A5020309922- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Vacuum and Plasma Arcs
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Ion-surface interactions and analysis
- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Electrical Fault Detection and Protection
- Pulsed Power Technology Applications
- Electrostatic Discharge in Electronics
- High voltage insulation and dielectric phenomena
- Welding Techniques and Residual Stresses
- Laser-Matter Interactions and Applications
- Diamond and Carbon-based Materials Research
- Electrical Contact Performance and Analysis
- Silicon Carbide Semiconductor Technologies
- Smart Grid Security and Resilience
- Gyrotron and Vacuum Electronics Research
- Radiation Effects in Electronics
- Radiation Detection and Scintillator Technologies
- Ionosphere and magnetosphere dynamics
- Particle Detector Development and Performance
- Thermal Analysis in Power Transmission
- Radiation Therapy and Dosimetry
ETH Zurich
2020-2024
United States Naval Research Laboratory
2018-2022
École Polytechnique Fédérale de Lausanne
2022
Naval Research Laboratory Plasma Physics Division
2020
Cornell University
2015-2018
Los Alamos National Laboratory
2018
Abstract CO2 has emerged as a leading candidate in the search for more environmentally friendly alternative to SF6. In high-voltage circuit breakers, where gas serves both gaseous insulation and switching medium, commercially available solutions use either alone or primary component of mixture. order breakers provide performance necessary support growing energy demands, thorough understanding transient arc properties during current interruption process is urgently needed. To these efforts,...
Z-pinch experiments with a hybrid configuration of deuterium gas puff have been carried out on the HAWK (NRL, Washington, DC) and GIT-12 (IHCE, Tomsk) pulsed power generators at 0.7 MA 3 currents, respectively. On GIT-12, neutron yields reached an average value 2 × 1012 neutrons, deuterons were accelerated up to energy 30 MeV. This was 50 times ion provided by generator driving voltage 0.6 MV highest observed in z-pinches dense plasma foci. To confirm these unique results independently...
Voltage–current characteristics of free burning arcs in SF6 and air have been known for decades. As the demand an SF6-free solution is increasing, there accompanying need to determine arc parameters alternative gases. An unblown experiment has established voltage–current gases, which not yet thoroughly studied. In this experiment, measurements were performed a number gases under consideration alternatives, including CO2 mixtures CO2/O2 with without C4F7N or C5F10O additives at concentrations...
We describe a series of experiments performed to study the shock structure generated during implosion gas-puff Z-pinch. The Z-pinch is produced by double-annular with center jet driven Cornell University's COBRA generator operating 1 MA, 200 ns current pulse. Using 532 nm laser interferometry and 100 MHz multi-frame cameras, observed form early in implosion. appears be created layer at outer radius imploding plasma which acts as piston moving inward several hundred km s−1. dynamics its...
We have shown that the Zeeman splitting of sodium (Na) D-lines at 5890 Å and 5896 can be used to measure magnetic field produced by current flowing in an exploding wire prior explosion. After explosion, lines question are either not visible strong continuum from plasma, or too broad methods discussed this paper. determined fields range 10-20 T, which lies between small Paschen-Back regimes for Na D-lines, over a period about 70 ns on 10 kA peak machine. The source is evaporated drops water...
This contribution will present thermal current interruption measurements performed in pure CO2 with a puffer circuit-breaker test device and establish statistical method to assess the reignition probability as function of prospective slope. Its efficacy be demonstrated limit scaling respect pressure buildup inside device. A separate apply these methods evaluate influence fluorinated additives on switching performance.
We have shown that Zeeman splitting of the sodium (Na) D-lines at 5890 and 5896 Å can be used to measure magnetic field (B-field) produced in high current pulsed power experiments. measured B-field next a return conductor hybrid X-pinch experiment near peak about 500 kA. Na is deposited on then desorbed excited by radiation from X-pinch. The D-line emission spectrum implies B-fields 20 T with post 4 mm diameter or up 120 wire 0.455 diameter. These measurements were consistent lower than...
Cylindrical reflex triodes (CRTs) driven by a pulsed power generator can produce relatively low-endpoint X-ray spectra (~250 keV) that be suitable for certain radiation-matter interaction studies. CRTs have several advantages over other triode configurations, the most significant being ability to operate multiple concentric CRTs, connected either in parallel or series. Such configurations result increased output without increasing endpoint changing pulsed-power generator. This article...
