RESUN - david-macmahon/wiki_convert_test GitHub Wiki

Project RESUN (Radio EVLA Search for UHE Neutrinos) is an experiment that measures the isotropic Ultra High Energy (UHE: E > 10¹⁹ eV) neutrino flux via observations of neutrino-lunar baryon interactions. Potential UHE neutrino sources include Active Galactic Nuclei (AGN) primaries, GZK-induced showers from UHE cosmic rays, Z-bursts from massive primordial remnant particles, and topological defects. For distant ( > 50 Mpc, 1 Mpc = 3 x 10²² m) sources, neutrinos are the only way to probe physical processes at UHE energies, due to the strong interaction of cosmic ray primaries with Cosmic Microwave Background photons.

The experiment utilizes multiple 4 antenna sub-arrays of Expanded Very Large Array (EVLA) antennas to monitor the lunar limb for nanosecond-duration Cerenkov radio bursts in a 50MHz band centered at 1.4 GHz. Antenna receiver voltage levels are sampled, thresholded, timestamped, compared to other sub-array antennas, and stored using two, 2-channel ADC2x1000-8 units attached to one IBOB device. The ADC's are clocked at 400MHz (10ns per channel), slightly oversampling the bandwidth to include receiver power past the 3dB roll-off point.

Phase-A:

45 hrs, completed in March 2008, utilized one sub-array of 4 EVLA antennas with 50MHz bandwidth (RCP). Each antenna is offset from lunar center to specifically target the lunar limb (~ 33% limb coverage). This phase had two goals:

1. provide proof-of-concept demonstration of the hardware and software schemes needed for Phase-B

1. verify the lower limit to isotropic UHE neutrino flux determined from previous experiments.

Although no detections were made, we verified the most sensitive previously published lower flux limit for isotropic neutrinos in the energy range 10^20.5-21.5 eV. (results in press)

Phase-B:

200 hrs, starting Sept. 2009, will utilize four 4-antenna sub-arrays with 100MHz bandwidth (sampling both RCP and LCP polarization channels). The antennas in each sub-array are offset to different locations on the lunar limb, providing 100% coverage and beam overlap for finer pulse location resolution. The combination of full limb coverage, dual polarization, and 5x more observing time will probe neutrino fluxes more than one order of magnitude lower than has ever been observed.

Ted Jaeger, Prof. Robert Mutel (University of Iowa)

With Advice and Assistance From: Peter McMahon, Andrew Siemion, Dan Werthimer (CASPER), Dan Mertely, Barry Clark (NRAO - VLA)

RESUN Home Page (External Site)

Analytic Lunar Aperture Formulation