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1

A new concept of fusion neutron monitoring for PF-1000 device

Jednorog S., Laszynska E., Bienkowska B., Ziolkowski A., Paduch M., Szewczak K., Mikszuta K., Malinowski K., Bajdel M., Potrykus P.

Nukleonika

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2017

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Vol. 62, No. 1

17--22

EN

The power output of plasma experiments and fusion reactors is a crucial parameter. It is determined by neutron yields that are proportional and directly related to the fusion yield. The number of emitted neutrons should be known for safety reasons and for neutron budget management. The PF-1000 is the large plasma facility based on the plasma focus phenomenon. PF-1000 is operating in the Institute of Plasma Physics and Laser Microfusion in Warsaw. Neutron yield changes during subsequent pulses, which is immanent part of this type device and so it must be monitored in terms of neutron emission. The reference diagnostic intended for this purpose is the silver activation counter (SAC) used for many years. Our previous studies demonstrated the applicability of radio-yttrium for neutron yield measurements during the deuterium campaign on the PF-1000 facility. The obtained results were compared with data from silver activation counter and shown linear dependence but with some protuberances in local scale. Correlation between results for both neutron monitors was maintained. But the yttrium monitor registered the fast energy neutron that reached measurement apparatus directly from the plasma pinch. Based on the preliminary experiences, the yttrium monitor was designed to automatically register neutron-induced yttrium activity. The MCNP geometrical model of PF-1000 and yttrium monitor were both used for calculation of the activation coefficient for yttrium. The yttrium monitor has been established as the permanent diagnostic for monitoring fusion reactions in the PF-1000 device.

2

Evolution of the small ball-like structures in the plasma focus discharge

Cikhardtova B., Kubes P., Cikhardt J., Paduch M., Zielinska E., Kravarik J., Rezac K., Kortanek J.

Nukleonika

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2016

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Vol. 61, No. 2

155--159

EN

The experiments were carried out in the PF-1000 plasma-focus device at the maximum current reaching about 2 MA, at the deuterium or neon filling and with deuterium injected from a gas-puff nozzle placed on the axis of the anode face. Ball-like structures of diameters of 1–12 mm were identifi ed in interferometric and XUV pinhole camera frames. We made the statistical description of their parameters. A lifetime of the ball- -like structures was in the range from 30 to 210 ns, and in some cases even more. These structures appeared mostly at the surface of the imploding plasma shell and they did not change their position in relation to the anode end. During the evolution of these structures, interferometric fringes were observed near the surfaces of the structures only, and their internal parts were initially chaotic (without noticeable) fringes. Subsequently the number of interferometric fringes increased (the internal ‘chaotic’ area was fi lled with fringes too) and later on it decreased. The radii of the ball-like structures were mostly increasing during their existence. The maximum electron density reached the value of 1024 to 1025 m–3. The ball-like structures decayed by absorption inside the expanded pinch column and/or gradually expired in rare plasma outside of the dense plasma column.

3

Irradiation of austenitic steel 10Cr12Mn14Ni4AlMo and titanium alloy Ti-Al-V by pulsed streams of fast nitrogen ions and plasma in a dense plasma focus

Gribkov V. A., Pimenov V. N., Roschupkin V. V., Maslyaev S. A., Demina E. V., Lyakhovitsky M. M., Dubrovsky A. V., Sasinovskaya

Nukleonika

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2012

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Vol. 57, No. 2

291-295

EN

Austenitic steel 10Cr12Mn14Ni4AlMo and Ti-4Al-3V alloy were irradiated with nanosecond pulsed nitrogen ion and plasma streams in plasma focus devices. The two different modes of the treatment were applied: high power density (greater-than or equal to 10 8 W/cm2) irradiation with melting of the surface layer and irradiation with power density similar to 10 7 W/cm2 below the melting threshold. Structure and phase changes as well as the mechanisms of modification and hardening of the surface layers of the steel and titanium alloy upon applied irradiation are discussed.

4

Fusion reaction scaling in a mega - amp dense plasma focus

Lerner E. J., Murali S. K., Blake A. M., Shannon D. M., van Roessel F. J.

