scholarly journals Time-resolved hard X-ray emission from a small plasma focus

1995 ◽  
Vol 13 (1) ◽  
pp. 129-134 ◽  
Author(s):  
S.P. Moo ◽  
C.S. Wong
Keyword(s):  
Experimental Study ◽  
Plasma Focus ◽  
Anode Voltage ◽  
Plastic Scintillator ◽  
Temporal Evolution ◽  
Voltage Divider ◽  
X Rays ◽  
Time Resolved ◽  
X Ray ◽  
Second Period

Some results of an experimental study of the hard X rays emitted from a 15-kV, 3-kJ plasma focus operated in argon are reported. The temporal evolution of the hard X rays detected by a plastic scintillator-photomultiplier detector and the voltage across the focus tube measured by a resistive voltage divider are simultaneously recorded on a two-channel digitizing oscilloscope. Metal absorbers of various thicknesses are used to provide some indications of the energies of the X rays. When the time delay of the detector system with respect to the anode voltage is taken into account, the hard X rays are observed to be emitted about 15 ns before the peak of the anode voltage and last for about 100 ns. There are two periods of emission, the X rays emitted in the first period being more intense, more energetic, and more directional than the X rays emitted in the second period. The X rays are attributed to the bombardment of the anode by energetic electrons generated in the pinch and the disruption phases of the focus.

scholarly journals Measurements of fast electron beams and soft X-ray emission from plasma-focus experiments

Nukleonika ◽  
2016 ◽  
Vol 61 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Władysław Surała ◽  
Marek J. Sadowski ◽  
Roch Kwiatkowski ◽  
Lech Jakubowski ◽  
Jarosław Żebrowski
Keyword(s):  
Plasma Focus ◽  
Fast Electron ◽  
Hot Spots ◽  
Electron Beams ◽  
Experimental Studies ◽  
Neutron Counter ◽  
X Rays ◽  
Strong Electron ◽  
Time Resolved ◽  
X Ray

Abstract 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 modified 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 filling, many strong electron signals were recorded in all the measuring channels. Those signals were well correlated with the first 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 confirmed 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 films, showed the appearance of some filamentary 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.

Time resolved X-ray photography of a dense plasma focus

1977 ◽  
Vol 55 (3) ◽  
pp. 194-197 ◽  
Author(s):  
J. C. Burnett ◽  
J. Meyer ◽  
G. Rankin
Keyword(s):  
Plasma Focus ◽  
Dense Plasma ◽  
Dense Plasma Focus ◽  
X Rays ◽  
Temporal Development ◽  
Resolution Time ◽  
Time Resolved ◽  
X Ray ◽  
Hot Plasma ◽  
Schlieren Photography

The temporal development of the hot plasma in a dense plasma focus is studied by X-ray streak photography of ~2 ns resolution time. It is shown that initially a uniform X-ray emitting pinch plasma is formed which subsequently cools down until X-ray emission stops after ~50 ns. At a time of around 100 ns after initial X-ray emission coinciding with the break-up time of the pinch a second burst of X-rays is observed coming from small localized regions. The observations are compared with results obtained from time-resolved shadow and schlieren photography of a similar dense focus discharge (Peacock, Hobby, and Morgan).

Structural dynamics of PZT thin films at the nanoscale

2005 ◽  
Vol 902 ◽  
Author(s):  
Alexei Grigoriev ◽  
Dal-Hyun Do ◽  
Dong Min Kim ◽  
Chang-Beom Eom ◽  
Bernhard Adams ◽  
...  
Keyword(s):  
Crystal Lattice ◽  
Lattice Distortion ◽  
Piezoelectric Effect ◽  
Polarization Switching ◽  
X Rays ◽  
Time Resolved ◽  
X Ray ◽  
Converse Piezoelectric Effect ◽  
Ferroelectric Capacitors ◽  
Crystal Lattice Distortion

AbstractWhen an electric field is applied to a ferroelectric the crystal lattice spacing changes as a result of the converse piezoelectric effect. Although the piezoelectric effect and polarization switching have been investigated for decades there has been no direct nanosecond-scale visualization of these phenomena in solid crystalline ferroelectrics. Synchrotron x-rays allow the polarization switching and the crystal lattice distortion to be visualized in space and time on scales of hundreds of nanometers and hundreds of picoseconds using ultrafast x-ray microdiffraction. Here we report the polarization switching visualization and polarization domain wall velocities for Pb(Zr0.45Ti0.55)O3 thin film ferroelectric capacitors studied by time-resolved x-ray microdiffraction.

