EUV (13.5-nm) light generation using a dense plasma focus device

Dense Plasma Focus (DPF) devices are pulse plasma devices which are capable to generate few keV to MeV ions. The burst of energetic ions presents in plasma shots generated by DPF devices, can be used for impanation in the desired materials for various application from electronics to spintronics. Here, we present an advance way of gradient implantation using DPF in the heavy metal without much effecting the surface properties of the thin film. In order to implant desired ions such as oxygen, carbon, nitrogen, argon etc. new electrodes were designed, providing gentler plasma pinch phase, with increased plasma volume. To study the effect of the new electrode design electrical characteristics were performed in detail and with the help Lee code the plasma parameter like plasma temperature, plasma duration etc. was estimated. Optical imaging diagnostic (using gated ICCD camera), faraday cup measurements and x-ray pin-diode spectroscopy, was used to investigate the plasma dynamics, plasma density and plasma temperature. The designed electrode assembly can be used to generate defects and modify the material properties required for electronics, photonics and spintronics applications.

Fabrication of nanoparticles and nanostructured materials is at the heart of modern nanoscience. In the present work, we are reporting the fabrication of Iron nanoparticles making use of high temperature, high density, and extremely non equilibrium pulsed plasma produced in 3.3 KJ Mather type Dense Plasma Focus (DPF) device. The Iron nanoparticles were deposited on quartz substrate at a distance of 5 cm above the ion source. The Iron nanoparticles are characterized structurally using X-ray diffractometer and topographically using Atomic force microscopy (AFM). The magnetic property was investigated using Magnetic Force Microscopy (MFM). It is found that these nanoparticles have a dimension in the range of 20-60 nm size and are magnetic in nature.

Room temperature deposition of titanium carbide thin films using dense plasma focus device

Hard TiCx/SiC/a-C:H nanocomposite thin films using pulsed high energy density plasma focus device

The dense plasma focus (DPF) device has great potential as a fusion energy generator using hydrogen-boron (pB11) fuel1. Experiments using deuterium have already demonstrated mean ion energies >200 keV, in the range needed for burning pB112. To test that potential, we are preparing for experiments with hydrogen-boron fuel in the megampere DPF device, FF-2B. We plan to use isotopically-pure decaborane (B10H14) as the fuel source and have installed equipment for the safe handling and disposal of the toxic vapors from this material. High isotopic purity of the boron-11 is required to avoid generation of radioactive Be-7. While the main pB11 fusion reaction produces no neutrons, two side reactions do produce both neutrons and radioactive C-11. We show how these reaction products can be used with suitable detectors to provide accurate data on fusion yield, and the density and ion energy of the confined fusion-producing plasma.

Dense plasma focus (DPF) devices are conventionally operated with a polarity such that the inner electrode (IE) is the anode. It has been found that interchanging the polarity of the electrodes (i.e., IE as the cathode) can cause an order of magnitude decrease in the neutron yield. This polarity riddle has previously been studied empirically through several experiments and is yet not well understood. We have performed kinetic simulations using the particle-in-cell modeling to investigate the problem. This is the first time that both polarities have been studied with simulations in great detail. In our simulations, we have modeled the entire beam and plasma target formation processes, but we did not consider differences in break-down conditions caused by the two polarities. We have found that when using reverse polarity ions are still accelerated and, in fact, attain similar energy spectra as in the standard polarity case. The difference is that the fields are flipped and thus ions are accelerated in the opposite direction. So, in the reverse polarity case, the majority of the “plasma target” (formed by the imploding plasma) is in the opposite direction of the beam, and thus, the beam hits the IE and produces few neutrons. With a better inner electrode configuration, reverse polarity is able to create a high-quality ion beam as well as a high-density target. Both can be comparable to that generated by standard polarity. Furthermore, we will show that it is easier to add an additional solid catcher target to a DPF device with reverse polarity, potentially enabling it to generate more neutrons than standard polarity.

