The GAMMA-400 (Gamma Astronomical Multifunctional Modular Apparatus) will be a new generation satellite gamma-observatory. The gamma-ray telescope GAMMA-400 consists of the anticoincidence system ...(top and lateral sections—ACtop and AClat), the converter-tracker (
C
), the time-of-flight system TOF (two sections
S
1 and
S
2), the position-sensitive and electromagnetic calorimeters (CC1 and CC2), the scintillation detectors of the calorimeter (
S
3 and
S
4) and lateral anticoincidence detectors of the calorimeter LD. Two apertures used for observation of transient events do not require the best angular resolution as for the gamma-ray bursts and solar flares from both upper and lateral directions. Additional aperture allows the particle registering from upper direction, which do not interact with converter-tracker and do not form a TOF signal. The lateral aperture allows registering of γ-quanta in perpendicular direction with respect to main axis of GAMMA-400 due to CC2, LD,
S
3, and
S
4. The thickness of CC2 in this direction is ∼44
X
0
and this allows detection of gammas, electrons and positrons with energies up to 10 TeV. The results of calculation of the fractal dimension of temporal profiles of additional aperture prototype of GAMMA-400 during its calibration using secondary positron beam of the synchrotron C-25P “PAKHRA” of Lebedev Physical Institute confirm the absence of any correlation between the AC and CC1 characteristics and correspondence of additional aperture background to Poisson statistics or Erlang one with shape parameter up to 10.
The GAMMA-400 gamma-ray telescope is planned for the launch at the end of this decade on the Navigator service platform designed by Lavochkin Association on an elliptical orbit with following initial ...parameters: an apogee ~300000, a perigee ~500 km, a rotation period ~7 days and inclination of 51.4°. The apparatus is expected to operate more than 5 years, reaching an unprecedented sensitivity for the search of dark matter signatures and the study of the unresolved and so far unidentified gamma-ray sources. An electronics system, which consists of 14 front-end multichannel electronics modules and the main processing unit with a total power consumption of about 400 W (74W for main processing unit), has been developed for providing fast trigger and veto for the data taking to the experiment. The communication between front-end modules, main processing unit and scientific data acquisition system of the gamma-ray telescope is performed via high-speed SPACEWIRE network. To assure the long-term reliability in space environment, a series of critical issues such as the radiation hardness, thermal design, components and board level quality control, warm and cold redundancy are taken into consideration. The main design concepts for the system, measurements setups together with some test results are presented.
The direct reconstruction of pp elastic scattering amplitudes at the SPASCHARM experiment is discussed. The observables are expressed in terms of invariant amplitudes. These amplitudes are deduced ...analytically by solving bilinear relations. Monte-Carlo simulations of elastic scattering as well background reactions were carried out. Elastic and diffraction interactions of protons were simulated by using PYTHIA generator for 16 GeV incident protons, designed Setup geometry and the resolution of the detectors. The criteria to select elastic processes are discussed and presented. Two-dimensional distributions of the product of the tangents of the polar angles of the recoil particle and the scattered particle versus difference of the azimuth angles of these particles, were obtained. The estimated ratio of the signal to background S/(S+B) is about 0.99.
The future space-based GAMMA-400 gamma-ray telescope will be installed on the Navigator platform of the Russian Astrophysical Observatory. A highly elliptical orbit will provide observations for 7-10 ...years of many regions of the celestial sphere continuously for a long time (~ 100 days). GAMMA-400 will measure gamma-ray fluxes in the energy range from ~ 20 MeV to several TeV and electron + positron fluxes up to ~ 20 TeV. GAMMA-400 will have an excellent separation of gamma rays from the background of cosmic rays and electrons + positrons from protons and an unprecedented angular (~ 0.01° at E
γ
= 100 GeV) and energy (~ 1% at E
γ
= 100 GeV) resolutions better than for Fermi-LAT, as well as ground-based facilities, by a factor of 5-10. Observations of GAMMA-400 will provide new fundamental data on discrete sources and spectra of gamma-ray emission and electrons + positrons, as well as the nature of dark matter.
The future space-based GAMMA-400
-ray telescope will operate onboard the Russian astrophysical observatory in a highly elliptic orbit during 7 years. Observing
-ray sources from Galactic plane,
-ray ...bursts,
-ray diffuse emission,
rays from the Sun, and
rays from dark matter particles will be performed uninterruptedly for a long time (
100 days) in point-source mode in contrast to scanning mode for Fermi-LAT and other space- and ground-based instruments. GAMMA-400 will measure
rays in the energy range from
20 MeV to several TeV units, have the unprecedented angular (
at
GeV) and energy (
at
GeV) resolutions better than for Fermi-LAT, as well as ground-based
-ray facilities, by a factor of 5–10, and perfectly separate
rays from cosmic-ray background.
The GAMMA-400 γ-ray telescope installed at the Russian space observatory is intended for precision measurements in the energy range of 20 MeV–1000 GeV of γ-ray emission (with the angular and energy ...resolutions several times better than that of current γ-ray telescopes) from discrete sources; measurement of the energy spectra of Galactic and extragalactic diffuse γ-ray emission; studies of γ-ray emission from the active Sun; and measurements of fluxes of γ-ray emission and electron–positron cosmicray component, which are probably associated with the annihilation or decay of dark-matter particles.
