| 1. |
- Abdellaoui, G., et al.
(författare)
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Meteor studies in the framework of the JEM-EUSO program
- 2017
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Ingår i: Planetary and Space Science. - : Elsevier. - 0032-0633 .- 1873-5088. ; 143, s. 245-255
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Tidskriftsartikel (refereegranskat)abstract
- We summarize the state of the art of a program of UV observations from space of meteor phenomena, a secondary objective of the JEM-EUSO international collaboration. Our preliminary analysis indicates that JEM-EUSO, taking advantage of its large FOV and good sensitivity, should be able to detect meteors down to absolute magnitude close to 7. This means that JEM-EUSO should be able to record a statistically significant flux of meteors, including both sporadic ones, and events produced by different meteor streams. Being unaffected by adverse weather conditions, JEM-EUSO can also be a very important facility for the detection of bright meteors and fireballs, as these events can be detected even in conditions of very high sky background. In the case of bright events, moreover, exhibiting some persistence of the meteor train, preliminary simulations show that it should be possible to exploit the motion of the ISS itself and derive at least a rough 3D reconstruction of the meteor trajectory. Moreover, the observing strategy developed to detect meteors may also be applied to the detection of nuclearites, exotic particles whose existence has been suggested by some theoretical investigations. Nuclearites are expected to move at higher velocities than meteoroids, and to exhibit a wider range of possible trajectories, including particles moving upward after crossing the Earth. Some pilot studies, including the approved Mini-EUSO mission, a precursor of JEM-EUSO, are currently operational or in preparation. We are doing simulations to assess the performance of Mini-EUSO for meteor studies, while a few meteor events have been already detected using the ground-based facility EUSO-TA.
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| 2. |
- Abdellaoui, G., et al.
(författare)
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First observations of speed of light tracks by a fluorescence detector looking down on the atmosphere
- 2018
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Ingår i: Journal of Instrumentation. - : IOP PUBLISHING LTD. - 1748-0221. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- EUSO-Balloon is a pathfinder mission for the Extreme Universe Space Observatory onboard the Japanese Experiment Module (JEM-EUSO). It was launched on the moonless night of the 25(th) of August 2014 from Timmins, Canada. The flight ended successfully after maintaining the target altitude of 38 km for five hours. One part of the mission was a 2.5 hour underflight using a helicopter equipped with three UV light sources (LED, xenon flasher and laser) to perform an inflight calibration and examine the detectors capability to measure tracks moving at the speed of light. We describe the helicopter laser system and details of the underflight as well as how the laser tracks were recorded and found in the data. These are the first recorded laser tracks measured from a fluorescence detector looking down on the atmosphere. Finally, we present a first reconstruction of the direction of the laser tracks relative to the detector.
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| 3. |
- Bisconti, F, et al.
(författare)
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Mini-EUSO engineering model : Tests in open-sky condition
- 2019
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Ingår i: 36th International Cosmic Ray Conference, ICRC 2019. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- Mini-EUSO is a UV telescope that will look downwards to the Earth’s atmosphere onboard the International Space Station. With the design of the ultra-high energy cosmic ray fluorescence detectors belonging to the JEM-EUSO program, it will make the first UV map of the Earth by observing atmospheric phenomena such as transient luminous events, sprites and lightning, as well as meteors and bioluminescence from earth. Diffused light from laser shots from the ground, which mimic the fluorescence light emitted by Nitrogen molecules when extensive air showers pass through the atmosphere, can be used to verify the capability of this kind of detector to observe ultra-high energy cosmic rays. To validate the electronics and the trigger algorithms developed for Mini-EUSO, a scaled down version of the telescope with 1:9 of the original focal surface and a lens of 2.5 cm diameter has been built. Tests of the Mini-EUSO engineering model have been made in laboratory and in open sky condition. In this paper, we report results of observations of the night sky, which include the detection of stars, meteors, a planet and a rocket body reflecting the sunlight. Interesting results of the observation of city lights are also reported.
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| 4. |
- Casolino, M, et al.