Tungsten is one of the prime candidates for a first-wall material near the divertor area due to its high temperature strength, high thermal conductivity, low erosion rate and low tritium retention. The erosion resistance of tungsten to the edge plasmas and transient events are carefully investigated in a simulated fusion environment. Here, we use the dense plasma focus (DPF) device operated in a D2 as a source for pulsed fusion plasma. The tungsten (α-W) substrates with a preferential growth direction along (110) plane were used. These pristine-W samples were nanostructurized using a (i) low-temperature continuous nitrogen RF plasma system and (ii) coated with 60 nm tungsten film, using high-temperature argon plasma in a dense plasma focus (DPF) device. The low- temperature plasma treatment created mesh-like porous nanostructure on the surface of pristine-W with change in crystalline orientation to (200), while the DPF-based deposition resulted in a nanocrystal (30–50 nm) decorated surface with enhanced (200) orientation. The crack propagation and bubble formation during DPF D2 plasma exposure were significantly controlled by the surface modification of tungsten. The mesh-like structure was modified to form loosely bound spherical nanoparticles, while the nanocrystals remained tightly bound and grew in size with D2 plasma exposure. The better adhesion of the nanocrystals and controlled growth along the (200) direction resulted in least change in hardness measurements for the nanocrystal decorated samples. Thus, nanocrystal decoration of tungsten with a preferential growth direction of (200) can help reduce the fusion-induced damage in first-wall materials.

A source of thermonuclear energy based on the dense plasma focus (DPF) device in a hybrid fusion-fission version is proposed. The device would be physically compact (chamber diameter 3 m), would require a small uranium blanket (1–4 t), and could be expected to deliver 100–300 MWe; fuel replacement would be necessary every 2–5 years and construction and maintenance should be relatively simple. In its initial operating phase such a facility would be a net energy consumer and would breed fissile material; as the fissile content in the blanket increases, the installation would become a net energy producer. Under the proposed scheme of blanket operation, up to 50% of the uranium could be burned while maintaining electrical output and without refabrication of fuel elements. If desired, operation could continue after the fuel is almost completely exhausted to burn the nuclear waste. It is thought that the new source could become both technologically and economically feasible in the near future. Smooth control should present no problem and the speed at which the device could be brought up to full load should greatly improve the flexibility of the overall electrical supply system. Decentralized use of the new sources could reduce transmission losses and associated problems, while the sources could also operate in the same way as conventional fission power stations for heat production; moreover, the new hybrids could be used to replace the boiler sections of outworn fossil-fuel stations whilst still utilizing the existing turbines, generators, etc. Finally, due to its long fuel cycle the proposed source is essentially proliferation safe.

Effect of preionization on the dynamics of current sheath in a small plasma focus device

Carbonitride thin films have been deposited on silicon substrate by the irradiation of energetic nitrogen ions emanated from dense plasma focus device. The carbon ions are ablated by the irradiation of relativistic electrons from the insert material (graphite) placed at the anode tip. The x-ray diffraction analysis demonstrates that a polycrystalline thin film consisting of various compounds such as Si3N4, SiC, and C3N4 is formed on the silicon (100) substrate. Crystallinity of different compounds decreases with the increase in angular positions (0°, 10°, and 20°). Raman spectroscopy shows the appearance of graphitic and disordered bands with silicon nitride and silicon carbide indicating the formation of carbonitride. Raman spectra also indicate that broadening of bands increases with the increase in focus deposition shots, leading to the amorphization of the thin film. The amorphization of the thin films depends on the ion energy flux as well as on the sample angular position. The scanning electron microscopy exhibits the damaging of the substrate surface at 0° angular position. The microstructure shows the tubular shape for higher ion dose (40 focus shots). At 10° angular position, a two phase phenomenon is observed with the ordered phase in the solid solution. A smooth and uniform surface morphology showing a small cluster is observed for the 20° angular position.

