Mathias Cyamukungu

Calibration results obtained with Liulin-4 type dosimeters.

The Mobile Radiation Exposure Control Systems (Liulin-4 type) main purpose is to monitor simultaneously the doses and fluxes at 4 independent places. It can also be used for personnel dosimetry. The system consists of 4 battery-operated 256-channel dosimeters-spectrometers. We describe results obtained during the calibrations of the spectrometers at the Cyclotron facilities of the University of Louvain, Belgium and of the National Institute of Radiological Sciences-STA, Chiba, Japan with protons of energies up to 70 MeV. The angular sensitivities of the devices are studied and compared with Monte-Carlo predictions. We also present the results obtained at the HIMAC accelerator with 500 MeV/u Fe ions and at the CERN high energy radiation reference fields. Records made during airplane flights are shown and compared with the predictions of the CARI-6 model.

The Energetic Particle Telescope (EPT) on Board PROBA-V: Description of a New Science-Class Instrument for Particle Detection in Space

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.

Development strategies for an African computer network

Abstract Taking into account the cost and the services requirements, an evolutionary path for African computer networks is proposed. It is based upon existing technologies, such as HealthNet, Fidonet, UUCP and Internet nodes, but can evolve in order to fit long‐term needs.

12B nuclear spin lattice relaxation time and electron-electron interaction in noble metals

Abstract We have measured the Korringa contribution T 1e to the nuclear spin lattice relaxation time of the interstitial 12 B in noble metals. The Korringa product of 12 B shows that the conduction-electron spin susceptibility is exchange enhanced similarly to that sensed by the matrix nucleus. The enhancement factors are equal within the experimental errors for both interstitial and matrix positions in Cu and Ag. The small difference of the enhancement factors in Au can be attributed to a probe effect.

Angular Distribution of Protons Measured by the Energetic Particle Telescope on PROBA-V

Angular distribution and contamination of proton spectra measured at LEO are considered as possible sources of discrepancies between fluxes obtained by different instruments. In particular, not accounted for pitch angle distribution and East/West asymmetry of energetic proton fluxes have been suspected of leading to the reported underestimates of these fluxes by the NASA Model AP8. The energetic particle telescope (EPT) was designed as a science-class instrument aimed at providing uncontaminated fluxes of electrons ( 0.5-20 MeV), protons ( 9.5-300 MeV) and α-particles ( 38-1200 MeV) getting into the instrument from within a well-defined Field Of View (FOV). The PROBA-V satellite with EPT was 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. Based on the data acquired by the EPT on board PROBA-V, we account for flux angular distribution effects to provide a definitive reply to the basic question: “does AP8 underestimate E > 100 MeV proton fluxes around B/B0 = 1.1, L = 1.3”?

The Energetic Particle Telescope (EPT) concept and performances

The forecast of energetic particle fluxes on time scales of hours to weeks, at a given position in space, can be achieved on the basis of experimentally determined particle lifetimes and on real-time measurements of contamination-free spectra. Such elaborated measurements can be provided by the Energetic Particle Telescope (EPT) without any further post-processing. This instrument directly acquires energy spectra of electrons (0.2 - 10 MeV), protons (4 - 300 MeV), α- particles (16 - 1000 MeV) and heavier ions (up to 300 MeV/nucleon). The EPT was developed at the Center for Space Radiations - UCL-Belgium. This paper contains a brief description of the EPT concept and the definition of channels along with a more detailed presentation of the general performances based on the intrinsic detection efficiency functions and the validation test results from an Engineering Model. The EPT capabilities for space-weather related applications are highlighted by an example of forecast of an electron flux.

Proton Spectra Detected by the Proton Switches on the CRRES Satellite

A thorough detector characterization method is described and applied to analyze the data from the proton switches flown on the Combined Release and Radiation Effects Satellite (CRRES). The results are compared with the CRRESPRO model based on observations of the proton telescope (PROTEL), which was on board the same satellite. A general good agreement is observed at positions where the flux of high energy protons is low. In regions of harder proton spectra, the CRRESPRO fluxes are higher than those deduced from the proton switches data. One possible explanation for this discrepancy may be that high energy protons penetrating into the PROTEL detector ly accounted for.

Characterization of Solar Energetic H and He Spectra Measured by the Energetic Particle Telescope (EPT) On-Board PROBA-V During the January 2014 SEP Event

On January 6, 2014 a Solar Energetic Particle (SEP) event started that led to a 1030 cm

Perspectives for provision of high quality space radiation environment data using the Energetic Particle Telescope (EPT)

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