Expose Facility (EuTEF) on the ESA Columbus module shows that the docking of the Space Shuttle wi... more Expose Facility (EuTEF) on the ESA Columbus module shows that the docking of the Space Shuttle with the International Space Station (ISS) decreased the South-Atlantic Anomaly (SAA) maxima dose rates from about 1500 Gy h -1 down to 600-700 Gy h -1 or by factor of 2. The dose rate data at the same time from another Bulgarian built instrument (R3DR) of the EXPOSE-R mission outside the Russian "Zvezda" module showed that: 1) before the Space Shuttle docking, the SAA dose rates measured with R3DR were higher (2500 Gy h -1 ) than the R3DE data; 2) The relative decrease of the SAA dose rates after the shuttle docking was only by a factor of 1.25. These differences are explained by the smaller shielding of R3DR from the body of ISS and by the larger distance of it from the body of Space Shuttle. Very similar data, but with smaller dose rates were obtained with a third Bulgarian built instrument (Liulin-5) inside Russian "Pirs" module. The analysis of the ascending/descending SAA dose rate maxima of the three instruments shows that the effect can be simply explained by the additional shielding against the 30 to 150 MeV protons of the SAA, provided by the 78 tons Shuttle to the instruments and by changing of the ISS 3D mass distribution when the ISS rotates. SERCO S.p.A., Italy,
The Radiation Monitor (RADOM) payload is a miniature dosimeter-spectrometer onboard Chandrayaan-1... more The Radiation Monitor (RADOM) payload is a miniature dosimeter-spectrometer onboard Chandrayaan-1 mission for monitoring the local radiation environment in near-Earth space and in lunar space. RADOM measured the total absorbed dose and spectrum of the deposited energy from high energy particles in near-Earth space, en-route and in lunar orbit. RADOM was the first experiment to be switched on soon after the launch of Chandrayaan-1 and was operational till the end of the mission. This paper summarizes the observations carried out by RADOM during the entire life time of the Chandrayaan-1 mission and some the salient results. † Corresponding author (email: santoshv@prl.res.in)
Comprehensive study of the dose, flux and spectra data obtained by Liulin MDU measurements on spa... more Comprehensive study of the dose, flux and spectra data obtained by Liulin MDU measurements on spacecrafts (4 different experiments) and aircrafts since 2001 is performed with the aid to understand how well these parameters can characterize the near Earth radiation environment. It is found that the most informative is the form of the spectrum of the deposited energy. Different places
Data obtained by Liulin type instruments on ISS and aircrafts are analyzed to try to evaluate the... more Data obtained by Liulin type instruments on ISS and aircrafts are analyzed to try to evaluate the contribution of neutron component in the spectra of energy deposited in Si-detector. The dose in Si, D(Si), was converted to obtain an apparent dose equivalent Happ. The conversion coefficients used were obtained during calibrations of Liulin type instruments at the CERN (CERF) and
Liulin type detectors are recently used in a wide range of cosmic radiation measurements, e.g. at... more Liulin type detectors are recently used in a wide range of cosmic radiation measurements, e.g. at alpine observatories, onboard aircrafts and spacecrafts. They provide energy deposition spectra up to 21 MeV, higher energy deposition events are stored in the last (overflow) channel. Their main advantages are portability (about the same size as a pack of cigarettes) and ability to record
... accumulation of further on-flight data is also necessary; particularly it would be important ... more ... accumulation of further on-flight data is also necessary; particularly it would be important to perform on-board measurements in situations ... 7] W. Snyder Friedberg, DN Faulkner, Radiation exposure of air ... 8] S. Roesler, W. Heinrich and H. Schraube, Monte Carlo calculations of the ...
ABSTRACT The paper deals with a rocket experiment, carried out on October 25, 1977, in which a va... more ABSTRACT The paper deals with a rocket experiment, carried out on October 25, 1977, in which a variety of measurements were made at heights up to 1500 km. The discussion is limited to data on O(+), H(+), and He(+) ion densities, electron density and temperature profiles, and ion density profiles, obtained during the descent stage at heights between 300 and 1350 km. Good agreement with calculated data is established.
Whereas in polar regions, the theoretically predicted NO(+) behavior seems to correlate with obse... more Whereas in polar regions, the theoretically predicted NO(+) behavior seems to correlate with observations, the appearance of NO(+) at heights of 400 to 500 km in the equatorial regions, where the electric fields are less strong, is yet to be explained. In the present paper, OGO-6 and Intercosmos-8 data are used as a basis to analyze the behavior of NO(+) ions in the equatorial regions. Possible causes for the anomalously high NO(+) densities above the equator are discussed on the basis of two groups of data. One group comprises transits for which an equatorial increase in electron flux was not recorded. The other group comprises data revealing a close relationship between particle precipitations and NO(+) ion density increases.