Nukleonika

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2012

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Vol. 57, No. 2

205-209

EN

The dense plasma focus (DPF) is one of the most efficient sources of fusion reactions for a given energy input. For smaller DPFs, fusion output scales as I4 or faster, where I is peak current. However, energy output in high-current machines saturates at 1012 reactions with deuterium as fill gas. To attempt to overcome this saturation, experiments at the focus fusion-1 (FF-1) facility have tested the use of smaller-radius electrodes (2.8 cm radius anode) and higher fill-gas densities more than 30 T.

5

Optical emission spectroscopy of plasma streams in PF-1000 experiments

Jakubowska K., Kubkowska M., Skladnik-Sadowska E., Malinowski K., Marchenko A. K., Paduch M., Sadowski M. J., Scholz M.

Nukleonika

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2011

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Vol. 56, No. 2

125-129

EN

The optical spectroscopy in the visible range was used to determine properties of the dense magnetized plasma generated in the PF-1000, a 1 MJ plasma focus device operating in the Institute of Plasma Physics and Laser Microfusion (IPPLM) in Warsaw, Poland. The experiments were performed in a vacuum chamber pumped out to the basic pressure of 2 x 10.5 hPa. The initial pressure of the pure deuterium filling was 2.9 hPa, while that of the deuterium--argon mixture was 1.07 hPa of D2 and 0.13 hPa of Ar. The deuterium-plasma emission contained the Balmer series (Dalfa, Dbeta and Dgamma) and a few distinct copper (Cu I) lines originating from the inner electrode material. The emission of the deuterium-argon plasma was rich in Ar II lines. The electron density (ne), averaged over line of sight, of order of 1016 cm.3 was calculated on the basis of the Dalfa and Dbeta emission only, because the D�ż line was strongly self-absorbed. A group of the Ar II spectral lines was used to estimate the excitation temperature (Texc = 3 eV) by means of a Boltzmann plot. Additionally, the temporal evolution of the electron density was determined on basis of the Stark broadening of the Dalfa and Dgamma lines.

6

PF-6 an effective plasma focus as a source of ionizing radiation and plasma streams for application in material technology, biology and medicine

Gribkov V., Dubrovsky A., Scholz M., Jednorog S., Karpiński L., Tomaszewski K., Paduch M., Miklaszewski R., Pimenov V., Ivanov L. I., Dyomina E. V., Maslyaev S. A., Orlova M. A.

Nukleonika

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2006

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Vol. 51, nr 1

55-62

EN

A review of results on the design and operation of the new efficient Dense Plasma Focus device PF-6 of medium size (transportable) having bank energy of ca. 7 kJ and possessing a long lifetime is presented. New data on the interaction of the pulsed fast ion beams and dense plasma streams generated at this apparatus with various materials are given. These results are compared with the analogous information received at the biggest facility PF-1000. It is shown that it is possible to have about the same power flux density (in the range of 105 109 W/cm2) in both devices however in different areas. Doses of soft X-rays produced by the device within the resists for the goals of microlithography and micromachining appear to be several times less that it is with the conventional X-ray tube. In biological application of this device, medium- and hard-energy X-rays are exploited in the field of radioenzymology. It was found that the necessary dose producing activation/inactivation of enzymes can be by several orders of magnitude lower if used at a high-power flux density in comparison with those received with isotope sources. In medicine, short-life isotope production for the goals of the positron emission tomography (medicine diagnostics) is possible by means of the fast ions generated within DPF. All these experiments are discussed in the framework of pulsed radiation physics and chemistry in its perfect sense thereto the criteria are formulated.

7

Dense Plasma Focus as a powerful source of monochromatic X-ray radiation

Dubrovsky A., Gribkov V., Ivanov Y., Karpiński L., Orlova M.

Nukleonika

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2006

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Vol. 51, nr 1

21-28

EN

A review of some experimental results obtained using the dense plasma focus (DPF) device PF-1000 is presented. The copper Ka1,2 radiation line generated by DPF in the case of device anode made of copper was the main object of this study. The predominance of this characteristic radiation over other kinds of radiation in the DPF X-ray spectrum is shown. A brief description of a new DPF 6.0 device as well as a radioenzymology experiment carried out within this device is presented.

8

Influence of powerful pulses of hydrogen plasma upon materials in PF-1000 device

Pimenov V., Gribkov V., Dubrovsky A., Mezzetti F., Scholz M., Ugaste U., Dyomina E., Ivanov L., Maslyaev S., Miklaszewski R., Borowiecki M., De Chiara P., Pizzo L., Szydlowski A., Volobuev I. V.

