Next Generation neutrino detector in the South Pole

Hagar Landsman, University of Wisconsin, Madison

Askaryan Under-Ice Radio Array

Outline

Askaryan Effect and neutrino detection

Why Ice? Why Radio?

Radio detection

Experiment Design and prospective

Askaryan

Under ice

Radio

Array

Tribute to ATLAS@LHC.CERN

45 m

25 m

Ice Cube ~ 1kmThe Future:Hybrid Detector ~10 km

Quest for UHE neutrinos • GZK Cut-off p+CMB

– No cosmic rays from proton above 1020 eV

– As a by-product – neutrino flux

– A non detection will be even more exciting

• Point Sources of neutrinos

• Dark matter

Why so big?

• To detect 10 GZK events/year, a detection volume of 100 km3 ice is needed.

• A larger detector requires a more efficient and less costly technology.

• Alternative options include radio and acoustic detection.

Neutrino interact in ice showers

dCRdP

Charge asymmetry: 20%-30% more electrons than positrons.

Moliere Radius in Ice ~ 10 cm:This is a characteristic transverse dimension of EM showers. <<RMoliere (optical), random phases P N >>RMoliere (RF), coherent P N2

Hadronic (initiated by all flavors)EM (initiated by an electron, from e)

Askaryan effect

Vast majority of shower particles are in the low E regime dominates by EM interaction with matter

Less Positrons:Positron in shower annihilate with electrons in matter e+ +e- Positron in shower Bhabha scattered on electrons in matter e+e- e+e-

More electrons:Gammas in shower Compton scattered on electron in matter e- + e- +

Many e-,e+, Interact with matter Excess of electrons Cherenkov radiation Coherent for wavelength larger than shower dimensions

As the energy increases, the multiplicity of the shower increases and the charge asymmetry increases.

As the energy increases, mean free path of electrons is larger then atomic spacing (~1 PeV) (LPM effect). Cross section for pair production and bremsstrahlung decreases longer, lower multiplicity showers

The Neutrino Energy threshold for LPM is different for Hadronic and for EM showers

Large multiplicity of hadronic showers. Showers from EeV hadrons have high multiplicity ~50-100 particles. Photons from short lived hadrons Very few E>100 EeV neutrinos that initiate Hadronic showers will have LPM

LPM effectLandau-Pomeranchuk-Migdal

In high energy, Hadronic showers dominate

Some flavor identification ability

Measurements of the Askaryan effect

Typical pulse profileStrong <1ns pulse 200 V/mSimulated curve normalized to experimental results

Expected shower profiled verified

Expected polarization verified (100% linear) Coherence verified.

New Results, for ANITA calibration – in Ice

SaltIce

D.S

alzb

erg,

P. G

orha

m e

t al.

• Were preformed at SLAC (Saltzberg, Gorham et al. 2000-2006) on variety of mediums (sand, salt, ice)

• 3 Gev photons are dumped into target and produce EM showers.

• Array of antennas surrounding the target Measures the RF output

Results:

RF pulses were correlated with presence of shower

Why Ice? Why Radio?

- Long attenuation - Radio ~1km- Optical attenuation in ice 100m

- No scattering for Radio In ice.

- A lot of it.

- Free to use.

- South pole is isolated. RF quiet.

- Antennas are cheaper and more robust than PMTs.

- No need to drill wide holes lower drilling cost of deployment w.r.t optical detectors

1016 - ~1023 eV

optical

Radio

Acou

stic

Ice, n

o bubbles (1.5-2

.5 km)

Ice, bubbles (0.9 km)W

ater (Baika

l 1km

)

Eff

ect

ive

Vo

lum

e p

er

Mo

du

le (

Km

3 )Energy (eV)

1012 1013 1014 1015 1016

Astro-ph/9510119 P

.B.P

rice 1995

1017

Effective volume per detector element for e induced cascades

IceCube•Pressure vessel•Connectors•Mainboard•DAQ•Cables•Holes

ANITA LABRADOR chip:•low power consumption•low deadtime•large bandwidth•cold rated

RICE Antennas

Data analysisElectronics and control

KU

University of Maryland

University of Delaware

University of Hawaii

KansasUniversity

University of Wisconsin - Madison

Penn State University

Deployment in thecoming seasonsurface

junction box

Counting house

Each unit is composed of :− 1 Digital Radio Module (DRM) – Electronics− 4 Antennas− 1 calibration units

Signal conditioning and amplification happen at the front end, signal is digitized and triggers formed in DRM

Co-Deployment on spare breakouts on IceCube cables (top/bottom) or on a special breakout

Depth possibilities:−Top (1450 m) : Colder Ice, less volume−Bottom (2450 m) : Warmer Ice, more volume−Dust layer : less efficient spot for ~400nm

RF attenuation is longer at colder ice

Not to scale!

