RNO - The Radio Neutrino Observatory · The Radio Neutrino Observatory (RNO) is a proposed next-generation in-ice Askaryan experiment at the South Pole expected to have world-leading

RNO - The Radio Neutrino Observatory

Cosmin Deaconuon behalf of the RNO Collaboration

Lake Louise Winter Institute 2019

E. Oberla photo

The Radio Neutrino Observatory (RNO) CollaborationRNO is a proposed next-generation ultra-high energy neutrino observatory embeddedin the Antarctic ice sheet near the South Pole

Cosmin Deaconu (UChicago/KICP) RNO - The Radio Neutrino Observatory LLWI19 2 / 15

What RNO is trying to measure: Ultra-High-Energy ν’s ( > 10 PeV )

High-energy physics: measure UHE ν properties (cross-section, etc.)Astrophysics: understand sources of UHE particles, primary composition of CR


High-energy multimessenger astrophysics picture

(M. Ahlers)

Neutrinos are ideal messengers since mostly do not interact on way hereExpected flux is very low, so need a big detector


High-energy physics picture

Verify Standard Model ν −N cross-section at anew energy scale by using Earth as a filter.

Phys. Rev. D 83, 113009

BSM models could enhance or suppresscross-sections at high energies

Can also probe flavor ratios, Lorentzinvariance, sterile neutrinos, exotic DM, etc.


https://journals.aps.org/prd/abstract/10.1103/PhysRevD.83.113009

Detection mechanism: Radio emission from Askaryan effect in iceAskaryan (charge-excess) radiation: Fast-moving charge density in dielectric →coherent emission (∝ E 2) at long (radio) wavelengths

I Charge excess from processes (positron annihilation; Bhabha, Moller and Comptonscattering) involving electrons in material

I At wavelengths larger than O(lateral width), don’t resolve individual charges

Confirmed in ice with SLAC beam test (Phys.Rev.Lett.99:171101,2007).Radio attenuation length in ice is ∼ 1 km


https://doi.org/10.1103/PhysRevLett.99.171101

Current ice-based Askaryan ν experiments

ANITA*

Antennas on a high-altitudelong-duration balloon

ARA*

Externally-powered deeplow-gain antennas

ARIANNA

Self-powered, surfacehigh-gain antennas

RNO contains members from all three experiments.*denotes an experiment I work on. Shameless plug: New ANITA results: arXiv:1902.0400


https://arxiv.org/abs/1902.04005

Ice considerations: Surface vs. deep antennas

Near-surface antennas are easier to deploy,and more flexible (can use higher gainantennas, same antenna for allpolarizations.)

But top layer of ice (“firn”) has densitygradient → index of refraction gradient sonot all signals reach surface

Deep antennas see more volume, butdrilling adds to cost and antenna optionslimited by borehole size

Another consequence of firn is existence ofwith multiple paths (“direct” and“refracted”) which allow for more precisevertexing

Firn

Deep ice


RNO design

Surface Array

Deep Pointing Array

Dee

p T

rigg

er A

rray

Calibrationpulser

61 Stations, each with a surface (LPDA) anddeep (VPol bicone + HPol slot) component,combining elements of both ARA andARIANNA stations.


Primary trigger: deep phased array

Phased array (PA) trigger combinessignals from multiple deep antennas toincrease effective gain of deep antennas

Beamforming done electronically usingstreaming digitizers and FPGA

Prototype currently operating as part ofARA5 station (arxiv:1809.04573, acceptedto NIM).

Allows triggering on much lowersingle-antenna VSNR than single antennatrigger previously used by ARA andARIANNA

PA only 1-D, need outrigger antennas forpointing / reconstruction.

10−

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ampl

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Coherently Averaged Waveform

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Dedispersed Averaged Waveform

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du]

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Mean Voltage SNR at Phased Array

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Tri

gger

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icie

ncy

ARA-5 Tunnel Diode Trigger (6 Hz)

Projected 8-Antenna Array With Improved Timing (10 Hz)Achieved 7-Antenna Phased Array Prototype (10 Hz)


https://arxiv.org/abs/1809.04573

RNO design drivers

While most sensitivity comes from deep PA, surfacecomponent (with a self-trigger option) for more precisereconstruction of subset of events visible in both deep andsurface and can help veto cosmic rays that may mimic in-iceneutrinos.

