tau Detec#on with Radio 6-8 m Dual-pol LPDA Concept: J. Nam, NTU, 2017 ν τ sta#on consist of 3 Flavor ra1o is intriguing probe for ν towers with 2 1) source physics 2) oscilla#on dual pol LPDA 3) decay 4)mass hierarchy
Detector Concepts 1 sta#on of 37, 2km spacing 1 sta#on in array of 36 x36, 1km spacing 200 m 4m 20m ARIANNA ARA S. Barwick, et al., IEEE Trans. Nucl Sci. (2015) P. Allison, et al, Astropart. Phys. 35 (2012)
Horizontal Cosmic Ray (HCR) tower (prototype installed November 2016) Goals • 1) Evalua#on construc#on/robustness 2) Long-term RFI survey 3) Evalua#on of angular resolu#on 4) Evalua#on of CR backgrounds 5) Measurement of CR Flux vs theta 4 antennas (3 Hpol + 1 Vpol) poin1ng • to the mountain Galac#c excess clearly seen! RF Power vs Time
HiCal and Angular Resolu#on 600 km ~40 km HCR Tower All ARIANNA sta#ons observed signals from HiCal
HiCal and Angular Resolu#on S.Wang, NTU, 2016 Launched HCR tower December HiCal GPS 2016 No pulses observed un#l preliminary HiCal visible above Minna Bluff
Bounce Tests Pulser->Seavey TRX->Sta#on LPDA LPDA LPDA ARIANNA LPDA Trx Station water
Field Ajenua#on Length in ice S. Pole, Antarc#ca ARIANNA site, Ross Ice Shelf 1 km J. Hanson, et al., J. Glac. 61 (2015) Shorter, due to warmer ice along reflected path Similar numbers for Greenland at 75MHz S. Wissel, et al. (ICRC -2015) Reflec#vity ~ perfect mirror
ARIANNA Site is RF Quiet
Opera#onal Efficiency = 0.87 C. Persichilli, CHEAPR, 2016 A B Losses due to : 1. Data transfer G 2. Calibra#on runs C F 1 km E D
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