130 likes | 290 Views
The ν Moon project: Detecting UHE cosmic-rays and neutrinos hitting the Moon. ν Moon Collaboration: J. Bacelar (KVI) R.Braun (ASTRON) G. de Bruyn (ASTRON) H. Falcke (ASTRON) O. Scholten (KVI) B. Stappers (ASTRON) R. Strom (ASTRON). Neutrino detection needs large detector volumes!.
E N D
The νMoon project: Detecting UHE cosmic-rays and neutrinos hitting the Moon νMoon Collaboration:J. Bacelar (KVI) R.Braun (ASTRON) G. de Bruyn (ASTRON) H. Falcke (ASTRON) O. Scholten (KVI) B. Stappers (ASTRON) R. Strom (ASTRON)
Neutrino detection needs large detector volumes! Use the moon …
Cosmic Ray Westerbork antennas 100 MHz Radio Waves
Vacuum Moon n=1.5-1.8 θc ≈ 560 Cosmic particle interaction • Particle hits Moon (radius=1700 km; area = 6×106 km2): • Interacts: protons within meters, V • Askaryan effect -> Coherent Cherenkov emission • Shower development -> including LPM effect • Transmission through Moon material λr= 15[m] / [GHz] = 7m (at 2.2 GHz) • Transmissivity across Moon surface – vacuum boundary 60 km @ 1021 eV 6 km @ 1024 eV Vacuum Moon n=1.5-1.8 Spread emitted power density in a gaussian of width Δθc≈λ/ℓ Hadronic component: Δθc= 2.5 (3/) = 3.50 (at 2.2 GHz) EM component Δθc= 2.5 (3/)(4.1014 / E)1/3 = 0.0250 θc ≈ 560 θc 2.2 GHz
Vacuum Moon n=1.5-1.8 θc ≈ 560 Cosmic particle interaction • Particle hits Moon (radius=1700 km; area = 6×106 km2): • Interacts: protons within meters, V • Askaryan effect -> Coherent Cherenkov emission • Shower development -> including LPM effect • Transmission through Moon material λr= 15[m] / [GHz] = 150 m (at 0.1 GHz) • Transmissivity across Moon surface – vacuum boundary 60 km @ 1021 eV 6 km @ 1024 eV Spread emitted power density in a gaussian of width Δθc≈λ/ℓ Hadronic component: Δθc= 2.5 (3/) = 750 (at 0.1 GHz) EM component Δθc= 2.5 (3/)(4.1014 / E)1/3 = 0.50 θc 100 MHz
Where can one do this experiment at 150 MHz ? • GMRT in India (30 dishes 45m diameter) • Problem: Data acquisition, Ionosphere, Interference,separation between telescopes • WSRT Westerbork – available at present (14 dishes 25 m diameter) • Use “PUMA II” backend for pulsar observations • LOFAR – available in the future • Dedicated mode for moon experiment
Westerbork (WSRT) Experiment • Basic Properties: • 14 x 25 m diameter dishes • 12 dishes phased-up • 110 hour observation time • 40 M samples/sec (PuMa II) • Full Polarization information • 117-175 MHz band • 8 dual-pol bands of 20 MHz • 3×1020 eV would give 15 σ peak (req.) • 2 separate 4’ × 6° pencil beams • covering 50% of moon Westerbork Synthesis Radio Telescope
Westerbork (WSRT) Experiment 4 freq.bands 4 freq.bands Westerbork Synthesis Radio Telescope
Schedule • Pilot experiment at WSRT, followed by campaign at LOFAR • First: Director’s time at WSRT • 2005, 14th June 17:00-19:00 several different daq. Options tried (PuMa I) • 2005, 8th July 07:00-09:00 measurements at 117 and 162 MHz (PuMa I) • 2006, 20th Feb. 06 05:00-06:00 measurement with PuMaII • 2006: νMoon approved as Long-Term Project • First 110 hrs granted, starting July 15, 2006 • A total of 510 hrs requested for subsequent years • Currently observed 24 hrs / 12 hrs of useful data
Processing Pipeline Spectrum before & after interference excision • 18 TB raw data per 6 hr slot • Excision of narrow-band interference • De-Dispersion of ionosphere with GPS TEC values • Indentification of peaks • 100:1 to 180 GB
First Data Products: Noise Distribution & Power Spectra Simulation of data for 15 events within 1 hour data taking Noise is Gaussian down to 10-7 10 s of data
Expected Sensitivity Cosmic Rays Neutrinos TDs GZK ν´s Scholten et al. (NuMoon Collab.) 2006, Astropart. Phys., in press
Summary • Low-Frequency radio observations are ideal to study super-GZK particles. • Westerbork experiment has just begun • Data pipeline is working • 100 hrs granted, 500 hrs expected in total • Search for pulses is next … • Very interesting first limit within one year!? • LOFAR will improve limits(?) even more