EAS radio detection at large impact parameter: the inverse problem and the design of a giant array

Contribution to the 30th ICRC, July 2007, Merida, MexicoInternational audienceExtensive air shower radio electric fields can be evaluated at large impact parameter with analytical expressions. Such a theoretical tool is most valuable in the present phase where the capabilities of the radio detection of extensive air shower are under investigations. It can help shaping strategies for the analysis of radio detection data. It can also be used to perform non trivial test of much more detailed numerical approaches which are currently under development. The approximation leading to such a formulation will be presented and two applications will be discussed: the "inverse" problem of how to go from a sampling of the radio electric field on a few antennas to the main characteristics of the extensive air shower, and the question of the antenna spacing of a giant array for ultra high energy cosmic rays

Radioelectric fields from cosmic-ray air showers at large impact parameters

International audienceWe discuss electric fields generated by cosmic-ray air showers at large impact parameters b. An approximation relevant to this situation is given. The formulation makes explicit the relationship between the shower profile and the radio pulse shapes at large b, putting forward one important observational consequence, namely the decrease of the high-frequency cutoff νc∝1/b when the impact parameter increases. The approximation is also used to give a detailed comparison between two emission models, the geosynchrotron model and the transverse current model

Radio background measurements at the Pierre Auger Observatory

Mesures du bruit de fond radio sur le site de l'observatoire Pierre Auge

The Stereo experiment: search for a sterile neutrino

International audienc

Measurement of the electron drift velocity for directional dark matter detectors

Three-dimensional track reconstruction is a key issue for directional Dark Matter detection. It requires a precise knowledge of the electron drift velocity. Magboltz simulations are known to give a good evaluation of this parameter. However, large TPC operated underground on long time scale may be characterized by an effective electron drift velocity that may differ from the value evaluated by simulation. In situ measurement of this key parameter is hence a way to avoid bias in the 3D track reconstruction. We present a dedicated method for the measurement of the electron drift velocity with the MIMAC detector. It is tested on two gas mixtures : $\rm CF_4$ and $\rm CF_4+CHF_3$. We also show that adding $\rm CHF_3$ allows us to lower the electron drift velocity while keeping almost the same Fluorine content of the gas mixture.Comment: Proceedings of the 4th international conference on Directional Detection of Dark Matter (CYGNUS 2013), 10-12 June 2013, Toyama, Japa

In situ measurement of the electron drift velocity for upcoming directional Dark Matter detectors

Three-dimensional track reconstruction is a key issue for directional Dark Matter detection and it requires a precise knowledge of the electron drift velocity. Magboltz simulations are known to give a good evaluation of this parameter. However, large TPC operated underground on long time scale may be characterized by an effective electron drift velocity that may differ from the value evaluated by simulation. In situ measurement of this key parameter is hence needed as it is a way to avoid bias in the 3D track reconstruction. We present a dedicated method for the measurement of the electron drift velocity with the MIMAC detector. It is tested on two gas mixtures: CF4 and CF4 + CHF3. The latter has been chosen for the MIMAC detector as we expect that adding CHF3 to pure CF4 will lower the electron drift velocity. This is a key point for directional Dark Matter as the track sampling along the drift field will be improved while keeping almost the same Fluorine content of the gas mixture. We show that the drift velocity at 50 mbar is reduced by a factor of about 5 when adding 30% of CHF3.Comment: 19 pages, 14 figures. Minor corrections, matches published version in JINS

MIMAC: MIcro-tpc MAtrix of Chambers for dark matter directional detection

Directional detection of non-baryonic Dark Matter is a promising search strategy for discriminating WIMP events from neutrons, the ultimate background for dark matter direct detection. This strategy requires both a precise measurement of the energy down to a few keV and 3D reconstruction of tracks down to a few mm. The MIMAC (MIcro-tpc MAtrix of Chambers) collaboration has developed in the last years an original prototype detector based on the direct coupling of large pixelized micromegas with a special developed fast self-triggered electronics showing the feasibility of a new generation of directional detectors. The first bi-chamber prototype has been installed at Modane, underground laboratory in June 2012. The first undergournd background events, the gain stability and calibration are shown. The first spectrum of nuclear recoils showing 3D tracks coming from the radon progeny is presented.Comment: Proceedings of the 4th International Conference on Directional Dark Matter Detection CYGNUS2013, held in Toyoma (Japan), June 201

Trigger and readout electronics for the STEREO experiment

The STEREO experiment will search for a sterile neutrino by measuring the anti-neutrino energy spectrum as a function of the distance from the source, the ILL nuclear reactor. A dedicated electronic system, hosted in a single microTCA crate, was designed for this experiment. It performs triggering in two stages with various selectable conditions, processing and readout via UDP/IPBUS of 68 photomultiplier signals continuously digitized at 250 MSPS. Additionally, for detector performance monitoring, the electronics allow on-line calibration by driving LED synchronously with the data acquisition. This paper describes the electronics requirements, architecture and the performances achieved.Comment: Topical Workshop on Electronics for Particle Physics (TWEPP) 2015, Lisboa. 9 pages, 9 figure