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Wyszukujesz frazę "Sadowski, J" wg kryterium: Autor


Wyświetlanie 1-10 z 10
Tytuł:
Measurements of fast electron beams and soft X-ray emission from plasma-focus experiments
Autorzy:
Surała, W.
Sadowski, M. J.
Kwiatkowski, R.
Jakubowski, L.
Żebrowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/147850.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron beams
X-ray emission
plasma focus
hot spots
Opis:
The paper reports results of the recent experimental studies of pulsed electron beams and soft X-rays in plasma-focus (PF) experiments carried out within a modifi ed PF-360U facility at the NCBJ, Poland. Particular attention was focused on time-resolved measurements of the fast electron beams by means of two different magnetic analyzers, which could record electrons of energy ranging from about 41 keV to about 715 keV in several (6 or 8) measuring channels. For discharges performed with the pure deuterium fi lling, many strong electron signals were recorded in all the measuring channels. Those signals were well correlated with the fi rst hard X-ray pulse detected by an external scintillation neutron-counter. In some of the analyzer channels, electron spikes (lasting about dozens of nanoseconds) and appearing in different instants after the current peculiarity (so-called current dip) were also recorded. For several discharges, fast ion beams, which were emitted along the z-axis and recorded with nuclear track detectors, were also investigated. Those measurements confi rmed a multibeam character of the ion emission. The time-integrated soft X-ray images, which were taken side-on by means of a pinhole camera and sensitive X-ray fi lms, showed the appearance of some fi lamentary structures and so-called hot spots. The application of small amounts of admixtures of different heavy noble gases, i.e. of argon (4.8% volumetric), krypton (1.6% volumetric), or xenon (0.8% volumetric), decreased intensity of the recorded electron beams, but increased intensity of the soft X-ray emission and showed more distinct and numerous hot spots. The recorded electron spikes have been explained as signals produced by quasi-mono-energetic microbeams emitted from tiny sources (probably plasma diodes), which can be formed near the observed hot spots.
Źródło:
Nukleonika; 2016, 61, 2; 161-167
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recent measurements of soft X-ray emission from the DPF-1000U facility
Autorzy:
Surała, W.
Sadowski, M. J.
Paduch, M.
Zielinska, E.
Tomaszewski, K.
Powiązania:
https://bibliotekanauki.pl/articles/148171.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma focus
X-ray emission
X-ray images
gas puffing
filaments
hot spots
Opis:
Soft X-ray imaging is a very useful diagnostic technique in plasma-focus (PF) experiments. This paper reports results of four experimental sessions which were carried out at the DPF-1000U plasma-focus facility in 2013 and 2014. Over 200 discharges were performed at various experimental conditions. Measurements were taken using two X-ray pinhole cameras with a line of sight perpendicular to the z-axis, at different azimuthal angles (about 20° and 200°), and looking towards the centre of the PF-pinch column. They were equipped with diaphragms 1000 μm or 200–300 μm in diameter and coated with filters of 500 μm Al foil and 10 μm Be foil, respectively. Data on the neutron emission were collected with silver activation counters. For time-resolved measurements the use was made of four PIN diodes equipped with various fi lters and oriented towards the centre of the PF-column, in the direction perpendicular to the electrode axis. The recorded X-ray images revealed that when the additional gas-puff system is activated during the discharge, the stability of the discharge is improved. The data collected in these experiments confi rmed the appearance of a filamentary fi ne structure in the PF discharges. In the past years the formation of such fi laments was observed in many Z-pinch type experiments. Some of the recorded X-ray images have also revealed the appearance of the so-called hot- -spots, i.e. small plasma regions of a very intense X-ray emission. Such a phenomenon was observed before in many PF experiments, e.g. in the MAJA-PF device, but it has not been investigated so far in a large facility such as the DPF-1000U. The time-resolved measurements provided the evidence of a time lapse between the X-ray emission from plasma regions located at different distance from the anode surface. The formation of distinct ‘hot-spots’ in different instants of the DPF-1000U discharge was also observed.
Źródło:
Nukleonika; 2015, 60, 2; 303-308
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Progress in MJ plasma focus research at IPPLM
Autorzy:
Scholz, M.
Karpinski, L.
Krauz, V. I.
Kubeš, P.
Paduch, M.
Sadowski, M. J.
