The results of measurements of fluxes and spectra carried out using the RELEC (relativistic electrons) equipment onboard the
VERNOV
satellite in the second half of 2014 are presented. The
VERNOV
...satellite was launched on July 8, 2014 in a sun-synchronous orbit with an altitude from 640 to 830 km and an inclination of 98.4°. Scientific information from the satellite was first received on July 20, 2014. The comparative analysis of electron fluxes using data from RELEC and using experimental data on the electron detection by satellites
Elektro-L
(positioned at a geostationary orbit) and
Meteor-M no. 2
(positioned at a circular polar orbit at an altitude of about 800 km as the
VERNOV
satellite) will make it possible to study the spatial distribution pattern of energetic electrons in near-Earth space in more detail.
In this paper the task of the operative monitoring of radiation conditions in the near-Earth space is considered as a part of a project Universat-SOCRAT of the system of small satellites, which is ...being developed at Moscow State University. The scientific approach to the realization of this task is determined. The choice of the satellite orbits and spatial orientation and the configuration of energetic charged particle detectors is validated taking into account other tasks performed by the projected satellite system.
The generation of transients in the Earth’s upper atmosphere under the action of electron fluxes and high- and low-frequency electromagnetic waves has been studied onboard the small Vernov spacecraft ...(solar synchronous orbit, 98° inclination, height 640–830 km). The studies were carried out with ultraviolet (UV, 240–380 nm), red–infrared (IR, 610–800 nm), gamma-ray (0.01–3 MeV), and electron (0.2–15 MeV) detectors as well as with high-frequency (0.05–15 MHz) and low-frequency (0.1 Hz–40 kHz) radio receivers. Artificial optical signals distributed along the meridian in an extended region of latitudes in the Earth’s Northern and Southern Hemispheres modulated by a low frequency were recorded during the nadir observations at nighttime. Examples of the oscillograms of such signals in the UV and IR spectral ranges and their global distribution are presented. The emission generation altitude and the atmospheric components that can be the sources of this emission are discussed. Particular attention is given to the technogenic causes of this glow in the ionosphere under the action of powerful low- and high-frequency radio stations on the ionosphere.
The RELEC scientific instrumentation onboard the Vernov spacecraft launched on July 8, 2014, included the DRGE gamma-ray and electron spectrometer. This instrument incorporates a set of scintillation ...phoswich detectors, including four identical X-ray and gamma-ray detectors in the energy range from 10 keV to 3 MeV with a total area of ~500 cm
2
directed toward the nadir, and an electron spectrometer containing three mutually orthogonal detector units with a geometry factor of ~2 cm
2
sr, which is also sensitive to X-rays and gamma-rays. The goal of the space experiment with the DRGE instrument was to investigate phenomena with fast temporal variability, in particular, terrestrial gammaray flashes (TGFs) and magnetospheric electron precipitations. However, the detectors of the DRGE instrument could record cosmic gamma-ray bursts (GRBs) and allowed one not only to perform a detailed analysis of the gamma-ray variability but also to compare the time profiles with the measurements made by other instruments of the RELEC scientific instrumentation (the detectors of optical and ultraviolet flashes, the radio-frequency and low-frequency analyzers of electromagnetic field parameters). We present the results of our observations of cosmicGRB 141011A and GRB 141104A, compare the parameters obtained in the GBM/Fermi and KONUS–Wind experiments, and estimate the redshifts and
E
iso
for the sources of these GRBs. The detectability of GRBs and good agreement between the independent estimates of their parameters obtained in various experiments are important factors of the successful operation of similar detectors onboard the Lomonosov spacecraft.
In this paper, data obtained by the Vernov satellite are discussed in comparison with the data obtained by Universitetsky–Tatiana-1, 2 satellites. The advanced instrumentation onboard the Vernov ...satellite improved the capabilities of the data-transmission system, providing an opportunity to acquire more detailed information on transient atmospheric events (TAEs), including a wider range of TAE photon numbers (event brightness) down to lower photon numbers, the opportunity to observe the events in ultraviolet range without the considerable inclusion of red–infrared photons (which indicates the substantial contribution of electric discharges, lightning precursors, at the altitudes of thunderstorm clouds), and the observation of TAE series at a rate of about 10–100 occurrences per second with a period from tens of seconds to several minutes.