This contribution aims to compare the thermal interruption performance of pure CO2with a mixture CO2/C4F7N. Measurements primarily show higher interrupting capability for amixture with C4F7N. Detailed analysis shows distinct difference in failure mechanism which forCO2/C4F7N is and CO2 mostly “hot dielectric” failure. The failuremechanism relevant test duties most severe TRV. influence ablated nozzlematerial on process can be ruled out.
Ar gas puff z-pinch experiments were conducted on the 0.9-MA, 200-ns COBRA generator at Cornell University. In experiments, a triple-nozzle valve was used to produce load with concentric outer and inner puffs central jet. We planer laser-induced fluorescence measure initial profile of load, two four-frame 4-ns gated extreme ultraviolet cameras image imploding plasma, filtered photoconducting diamond detectors X-ray output. have observed shock heating and/or photoionization dense center jet...
Abstract In recent years, significant achievements have been made with respect to the development of SF 6 -free gas insulated substations (GIS). parallel, interest in installing GIS by utilities increased steadily and tenders for new or upgrades, which regularly also include alternative technologies. The excellent performance was unequivocally accepted all vendors users so that community became used single technology solutions. This is no longer case mixtures, multiple technological...
A free-burning arc experiment was performed in a gas mixture composed of CO2/O2/C5F10O (85%/10%/5%). An optical emission spectroscopy (OES) diagnostic developed to obtain spatially resolved spectra at high frame rate. Spectral measurements are compared with simulated estimate parameters including temperature and composition. These techniques used characterize the its associated electrode jets over range conditions, order study influence ablated Cu/W on characteristics. The observed indicate...
The Aerogel Cherenkov Detector for Cygnus (ACD/C) is a time-dependent, x-ray spectral detector that uses SiO2 aerogels spanning an index of refraction (n = 1.02-1.07) corresponding to 1.1-2.3 MeV energy threshold. ACD/C was developed pulsed power sources like located at the Nevada National Site and Mercury Naval Research Laboratory (NRL). Aerogels sit between measurement capabilities gas (>2 MeV) solids such as fused silica (>0.3 MeV). aluminum converter Compton scatter incoming x-rays...
We present experiments performed on the 1 MA COBRA generator using a low density, annular, gas-puff z-pinch implosion as an opening switch to rapidly transfer current pulse into single metal wire axis. This axial configuration was studied for its promise and means of enhancing x-ray output wire. demonstrate that can be switched from plasma wire, timing controlled by plenum backing pressure. X-ray detector measurements indicate pressure Kr or Xe shots with copper this offer significant...
An experimental campaign was recently completed at the U.S. Naval Research Laboratory's Mercury pulsed-power facility, where feasibility of using a 5 MV inductive voltage adder (IVA) as pulsed photoneutron source studied. In these experiments, large-area bremsstrahlung diode fielded on accelerator, producing an intense, x-ray beam, which generated photoneutrons when striking appropriate target. This paper reports simulations that were performed to study production electron beam in diode, and...
The 670 kA Hawk pulsed power generator at NRL has been configured as a fast (1.2 μs rise time), high inductance (607 nH) driver for dynamic dense plasma focus (DPF) load in order to create testbed the study of charged particle acceleration mechanisms imploding plasmas. current pulse is initiated deuterium injected radially by three Marshall guns. This accelerated through coaxial region, and pinches onto neutral axially gas-puff valve. Promising experimental results along with recent...
Abstract A detailed study of the evolution transient arc properties in SF6 alternative gas mixtures was carried out on an experimental puffer circuit breaker. Thermal interruption tests were performed several CO2-based under short-line fault-like current and voltage stresses, with test-device providing a similar environment performance to commercial The time-evolution including radius, temperature, electron density investigated using high speed imaging optical emission spectroscopy...
The Naval Research Laboratory's Hawk pulsed power generator is being used to drive a dense plasma focus (DPF) in order study the phenomenon of charged particle acceleration imploding plasmas. fast rise time, 1.2 μS, and high inductance, 607 nH, 220 kJ, 0.65 MA peak current Marx are unusual compared typical DPF driver parameters. In addition electrical parameters, local or gas injection initialize DPF, rather than more traditional static fill gas. A suite diagnostics development benchmark...
Charged particle acceleration has been investigated in a dense plasma focus (DPF) driven by the Hawk pulsed-power generator at Naval Research Laboratory. Neutron yields of over <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$5.0\times 10^{10}$</tex> have measured peak current xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{I}=670\text{kA}$</tex> ) significantly above yield expected this based on purely I <sup...