Design and operation of ARGONTUBE: a 5 m long drift liquid argon TPC

The Liquid Argon Time Projection Chamber (LArTPC) is a prime type of detector for future large-mass neutrino observatories and proton decay searches. In this paper we present the design and operation, as well as experimental results from ARGONTUBE, a LArTPC being operated at the AEC-LHEP, University of Bern. The main goal of this detector is to prove the feasibility of charge drift over very long distances in liquid argon. Many other aspects of the LArTPC technology are also investigated, such as a voltage multiplier to generate high voltage in liquid argon (Greinacher circuit), a cryogenic purification system and the application of multi-photon ionization of liquid argon by a UV laser. For the first time, tracks induced by cosmic muons and UVlaser beam pulses have been observed and studied at drift distances of up to 5 m, the longest reached to date.

First measurements with ARGONTUBE, a 5m long drift Liquid Argon TPC

The Liquid Argon Time Projection Chamber (LAr TPC) technique is a promising technology for future neutrino detectors. At LHEP of the University of Bern (Switzerland), an R&D program towards large detectors are on-going. The main goal is to show the feasibility of long drift paths over many meters. Therefore, a liquid Argon TPC with 5m of drift distance was constructed. Many other aspects of the liquid Argon TPC technology are also investigated, such as a new device to generate high voltage in liquid Argon (Greinacher circuit), a recirculation filtering system and the multi-photon ionization of liquid Argon with a UV laser. Two detectors are built: a medium size prototype for specific detector technology studies, and ARGONTUBE, a 5m long device.

The Beach in Anglophone Literatures and Cultures: Reading Littoral Space

From early colonial encounters to the ecological disasters of the twenty-first century, the performativity of contact has been a crucial element in the political significance of the beach. Conceptualising the beach as a creative trope and as a socio-cultural site, as well as an aesthetically productive topography, this collection examines its multiplicity of meanings and functions as a natural environment engendering both desire and fear in the human imagination from the Victorian period to the present. The contributors examine literature, film, and art, in addition to moments of encounter and environmental crisis, to highlight the beach as a social space inspiring particular codes of behaviour and specific discourses, as a geographical frontier between land and water, as an historical site of contact and conflict, and as a vacationscape promising regeneration and withdrawal from everyday life. The diversity of the beach is reflected in the geographical range, with essays on locales and texts from Britain, Ireland, the Caribbean, South Africa, the United States, Polynesia, and New Zealand. Focusing on the changed function of the beach as a result of processes of industrialisation and the rise of a modern leisure and health culture, this interdisciplinary volume theorises the beach as a demarcater of the precarious boundary between land and the sea, as well as between nature and culture.

Measurement of the drift field in the ARGONTUBE LAr TPC with 266 nm pulsed laser beams

ARGONTUBE is a liquid argon time projection chamber (LAr TPC) with a drift field generated in-situ by a Greinacher voltage multiplier circuit. We present results on the measurement of the drift-field distribution inside ARGONTUBE using straight ionization tracks generated by an intense UV laser beam. Our analysis is based on a simplified model of the charging of a multi-stage Greinacher circuit to describe the voltages on the field cage rings.

Développement de l'écotourisme dans la région de Mananara-Nord et du Triangle Bleu, Littoral Nord-Est, Madagascar: Concept de travail

Concept de travail du projet de développement de l'écotourisme dans la région de Mananara-Nord et du Triangle Bleu, Littoral Nord-Est, Madagascar: objectifs de l'étude, résultats attendus, approche choisie, étapes du travail.

Développement de l'écotourisme dans la région du Triangle Bleu, Littoral Nord-Est de Madagascar: Collecte de données auprès de voyagistes en Suisse

Rapport des enquêtes menées en Suisse quant au secteur de l'écotourisme: tendances, entretiens auprès des voyagistes en Suisses et des touristes à Madagascar.