A lunar radio experiment with the Parkes radio telescope for the LUNASKA project

Abstract

We describe an experiment using the Parkes radio telescope in the 1.2-1.5 GHz frequency range as part of the LUNASKA project, to search for nanosecond-scale pulses from particle cascades in the Moon, which may be triggered by ultra-highenergy astroparticles. Through the combination of a highly sensitive multi-beam radio receiver, a purpose-built backend and sophisticated signal-processing techniques, we achieve sensitivity to radio pulses with a threshold electric field strength of 0.0053 µV/m/MHz, lower than previous experiments by a factor of three. We observe no pulses in excess of this threshold in observations with an effective duration of 127 hours. The techniques we employ, including compensating for the phase, dispersion and spectrum of the expected pulse, are relevant for future lunar radio experiments.

Comprehensive approach to tau-lepton production by high-energy tau neutrinos propagating through the Earth

“…The detection of or tighter limits on this cosmogenic UHE neutrino flux has the potential to significantly constrain models of UHE cosmic-ray sources [8,11,12]. UHE neutrinos have been searched for in the past decades with several experiments using the Moon [13][14][15], the Earth's crust with the Pierre Auger Observatory [11], and the Antarctic ice cap with IceCube [12] and ANITA [16], each producing the most constraining limits to date in different parts of the UHE band. Recently an extra-terrestrial flux of neutrinos extending above 10 15 eV has been detected with IceCube [17].…”

Sensitivity of lunar particle-detection experiments

“…A lunar-origin pulse should be detected only in the beam directed at the correct part of the moon, whereas local radio-frequency interference will generally be seen simultaneously in multiple beams. Two recent experiments that used this approach are NuMoon [14] and LUNASKA Parkes [17]. However, telescope beams overlap to some degree, and a sufficiently strong lunar-origin pulse may be detected in multiple beams, and incorrectly classified as interference [19].…”

“…[11,15]); others have corrected it in real time with a filter matched to the STEC (e.g. [13,17]), or recorded the received signal with its full time resolution, allowing the correction to be applied retrospectively (e.g. [14]).…”

“…A particle cascade developing in the dense medium of the lunar regolith produces a strong Askaryan radio pulse [8], and the lunar Askaryan technique employs an Earth-based radio telescope -or, potentially, a satellite in lunar orbit [9] -to search for this. Eight such experiments have been published to date [10][11][12][13][14][15][16][17]; see Ref. [18] for a summary and analysis.…”

TEC, Trigger and Check, preparing LOFAR for Lunar observations

“…Previous measurements with radio telescopes such as Parkes [2][3][4] and WSRT [5,6] have developed these techniques and set limits to the flux of these particles. However, it requires even larger telescopes, such as the SKA [7] or FAST, to be sensitive to the known cosmic ray flux.…”