RNO design based on trade study of various factors:I Maximize volume/station with deeper PA trigger (a)I Maximize sky coverage with deeper PA trigger (b)I Maximize surface-deep coincidences and fraction of

direct/reflected events with shallower PA trigger (c,d)I Minimize drilling cost and deployment time with shallower

holes

Baseline design is 60 m holes with 50 m PA, but leaving dooropen to deeper drilling.


RNO projected sensitivity

105 106 107 108 109 1010 1011

Neutrino Energy [GeV]10 11

10 10

10 9

10 8

10 7

10 6

E2 [G

eV c

m2 s

1 sr

1 ]

GRAND 10kIceCube

ANITA I - III

Auger

ARA

Best fit UHECR, Heinze et al.Best fit UHECR + 3 , Heinze et al.10% protons in UHECRs, van Vliet et al.allowed from UHECRs, van Vliet et al.

RNO (trigger): 61 stations, 5 yearsRNO 100m (trigger): 61 stations, 5 years Trigger-level sensitivity shown. With

ample reco antennas, expect analysislevel to be close.

Backgrounds expected to be low(< 0.01 / station / year).

I Thermal fluctuations negligible (nocorrelation between trigger andpointing arrays)

I RFI will reconstruct to surface; canbe cut with small sensitivity loss

I Any background from cosmic raysignals entering ice likely vetoableby surface antennas

Cutoff Energy on IceCube Flux 108 GeV 108.5 GeV 109 GeV 109.5 GeV 1010 GeVExpected Number of Neutrinos 5.1 9.7 14.3 18.2 21.4


RNO timeline

First deployment in2021 (if funded thisyear)

Expected number ofneutrinos vs. time fromvarious astrophysicalsource models andcosmogenic fluxes.

I Some of these add!


Takeaways

Ultra-high energy neutrinos teach us about both astrophysics and particle physics

Radio detection allows for instrumentation of large detection volumes with relatively fewdetectors.

The Radio Neutrino Observatory (RNO) is a proposed next-generation in-ice Askaryanexperiment at the South Pole expected to have world-leading sensitivity above 10 PeV.

I Sensitive to reasonable cosmogenic neutrino modelsI Can probe high-energy behavior of IceCube-measured astrophysical flux

Stay tuned!


Thank you!

E. Oberla photo


Backup slides


Beamforming


Sky coverage and pointing ability useful for multimessenger astronomy

Assumes 1-degree RF signal resolution, 10-degree polarization resolution, 2-degree off-coneangle resolution; background is relative acceptance at 1017 eV.


Station Block Diagram

Fiber to ICL

Power from ICLDAQ

RFo

F

DC

(see detail)

LNA

RF+DCD

ow

nhole

Surface

DFE

Dow

nhole

Fro

nt-

End

LNA

RFo

F TX

DC

Pass

-th

rough

RFoF to DAQ

additional antennas

RF to antenna

SBC based on OSD3358 w/ FPGA Cape

128 GB local Storage

16 Ch. LAB4D2048 samples@ 2 GSPS

16 Ch. Auxenvelope trig.

FPGA16 Ch. LAB4D

2048 samples@ 2.5 GSPS

8‐channelsADC07D15207‐bit 1.5 GSPS

+15V

High‐speedSerial +UART

16 Ch. Auxenvelope trig.

Trigger, Clock

Photodiode

+40dB10dB coupler

Schottkydiode detector

RF‐over‐Fiber in

FPGA

FPGA

Digitizer + Envelope Trigger Boards

8-channel realtime 7-bit digitization for phased trigger

Controller Board

Second-Stage Front-End

Envelope out to aux. trigger

RF out todigi�za�on

Phased Array Trigger Board

12x Surface

Channels (Coax)

15x Downhole Channels

(Fiber)

8x Downhole

Trigger Channels

(Fiber)

Ethernet Comm

s

(fiber)

Coax input (for surface)


ν’s by energy

108 109 1010

Neutrino Energy [GeV]

0

2

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Expe

cted

Num

ber o

f Neu

trino

s

IceCube E 2.19 Extrap.Kotera SFR1


Hardware pictures


Surface RFI cut


Documents

RNO - The Radio Neutrino Observatory · The Radio Neutrino Observatory (RNO) is a proposed next-generation in-ice Askaryan experiment at the South Pole expected to have world-leading