P. Gorodetzky

Generator of two single electrons separated in time adjustable between 300 ps and 100 ns

Abstract A device to generate two single electrons which follow each other with a tunable time difference between 300 ps and 100 ns has been developed. This was motivated by the necessity of testing high performance gaseous detectors employed for tracking in high particle flux and high repetition rate experiments as well as in a large field of single electron counting devices. Two electrons allow to study in a controlled way the basic effects of pile-up in such a detector.

The focal surface of the EUSO telescope

The Extreme Universe Space Observatory (EUSO) is a space mission to study extremely high-energy cosmic rays. The EUSO instrument is a wide-angle refractive telescope in near-ultraviolet wavelength region to observe time-resolved atmospheric fluorescence images of the extensive air showers from the International Space Station. The Focal surface is an aspherical curved surface, and its area amounts to about 4.5 m2. The focal surface detector is designed as a mosaic of multianode photomultipliers (MAPMT) for the single photoelectron counting capability. The strongest requirement for the focal surface detector is the maximization of the photon detection efficiency together with the uniformity over the focal surface. We have developed a new type of MAPMT. It is modified from the ordinary one and has a grid between the photocathode and the first dynode to electrostatically demagnify the photoelectron image on the dynode. We are also developing the HV supply system for a great number of MAPMTs. EUSO experiments the day-time and night-time every 90 minutes. The heat flow must be considered to stabilize the PMT characteristics, in parallel with the heat dissipation of the electronics attached on the focal surface supporting structure.

The photo-detector for the EUSO experiment

Abstract The EUSO experiment is currently under study by ESA for a possible installation on the International Space Station. The experiment is designed to study, by means of a space-based observational apparatus, the Extensive Air Showers produced in the atmosphere by Extreme High-Energy Cosmic Rays. The design of a fast, single-photon sensitive photo-detector in the near UV, covering a large area with a few hundreds thousands pixels, and suitable for 3 years of operation in space is a challenging task. The basic aspects of the current EUSO photo-detector design, based on the presently known requirements and constraints, and the results of the preliminary studies carried on so far will be described.

The solar neutrino project HELLAZ: status report on the hardware and the simulation

Abstract We report the status of the solar neutrino project called HELLAZ. In a high pressure time projection chamber filled with helium, the detection of each ionization electron of the track produced by the recoil electron from elastic scattering induced by solar neutrinos, will yield the low energy, high resolution solar neutrino spectrum. Two topics are presented: the preliminary test of the direction of the primary electron track from the cloud analysis and tests of Micromegas gas chambers giving a good discrimination between adjacent ionization electrons. These two tests seem rather encouraging.

Focal surface for EUSO telescope

The Extreme Universe Space Observatory (EUSO) is a wide angle refractive telescope in near-ultraviolet wavelength region to detect extremely high energy cosmic rays by observing time-resolved air-fluorescence images of the extensive air showers from the International Space Station. The focal surface detector of the EUSO is designed to be a mosaic of multianode photomultipliers to realize the single photoelectron counting capability. We describe the current status of the conceptual design and the feasibility study of the focal surface of the EUSO telescope.