The future space-based GAMMA-400 gamma-ray telescope will operate onboard the Russian astrophysical observatory in a highly elliptic orbit during 7 years to observe Galactic plane, Galactic Center, ...Fermi Bubbles, Crab, Vela, Cygnus X, Geminga, Sun, and other regions and measure gamma- and cosmic-ray fluxes. Observations will be performed in the point-source mode continuously for a long time (∼100 days). GAMMA-400 will measure gamma rays in the energy range from ∼ 20 MeV to several TeV and cosmic-ray electrons + positrons up to several tens TeV. GAMMA-400 instrument will have very good angle and energy resolutions, high separation efficiency of gamma rays from cosmic-ray background, as well as electrons + positrons from protons. The main feature of GAMMA-400 is the unprecedented angular resolution for energies > 30 GeV better than the space-based and ground-based gamma-ray telescopes by a factor of 5–10. GAMMA-400 observations will permit to resolve gamma rays from annihilation or decay of dark matter particles, identify many discrete sources, clarify the structure of extended sources, specify the data on cosmic-ray electron + positron spectra.
GAMMA-400 (Gamma Astronomical Multifunctional Modular Apparatus) will be the new generation satellite gamma-observatory. The gamma-ray telescope GAMMA-400 consists of anticoincidence system (top and ...lateral sections - ACtop and AClat), the converter-tracker (C), time-of-flight system (two sections S1 and S2), position-sensitive calorimeter CC1, electromagnetic calorimeter CC2, scintillation detectors of the calorimeter (S3 and S4) and lateral detectors of the calorimeter LD.Three apertures provide events registration both from upper and lateral directions. The main aperture provides the best angular (all double (X, Y) tracking coordinate detectors layers information analysis) and energy resolution (energy deposition in the all detectors studying). The main aperture created firstly due to converter-tracker (C): gammas converted in tungsten conversion foils are registered. Triggers in the main aperture will be formed using information about particle direction provided by time of flight system and presence of charged particles or backsplash signal formed according to analysis of energy deposition in combination of both layers anticoincidence systems ACtop and AClat individual detectors. Other two apertures used for observation of transient events do not require best angular resolution as gamma-ray bursts and solar flares both from upper and lateral directions. Additional aperture allows particles registering from upper direction, which don't interact with converter-tracker and don't formed TOF signal. Particles detection in additional aperture starts with signal of CC1 fast discriminators in anticoincidence with TOF. Energy band for gammas registration in this aperture is similar to the main one. In the lateral aperture low energy (0.2-100 MeV) photons classified by using simple anticoincidence signals from the individual detectors of LD and CC2. Higher energies γ-quanta (E>100 MeV) recognized using energy deposition analysis in the individual detectors of S3, S4, LD and CC2. Prototype of additional aperture functioning of GAMMA-400 contains two detectors. One of them AC/LD prototype based on BC-408 scintillator with dimensions of 128x10x1 cm3. Other is CC1 prototype composed of CsI(Tl) crystal with dimensions of 33x5x2 cm3. The positron beam with energies 100-300 MeV was used for calibration of prototypes of GAMMA-400 detectors on synchrotron "PAKHRA". We calculate fractal dimension of temporal profiles measured during calibrations of AC/LD and CC1 prototypes. Preliminary results are 1.50±0.05 and 1.48±0.08 correspondingly. This is similar to Poisson statistics or Erlang one with coefficient up to 10.
The GAMMA-400 project will be the new generation of satellite gamma-observatory. GAMMA-400 space-based gamma-ray telescope represents the core of the scientific complex intended to perform a search ...for signatures of dark matter in the cosmic gamma-emission, measurements of diffuse gamma-emission characteristics, investigation of extended and point gamma-ray sources, studying of high energy component of gamma-ray bursts and solar flares emission. Four fast plastic sub-detectors of the gamma-ray telescope are included in fast trigger logic in the main telescope aperture. This aperture expected angular and energy resolution are ∼0.01° and ∼1-2% respectively for gammas with the energy >100 GeV and electron/protons rejection factor ∼5-105. Prototype of anticoincidence detector based on long BC-408 scintillators with SiPM readout for gamma-ray telescope was tested on a 300 MeV secondary positron beam of synchrotron C-25P «PAKHRA» of Lebedev Physical Institute in Russia. The measurement setup, design concepts for the prototype detector and chosen solutions together with some test results are discussed. Two other apertures (additional and lateral) allow analyzing transient events not required precision angular resolution, for examples, GRBs and solar flares. Similar plastics sub-detectors included in their fast trigger logic. Using of all three apertures allows making more effective observations of GRBs (better signal to noise ratio), more detailed study of its high energy afterglow due long term measurements (because of high apogee orbit provides low background variations with time) and detailed analysis of the sources luminosity variability (spectral, angular and temporal).
Status of the GAMMA-400 project Galper, A.M.; Adriani, O.; Aptekar, R.L. ...
Advances in space research,
01/2013, Volume:
51, Issue:
2
Journal Article
Peer reviewed
Open access
The preliminary design of the new space gamma-ray telescope GAMMA-400 for the energy range 100MeV–3TeV is presented. The angular resolution of the instrument, 1–2° at Eγ∼100MeV and ∼0.01° at ...Eγ>100GeV, its energy resolution ∼1% at Eγ>100GeV, and the proton rejection factor ∼106 are optimized to address a broad range of science topics, such as search for signatures of dark matter, studies of Galactic and extragalactic gamma-ray sources, Galactic and extragalactic diffuse emission, gamma-ray bursts, as well as high-precision measurements of spectra of cosmic-ray electrons, positrons, and nuclei.
PDF
