The high-performance data acquisition system for the GAMMA-400 satellite-borne gamma-ray telescope

The future GAMMA-400 space mission is aimed for the study of gamma rays in the energy range from ~20 MeV up to ~1 TeV. The observations will carry out with GAMMA-400 gamma-ray telescope installed on-board the Russian Space Observatory. We present the detailed description of the architecture and performances of scientific data acquisition system (SDAQ) developing by SRISA for the GAMMA-400 instrument. SDAQ provides the collection of the data from telescope detector subsystems (up to 100 GB per day), the preliminary processing of scientific information and its accumulation in mass memory, transferring the information from mass memory to the satellite high-speed radio line for its transmission to the ground station, the control and monitoring of the telescope subsystems. SDAQ includes special space qualified chipset designed by SRISA and has scalable modular net structure based on fast and high-reliable serial interfaces.Comment: 8 pages, 6 figures, ICRC201

The comparative estimation of early postoperative complications after versions of surgery treatment perforative ulcers of stomach and duodenum

Results of surgical treatment of 280 patients with perforated gastric and duodenal ulcers are submitted. The simple suture of perforative ulcer has been performed at 48 (17,14%), excision of ulcer with suture - 84 (30%), after excision of perforated ulcer with suture a defect and cover of suture line by the serosa-muscular patch of stomach -142 (50,71%), excision of perforated ulcer with substitution of defect by the layerful patch of stomach - 6 (2,14%) patients. The rate of postoperative complications after simple suture of perforative ulcer was 41,67%, after excision of ulcer - 22,62%, after excision of perforated ulcer with suture a defect and cover of suture line by the serosa-muscular patch of stomach -10,56% , Only 1 patient after excision of perforated ulcer with substitution of defect by the layerful patch of stomach was execute relaparotomy on the occasion of slackflowing peritonitis, with following recovery. The rate of common mortality was 4,28%, after simple suture of perforative ulcer - 20,83%, after excision of ulcer with suture - 2,38%. The depositions and possibility of wider use excision of perforated ulcer with suture, and excision of perforated ulcer with suture a defect and cover of suture line by the serosa-muscular patch of stomach, for emergency surgery are discussed.Представлен опыт хирургического лечения 280 больных с перфоративными язвами желудка и двенадцатиперстной кишки в период 1998-2009 гг. Простое ушивание язвы выполнено 48 (17,14%), иссечение язвы с ушиванием - 84 (30%), иссечение язвы с ушиванием дефекта и укрытием линии швов серозно-мышечным лоскутом желудка -1 4 2 (50,71%), иссечение язвы с замещением дефекта полнослойным лоскутом желудка - 6 (2,14%) больным. Послеоперационные осложнения возникли после простого ушивания в 41,67%, после иссечения язвы с ушиванием - в 22,62%, после иссечения язвы с ушиванием дефекта и укрытием линии швов серозно-мышечным лоскутом желудка - в 10,56%. После иссечения язвы с замещением дефекта полнослойным лоскутом желудка только у 1 больного была выполнена релапаротомия по поводу вялотекрего перитонита, с последующим выздоровлением. Общая летальность составила 4,28%, при этом после простого ушивания - 20,83%, после иссечения язвы с ушиванием - 2,38%. Обсуждаются показания и возможность более широкого применения иссечения язвы с ушиванием, иссечения язвы с ушиванием дефекта и укрытием линии швов серозно-мышечным лоскутом желудка в экстренной хирургии

Dark Matter Search Perspectives with GAMMA-400

GAMMA-400 is a future high-energy gamma-ray telescope, designed to measure the fluxes of gamma-rays and cosmic-ray electrons + positrons, which can be produced by annihilation or decay of dark matter particles, and to survey the celestial sphere in order to study point and extended sources of gamma-rays, measure energy spectra of Galactic and extragalactic diffuse gamma-ray emission, gamma-ray bursts, and gamma-ray emission from the Sun. GAMMA-400 covers the energy range from 100 MeV to ~3000 GeV. Its angular resolution is ~0.01 deg(Eg > 100 GeV), and the energy resolution ~1% (Eg > 10 GeV). GAMMA-400 is planned to be launched on the Russian space platform Navigator in 2019. The GAMMA-400 perspectives in the search for dark matter in various scenarios are presented in this paperComment: 4 pages, 4 figures, submitted to the Proceedings of the International Cosmic-Ray Conference 2013, Brazil, Rio de Janeir

A separation of electrons and protons in the GAMMA-400 gamma-ray telescope

The GAMMA-400 gamma-ray telescope is intended to measure the fluxes of gamma rays and cosmic-ray electrons and positrons in the energy range from 100 MeV to several TeV. Such measurements concern with the following scientific goals: search for signatures of dark matter, investigation of gamma-ray point and extended sources, studies of the energy spectra of Galactic and extragalactic diffuse emission, studies of gamma-ray bursts and gamma-ray emission from the active Sun, as well as high-precision measurements of spectra of high-energy electrons and positrons, protons, and nuclei up to the knee. The main components of cosmic rays are protons and helium nuclei, whereas the part of lepton component in the total flux is ~10E-3 for high energies. In present paper, the capability of the GAMMA-400 gamma-ray telescope to distinguish electrons and positrons from protons in cosmic rays is investigated. The individual contribution to the proton rejection is studied for each detector system of the GAMMA-400 gamma-ray telescope. Using combined information from all detector systems allow us to provide the proton rejection from electrons with a factor of ~4x10E5 for vertical incident particles and ~3x10E5 for particles with initial inclination of 30 degrees. The calculations were performed for the electron energy range from 50 GeV to 1 TeV.Comment: 19 pages, 10 figures, submitted to Advances and Space Researc

