September 16-19, 2008 Hamburg 2008

Olaf ScholtenFor the NuMoon collaboration

KVI, Groningen

September 16-19, 2008 Hamburg 2008

Physics of Cosmic raysSpectrum is power lawFlux ~ E-3 Non thermal spectrum!

There must be sources!

Where? What? End point?

This talk:Measurement at highest

E

(Area Moon = 2 107 km2)

F(E)

[ m

2 s

r s

GeV

] -1

E [eV ]

10-28

104

109 1021

← 3

2 o

rders

of

magnit

ude

← 12 orders of magnitude

← 1 [m-2 s-1]

1 [km-2 y-1] UHECR

E-2.7

September 16-19, 2008 Hamburg 2008

Cosmic ray or neutrino

100MHz Radio waves

Detection:

LOFAR

Principle of the measurement

107 km2

September 16-19, 2008 Hamburg 2008

Askaryan effect: Coherent Cherenkov emission

• Leading cloud of electrons, v c

Typical size of order 10cm

Coherent Čerenkov for ν 2-5 GHz

cos θc =1/n , θc=56o for ∞ shower length

• Length of shower, L few m

Important for angular spreading

~10 cm

~2 mCosmic ray or neutrino

shower

Wave front

nano second pulses

September 16-19, 2008 Hamburg 2008

Use Westerbork radio observatory

NuMoon Experiment @ WSRT

4 frequencies

September 16-19, 2008 Hamburg 2008Trigger: pulse in all four frequency bands

+ dedispersion

18 TB raw data per 6 hr slotTime Frequency

Excise RFI

Trigger

September 16-19, 2008 Hamburg 2008

Trigger Power Spectrum

Gaussian noise

Effect successive steps in analysis

September 16-19, 2008 Hamburg 2008

Prelimenary Results

Analysis of 20 h data

Data taking is continuing

NuMoon collaboration:

O.S., Stijn Buitink, Heino Falcke, Ben Stappers, Kalpana Singh, Richard Strom

September 16-19, 2008 Hamburg 2008

Future: LOFAR

SKA, 1 year,

LFB: 100-300 MHz

MFB: 300-500 MHzFrom: O.S., SKA Design Study report

LOFAR Core 1 month

E-LOFAR, 1 year

September 16-19, 2008 Hamburg 2008

Conclusions

Detection of Ultra-High Enegy cosmic rays & neutrinos

Physics: What are the sources?

Challenge: implement real-time trigger in CEP

LOFAR as observer of short (n-sec) intermittent pulses.