The project of all-sky hard X-ray and soft gamma-ray monitoring on-board international space station

Further progress in hard X-ray and soft gamma-ray observations can be achieved in the experiments with wide-field code-aperture instruments, which allow, due to long exposure times, to achieve the timing of different astrophysical objects (possible even in the near-Earth missions). The deep all-sky survey at the level of registration similar to 100 new sources (mainly Active Galactic Nuclei) in the energy range similar to 0.3-1 MeV is possible in the observations made during similar to 10 years with the instrument with similar to 2 pi FOV, similar to 1000-3000 cm(2) effective area and similar to 3 degrees-5 degrees angular resolution. The gamma-telescope "Gammascope" with such characteristics is now being elaborated. It is proposed for the experiment on the International Orbital Station "Alpha". The instrument is based on a combination of the quasi-spherical coding-mask and NaI-CsI position-sensitive detector (PSD). (C) 1998 COSPAR. Published by Elsevier Science Ltd.