(författare)
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Mini-EUSO experiment to study UV emission of terrestrial and astrophysical origin onboard of the International Space Station
- 2019
-
Ingår i: 36th International Cosmic Ray Conference, ICRC 2019. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- Mini-EUSO will observe the Earth in the UV range (300 - 400 nm) offering the opportunity to study a variety of atmospheric events such as Transient Luminous Events (TLEs), meteors and marine bioluminescence. Furthermore it aims to search for Ultra High Energy Cosmic Rays (UHECR) above 1021 eV and Strange Quark Matter (SQM). The detector is expected to be launched to the International Space Station in August 2019 and look at the Earth in nadir mode from the UV-transparent window of the Zvezda module of the International Space Station. The instrument comprises a compact telescope with a large field of view (44?), based on an optical system employing two Fresnel lenses for light collection. The light is focused onto an array of 36 multi-anode photomultiplier tubes (MAPMT), for a total of 2304 pixels and the resulting signal is converted into digital, processed and stored via the electronics subsystems on-board. In addition to the main detector, Mini-EUSO contains two ancillary cameras[4] for complementary measurements in the near infrared (1500 - 1600 nm) and visible (400 - 780 nm) range and also a 8 × 8 SiPM imaging array.
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| 5. |
- Miyamoto, H, et al.
(författare)
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Space debris detection and tracking with the techniques of cosmic ray physics
- 2019
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Ingår i: 36th International Cosmic Ray Conference, ICRC 2019. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- Space Debris (SD) consist of non-operational artificial objects orbiting around the Earth, which could possibly damage space vehicles, such as the International Space Station (ISS) or other manned spacecrafts. The vast majority of such objects are cm-sized, not catalogued and usually the tracking data are not precise enough. Here we present the feasibility study of SD detection and tracking with techniques usually employed in cosmic-ray physics. For this purpose, we have evaluated the possibility of using Mini-EUSO, a space-borne fluorescence telescope to be deployed on the ISS, to track SD illuminated by the Sun. By means of ESAF (EUSO Simulation and analysis Framework) simulation and by developing the trigger algorithms, we estimated the minimum size and maximum distances of detectable SD. We then studied the number of possible SD detections using an ESA software called MASTER (Meteoroid and SD Terrestrial Environment Reference). With the Mini-EUSO Engineering Model (Mini-EUSO EM), we performed some measurements to estimate the reflectance of the most common SD materials and to demonstrate the ability of Mini-EUSO to detect SD events. We also performed some tests in open-sky conditions, identifying and tracking fast-moving objects. In particular, the detection of a rocket body allowed us to confirm the simulation outcomes predictions and the expected performance of the detector.
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| 6. |
- Miyamoto, H., et al.
(författare)
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The Euso@turlab : Test of mini-EUSO engineering model
- 2019
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- The TurLab facility is a laboratory, equipped with a 5 m diameter and 1 m depth rotating tank, located in the Physics Department of the University of Turin. Originally, it was mainly built to study systems of different scales where rotation plays a key role in the fluid behavior such as in atmospheric and oceanic flows. In the past few years the TurLab facility has been used to perform experiments related to the observation of Extreme Energy Cosmic Rays (EECRs) from space using the fluorescence technique. For example, in the case of the JEM-EUSO mission, where the diffuse night brightness and artificial light sources can vary significantly in time and space inside the Field of View of the telescope. The Focal Surface of Mini-EUSO Engineering Model (Mini-EUSO EM) with the level 1 (L1) and 2 (L2) trigger logics implemented in the Photo-Detector Module (PDM) has been tested at TurLab. Tests related to the possibility of using an EUSO-like detector for other type of applications such as Space Debris (SD) monitoring and imaging detector have also been pursued. The tests and results obtained within the EUSO@TurLab Project on these different topics are presented.
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| 7. |
- Bykova, E., et al.
(författare)
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Metastable silica high pressure polymorphs as structural proxies of deep Earth silicate melts
- 2018
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Ingår i: Nature Communications. - : NATURE PUBLISHING GROUP. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Modelling of processes involving deep Earth liquids requires information on their structures and compression mechanisms. However, knowledge of the local structures of silicates and silica (SiO2) melts at deep mantle conditions and of their densification mechanisms is still limited. Here we report the synthesis and characterization of metastable high-pressure silica phases, coesite-IV and coesite-V, using in situ single-crystal X-ray diffraction and ab initio simulations. Their crystal structures are drastically different from any previously considered models, but explain well features of pair-distribution functions of highly densified silica glass and molten basalt at high pressure. Built of four, five-, and six-coordinated silicon, coesite-IV and coesite-V contain SiO6 octahedra, which, at odds with 3rd Paulings rule, are connected through common faces. Our results suggest that possible silicate liquids in Earths lower mantle may have complex structures making them more compressible than previously supposed.