Expose Facility (EuTEF) on the ESA Columbus module shows that the docking of the Space Shuttle wi... more Expose Facility (EuTEF) on the ESA Columbus module shows that the docking of the Space Shuttle with the International Space Station (ISS) decreased the South-Atlantic Anomaly (SAA) maxima dose rates from about 1500 Gy h -1 down to 600-700 Gy h -1 or by factor of 2. The dose rate data at the same time from another Bulgarian built instrument (R3DR) of the EXPOSE-R mission outside the Russian "Zvezda" module showed that: 1) before the Space Shuttle docking, the SAA dose rates measured with R3DR were higher (2500 Gy h -1 ) than the R3DE data; 2) The relative decrease of the SAA dose rates after the shuttle docking was only by a factor of 1.25. These differences are explained by the smaller shielding of R3DR from the body of ISS and by the larger distance of it from the body of Space Shuttle. Very similar data, but with smaller dose rates were obtained with a third Bulgarian built instrument (Liulin-5) inside Russian "Pirs" module. The analysis of the ascending/descending SAA dose rate maxima of the three instruments shows that the effect can be simply explained by the additional shielding against the 30 to 150 MeV protons of the SAA, provided by the 78 tons Shuttle to the instruments and by changing of the ISS 3D mass distribution when the ISS rotates. SERCO S.p.A., Italy,
The Radiation Monitor (RADOM) payload is a miniature dosimeter-spectrometer onboard Chandrayaan-1... more The Radiation Monitor (RADOM) payload is a miniature dosimeter-spectrometer onboard Chandrayaan-1 mission for monitoring the local radiation environment in near-Earth space and in lunar space. RADOM measured the total absorbed dose and spectrum of the deposited energy from high energy particles in near-Earth space, en-route and in lunar orbit. RADOM was the first experiment to be switched on soon after the launch of Chandrayaan-1 and was operational till the end of the mission. This paper summarizes the observations carried out by RADOM during the entire life time of the Chandrayaan-1 mission and some the salient results. † Corresponding author (email: santoshv@prl.res.in)
Comprehensive study of the dose, flux and spectra data obtained by Liulin MDU measurements on spa... more Comprehensive study of the dose, flux and spectra data obtained by Liulin MDU measurements on spacecrafts (4 different experiments) and aircrafts since 2001 is performed with the aid to understand how well these parameters can characterize the near Earth radiation environment. It is found that the most informative is the form of the spectrum of the deposited energy. Different places
Data obtained by Liulin type instruments on ISS and aircrafts are analyzed to try to evaluate the... more Data obtained by Liulin type instruments on ISS and aircrafts are analyzed to try to evaluate the contribution of neutron component in the spectra of energy deposited in Si-detector. The dose in Si, D(Si), was converted to obtain an apparent dose equivalent Happ. The conversion coefficients used were obtained during calibrations of Liulin type instruments at the CERN (CERF) and
Liulin type detectors are recently used in a wide range of cosmic radiation measurements, e.g. at... more Liulin type detectors are recently used in a wide range of cosmic radiation measurements, e.g. at alpine observatories, onboard aircrafts and spacecrafts. They provide energy deposition spectra up to 21 MeV, higher energy deposition events are stored in the last (overflow) channel. Their main advantages are portability (about the same size as a pack of cigarettes) and ability to record
... accumulation of further on-flight data is also necessary; particularly it would be important ... more ... accumulation of further on-flight data is also necessary; particularly it would be important to perform on-board measurements in situations ... 7] W. Snyder Friedberg, DN Faulkner, Radiation exposure of air ... 8] S. Roesler, W. Heinrich and H. Schraube, Monte Carlo calculations of the ...
ABSTRACT The paper deals with a rocket experiment, carried out on October 25, 1977, in which a va... more ABSTRACT The paper deals with a rocket experiment, carried out on October 25, 1977, in which a variety of measurements were made at heights up to 1500 km. The discussion is limited to data on O(+), H(+), and He(+) ion densities, electron density and temperature profiles, and ion density profiles, obtained during the descent stage at heights between 300 and 1350 km. Good agreement with calculated data is established.
Whereas in polar regions, the theoretically predicted NO(+) behavior seems to correlate with obse... more Whereas in polar regions, the theoretically predicted NO(+) behavior seems to correlate with observations, the appearance of NO(+) at heights of 400 to 500 km in the equatorial regions, where the electric fields are less strong, is yet to be explained. In the present paper, OGO-6 and Intercosmos-8 data are used as a basis to analyze the behavior of NO(+) ions in the equatorial regions. Possible causes for the anomalously high NO(+) densities above the equator are discussed on the basis of two groups of data. One group comprises transits for which an equatorial increase in electron flux was not recorded. The other group comprises data revealing a close relationship between particle precipitations and NO(+) ion density increases.
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Papers by Tsvetan Dachev