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Turku, Finland

Valtonen E.,University of Turku | Eronen T.,University of Turku | Nenonen S.,Oxford Instruments | Andersson H.,Oxford Instruments | And 9 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2016

We have fabricated and tested a thin silicon detector with the specific goal of having a very good thickness uniformity. SOI technology was used in the detector fabrication. The detector was designed to be used as a ΔE detector in a silicon telescope for measuring solar energetic particles in space. The detector thickness was specified to be 20 μm with an rms thickness uniformity of±0.5%. The active area consists of three separate elements, a round centre area and two surrounding annular segments. A new method was developed for measuring the thickness uniformity based on a modified Fizeau interferometer. The thickness uniformity specification was well met with the measured rms thickness variation of 43 nm. The detector was electrically characterized by measuring the I-V and C-V curves and the performance was verified using a 241Am alpha source. © 2015 Elsevier B.V. All rights reserved. Source

Cyamukungu M.,Catholic University of Louvain | Benck S.,Catholic University of Louvain | Borisov S.,Catholic University of Louvain | Gregoire G.,Catholic University of Louvain | And 32 more authors.
IEEE Transactions on Nuclear Science | Year: 2014

This paper provides a detailed description of the Energetic Particle Telescope (EPT) accommodated on board the PROBA-V satellite launched on May 7th, 2013 on a LEO, 820 km altitude, 98.7 inclination and a 10:30-11:30 Local Time at Descending Node. The EPT is an ionizing particle spectrometer that was designed based on a new concept and the most advanced signal processing technologies: it performs in-flight electron and ion discrimination and classifies each detected particle in its corresponding physical channels from which the incident spectrum can be readily reconstructed. The detector measures electron fluxes in the energy range 0.5-20 MeV, proton fluxes in the energy range 9.5-300 MeV and He-ion fluxes between 38 and 1200 MeV. The EPT is a modular configurable instrument with customizable maximum energy, field of view angle, geometrical factor and angular resolution. Therefore, the features of the currently flying instrument may slightly differ from those described in past or future configurations. After a description of the instrument along with the data acquisition and analysis procedures, the first particle fluxes measured by the EPT will be shown and discussed. The web-site located at http://web.csr.ucl.ac.be/csr-web/probav/which daily displays measured fluxes and other related studies will also be briefly described. © 1963-2012 IEEE. Source

Kudina A.M.,Ukrainian Academy of Sciences | Borodenkoa Y.A.,Ukrainian Academy of Sciences | Grinyova B.V.,Ukrainian Academy of Sciences | Didenkoa A.V.,Ukrainian Academy of Sciences | And 9 more authors.
Instruments and Experimental Techniques | Year: 2010

CsI(Tl) crystal + Si photodiode scintillation assemblies have been designed to detect photons with energies of 60-1330 keV and protons with energies of 6-50 MeV. The spectrometric characteristics of the assemblies and their radiation hardness have been investigated. The assemblies are shown to have a high energy resolution: 19.6 and 4.6-5.0% for photons with energies of 59.6 and 662 keV and 3.9 and 1.5% for protons with energies of 10 and 20 MeV, respectively. The radiation hardness of these detectors is rather high: it corresponds to a dose of up to 103 Gy under photon irradiation and fluxes of up to 1012 protons/cm2 under exposure to protons. © 2010 Pleiades Publishing, Ltd. Source

Virtanen J.,Finnish Geospatial Research Institute | Poikonen J.,Kovilta Oy | Santti T.,Aboa Space Research Oy | Komulainen T.,Aboa Space Research Oy | And 10 more authors.
Advances in Space Research | Year: 2015

We describe a novel data-processing and analysis pipeline for optical observations of moving objects, either of natural (asteroids, meteors) or artificial origin (satellites, space debris). The monitoring of the space object populations requires reliable acquisition of observational data, to support the development and validation of population models and to build and maintain catalogues of orbital elements. The orbital catalogues are, in turn, needed for the assessment of close approaches (for asteroids, with the Earth; for satellites, with each other) and for the support of contingency situations or launches. For both types of populations, there is also increasing interest to detect fainter objects corresponding to the small end of the size distribution.The ESA-funded StreakDet (streak detection and astrometric reduction) activity has aimed at formulating and discussing suitable approaches for the detection and astrometric reduction of object trails, or streaks, in optical observations. Our two main focuses are objects in lower altitudes and space-based observations (i.e., high angular velocities), resulting in long (potentially curved) and faint streaks in the optical images. In particular, we concentrate on single-image (as compared to consecutive frames of the same field) and low-SNR detection of objects. Particular attention has been paid to the process of extraction of all necessary information from one image (segmentation), and subsequently, to efficient reduction of the extracted data (classification).We have developed an automated streak detection and processing pipeline and demonstrated its performance with an extensive database of semisynthetic images simulating streak observations both from ground-based and space-based observing platforms. The average processing time per image is about 13. s for a typical 2k-by-2k image. For long streaks (length >100 pixels), primary targets of the pipeline, the detection sensitivity (true positives) is about 90% for both scenarios for the bright streaks (SNR>1), while in the low-SNR regime, the sensitivity is still 50% at. SNR=0.5. © 2015 COSPAR. Source

Huovelin J.,University of Helsinki | Vainio R.,University of Helsinki | Andersson H.,Oxford Instruments | Valtonen E.,Aboa Space Research Oy | And 19 more authors.
Planetary and Space Science | Year: 2010

The Solar Intensity X-ray and particle Spectrometer (SIXS) on the BepiColombo Mercury Planetary Orbiter (MPO) will investigate the direct solar X-rays, and energetic protons and electrons which pass the Spacecraft on their way to the surface of Mercury. These measurements are vitally important for understanding quantitatively the processes that make Mercury's surface glow in X-rays, since all X-rays from Mercury are due to interactions of the surface with incoming highly energetic photons and space particles. The X-ray emission of Mercury's surface will be analysed to understand its structure and composition. SIXS data will also be utilised for studies of the solar X-ray corona, flares, solar energetic particles, and the magnetosphere of Mercury, and for providing information on solar eruptions to other BepiColombo instruments. SIXS consists of two detector subsystems. The X-ray detector system includes three identical GaAs PIN detectors which measure the solar spectrum at 1-20 keV energy range, and their combined field-of-view covers ∼1/4 of the whole sky. The particle detector system consists of an assembly including a cubic central CsI(Tl) scintillator detector with five of its six surfaces covered by a thin Si detector, which together perform low-resolution particle spectroscopy with a rough angular resolution over a field-of-view covering ∼1/4 of the whole sky. The energy range of detected particle spectra is 0.1-3 MeV for electrons and 1-30 MeV for protons. A major task for the SIXS instrument is the measurement of solar X-rays on the dayside of Mercury's surface to enable modeling of X-ray fluorescence and scattering on the planet's surface. Since highly energetic particles are expected to also induce a significant amount of X-ray emission via particle-induced X-ray emission (PIXE) and bremsstrahlung when they are absorbed by the solid surface of the planet Mercury, SIXS performs measurements of fluxes and spectra of protons and electrons. SIXS performs particle measurement at all orbital phases of the MPO as the particle radiation can occur also on the night side of Mercury. The energy ranges, resolutions, and timings of X-ray and particle measurements by SIXS have been adjusted to match with the requirements for interpretation of data from Mercury's surface, to be performed by utilising the data of the Mercury Imaging X-ray Spectrometer (MIXS), which will measure X-ray emission from the surface. © 2008 Elsevier Ltd. All rights reserved. Source

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