In this paper we present the Inverted-Conical light guide designed for optical crosstalk reduction in the scintillator-MAPMT assemblies. The research was motivated by the 30% crosstalk observed in ...UFFO X-ray telescope, UBAT, during the preliminary calibration with MAPMTs of 64 2.88×2.88 mm2 pixels and identically gridded YSO crystal matrices. We began the study with the energy and crosstalk calibrations of the detector, then we constructed a GEANT4 simulation with the customized metallic film model as the MAPMT photocathode. The simulation reproduced more than 70% of the crosstalk and explained it as a consequence of the total reflection produced by the photocathode. The result indicated that the crosstalk mechanism could be a common case in most of the contact-assembled scintillation detectors. The concept of the Inverted-Conical light guide was to suppress the total reflection by contracting the incident angle of the scintillation. We optimized the design in the simulation and fabricated a test sample. The test sample reduced 52% crosstalk with a loss of 6% signal yield. The idea of the Inverted-Conical light guide can be adapted by scintillation detectors multi-pixel, imaging-purpose scintillation detectors such as the ultra-fast GRB observatory UFFO-UBAT, whose performances are sensitive to responding time, image resolution, and geometrical modifications.
The work is devoted to observations of sharp growths of magnetospheric electron fluxes in the vicinity of the polar boundary of the outer radiation belt of the Earth according to the data of ...measurements on the Vernov and Lomonosov satellites. This precipitation was observed at the high-latitude boundary of the outer radiation belt toward the equator from the isotropization boundary, and can be caused by scattering waves of various physical natures, including electromagnetic and electrostatic waves.
The RELEС scientific payload of the
Vernov
satellite launched on July 8, 2014 includes the DRGE spectrometer of gamma-rays and electrons. This instrument comprises a set of scintillator ...phoswich-detectors, including four identical X-ray and gamma-ray detector with an energy range of 10 kev to 3 MeV with a total area of ~500 cm
2
directed to the atmosphere, as well as an electron spectrometer containing three mutually orthogonal detector units with a geometric factor of ~2 cm
2
sr. The aim of a space experiment with the DRGE instrument is the study of fast phenomena, in particular Terrestrial gamma-ray flashes (TGF) and magnetospheric electron precipitation. In this regard, the instrument provides the transmission of both monitoring data with a time resolution of 1 s, and data in the event-by-event mode, with a recording of the time of detection of each gamma quantum or electron to an accuracy of ~15 μs. This makes it possible to not only conduct a detailed analysis of the variability in the gamma-ray range, but also compare the time profiles with the results of measurements with other RELEC instruments (the detector of optical and ultraviolet flares, radio-frequency and low-frequency analyzers of electromagnetic field parameters), as well as with the data of ground-based facility for thunderstorm activity. This paper presents the first catalog of Terrestrial gamma-ray flashes. The criterion for selecting flashes required in order to detect no less than 5 hard quanta in 1 ms by at least two independent detectors. The TGFs included in the catalog have a typical duration of ~400 μs, during which 10–40 gamma-ray quanta were detected. The time profiles, spectral parameters, and geographic position, as well as a result of a comparison with the output data of other
Vernov
instruments, are presented for each of candidates. The candidate for Terrestrial gamma-ray flashes detected in the near-polar region over Antarctica is discussed.
On the basis of satellite observations obtained with the help of X-ray and gamma-ray detector units (BDRG/
Lomonosov
in Russian), using digital filtering methods, the analysis of time delays between ...the second pulsations of time profiles of hard X-ray radiation of different frequency bands from the solar flare that occurred on July 21, 2016 has been made. It is shown that the count rate in energy channels of 10–20, 20–35, and 35–60 keV detected by BDRG/
Lomonosov
are correlated with an accuracy up to 0.1 s. The result agrees well with the observations of the Gamma-ray Burst Monitor on board the
Fermi
satellite and supposes an effective acceleration of charged particles over the entire length of the flare magnetic arc.
Solar hard X-ray and
γ
-ray emissions were measured by the
Detector of the Roentgen and Gamma-ray Emissions
(DRGE) instrument, which is part of the RELEC set of instruments operated onboard the ...Russian satellite
Vernov,
from July 8, 2014 until December 10, 2014 (on a solar-synchronous orbit with an apogee of 830 km, perigee of 640 km, and an inclination of
98.4
∘
). RELEC measurements of 18 flares with X-ray energy
>
30
keV
, taken in September – October 2014, were connected with the same active region with the number AR 12172 during the first rotation and AR 12192 during the next one. These measurements were compared to the data obtained with RHESSI,
Konus-Wind
,
Fermi Observatory
,
Radio Solar Telescope Net
(RSTN), and the
Nobeyama Radioheliograph
(NoRH) operating at the same time. Quasi-periodicities with similar periods of
7
±
2
s
were found in about one third of all flares measured by RELEC (
Vernov
) from September 24 until October 30, 2014.
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