The GAMMA-400 space observatory: status and perspectives

The present design of the new space observatory GAMMA-400 is presented in this paper. The instrument has been designed for the optimal detection of gamma rays in a broad energy range (from ~100 MeV up to 3 TeV), with excellent angular and energy resolution. The observatory will also allow precise and high statistic studies of the electron component in the cosmic rays up to the multi TeV region, as well as protons and nuclei spectra up to the knee region. The GAMMA-400 observatory will allow to address a broad range of science topics, like search for signatures of dark matter, studies of Galactic and extragalactic gamma-ray sources, Galactic and extragalactic diffuse emission, gamma-ray bursts and charged cosmic rays acceleration and diffusion mechanism up to the knee

Capabilities of the GAMMA-400 gamma-ray telescope to detect gamma-ray bursts from lateral directions

The currently developing space-based gamma-ray telescope GAMMA-400 will measure the gamma-ray and electrons + positrons fluxes using the main top-down aperture in the energy range from ~20 MeV to several TeV in the highly elliptic orbit (without shadowing the telescope by the Earth and outside the radiation belts) continuously for a long time. The instrument will provide fundamentally new data on discrete gamma-ray sources, gamma-ray bursts (GRBs), sources and propagation of Galactic cosmic rays and signatures of dark matter due to its unique angular and energy resolutions in the wide energy range. The gamma-ray telescope consists of the anticoincidence system (AC), the converter-tracker (C), the time-of-flight system (S1 and S2), the position-sensitive and electromagnetic calorimeters (CC1 and CC2), the top and bottom scintillation detectors of the calorimeter (S3 and S4) and lateral detectors of the calorimeter (LD). In this paper, the capabilities of the GAMMA-400 gamma-ray telescope to measure fluxes of GRBs from lateral directions of CC2 are analyzed using Monte-Carlo simulations. The analysis is based on second-level trigger construction using signals from S3, CC2, S4 and LD detectors. For checking the numerical algorithm the data from space-based GBM and LAT instruments of the Fermi experiment are used, namely, three long bursts: GRB 080916C, GRB 090902B, GRB 090926A and one short burst GRB 090510A. The obtained results allow us to conclude that from lateral directions the GAMMA-400 space-based gamma-ray telescope will reliably measure the spectra of bright GRBs in the energy range from ~10 to ~100 MeV with the effective area of about 0.13 m2 (for each of the four sides of CC2) and total field of view of about 6 sr.Comment: 19 pages, 18 figures, the paper will be submitted to Advances in Space Researc

High-energy gamma-ray studying with GAMMA-400 after Fermi-LAT

Fermi-LAT has made a significant contribution to the study of high-energy gamma-ray diffuse emission and the observation of 3c3000 discrete sources. However, one third of all gamma-ray sources (both galactic and extragalactic) are unidentified, the data on the diffuse gamma-ray emission should be clarified, and signatures of dark matter particles in the high-energy gamma-ray range are not observed up to now. GAMMA-400, currently developing gamma-ray telescope, will have the angular ( 3c0.01\ub0 at 100 GeV) and energy ( 3c1% at 100 GeV) resolutions in the energy range of 10-1000 GeV better than the Fermi-LAT (as well as ground gamma-ray telescopes) by a factor of 5-10 and observe some regions of the Universe (such as Galactic Center, Fermi Bubbles, Crab, Cygnus, etc.) in the highly elliptic orbit (without shading the telescope by the Earth) continuously for a long time. It will permit to identify many discrete sources, to clarify the structure of extended sources, to specify the data on the diffuse emission, and to resolve gamma rays from dark matter particles

The GAMMA-400 gamma-ray telescope for precision gamma-ray emission investigations

The GAMMA-400 gamma-ray telescope with excellent angular and energy resolutions is designed to search for signatures of dark matter in the fluxes of gamma-ray emission and electrons + positrons. Precision investigations of gamma-ray emission from Galactic Center, Crab, Vela, Cygnus, Geminga, and other regions will be performed, as well as diffuse gamma-ray emission, along with measurements of high-energy electron + positron and nuclei fluxes. Furthermore, it will study gamma-ray bursts and gamma-ray emission from the Sun during periods of solar activity. The GAMMA-400 energy range is expected to be from â\u88¼20 MeV up to TeV energies for gamma rays, up to 10 TeV for electrons + positrons, and up to 1015eV for cosmic-ray nuclei. For 100-GeV gamma rays, the GAMMA-400 angular resolution is â\u88¼0.01° and energy resolution is â\u88¼1%; the proton rejection factor is â\u88¼5x105. GAMMA-400 will be installed onboard the Russian space observatory