REAS3: Monte Carlo simulations of radio emission from cosmic ray air showers using an "end-point" formalism

In recent years, the freely available Monte Carlo code REAS for modelling radio emission from cosmic ray air showers has evolved to include the full complexity of air shower physics. However, it turned out that in REAS2 and all other time-domain models which calculate the radio emission by superposing the radiation of the single air shower electrons and positrons, the calculation of the emission contributions was not fully consistent. In this article, we present a revised implementation in REAS3, which incorporates the missing radio emission due to the variation of the number of charged particles during the air shower evolution using an "end-point formalism". With the inclusion of these emission contributions, the structure of the simulated radio pulses changes from unipolar to bipolar, and the azimuthal emission pattern becomes nearly symmetric. Remaining asymmetries can be explained by radio emission due to the variation of the net charge excess in air showers, which is automatically taken into account in the new implementation. REAS3 constitutes the first self-consistent time-domain implementation based on single particle emission taking the full complexity of air shower physics into account, and is freely available for all interested users.Comment: 18 pages, 13 figures accepted by Astroparticle Physics (2010

The TIANSHAN Radio Experiment for Neutrino Detection

An antenna array devoted to the autonomous radio-detection of high energy cosmic rays is being deployed on the site of the 21 cm array radio telescope in XinJiang, China. Thanks in particular to the very good electromagnetic environment of this remote experimental site, self-triggering on extensive air showers induced by cosmic rays has been achieved with a small scale prototype of the foreseen antenna array. We give here a detailed description of the detector and present the first detection of extensive air showers with this prototype.Comment: 37 pages, 15 figures. Astroparticle Physics (in press

Assessing the Role of Mobile Device Applications as an Educational Tool for Increasing Knowledge and Awareness of Volatile Organic Compound Exposure

Exposure to volatile organic compounds (VOCs) has critical health implications for developing fetuses and subsequently for infants and young children. Research has suggested that this ambient air pollutant can be found indoors in quantities that may be hazardous to human health. In low-income neighborhoods in New York City such as northern Manhattan and the South Bronx, where there are disproportionately high rates of asthma and asthma-related hospitalizations, high rates of indoor exposure to VOCs persist. Simultaneously, as mobile devices expand, applications on mobile devices may be used to educate parents of children who reside in these geographic regions about indoor VOC emission sources and subsequently how to reduce exposure.Therefore, this study sought to assess the role of mobile device applications in reducing household VOCs by assessing the feasibility of existing health applications on both Apple and Android OS mobile devices without the use of a household air monitoring unit. An online survey assessed awareness of VOCs and identified knowledge of both emission sources and reduction methods of household VOCs among a sample of (N = 57) parents/guardians residing in the Northern Manhattan and Southern Bronx regions with children under the age of 5. A series of focus groups were conducted among a subset of participants to assess the adaptability of a mobile application prototype that specifically targets the reduction of VOCs. Lastly, a preliminary mobile device application mockup was created with potential features. The key findings of this study included the following: (a) the author identified no existing mobile device applications that could be utilized as a method for VOC reduction without the use of a physical in-home air monitor; (b) while parents had some baseline awareness of VOCs, there were gaps within their knowledge of VOCs, particularly with emission sources; (c) the feasibility of this proposed application as a potential source of intervention for indoor VOC mitigation was apparent through parent willingness to explore its possible use, while providing ample recommendations for optimal mobile device application design; and (d) the exploratory mockup of the proposed mobile device application was generated with suggested features

The MIDAS telescope for microwave detection of ultra-high energy cosmic rays

We present the design, implementation and data taking performance of the MIcrowave Detection of Air Showers (MIDAS) experiment, a large field of view imaging telescope designed to detect microwave radiation from extensive air showers induced by ultra-high energy cosmic rays. This novel technique may bring a tenfold increase in detector duty cycle when compared to the standard fluorescence technique based on detection of ultraviolet photons. The MIDAS telescope consists of a 4.5 m diameter dish with a 53-pixel receiver camera, instrumented with feed horns operating in the commercial extended C-Band (3.4 -- 4.2 GHz). A self-trigger capability is implemented in the digital electronics. The main objectives of this first prototype of the MIDAS telescope - to validate the telescope design, and to demonstrate a large detector duty cycle - were successfully accomplished in a dedicated data taking run at the University of Chicago campus prior to installation at the Pierre Auger Observatory.Comment: 13 pages, 18 figure

Development of a radio detection array for the observation of showers induced by UHE Tau neutrinos

International audienceDevelopment of a radio detection array for the observation of showers induced by UHE Tau neutrino

Strange quark matter in a chiral SU(3) quark mean field model

We apply the chiral SU(3) quark mean field model to investigate strange quark matter. The stability of strange quark matter with different strangeness fraction is studied. The interaction between quarks and vector mesons destabilizes the strange quark matter. If the strength of the vector coupling is the same as in hadronic matter, strangelets can not be formed. For the case of beta equilibrium, there is no strange quark matter which can be stable against hadron emission even without vector meson interactions.Comment: 19 pages, 8 figure