Powiązania:
https://bibliotekanauki.pl/articles/147514.pdf
Data publikacji:
2012
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma focus
PF-1000 facility
magnetic probes
interferometry
neutron yield scaling
Opis:
The results of studies of the plasma dynamics and neutron emission on a PF-1000 facility in the stage of pinch formation are presented. The measurements were performed using various modifications of the calibrated magnetic probes, 16 frame interferometry, silver activation counters and photomultiplier tube (PMT) neutron probes. The current measurements at a distance of 40 mm from the axis of the electrodes was measured. This dependence agrees well with the known scaling, Yn similar to I4. The evolution plasma density during pinch formation and a neutron emission were study.
Źródło:
Nukleonika; 2012, 57, 2; 183-188
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of optical spectra recorded during DPF-1000U plasma experiments with gas-puffing
Autorzy:
Zaloga, D. R.
Skladnik-Sadowska, E.
Kubkowska, M.
Ladygina, M. S.
Malinowski, K.
Kwiatkowski, R.
Sadowski, M. J.
Paduch, M.
Zielinska, E.
Makhlaj, V. A.
Powiązania:
https://bibliotekanauki.pl/articles/147780.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
electron density
gas-puff
optical spectrum
plasma focus
plasma stream
Opis:
The results are presented of the optical spectra measurements for free plasma streams generated with the use of the modifi ed DPF-1000U machine. This facility was recently equipped with a gas injection system (the so-called gas-puff) placed on the symmetry axis behind the central opening in the inner electrode. The DPF-1000U experimental chamber was fi lled up with pure deuterium at the initial pressure of 1.6 or 2.4 mbar. Additionally, when the use was made of the gas-puff system about 1 cm3 of pure deuterium was injected at the pressure of 2 bars. The gas injection was initiated 1.5 or 2 ms before the triggering of the main discharge. The investigated plasma discharges were powered from a condenser bank charged initially to 23 kV (corresponding to the energy of 352 kJ), and the maximum discharge current amounted to about 1.8 MA. In order to investigate properties of a dense plasma column formed during DPF-1000U discharges the use was made of the optical emission spectroscopy. The optical spectra were recorded along the line of sight perpendicular to the vacuum chamber, using a Mechelle®900 spectrometer. The recent analysis of all the recorded spectra made it possible to compare the temporal changes in the electron density of a freely propagating plasma stream for discharges without and with the gas-puffing. Using this data an appropriate mode of operation of the DPF-1000U facility could be determined.
Źródło:
Nukleonika; 2015, 60, 2; 309-314
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of plasma interactions with tungsten targets in PF-1000U facility
Autorzy:
Ladygina, M. S.
Skladnik-Sadowska, E.
Zaloga, D. R.
Sadowski, M. J.
Kubkowska, M.
Kowalska-Strzeciwilk, E.
Krawczyk, N.
Paduch, M.
Miklaszewski, R.
Garkusha, I. E.
Powiązania:
https://bibliotekanauki.pl/articles/147524.pdf
Data publikacji:
2016
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma-surface interaction
plasma streams
tungsten
plasma focus
PF-1000U
Opis:
This paper presents results of experimental studies of tungsten samples of 99.95% purity, which were irradiated by intense plasma-ion streams. The behaviour of tungsten, and particularly its structural change induced by high plasma loads, is of great importance for fusion technology. The reported measurements were performed within a modifi ed PF-1000U plasma-focus facility operated at the IFPiLM in Warsaw, Poland. The working gas was pure deuterium. In order to determine the main plasma parameters and to study the behaviour of impurities at different instants of the plasma discharge, the optical emission spectroscopy was used. The dependence of plasma parameters on the initial charging voltage (16, 19 and 21 kV) was studied. Detailed optical measurements were performed during interactions of a plasma stream with the tungsten samples placed at the z-axis of the facility, at a distance of 6 cm from the electrode outlets. The recorded spectra showed distinct WI and WII spectral lines. Investigation of a target surface morphology, after its irradiation by intense plasma streams, was performed by means of an optical microscope. The observations revealed that some amounts of the electrodes material (mainly copper) were deposited upon the irradiated sample surface. In all the cases, melted zones were observed upon the irradiated target surface, and in experiments performed at the highest charging voltage there were formed some cracks.
Źródło:
Nukleonika; 2016, 61, 2; 149-153
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Plasma Focus discharges in the PF-360 facility with additional D2 gaspuffed targets
Autorzy:
Stanislawski, J.
Baranowski, J.
Sadowski, M.
Zebrowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/147013.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
current sheath
deuteron beams
gas puffing
neutron yield
plasma focus
Opis:
The paper describes experimental studies of Plasma-Focus (PF) discharges carried out within the modernized PF- 360 facility, which was operated with an additional D2-gas puffing into the region of the collapsing current sheath and PF pinch formation, i.e. into space in front of the electrode outlet. The main aim of these studies was to increase a neutron yield from PF discharges by using fast deuteron beams, which are usually emitted from a pinch column and which can interact with additional D2-gas target.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 73-75
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of Plasma-Focus discharges within the PF-360 facility equipped with a planar D2O-ice target
Autorzy:
Zebrowski, J.
