Characterization of the photomultiplier tubes for the scintillation detectors of GRANDProto35 experiment

International audienceGRANDProto35 is the first stage of the GRAND project. It will be composed of an array of 35 radio antennas and 24 scintillation detectors in which the radio and scintillating subarrays will be triggered independently. The scintillation detector array allows to cross-check the radio array, thus quantitatively determine its detection efficiency. The photomultiplier of Hamamatsu R7725 is a candidate for the scintillation detector. The characteristics of the PMT will directly affect the resolution of the time and energy measurements and the dynamic detection range of a scintillation detector. A voltage divider circuit featured with dual-readout was designed for the PMT to cover a larger linear dynamic range (LDR). Some characteristics of the PMT were calibrated and investigated: the absolute gain, single photoelectron (SPE) energy resolution, transit time spread (TTS), linear dynamic range, and temperature dependence of the PMT gain. In this paper, details about the system setup, measurement methods, and results will be described

Detection of Extensive Air Showers with the self-triggered TREND radio array

International audienceWe demonstrate here the ability of TREND, a self-triggered antenna array, to autonomously detect and identify air showers induced by cosmic rays, from their radio emission, measured in the 50-100 MHz frequency range. TREND (Tianshan Radio Experiment for Neutrino Detection) is an array of 50 single polarised antennas, deployed over a total area of 1.5 km$^2$ on the site of the 21 cmA radio interferometer in the radio-quiet Tianshan mountains (China), that was running between 2011 and 2013. The TREND DAQ system was designed to allow for a trigger rate of up to 200 Hz per antenna, based on a very basic signal-over-threshold trigger condition. The reconstruction and discrimination of air showers from the ultra-dominant background noise is then performed through an offline treatment.We present here, for the first time, a detailed search for extensive air showers with the TREND data. We first explain the background-rejection algorithm which allowed to select about 500 air shower radio candidates from the $\sim7.10^8$ radio pulses recorded with the TREND array. We then show that the distribution of the directions of arrivals of these $\sim$500 candidates is compatible with what is expected for air showers. We finaly compute the TREND air shower detection efficiency, thanks to an end-to-end simulation chain which will be detailed here. Given the fairly basic TREND data acquisition chain, these results can be considered extremely encouraging in the perspective of future experiments using radio as a way to detect air showers, such as the Giant Radio Array for Neutrinos Detection

The Giant Radio Array for Neutrino Detection

International audienceHigh-energy neutrino astronomy will probe the working of the most violent phenomena in the Universe. The Giant Radio Array for Neutrino Detection (GRAND) project consists of an array of ~ 10^5 radio antennas deployed over ~200000km^2 in a mountainous site. It aims at detecting high-energy neutrinos via the measurement of air showers induced by the decay in the atmosphere of tau leptons produced by the interaction of cosmic neutrinos under the Earth surface. Our objective with GRAND is to reach a neutrino sensitivity of 5 x 10^-11E^-2GeV^-1cm^-2s^-1sr^-1 above 3 x 10^16eV. This sensitivity ensures the detection of cosmogenic neutrinos in the most pessimistic source models, and up to 100 events per year are expected for the standard models. GRAND would also probe the neutrino signals produced at the potential sources of UHECRs

The Giant Radio Array for Neutrino Detection

International audienceHigh-energy neutrino astronomy will probe the working of the most violent phenomena in the Universe. The Giant Radio Array for Neutrino Detection (GRAND) project consists of an array of ~ 10^5 radio antennas deployed over ~200000km^2 in a mountainous site. It aims at detecting high-energy neutrinos via the measurement of air showers induced by the decay in the atmosphere of tau leptons produced by the interaction of cosmic neutrinos under the Earth surface. Our objective with GRAND is to reach a neutrino sensitivity of 5 x 10^-11E^-2GeV^-1cm^-2s^-1sr^-1 above 3 x 10^16eV. This sensitivity ensures the detection of cosmogenic neutrinos in the most pessimistic source models, and up to 100 events per year are expected for the standard models. GRAND would also probe the neutrino signals produced at the potential sources of UHECRs