Nukleonika

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2002

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Vol. 47, nr 4

155-162

EN

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.

9

Experimental study of a powerful energy flow effect on materials in PF-1000 installation

Borowiecki M., De Chiara P., Dubrovsky A. V., Dyomina E. V., Gribkov V. A., Ivanov L. I., Maslyaev S. A., Mezzetti F., Miklaszewski R., Pimenov V. N., Pizzo L., Scholz M., Szydlowski A., Ugaste Y. E., Volobuev I. V.

Nukleonika

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2001

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Vol. 46, suppl. 1

117--122

EN

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.

10

Anisotropy of the neutron emission from PF-360 facility operated without and with solid-state targets

Czaus K., Baranowski J., Sadowski M., Skladnik-Sadowska E., Zebrowski J.

Nukleonika

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2001

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Vol. 46, suppl. 1

77--80

EN

The paper reports on detailed studies of an anisotropy of the fusion-produced neutrons emitted from the modernized PF-360 facility [10], which has been operated with a pure deuterium-gas filling, without and with some additional solidstate targets containing deuterium atoms. Under standard operational conditions, anisotropy of the neutron yield from the PF-360 facility is similar to that observed in other PF devices. For the first time the neutron emission anisotropy has been measured in the PF experiments performed with a planar cryogenic target covered with a heavy-ice (D2O) layer. Changes in the Yn(Φ)/Yn(90°) ratio, particularly for angles Φ = 0–60°, have been explained by the known features of the angular distribution of fast deuterons.

11

0.2-kJ and 2-kJ high rep rate Dense Plasma foci : their design, technology, and applications

Dubrovsky A. V., Gribkov V. A., Ivanov Y. P., Lee P., Lee S., Liu M., Samarin V. A.

Nukleonika

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2001

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Vol. 46, suppl. 1

107--111

EN

The paper presents various designs of several medium and small size Dense Plasma Focus (DPF) chambers intended for numerous applications, a description of technologies used in these facilities, and some results reached with these devices by using a number of diagnostic techniques. In present experiments the DP foci have been used mainly as an X-ray source. We discuss here how it is possible to satisfy absolutely new and very strict demands on the construction and technology for the devices to be eventually applied in science and industry. Between these characteristics there are a high repetition rate (typically 1…15 Hz) and a long lifetime (over 1 million shots). Their switching elements, a collector and chambers must withstand a high quasi-continuous heat load (up to 100 kW). High energy density in the central part of the chamber anode and the necessity to provide a channel for radiation extraction demanded a special construction and specific materials implementation in this region. Their X-ray spectrum should be tuned. They have to operate with different working gases and preferably in a wide range of pressures. All these points are discussed in this report. Capabilities of the described techniques are illustrated by results of the recent experimental studies carried out with facilities located at the Nanyang Technological University (NX1) as well as at the Lebedev Physical Institute (PF-0.2).

12

On possible formulation of problems of a Dense Plasma Focus used in material sciences

Gribkov V.

Nukleonika

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2000

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Vol. 45, nr 3

149-153

EN

The paper describes various possibilities at can be given by the use of dense plasma focus (DPF) device in material sciences. Main distinguishing features of such a device – availability of several different types of hard radiation and its high power flux density – determine the niche of applications of this type devices in the field. Some directions of materials investigation and treatment, which can be developed at present time, are discussed.

13

Installations based on high efficiency high repetition rate miniature DPF chambers for material science

Dubrovsky A., Gribkov V.

Nukleonika

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2000

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Vol. 45, nr 3

159-162

EN

The report describes two DPF installations based on a miniature plasma focus chamber: the installation PF-3 of the energy store W = 3 kJ and the installation PF-0.2 (W = 200 J). The possibility of an adaptation of the small DPF device for the experimental samples irradiation is reported. A new construction intended for experiments with samples of various materials is presented.

14

DPF device application in the material characterization

Dubrovsky A., Silin P., Gribkov V., Volobuev I.

Nukleonika

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2000

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Vol. 45, nr 3

185-187

EN

The ability of a dense plasma focus (DPF) installation, to serve as a unique powerful hard X-ray and neutron pulse generator, is discussed. A principle of the dynamic detection of defects, based on a small-scale DPF device, is described. The results of a dynamic defect detection experiment are presented. Different aspects of the application and adaptation of a small DPF chamber for the material science, are discussed.