44 research outputs found
Low-energy X-ray radiation after the biological shielding of electron accelerators
No full textThe bremsstrahlung of electrons from thick converters and its passage through concrete shielding of accelerators at different angles to the axis of the electron beam were calculated using GEANT4. Numerical estimates of the
residual low-energy component of X-ray radiation after passing through the biological protection were carried out
at an electron energy of up to 300 MeV. Additional reasons for the possible appearance of soft X-ray radiation
after the shielding are considered
Electric Solar Wind Sail Propulsion System Development
No full textThe electric solar wind sail (E-sail) was invented in 2006 and has thereafter been developed rapidly. This paper is a progress report of E-sail technical development as it stands in August 2011. We conclude that E-sail development is well underway, no major problems have been encountered so far and a revolutionary level of performance (1 N in nite Isp thrust from 100-200 kg package) seems realistic
Effective thickness of the planar detector in measurements of electrons energy loss
No full textAn experimental method of determining the active region thickness of Si planar detector was used. The method
based on the dependence the depletion layer thickness from voltage applied to the detector (U = 0:::60 V ). The
electron energy loss spectra emitted by 90Sr 90 Y in silicon planar detector were measured. The relative values
of most probable energy loss of electrons were de ned for different thickness of detector. The planar detector was
considered as a parallel-plate capacitor. The static (capacity) and dynamic (the detection efficiency and the energy
deposit) characteristics had a root dependence on voltage
Electric Solar Wind Sail in tailwind
No full textThe Electric Solar Wind Sail (E-sail) is a novelpropulsion concept that enables faster space travel tomany solar system targets. E-sail uses charged solarwind particles as the source of its propulsion. This isachieved by deploying long, conducting and chargedtethers, which get pushed by the solar wind byCoulomb drag [1].E-sail technology is being developed to technicalreadiness level (TRL) 4-5 by the European Union’sSeventh Framework Programme for Research andTechnological Development, EU FP7, in a projectnamed ESAIL (http://www.electric-sailing.fi/fp7).Prototypes of the key parts are to be produced. Thedesign will be scalable so that a real solar winddemonstration mission could be scaled up from them.We review here the latest results of the constantlyevolving E-sail project
Method for express determination of medical radionuclides 99mTc,67Cu concentration using spectrometer based on Si Planar detector
No full textThe method of express analysis provides the measurement of radiation spectra of medical radionuclides by a detection module based on an uncooled silicon planar detector and a "scintillator-silicon photosensor" type module. A spectrometric device for express analysis of radionuclide concentration has been developed and its prototyping has been carried out, confirming the operability of the device. The spectrometer analyzer is powered from the USB port of the PC (including a laptop) that provides the possibility of autonomous operation. Test measurements were carried out using the prototype of the spectrometer and X-ray sources, as well as spectral distributions of the radiation of real samples of 99mTc in a special container (glass ampoule). For a Si-PIN-detector with a thickness of 300 μm, the emission spectrum consists of a line of 99mTc with an energy of 140.5 keV and two peaks of the characteristic X-ray radiation (CXR) of technetium. The calculation in GEANT4 shows the matching of the 99mTc activities obtained from the registration of CXR and the main line. A measurement of the technetium concentration both by the 140.5 keV line and on the CXR radiation was proposed that significantly increases the speed of the data accumulation
Technique of thermal neutrons registration by two-channel spectrometric system based on uncooled si detectors and gadolinium converter
No full textA block diagram was developed and a working model of a small-sized two-channel spectrometric detection system for thermal neutrons registration was produced. The spectrometric system is created on the basis of silicon planar uncooled detectors and a metallic gadolinium converter. A method has been developed for measuring the thermal neutrons flux density (fluence) for use in nuclear physics and nuclear medicine. A two-detector spectrometric system based on planar Si detectors and Gd converters allows to register thermal neutrons by measuring the output
of conversion electrons with the possibility of accounting of background radiation
Registration of the thermal neutrons using uncooled Si planar detector
No full textВиконана реєстрація теплових нейтронів за допомогою планарного Si-детектора з конвертором нейтронів з природного металевого Gd . Для отримання теплових нейтронів використовувалося 239Pu-Be(α, n)-джерело швидких нейтронів з потоком 1,13·105 с-1 зі сповільнювачем з парафіну. Контрольне вимірювання потоку теплових нейтронів виконано за допомогою детектора-дозиметра МКС-01Р. Виміряно експериментальний спектр реакції Gd(n, γ)Gd. Спектр складався з електронів конверсії з енергією в діапазоні 30...200 кеВ, з максимумом при енергії ~ 70 кеВ і ліній ХРІ Gd. Фонове гамма-випромінювання виміряно Si-детектором без шару Gd. Програмний код GEANT4 використано для розрахунку потоку теплових нейтронів