Deployment in the coming season

Planning to deploy 4 units.with IceCube. Start mid December 2006

3rd hole (1400m)8th hole (1400m)9th hole (250m)10th hole(1400m)11th hole(250m) spare

IceCube Holes Map for 2006-2007

Toantenna

Toantenna

To

antenna

To

surface

ToCalibrationunitTo

antenna

Shielding separates noisy components

6 Penetrators: 4 Antennas 1 Surface cable 1 Calibration unit

TRACR BoardTrigger Reduction and Comm for RadioData processing, reduction, interface to MB

ROBUST BoardReadOut Board UHF Sampling and Triggering Digitizer card

SHORT BoardsSurf High Occupancy RF Trigger Trigger banding

MB (Mainboard)Communication, timing, connection to IC DAQ infrastructure,

Digital Radio Module (DRM)Digital Optical Module (DOM)

Multiple bandwidth trigger16 combinations of

triggers:− 4 antennas

− 4 bandwidth on each antenna

− Trigger condition will be tuned to maximize data rates within the cable bandwidth.

− Remove a noisy frequency

TRACR

DOM-MB

Metal Plate

Antennas

DRM electronics

ROBUST

Dipole AntennasIceCube DOM

IceCube DOM

17 cm

Time CalibrationQA

MonitoringControl

Time order

Event TriggerAnalysis

Sat.

Data

3.5 Kbytes25 Hz

3.5 Kbytes25 Hz

3.5 Kbytes25 Hz

DRM DRM

HUB

time

Data

Decrease rates to fit data storage/satellite volumeL3 - Data quality on surface (HUB)L4 - Send over satellite? Save to tapes?

Decrease rates to fit surface cable:L0 - Single frequency band trigger (SHORT, ROBUST)L1 – Multiple bands and multiple antennas (ROBUST)L2 – Higher level analysis filter-FFT (TRACR)

DRM

Offline processor

DAQ layout

Our Mission:• Build intermediate detector with improved effective

volume over RICE, using IceCube infrastructure

• Experiment new Antenna and electronic design• Further map the south pole ice radio properties• Check interference between IceCube and AURA

• Adapt form factors for narrower holes drilled exclusively for radio.

• Correlate events with RICE

• On the way to a super-duper-hybrid GZK neutrino detector

Pic

ture

by

Mar

k K

rasb

erg

Backup Slides

Askaryan Signal

Cherenkov angle=55.8o

Electric Field angular distributionElectric Field frequency spectrum

Astro-ph/9901278 A

lvarez-Muniz, V

azquez, Zas 1999

Askaryan Signal

Cherenkov angle=55.8o

Electric Field angular distributionElectric Field frequency spectrum

Astro-ph/9901278 A

lvarez-Muniz, V

azquez, Zas 1999

Excpected Signal

surface generated event as measured by RICE detectors at different depths

0

500

1000

1500

2000

0 100 200 300 400 500 600 700 800

Reflection studies @S.Pole, Jan. 2004 - S. Barwick

Fie

ld A

tten

uatio

n Le

ngth

(m

)

Freq (MHz)

Tave

T-50C

a larger, more technologically sophisticated array is needed for a neutrino observation… current hardware too expensive to scale up

•made surveys of rf properties of the ice at the South Pole

•set most stringent limits on the neutrino flux from 10^16 to 10^18 eV

•set limits on low scale gravity, magnetic monopoles and other exotica

Note: RICE uses a 95% C.L. upper limit

See latest results astro-ph/0601148 19 channels in depths 100m - 300m

2 GHz

Measurements of the Askaryan effect

Typical pulse profileStrong <1ns pulse

Measurements of the Askaryan effect

SLAC T444 (2000) in sand

Sand

Filed strength measure by….

E= prop to shower E