July 10, 2007 Detection of Askaryan radio pulses produced by cores of air showers. Suruj Seunarine, Amir Javaid, David Seckel, Philip Wahrlich, John Clem

July 10, 2007

Detection of Askaryan radio pulses produced by cores of air showers.

Suruj Seunarine, Amir Javaid, David Seckel, Philip Wahrlich, John Clem

D. Seckel, Univ. of Delaware

Askaryan pulses from air shower cores, Merida, 30th ICRC, July 10 2007 (Seckel)

Topics

• Concept: – A source to test radio techniques– CR composition ?

• Askaryan pulses & air shower dimensions

• Air shower properties (AIRES & CORSIKA)– Particle content– Radial and energy distributions

• Calculation of RF signal– Coherent addition of subshowers– Issues: near zone/far zone, ray tracing

• Composition studies

• Detection– IceCube: shallow array, AURA– ANITA


Theorist’s view of the UHE neutrino sky


Recall how radio works

5 m

10 cm

JC, SY: “How do you know when you haven’t seen anything?”


Radio Goals & Staging

• 100 events/yr above 1018 eV

• >1000 km3 sr

• Validation of design for field work

• Prototype projects – more than upper limits

• Detect Air Showers: Signal/Background/Calib


Askaryan pulses from air shower core


Critical dimensions


High energy ground level particles at SP

• CORSIKA/AIRES– Primary energy: 1,10,100,1000 PeV– Cutoff: 1,10,100,1000 GeV– Composition p & Fe

• Explore– Particle content rad - meson - baryon - mu

– Radial profiles Esh vs r

– Shower development dN/dE, ancestry


Ground level particles

e-

n,p


Radial distributions by particle ID

radiatingmesonsbaryonsmuons


E vs r (AIRES)


E vs r (CORSIKA)

Fraction of available energy approaches 10% by 100 PeV

Scaling allows use of high cutoff


Synthesis of Askaryan pulses

• Many ground level particles– Superposition

• Individual RF pulses– Event: (id, te, xe, n, E)

– SubShower: (ts, xs, n, (r,l,s))

– Resolve geometry to antenna– Launch EM pulse (scaled AVZ)– Propagation effects (1/r, attenuation)– Adjust phase to common time basis

• Response– CoAdd spectra (t, n, pol, (complex spectrum))– Antenna/DAQ


Subshowers & Coherence of RF pulses


Time Domain Waveforms


RF: (Ep = 1 EeV, Ecut = 1 TeV )

20 10 0 10 20600

400

200

0

200

400

t nsm

V

Simulat ed p ulse in a R ice ant enna ch 6


EeV/TeV again


RF Cerenkov Rings


RF vs Core Size


Determining Cosmic Ray Composition

• AIRES showers (from S. Seunarine)

• Esh(r<20 cm) as proxy for radio

• High-lite: 10 PeV, True iron


Comparison of Fe/p


Scaling & Rates

• Rate independent of D• Threshold increases with D• True for E-3

– But not for E-2

• Rate for 30m*30m @ 3PeV = 1/hour


Shallow Array Concepts

• Drill 16 x 30m holes – 1 dom per hole– 4 antennas per dom

• 2 x 50m cables to each of four nearby strings & SJB• 2 doms per cable


AURA geometry

255 0 260 0 265 0 270 0

0 .0

0 .5

1 .0

1 .5

2 .0

2 .5

3 .0

3 .5

t ns after impact V

offset

Simulat ed R IC E resp onse w A U R A t iming


ANITA (A. Javaid)

• Rate– A 1.5 106 km2 sr– 1400/day E>1019 – ? /day E>1020

• High, Thin, Ice


Summary

• Test beam for radio sure would be nice

• Air Shower Cores: Eeff ~ 10% Ep (at EeV)

• Synthetic RF looks usable• CR Composition Measurement

– Core energy anti-correlated with deep- – p-Fe separation

• Three scenarios– Small subsurface array w/IceTop– AURA– ANITA


END


Radial distributions by energy

-1.5 -1 -0.5 0 0.5 1 1.5 2xm

-1.5

-1

-0.5

0

0.5

1

1.5

2

ym

x,yfor rad : Log EGeV 10. , 17.7828 , 31.6228 , 56.2341 , 100.

-0.1 0 0.1 0.2xm

-0.1

0

0.1

0.2

ym


-1.5 -1 -0.5 0 0.5 1 1.5 2xm

-1.5

-1

-0.5

0

0.5

1

1.5

2

ym



Sample the Cerenkov Ring

Documents

July 10, 2007 Detection of Askaryan radio pulses produced by cores of air showers. Suruj Seunarine, Amir Javaid, David Seckel, Philip Wahrlich, John Clem