[en] The only two firmly identified galactic gamma-ray sources in the second COS B catalogue are the pulsars PSR 0531+21 (Crab) and PSR 0833-45 (Vela). In the region between 100 keV and 10 MeV the detailed shape of the emission is particularly important, since one expects a turn-off which is related to geometry of the source. A marginal evidence of such a turn-off just below 1 MeV has been reported for the Vela pulsar. In order to study sources with a well marked time signature in this energy band, the FIGARO - French Italian Gamma Ray Observatory was designed. The first version was launched in November 1983 from the Sao Manuel base (Brazil), and was destroyed in a free fall following a balloon burst at an altitude of 50 mbar. A brief description is given of the new improved version of the experiment, FIGARO 2, which is nearly completed and whose launch is scheduled before summer 1986

[en] The paper presents a large area, balloon borne, NaI(Tl) detector for low-energy gamma rays with temporal signature: Figaro. The main detector is a mosaic of 12 NaI(Tl) tiles 22.5 x 15 x 5 cm, for a total geometric area of 4050 sq cm. In the energy band 140 keV-6 MeV, the expected background counting rate at float altitude is in the range of two to three thousand counts per second. For pulsar analysis the expected 3sigma sensitivity for 5 hours exposition time is 2.5 10 to the -4th ph/sq cm.s.MeV (150-500 keV) 1.5 10 to the -4th ph/sq cm.s.MeV (1-6 MeV). This performance, together with the large effective area and the relatively short duration of a balloon flight, make Figaro particularly suitable for the identification of sources by means of temporal analysis. For objectives in the Northern sky, including the Crab pulsar, a transmediterranean flight is planned for the summer of 1982 a Southern mission is scheduled in Brazil for the fall of 1983 (Vela, PSR 1822-09)

[en] The balloon-borne experiment, named BAckground BYpass (BABY) belongs to a wider program that has as its final goal the detection and study of high-energy cosmic rays from space (satellite, Space Station). An information of fundamental importance for this class of projects concerns the nighttime background light. The instrument designed to detect fluorescence photons is basically composed of two collimated photomultipliers: a single photon-counting PMT and a charge integration PMT. We briefly report the details of the design, operation and performance of the detector, which was designed and completely built at the IFCAI-CNR Institute in Palermo. Preliminary analysis and results of the nocturnal background in the range of 300-400 nm are presented for the whole duration of the flight during the 1998 Mediterranean balloon flight campaign. A substantial part of the flight was at night over the sea

[en] The availability of a detector such as an RPC (resistive plate counter) opens new possibility on the future experiments for accelerator and non-accelerator physics. The main advantage consists on the possibility to obtain accurate tracking and timing with a low-cost detector and electronics. We report results on time resolution, signal transmission on long strips, efficiency and maintenance. A possible front-end electronics able to give tracking and timing information on each input channel operating in free-running mode will be illustrated together to the preliminary tests performed. (orig.)

[en] The Uv Light Transmission and Reflection in the Atmosphere (ULTRA) experiment has been designed to provide quantitative measurements of the backscattered Cherenkov signal associated to the Extensive Air Showers (EAS) at the impact point on the Earth surface. The knowledge of such information will test the possibility to detect the diffused Cherenkov light spot from space within the Ultra high-energy cosmic ray observation. The Cherenkov signal is necessary to give an absolute reference for the track, allowing the measurement of the shower maximum and easing the separation between neutrino and hadronic showers. In this paper we discuss the experimental set-up with detailed information on the detection method; the in situ and laboratory calibrations; the simulation of the expected detector response and finally the preliminary results on the detector performance

[en] UVscope is a portable multi-pixels photon detector developed at IASF-Pa to support experimental activities in the high-energy astrophysics and cosmic rays field. The instrument, working in single photon counting mode, is designed to directly measure light flux in the wavelengths range 300-650 nm. Thanks to its features and operational flexibility, the instrument can be used in a wide field of applications where the knowledge of the environmental luminosity is required, as in the characterization of sites for ground-based Cherenkov and fluorescence telescopes, and for cross-calibration of their cameras. The present version of UVscope is based on a Multi Anode Photo Multiplier Tube and it is completed by a motorized mount and a filter wheel which allow to make low-light measurements, at programmed pointing directions and at different filter wavelengths. In this paper, the instrument is firstly presented in all its components; then the procedures adopted for its absolute and relative calibration are detailed. The performance of UVscope is evaluated and, finally, current and planned scientific applications are described.

[en] ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana), is a flagship project of the Italian Ministry of Education, University and Research whose main goal is the design and construction of an end-to-end prototype of the Small Size of Telescopes of the Cherenkov Telescope Array. The prototype, named ASTRI SST-2M, will adopt a wide field dual mirror optical system in a Schwarzschild-Couder configuration to explore the VHE range of the electromagnetic spectrum. The camera at the focal plane is based on Silicon Photo-Multipliers detectors which is an innovative solution for the detection astronomical Cherenkov light. This contribution reports some preliminary results on the evaluation of the optical cross talk level among the SiPM pixels foreseen for the ASTRI SST-2M camera

[en] A new modular multichannel front-end time to digital electronics is described. The T and T (tracking and timing) electronics is characterised by a 2 ns time resolution with multihits recording capability, no ambiguity in event pulse reconstruction, low power consumption and daisy-chain interconnecting capability. The simple design and the low cost per channel make it preferable for use in cosmic rays and EAS as well as in accelerator experiments. A description of the environmental operation and tests of the T and T electronics is presented. This electronics is used in an EAS experiment in Leeds (UK) called COVER/PLASTEX. Results on the T and T electronic performances in this experiment are also presented. (orig.)

[en] The FIGARO II (French Italian GAmma, Ray Observatory) experiment designed to observe cosmic sources with a well established time signature is described. It consists of a large-area (3600 cm²) array of nine tiles of NaI(Tl), actively shielded against the environmental background, to be operated at high altitude by means of a stratospheric balloon for the detection of celestial gamma rays in the energy band 0.17-6.0 MeV. The performance of this experiment derived from calibrations with radioactive sources and flight data is presented. The actual sensitivity allows the detection of a pulsed signal with a flux of 5x10^-5 ph/(cm² s MeV) (≅ 6% of the Crab pulsar flux), in the whole energy band at 3 standard deviations in an observation time of 6 hours. (orig.)

[en] A front-end readout electronics of new design is described. This electronics can operate in cosmic ray and extended air showers (EAS) as well as in accelerator experiments. The T and T (tracking and timing) electronics has been planned to cover large area detectors avoiding the necessity of tedious and time consuming cable calibrations. It is characterized by a 2 ns time resolution, multihits recording capability, no ambiguity in event-pulse reconstruction, daisy-chain interconnection, low power consumption and low cost. (orig.)