LaBr3:Ce,CeBr3 and GAGG:Ce scintillators were investigated and the determined characteristics were compared with those obtained for the well-known and widely used CsI:Tl and NaI:Tl crystals. All the detectors were of the same size of 10 × 10 × 5 mm3. The aim of this test study was to single out scintillation detectors most suitable for γ-ray spectrometry and γ -ray emission radial profile measurements in high-temperature plasma experiments. Decay time, energy resolution, non-proportionality and full energy peak detection efficiency were measured for γ -ray energies up to 1770 keV. Due to their good energy resolution, short decay time and high detection efficiency for MeV gamma rays, LaBr3:Ce and CeBr3 scintillators are proposed as the best candidates for use especially under conditions of high count rates, which are expected in the forthcoming DT experiments.
The results of experimental investigations of powerful hydrogen plasma jets and fast ion beams interaction with various materials (austenitic chromium-manganese steels, pure vanadium, tungsten, graphite, copper, and their alloys: Cu-4 mass% Ni and Cu-10 mass% Ga) are presented. The materials were placed on the discharge axis of the PF-1000 device and irradiated with fluxes of fast ions (of energy in the range from tens keV up to several MeV) and with plasma streams (of power flux density q~(108 109) W/cm2). It was found that the fast ions and plasma streams caused different damages to the aforementioned materials. A diverse character of the damages to the individual investigated material was revealed. Some peculiarities of the process as well as the correlation between the surface density of the "macroscopic" structural defects (blisters and craters) and the fluence of the fast ions implanted in the specimen are discussed.
We present the results of experiments focused on energy transformations during the implosion of the hydrogen current sheath towards an Al wire (120 ěm in diameter) positioned on the top of the inner electrode of the PF-1000 plasma focus facility at the IPPLM in Warsaw. A wire corona is formed at the current sheath impact and ~60 ns after the impact a soft X-ray pulse is emitted. Its spectrum contains AlVI-XII lines accompanied by their satellites. The amount of emitted energy is recorded by two filtered PIN diodes and thermoluminescent dosimeters and depends on symmetry of the current sheath and quality of the current sheath focus. The mean value of energy of keV photons emitted in the runs done without the wire (~1 J) is higher than the energy obtained with the wire (~0.4 J). A time delay between the impact of the current sheath and X-ray pulse, the plasma focus dynamics and soft X-ray emission are interpreted by an axial magnetic field generation and transformations.
This paper presents the results of the diagnostics observing the impact of the plasma sheath imploded in megaamper Z-pinch or plasma focus devices onto the Al or C wires of 30-300 mi m in diameter fixed in the center axis. The discharges were operated with a maximum current of 1.5-3 MA at two devices, PF 1000 at IPFLM in Warsaw, and Stand 300 at RRC Kurchatov Institute in Moscow. At the plasma impact the 10-50 ns XUV pulse was emitted in K-shell lines from the ring or helical-like forms on the surface of the wire corona. The scenario of the production of the non-equilibrium intensities of the C and Al H-like and He-like lines is discussed considering fast transformation of magnetic field, electron beams acceleration, total ionization of the ions and fast recombination in dense and magnetized wire corona.
The paper reports on actual operational characteristics of the PF-1000 facility and it presents results of the first neutron experiments performed with a new set of large Mather-type electrodes, which were designed for shots up to 1000 kJ. Dynamics of a current-sheath was studied by means of two high-speed streak cameras and a two-frame camera. The last one was used for the side-on observation of the pinch column. The high-speed streak pictures were taken side-on behind slits oriented in the radial or axial direction. On the basis of the pictures taken behind the radial slit, average values of the radial compression and expansion velocities were estimated. Time-resolved X-ray signals were measured with PIN diodes covered by different filters, and they were compared with other traces (voltage waveforms, dI/dt signals, and neutron-induced pulses) in order to determine their correlation. The total neutron yield (Ytot), i.e. the number of neutrons produced during a single discharge and emitted in various directions, was measured by means of several silver-activation detectors placed at different angles around the PF-1000 experimental chamber.
The report describes some of the results obtained in an experimental study of the impact of a powerful plasma stream and a fast ion beam generated in a PF-1000 device on different materials perspective for the use in radiation loaded parts of pulsed plasma installations. Investigations were done during and after the interaction processes. It is shown that in case of irradiation of samples only by high power flux density plasma streams the effect of detachment still preserved. At the same time a low power flux density high-energy ion beam plays an important role in the process of saturation of the irradiated material by hydrogen.
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