The Giant Radio Array for Neutrino Detection

International audienceHigh-energy neutrino astronomy will probe the working of the most violent phenomena in the Universe. The Giant Radio Array for Neutrino Detection (GRAND) project consists of an array of ~ 10^5 radio antennas deployed over ~200000km^2 in a mountainous site. It aims at detecting high-energy neutrinos via the measurement of air showers induced by the decay in the atmosphere of tau leptons produced by the interaction of cosmic neutrinos under the Earth surface. Our objective with GRAND is to reach a neutrino sensitivity of 5 x 10^-11E^-2GeV^-1cm^-2s^-1sr^-1 above 3 x 10^16eV. This sensitivity ensures the detection of cosmogenic neutrinos in the most pessimistic source models, and up to 100 events per year are expected for the standard models. GRAND would also probe the neutrino signals produced at the potential sources of UHECRs

The GRANDproto35 experiment

International audienceThe very low flux of ultra-high-energy cosmic-rays (UHECRs) requires detectors with a large effective area and high duty cycle to obtain a statistically relevant sample. Radio detection of extensive air showers (EAS) presents attractive aspects for future giant detectors of high energy cosmic particles, with very low cost per detection unit, easiness of deployment over large areas, and a duty cycle close to 100%. However autonomous detection of EAS -a necessary step towards the realization of this type of ambitious detectors- remains a challenge.GRANDproto35 aims at demonstrating that radio-detection of air showers can be performed with very good background rejection, high efficiency, and an almost 100% duty cycle. The 35 GRANDproto antennas will perform a full measurement of the detected wave polarization. This makes GRANDproto35 uniquely qualified for the investigation of polarization characteristics of the radio emission from EAS, which may contribute to discriminate them from background signals. In addition, an array of 24 scintillators will allow offline cross-checks of the nature of the selected radio-candidates. We detail here the principle, progress and prospects of GRANDproto35, which serves as a step towards the Giant Radio Array for Neutrino Detection (GRAND) project. GRAND will consist of an array of ∼ 10^5 radio antennas deployed over ∼ 200, 000 km^2 in mountainous sites

The Giant Radio Array for Neutrino Detection

International audienceHigh-energy neutrino astronomy will probe the working of the most violent phenomena in the Universe. The Giant Radio Array for Neutrino Detection (GRAND) project consists of an array of ~ 10^5 radio antennas deployed over ~200000km^2 in a mountainous site. It aims at detecting high-energy neutrinos via the measurement of air showers induced by the decay in the atmosphere of tau leptons produced by the interaction of cosmic neutrinos under the Earth surface. Our objective with GRAND is to reach a neutrino sensitivity of 5 x 10^-11E^-2GeV^-1cm^-2s^-1sr^-1 above 3 x 10^16eV. This sensitivity ensures the detection of cosmogenic neutrinos in the most pessimistic source models, and up to 100 events per year are expected for the standard models. GRAND would also probe the neutrino signals produced at the potential sources of UHECRs

The Giant Radio Array for Neutrino Detection

The Giant Radio Array for Neutrino Detection (GRAND) is a planned array of ~ 2·105 radio antennas deployed over ~ 200 000 km2 in a mountainous site. It aims primarly at detecting high-energy neutrinos via the observation of extensive air showers induced by the decay in the atmosphere of taus produced by the interaction of cosmic neutrinos under the Earth surface. GRAND aims at reaching a neutrino sensitivity of 5 · 10−11 E−2 GeV−1 cm−2 s−1 sr−1 above 3 · 1016 eV. This ensures the detection of cosmogenic neutrinos in the most pessimistic source models, and ~50 events per year are expected for the standard models. The instrument will also detect UHECRs and possibly FRBs. Here we show how our preliminary design should enable us to reach our sensitivity goals, and discuss the steps to be taken to achieve GRAND, while the compelling science case for GRAND is discussed in more details in [1]