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| 8. |
- Casolino, M., et al.
(författare)
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Science of Mini-EUSO detector on board the International Space Station
- 2017
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Ingår i: Proceedings of Science. - Trieste, Italy : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- The Mini-EUSO space experiment ("UV atmosphere" in Russian Space Program) is a telescope designed to perform observations of night-time Earth in the UV spectrum. The instrument comprises a compact telescope with a large field of view (44°x44°), based on an optical system employing two 25 cm diameter Fresnel lenses (focal length ∼ 30 cm) for increased light collection. Mini-EUSO will study different scientific phenomena ranging from strange quark matter and Ultra High Energy Cosmic Rays (UHECRs) to bioluminescence and atmospheric physics. It will also create the first night-time map of the Earth in UV light. The mission will raise the technology readiness level (TRL) of the future JEM-EUSO missions to observe UHECRs from space. The Mini-EUSO measurements will be performed from the ISS through a UV transparent window in the Russian Zvezda Service Module. Launch is foreseen between Autumn 2017 and beginning 2018 in the framework of the next manned ASI (Italian Space Agency) flight and observations are supposed to continue with Russian cosmonauts for several years.
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| 9. |
- Aladov, V ,A., et al.
(författare)
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A study of thermal regime in the high-power LED arrays
- 2018
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Ingår i: St. Petersburg Polytechnical University Journal: Physics and Mathematics. - : Polytechnical Univ Publishing House. - 2405-7223. ; 11:3, s. 39-51
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Tidskriftsartikel (refereegranskat)abstract
- Thermal resistance and temperature distribution for high-power AlGaInN LED chip-on-board arrays were measured by different methods and tools. The p-n junction temperature was determined through measuring a temperature-dependent forward voltage drop on the p-n junction, at a low measuring current after applying a high heating current. Furthermore, the infrared thermal imaging technique was employed to obtain the temperature map for the test object. A steady-state 3D computational model of the experimental setup was created including temperature-dependent power dissipation in the LED chips. Simulations of the heat transfer in the LED array were performed to further investigate temperature gradients observed in the measurements. Simulations revealed possible thermal deformation of the assembly as the reason for the hot spot formation. The bending of the assembly was confirmed by surface curvature measurements.
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| 10. |
- Belov, A., et al.
(författare)
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Mini-EUSO photodetector module data processing system
- 2017
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Ingår i: Proceedings of Science. - : Sissa Medialab Srl.
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Konferensbidrag (refereegranskat)abstract
- Mini-EUSO is a UV telescope which is developed by the JEM-EUSO collaboration to be placed on board the International Space Station (ISS) to carry out measurements of UV atmosphere airglow and transient luminous events (TLEs) in a wide field of view (>40°) and high temporal resolution (2.5 μs). Mini-EUSO is developed to be a space qualified pathfinder of future JEMEUSO missions. Optical system of the detector consists of two Fresnel lenses of 25 cm diameter. The focal surface is composed of 36 produced by Hamamatsu multi anode photomultiplier tubes (MAPMT), each with 64 pixels. The output signal of all 2304 pixels is digitized and then passed to the data processing system that was specially developed for the experiment and is being discussed in this work. Data processing system is based on produced by Xilinx ZYNQ chip that contains both programmable part (FPGA) and processor. Such combination in a single chip gives a big advantage for processing a data gathered from focal surface including fast multi-level trigger algorithms, data buffering, MAPMTs high voltage control algorithms, interfaces with front-end electronics and with the separate central processor unit for data storage. The multi-level trigger was developed for the mini-EUSO instrument to perform measurements in various time scales (temporal resolutions 2.5 μs, 320 μs, 40 ms). This trigger was successfully implemented and tested.
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