[en] An imaging detector in the gamma range has its applications in various and different fields spanning from the medical diagnostic to the gamma astronomy. One of the techniques used in building such kind of 'gamma cameras' is based on the replication of individual pixel, each one being a stand alone detector. This kind of philosophy has been used in the construction of the PICsIT detector. PICsIT is the high-energy detector layer of the Imager IBIS that is one of the major instruments on board the INTEGRAL satellite observatory that the European Space Agency (ESA) will launch next October from Baikonour. PICsIT is made of 4096 CsI(Tl) scintillating detector 8.4 x 8.4 x 30 mm in size coupled to a PIN PD. Its operative range is 180-20400 keV and its operative modes allows to collect the information from both photoelectric events, which involves just one pixel and Compton or Pair events that involves more than one pixel at the same time. PICsIT is operating with a coded mask placed 3 m far from the detector. PICsIT has been integrated in the INTEGRAL satellite since the end of the year 2001 and is now undergoing the test foreseen for this kind of experiments

[en] The Simbol-X telescope characteristics and the mission scientific requirements impose a challenging calibration plan with a number of unprecedented issues. The 20 m focal length implies for the incoming X-ray beam a divergence comparable to the incidence angle of the mirror surface also for 100 m-long facilities. Moreover this is the first time that a direct focussing X-ray telescope will be calibrated on an energy band covering about three decades, and with a complex focal plane. These problems require a careful plan and organization of the measurements, together with an evaluation of the calibration needs in terms of both hardware and software.

[en] IBIS is the gamma-ray imaging telescope onboard the ESA satellite INTEGRAL, which will be launched in 2001, PICsIT, the high-energy (140 keV-10 MeV) detector of IBIS, consists of a 64x64 units array. Each detection unit is a congruent with 0.8 cm2, 3 cm thick CsI(TI) crystal coupled with a photodiode. The engineering model (EM) of PICsIT has now been tested, calibrated, and integrated in IBIS for delivery to ESA. The calibration of PICsIT EM has allowed for the first time its scientific qualification in terms of: energy threshold, linearity, energy resolution, and photopeak efficiency (for events of various multiplicity)

[en] PICsIT is the high-energy detector layer of the IBIS Imager, composed of 4096 CsI(Tl) scintillator detectors 8.4 x 8.4 x 300 mm in size with Photodiode readout. The detector operates in the 175 keV-20.4 MeV range and its data generation modes make it possible to collect information from single events and multiple coincident events. PICsIT is surrounded by the active BGO VETO and is located about 3 metres below the coded mask. The entire PICsIT plane is physically divided into 8 modules and logically divided into smaller units. The overall performance of the plane is directly related to the behaviour of each individual pixel, including its electronics, the system interconnection logic, and interaction with the other sub-systems. Pixels and electronic parameters were monitored constantly during instrument assembly. The following report describes PICsIT design and contains a summary of on-ground test results. (authors)

[en] Four different phoswich units were included in a modular hard X-ray ballon experimental launched on August 10, 1982 in order to check the dependence of background level and rejection efficiency of NaI(Tl)/CsI(Na) phoswich detectors on scintillator thicknesses. The results concern the dependence of the background intensity on both the thickness of the active shield, for a fixed primary detector thickness, and on the thickness of the primary detector, given the active shield thickness. A direct comparison of phoswich detectors with passively shielded NaI(Tl) crystals is also given. As a consequence practical hints for designing new phoswich detectors are derived and the limiting sensitivity of these detectors for hard X-ray observations of celestial sources is inferred. (orig.)

