GAMMA-400 Î³-ray telescope is designed to measure fluxes of Î³-rays and the electron-positron cosmic ray component possibly generated in annihilation or decay of dark matter particles; to search for and study in detail discrete Î³-ray sources, to examine the energy spectra of Galactic and extragalactic diffuse Î³-rays, to study Î³-ray bursts and Î³-rays from the active Sun. GAMMA-400 consists of plastic scintillation anticoincidence top and lateral detectors, converter-tracker, plastic scintillation detectors for the time-of-flight system (TOF), two-part calorimeter (CC1 and CC2), plastic scintillation lateral detectors of calorimeter, plastic scintillation detectors of calorimeter, and neutron detector. The converter-tracker consists of 13 layers of double (x, y) silicon strip coordinate detectors (pitch of 0.08 mm). The first three and final one layers are without tungsten while the middle nine layers are interleaved with nine tungsten conversion foils. The thickness of CC1 and CC2 is 2 X0(0.1Î»0) and 23 X0(1.1Î»0) respectively (where X0is radiation length and Î»0is nuclear interaction one). The total calorimeter thickness is 25 X0or 1.2Î»0for vertical incident particles registration and 54 X0or 2.5Î»0for laterally incident ones. The energy range for Î³-rays and electrons (positrons) registration in the main aperture is from â¼0.1 GeV to â¼3.0 TeV. The Î³-ray telescope main aperture angular and energy resolutions are respectively â¼0.01 and â¼1% for 102GeV Î³-quanta, the proton rejection factor is â¼5Ã105. The first three strip layers without tungsten provide the registration of Î³-rays down to â¼20 MeV in the main aperture. Also this aperture allows investigating high energy light nuclei fluxes characteristics. Electrons, positrons, light nuclei and gamma-quanta will also register from the lateral directions due to special aperture configuration. Lateral aperture energy resolution is the same as for main aperture for electrons, positrons, light nuclei and gamma-quanta in energy range E>1.0 GeV. But using lateral aperture it is possible to detect low-energy gammas in the ranges 0.2 - 10 MeV and 10 MeV - 1.0 GeV with energy resolution 8% - 2% and 2% correspondingly accordingly to GAMMA-400 "Technical Project" stage results. Angular resolution in the lateral aperture provides only for low-energy gamma-quanta from non-stationary events (GRB, solar flares and so on) due segments of CC2 count rate analysis. GAMMA-400 Î³-ray telescope will be installed onboard the Russian Space Observatory GAMMA-400. The lifetime of the space observatory will be at least seven years. The launch of the space observatory is scheduled for the early 2020s.
|Titolo:||Space γ-observatory GAMMA-400 Current Status and Perspectives|
|Appare nelle tipologie:||1.1 Articolo in rivista|