Current sheath dynamics is an important parameter for good focusing or pinching in a dense plasma focus device. In this paper, we present pinching evidence and details of the filamentary structure of the current sheath in a miniature plasma focus device using a time-resolved laser shadowgraphic technique and time-integrated optical imaging.

The results of characterization experiments carried out on a newly developed dense plasma focus device based intense pulsed neutron source with efficient and compact pulsed power system are reported. Its high current sealed pseudospark switch based low inductance capacitor bank with maximum stored energy of ∼10 kJ is segregated into four modules of ∼2.5 kJ each and it cumulatively delivers peak current in the range of 400 kA-600 kA (corresponding to charging voltage range of 14 kV-18 kV) in a quarter time period of ∼2 μs. The neutron yield performance of this device has been optimized by discretely varying deuterium filling gas pressure in the range of 6 mbar-11 mbar at ∼17 kV/550 kA discharge. At ∼7 kJ/8.5 mbar operation, the average neutron yield has been measured to be in the order of ∼4 × 109 neutrons/pulse which is the highest ever reported neutron yield from a plasma focus device with the same stored energy. The average forward to radial anisotropy in neutron yield is found to be ∼2. The entire system is contained on a moveable trolley having dimensions 1.5 m × 1 m × 0.7 m and its operation and control (up to the distance of 25 m) are facilitated through optically isolated handheld remote console. The overall compactness of this system provides minimum proximity to small as well as large samples for irradiation. The major intended application objective of this high neutron yield dense plasma focus device development is to explore the feasibility of active neutron interrogation experiments by utilization of intense pulsed neutron sources.

: Particle-beam diagnostic tools have been developed to study the particle beams generated by a dense plasma focus device (DPF). These tools include an ion Faraday cup, solid state nuclear track detectors (SSNTD), electron beam Rogowski coils, an electron beam Faraday cup, and an electron beam magnetic spectrometer. These tools (excepting the SSNTD) all have a bandwidth of greater than 100 MHz and experimental tests of these devices are consistent with theory. The SSNTD have been applied in a unique way to study deuteron beams of high fluence ( 10 to the 15th power/sq cm) generated by the DPF and the preliminary results are consistent with the neutron yield of the DPF using a beam-target model for neutron generation. Electron and ion energy spectras of the accelerated electron and ion beams have been measured using the above tools and it is found that the number of particles per unit energy obey a power law with particle energy for both types of particles. The exponent of this power law is roughly the same for both types of particles and varies between -3.3 and -4.0. Parallel plate coupling between the DPF device and the capacitor bank and an 80 kV trigger pulse with a rise time of less than 5 ns on the mainbank spark gaps appear to result in superior DPF performance in terms of neutron yield when compared with other DPF devices of the same mainbank current or bank energy. The application of the results of this research to opening switch technology is discussed.

A new low energy (1.5 kJ) Mather-type dense plasma focus, called Sahand University of Technology Dense Plasma Focus (SUT-DPF) device has been designed, constructed and operated. The paper reports on the preliminary results with argon as filling gas. A Rogowski coil has been used to measure the experimental discharge current. The current signal contains a set of data from physical processes in the device as well as discharge current characteristics. The device circuit parameters were calculated using the short-circuit test. In a typical discharge experiment, these values were obtained: the discharge period was 15.4 ± 0.1 μs, the discharge current 100.8 ± 0.7 kA, the total inductance of the device 197 ± 3 nH and electrical resistance of circuit 11.3 ± 1 mΩ. The Rogowski coil sensitivity was obtained 49.65 ± 0.3 kA/V. A resistive voltage divider was also used to measure the transient voltage across the plasma. The experimental results showed that the pinch time at a constant pressure of the argon gas, decreased by increasing the charging voltage. The optimum pressure for 5, 6.5 and 7.5 kV obtained 0.75, 1 and 1.5 mbar, respectively.

On the structural, morphological and electrical properties of tantalum oxy nitride thin films by varying oxygen percentage in reactive gases plasma