Detection of UHE Shower Cores by ANITA

By

Amir Javaid

University Of Delaware

Topics Detection of Shower cores by ANITA Brief look at the shower Cores Rough estimates for event rate & shower core analysis

summary Summary of UD Monte Carlo Simulator for Shower core

detection by ANITA Present status of UD Monte Carlo Future Plans for a Monte Carlo simulator Some preliminary results from Monte Carlo Simulator

test runs Search for a better Model for Antarctic topography

Detection of Shower cores by ANITA schematic

Detection of Shower cores by ANITA

Energy in the Shower cores above 100PeV~10% (Corsika Shower Simulations)

Shower cores will produce Askaryan pulse. Pulses may be strong enough to be detected by ANITA

payload Askaryan pulses moving downwards and reflecting back

from the bed rock are the most favorable for detection Regions with thin ice and high elevation are most suitable for

shower core detection by ANITA. Ice thickness<1km & surface elevation >1km

Approximately 8% of the area in Antarctica satisfies the above conditions.

Detection of Shower cores by ANITA (contd ..)

Ice thickness Histogram (Bedmap) Suitable area~8% Histogram

Area suitable for Shower core detection ~8%

Brief look at the shower Cores

To analyze the properties of the shower cores a library of Corsika shower runs has been generated

Present energy span of this library is from 10PeV -1EeV The detector elevation is set at the South Pole and

zenith angle is chosen to be zero Showers are produce in South Pole magnetic field Flat detector and curved atmosphere model is used.

Brief look at the shower Cores (Corsika Simulation runs)

1 EeV primary proton shower footprint at South Pole for 10m2 area

Brief Look at the shower Cores (contd..)

1 EeV primary proton shower footprint at South Pole for 1m2 area

Brief Look at the shower Cores (contd..)

1 EeV primary proton shower footprint at South Pole for 10cm2 area

Brief look at the shower cores (contd ..)

150 PeV ~15% of Total Shower

Rough estimates for event rate above 1019eV for ANITA

• Air Showers

For one steradian around the vertical axis the Event Rate estimated for ANITA payload horizon ~ 1.5×1016cm2 from the measured cosmic ray flux data is ~1400 events per day[1].

• Neutrinos For 2 π steradian the Event Rate estimated for ANITA horizon from the Waxman Bahcall flux model is~237 interactions per day[1].

[1] ftp://ftp.bartol.udel.edu/anita/amir/EventRate_analysis_V1.4.pdf

Present Status of UD Monte Carlo Simulator

UD MC is in testing Stage. It is based on the SADE0.1 MC by Shahid Hussain

modified to fit the ANITA event Geometry. For testing purpose AVZ parameterized Askaryan pulses

are used. It uses Bedmap for ice thickness, bedrock elevation and

surface elevation. Interpolation is used to fill the gaps in Bedmap data. For testing purpose Snell’s law with constant refractive of

ice for ray tracing is used.

Present Status of UD Monte Carlo Simulator (contd ..)

More sophisticated ray tracing techniques do exist in UD MC.

It assumes that the ice and bedrock surfaces are flat. Perfect reflection from bedrock and perfect transmission from ice/air surface.

Point detector model with orientation. Constant attenuation model for testing purpose. More realistic attenuation models are also built in UD

MC.

Future Plans for UD Monte Carlo simulator

Development of parameterization of Askaryan pulses from shower cores.

Use of Fresnel reflection and transmission. Better model of surface roughness for bedrock and

ice/air surface. Realistic Detector and triggering model. Effective area calculation

Preliminary Results (UD MC)

Test Run geometry Detector position

Latitude=-79.2993 deg Longitude=-90o deg, Altitude=36986.5m

Event position & Energy

Latitude=-78 deg, Longitude=-90 deg, depth=198.3m

Energy=100PeV, Cherenkov Angle=55.85 deg

Test runs

Red Arrows show various shower axes used to test the code

Xparallel

depth

Altitude

Rbn

Xperp

Shower axes

Event Vertex

Test Run Results (contd..)

Direct Ray Spectrum (100PeV)

0.0E+00

1.0E-04

2.0E-04

3.0E-04

4.0E-04

5.0E-04

6.0E-04

7.0E-04

8.0E-04

0 0.5 1 1.5 2 2.5 3

Frequency (GHz)

V/M

Hz

55.8 deg 56.8 deg 57.8 deg 58.8 deg 59.8 deg54.8 deg 53.8 deg 52.8 deg 51.86 deg

Test Run Results (contd..)Reflect Ray Spectrum (100PeV)

0.0E+00

1.0E-05

2.0E-05

3.0E-05

4.0E-05

5.0E-05

6.0E-05

0 0.5 1 1.5 2 2.5 3

Frequency (GHz)

V /

MH

z

55.8 deg 54.8 deg 53.8 deg 52.8 deg 51.8 deg

56.8 deg 57.8 deg 58.8 deg 59.8

Test Run Results (contd..)

Angular distribution

0.0E+00

1.5E-07

3.0E-07

4.5E-07

6.0E-07

7.5E-07

9.0E-07

1.1E-06

1.2E-06

1.4E-06

1.5E-06

1.7E-06

1.8E-06

49 50 51 52 53 54 55 56 57 58 59 60 61 62

theta (angle from shower axis)

Inte

gra

ted

Vo

ltag

e (

Vo

lts)

ray direct ray reflect

Search for a better Model for Antarctic topography

For modeling of the surface and bedrock roughness much high resolution Antarctic topographical models are needed.

One option is the Radarsat Antarctic Mapping (RAMP) Project Digital Elevation Model Version 2 available from The National Snow and Ice Data Center.

RAMP 1 km, 400 m, and 200 m DEM data are provided in ARC/INFO and binary grid formats, and the 1 km and 400 m DEMs are also available in ASCII format.

Search for a better Model for Antarctic topography (contd..)

Surface Elevation (Radarsat data & Bedmap)

0

500

1000

1500

2000

2500

3000

3500

4000

-90 -88 -86 -84 -82 -80 -78 -76 -74 -72 -70

Latitude

Su

rfa

ce

Ele

va

tio

n

lon = 90 w gs lon = 90 osu lon = 90 Bedmap interp lon = 90 Bedmap no interp

lon = -150 w gs lon =-150 osu lon = -150 bedmap interp lon = -150 bedmap no interplon = -30 w gs lon = -30 osu lon = -30 bedmap interp lon = -30 bedmap no interp

Search for a better Model for Antarctic topography (contd..)

Radarsat Surface elevation 400mRes Bedmap Surface elevation 5km Res

Summary

Detailed analysis of shower cores Askaryan Pulse parameterization is in progress

Development of UD Monte Carlo is moving towards more robustness

Feasibility check of the Radarsat RAMP model for the use in Monte Carlo. These files are large (~2.5 GB), which mean more cpu cycles are required.

Plan of ANITA -1 flight data analysis for shower core events.