[en] The Phoswich Detection System (PDS) is the high-energy (15-300 keV) instrument on board the Italian-Dutch X-ray astronomy satellite SAX. Functional tests were carried out at BICRON (Newbury, Ohio USA) and at LABEN (Vimodrone Italy). Full ground calibrations have been performed between the end of 1994 and the beginning of 1995. The authors describe in the following the system that they used to acquire and analyse the data coming from the PDS experiment during the ground tests and calibration. It will be used to store and maintain data during both the pre-operational and the operational phases. In a previous report (Dal Fiume D., Frontera F., Orlandini M., and Trifoglio M., AIP Conf. Proc., 61 (1994) 395) they described the general architecture of the data analysis system. In this report they give a detailed description of the entire system, including the hardware and software developed by LABEN to acquire data during on-ground tests. A complete description of the different modules, user interface, inter-process communications, analysis and display tools are presented. Current status of the project is discussed

[en] The Minicalorimeter (MCAL) onboard the AGILE satellite is a 1400 cm² scintillation detector sensitive in the energy range 0.3-200 MeV. MCAL works both as a slave of the AGILE Silicon Tracker and as an autonomous detector for transient events (BURST mode). A dedicated onboard Burst Search logic scans BURST mode data in search of count rate increase. Peculiar characteristics of the detector are the high energy spectral coverage and a timing resolution of about 2 microseconds. Even if a trigger is not issued, BURST mode data are used to build a broad band energy spectrum (scientific ratemeters) organized in 11 bands for each of the two MCAL detection planes, with a time resolution of 1 second. After the first engineering commissioning phase, following the AGILE launch on 23rd April 2007, between 22nd June and 5th November 2007 eighteen GRBs were detected offline in the scientific ratemeters data, with a detection rate of about one per week. In this paper the capabilities of the detector will be described and an overview of the first detected GRBs will be given

[en] The broad-band 0.1-200 keV spectra of a selected sample of Seyfert 2 galaxies have been measured within the BeppoSAX Core Programme. Here we present the first results obtained for 3 objects, NGC 7172, MKN 3 and NGC 7674. The broad band BeppoSAX data illustrate the high spectral complexity often found in Seyfert 2 galaxies predicted by unified models: NGC 7172 is found to be a Compton-thin source in which the primary emission is seen through absorbing material; MKN 3 is a border line object where the emission is partly seen directly and partly reprocessed by the absorbing material; NGC 7674 is an example of a Compton-thick source where the primary emission is hidden and only reprocessed radiation is observed

[en] AGILE is an ASI (Italian Space Agency) Small Space Mission for high energy astrophysics in the range 30 MeV - 50 GeV. The AGILE satellite is currently in the C phase and is planned to be launched in 2005. The Payload shall consist of a Tungsten-Silicon Tracker, a CsI Minicalorimeter, an anticoincidence system and a X-Ray detector sensitive in the 10-40 KeV range. The purpose of the Minicalorimeter (MCAL) is twofold. It shall work in conjunction with the Tracker in order to evaluate the energy of the interacting photons, and it shall operate autonomously in the energy range 250KeV-250 MeV for detection of transients and gamma ray burst events and for the measurement of gamma ray background fluctuations. We present the architecture of the Test Equipment we have designed and developed in order to test and verify the MCAL Simplified Electrical Model prototype which has been manufactured in order to validate the design of the MCAL Proto Flight Model

[en] AGILE, the Italian space mission dedicated to gamma-ray and hard-X astrophysics, was successfully launched on 23rd April 2007 and is currently fully operative. The Mini-Calorimeter (MCAL) on-board the AGILE satellite is a scintillation detector made of 20 kg of segmented CsI(Tl) scintillator with photodiode readout with a total geometrical area of 1400 cm². MCAL can work both as a slave of the AGILE Silicon tracker and as an independent detector for gamma-ray bursts (GRB) detection in the 300 keV - 100 MeV energy range. Despite its limited thickness, due to weight constraints, MCAL has proven to successfully self-trigger GRBs at MeV energies providing photon-by-photon data with less than 2 μs time resolution and almost all-sky detection capabilities. The instrument design and characteristics, as well as the in-flight performance after one year of operation in space and the scientific results obtained so far are reviewed and discussed.