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Browsing by Author "Dankowski, Jan"

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    Principles of a method to use CVD diamond detectors for spectrometric measurements of particles in mixed radiation field emitted by D-D and D-T fusion plasmas
    (Institute of Nuclear Physics Polish Academy of Sciences, 2014) Drozdowicz, Krzysztof; Dankowski, Jan; Igielski, Andrzej; Jaskóła, Marcin; Korman, Andrzej; Kurowski, Arkadiusz; Marczewska, Barbara; Nowak, Tomasz; Wiącek, Urszula; Woźnicka, Urszula; Gabańska, Barbara
    Future thermonuclear reactors for needs of power plants will operate with the deuterium-tritium fuel. Neutron, alpha particle, and energy are created in the fusion reaction between these isotopes. Measurement of energy of the reaction products is important to control energetic balance in the thermonuclear plasma. Fast neutrons (14 MeV) should deliver energy outside the tokamak. Alpha particles are the ash of the reaction but they should also leave their energy (3.6 MeV) in the plasma to maintain the fusion reaction. Therefore, knowledge of the energy of alpha particles escaping from plasma (the lost alpha particles) is essential. Because of a short range of alpha particles the measurement has to be performed inside the tokamak, in harsh surrounding (high temperature and high particle fluxes). Diamond seems to be a proper material for use it as a semiconductor detector under those conditions. A diamond detector (synthetic high purity CVD monocrystal) was tested in aspect of its potential application for spectrometric diagnostic of the ions in tokamaks. The energy calibration of the diamond detectors of the different thickness was performed using isotopic sources: energies around 5 MeV from the 239Pu + 241Am + 244Cm source, and 6.8 and 8.7 MeV from the 212Bi + 212Po source. Additionally, monoenergetic ions beams (alpha particles and protons) were obtained from a van de Graaff accelerator in the 0.4 – 2 MeV energy range. A very good linearity of the amplitude signal vs. energy was obtained. At any working tokamak, a mixed radiation field is present consisting of various particles, like n, α, γ, p, d, t. Their contributions fluctuate depending on a regime of tokamak work and on plasma instabilities. Thus, the CVD diamond detector response in a mixed radiation field can be properly studied only in well-defined conditions of a laboratory experiment. Detection of ions and neutrons was performed at our 14 MeV neutron generator, IGN-14, where (i) the same nuclear reaction as in the D-T plasma occurs and (ii) also other types of radiation similar as at tokamaks are observed (owing to a number of different reactions on the generator target). A new measuring chamber at IGN-14 was designed and built to make possible observation of responses of detectors placed symmetrically or at different angles in respect to the primary ion beam. Two identical or different type detectors can be compared at the same time. A complex spectrograms were obtained and analysed to distinguish signals from various particles.
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    Spectrometric properties of the CVD diamond detector for measurement of the ‘lost alpha particles’
    (Institute of Nuclear Physics Polish Academy of Sciences, 2010) Wodniak, Iwona; Dankowski, Jan; Drozdowicz, Krzysztof; Gabańska, Barbara; Igielski, Andrzej; Kurowski, Arkadiusz; Maczewska, Barbara; Nowak, Tomasz
    Measurement of energy of the ‘escaping alpha particles’ from the thermonuclear reaction in the tokamak is important to get information on the energetic balance in future thermonuclear reactors producing electrical energy. Detectors will work in a harsh environment (high fluxes of particles, high temperature). Synthetic (CVD) diamond can be used in this case as a semiconductor detector. Tests with such a detector are described. Energy calibration has been carried out with a triple alpha particle isotopic source, 239Pu, 241Am, 244Cm (PAC), with the α energy peaks at ca. 5.2, 5.5 and 5.8 MeV. A very good energy resolution has been obtained, comparable with the resolution of the classic silicon detector. Energy response has been also investigated with the use of monoenergetic alpha particle beams (0.4 to 2 MeV) from the Van de Graaf accelerator. The amplitude linearity of the signal is very good, including besides results of measurements with the PAC source.
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    Technical design and operation tests of the DET-12 device for detection of delayed neutrons
    (Institute of Nuclear Physics Polish Academy of Sciences, 2014) Bieńkowska, Barbara; Drozdowicz, Krzysztof; Gabańska, Barbara; Igielski, Andrzej; Janik, Władysław; Kurowski, Arkadiusz; Tracz, Grzegorz; Wiącek, Urszula; Dankowski, Jan
    A technical design of the device for detection of delayed neutrons emitted from neutron-activated fissionable material samples has been performed according to physical assumptions which were earlier elaborated. The DET-12 device was constructed. The detection system was composed, consisting of twelve 3He neutron detectors, related electronics lines, and the data acquisition and recording system. The detectors were adjusted to work in groups by three connected to one preamplifier, considering a weak intensity of emission of the delayed neutrons. Laboratory measurement tests of the device operation were made with use of an isotopic neutron source. A total efficiency of neutron detection in DET-12 was experimentally determined and a relative benchmark calculation was made by means of a Monte Carlo modelling of the neutron transport in the device from the source to detectors.