Baranowski, J.
Jakubowski, L.
Sadowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/147057.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
cryogenic target
ion beams
neutron yield
plasma focus
X-rays
Opis:
The paper reports on investigations of dense magnetized plasmas produced within a modernized PF-360 facility, which was operated with an additional planar cryogenic target placed in the front of the electrode outlet and covered with D2O-ice layers. The main aim of these studies was to overcome the neutron saturation effect and to increase the maximum neutron yield from PF discharges by using fast deuteron beams. Such beams are usually emitted from a pinch region and can produce fast neutrons from D-D reactions during their interactions with the additional target.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 65-68
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of Plasma-Focus discharges within the PF-360 facility equipped with needle D2O-ice target
Autorzy:
Baranowski, J.
Jakubowski, L.
Sadowski, M.
Zebrowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/147583.pdf
Data publikacji:
2001
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
cryogenic target
current sheath
neutrons yield
plasma focus
X-ray
Opis:
The paper describes a new technique which has been investigated in order to overcome the neutron saturation effect and to increase the neutron yield from the plasma-focus (PF) discharges [1]. The PF-360 experimental facility was constructed at the Andrzej Soltan Institute for Nuclear Studies (IPJ) in Swierk, Poland in the late 70s [4, 5]. Recently in order to improve the neutron yield from the PF-360 machine, it was proposed to use a cryogenic deuterium target, which might be placed within the plasma-focus region. For this purpose, we have been made a needle-like cryogenic target covered with a thin „heavy-ice“ layer. A considerable increase in the average neutron yield (from 1.7×1010 to about 2.2×1010 neutrons/shot) has been achieved for 122 kJ PF discharges when the needle target top was placed at a distance of about 100 mm from the electrode ends.
Źródło:
Nukleonika; 2001, 46, suppl. 1; 69-71
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of characteristics of pulsed ion beams emitted from different small PF devices
Autorzy:
Sadowski, M.
Skladnik-Sadowska, E.
Baranowski, J.
Zebrowski, J.
Kelly, H.
Lepone, A.
Marquez, A.
Milanese, M.
Moroso, R.
Pouzo, J.
Powiązania:
https://bibliotekanauki.pl/articles/146809.pdf
Data publikacji:
2000
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
Faraday cups
ion beams
plasma focus
Thomson analyzers
track detectors
Opis:
The paper concerns studies of pulsed ion beams emitted from different small-energy (5–50 kJ) devices of the plasma focus (PF) type. Emission characteristics of the ion beams as measured with nuclear track detectors (NTDs), Faraday-type collectors (FC), and Thomson-type analyzers, are summarized. Common features of the ion emission are considered and some differences are discussed.
Źródło:
Nukleonika; 2000, 45, 3; 179-184
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Status of a mega-joule scale Plasma-Focus experiments
Autorzy:
Scholz, M.
Bieńkowska, B.
Borowiecki, M.
Ivanova-Stanik, I.
Karpiński, L.
Stępniewski, W.
Paduch, M.
Tomaszewski, K.
Sadowski, M.
Szydłowski, A.
Kubeš, P.
Kravárik, J.
Powiązania:
https://bibliotekanauki.pl/articles/147496.pdf
Data publikacji:
2006
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
plasma focus
dense magnetized plasma
neutron yield
Opis:
This paper presents results of the recent plasma-focus (PF) experiments carried out with PF facilities, which was operated at energies ranging from 0.5 MJ to about 1 MJ. Particular attention has been paid to pinch evolution, the emission of pulsed X-ray, fast electron beams, and fusion produced neutrons. Some theoretical models of the initial breakdown, which occurs at the insulator surface, are compared. It is pointed out that modeling of the breakdown is sensitive to kinetics of ionization processes and transport coefficients. Progress in experimental studies of the axial acceleration phase is unsatisfactory. Important experimental data have been collected, but new measurements are still needed. For the radial collapse phase, it was shown that the MHD modeling is efficient until the maximum compression, but plasma instabilities require more sophisticated approaches. The pinch phase was investigated by means of different diagnostics. Fusion neutron yields were measured in different experiments, but some discrepancies in scaling must still be explained. The conclusions concern directions for further studies and optimization of large-scale high-current PF facilities.
Źródło:
Nukleonika; 2006, 51, 1; 79-84
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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