scholarly journals Theoretical and experimental study of inertial gases admixtures influence on the hard x-ray emission of plasma focus

2015 ◽  
Vol 653 ◽  
pp. 012023
Author(s):  
A K Dulatov ◽  
B D Lemeshko ◽  
Yu V Mikhailov ◽  
I A Prokuratov ◽  
A N Selifanov
Keyword(s):  
Experimental Study ◽  
Plasma Focus ◽  
X Ray

SOFT X-RAY EMISSION IN THE (1.0–1.5 KEV) WINDOW WITH NITROGEN FILLING IN A LOW ENERGY PLASMA FOCUS

2002 ◽  
Vol 16 (09) ◽  
pp. 309-318 ◽  
Author(s):  
M. SHAFIQ ◽  
SARTAJ ◽  
S. HUSSAIN ◽  
M. SHARIF ◽  
S. AHMAD ◽  
...  
Keyword(s):  
Plasma Focus ◽  
Pressure Range ◽  
Filling Pressure ◽  
Pinhole Camera ◽  
Low Energy ◽  
X Rays ◽  
System Efficiency ◽  
Current Sheath ◽  
Pin Diodes ◽  
X Ray

A study of soft X-ray emission in the 1.0–1.5 keV energy range from a low energy (1.15 kJ) plasma focus has been conducted. X-rays are detected with the combination of Quantrad Si PIN-diodes masked with Al (50 μm), Mg (100 μm) and Ni (17.5 μm) filters and with a pinhole camera. The X-ray flux is found to be measurable within the pressure range of 0.1–1.0 mbar nitrogen. In the 1.0–1.3 keV and 1.0–1.5 keV windows, the X-ray yield in 4π-geometry is 1.03 J and 14.0-J, respectively, at a filling pressure of 0.25 mbar and the corresponding efficiencies are 0.04% and 1.22%. The total X-ray emission in 4π-geometry is 21.8 J, which corresponds to the system efficiency of about 1.9%. The X-ray emission is found dominantly as a result of the interaction of energetic electrons in the current sheath with the anode tip. Images recorded by the pinhole camera confirm the emission of X-rays from the tip of the anode.

scholarly journals Time-Resolved Macromolecular Crystallography at Pulsed X-ray Sources

2019 ◽  
Vol 20 (6) ◽  
pp. 1401 ◽  
Author(s):  
Marius Schmidt
Keyword(s):  
Structural Biology ◽  
Free Electron ◽  
Reaction Dynamics ◽  
X Rays ◽  
Free Electron Lasers ◽  
Macromolecular Crystallography ◽  
Time Resolved ◽  
X Ray ◽  
Methodological Aspects

The focus of structural biology is shifting from the determination of static structures to the investigation of dynamical aspects of macromolecular function. With time-resolved macromolecular crystallography (TRX), intermediates that form and decay during the macromolecular reaction can be investigated, as well as their reaction dynamics. Time-resolved crystallographic methods were initially developed at synchrotrons. However, about a decade ago, extremely brilliant, femtosecond-pulsed X-ray sources, the free electron lasers for hard X-rays, became available to a wider community. TRX is now possible with femtosecond temporal resolution. This review provides an overview of methodological aspects of TRX, and at the same time, aims to outline the frontiers of this method at modern pulsed X-ray sources.

scholarly journals Observation and interpretation of neutron origin prior to hard X rays and pinch in a hundred joules plasma focus device

2017 ◽  
Vol 35 (4) ◽  
pp. 656-662 ◽  
Author(s):  
J. Jain ◽  
J. Moreno ◽  
D. Morales ◽  
S. Davis ◽  
B. Bora ◽  
...  
Keyword(s):  
Plasma Focus ◽  
Time History ◽  
Temporal Correlation ◽  
Axial Direction ◽  
Plasma Focus Device ◽  
X Rays ◽  
X Ray ◽  
History Analysis ◽  
Time Of Origin ◽  
Qualitative Discussion

AbstractThe temporal correlation between neutron and hard X-ray (HXR) emissions from a hundred joules plasma focus device (PF-400J) was studied. A method, time history analysis, to estimate the time of origin of neutrons with respect to HXRs is applied. In most of the discharges, it was found that neutrons are originated before HXRs in the axial direction and after HXRs in the radial direction. In some discharges, the time difference between HXRs and neutrons origin was found large enough, so that it can be interpreted that those neutrons would have been originated before the pinch. A qualitative discussion is conjectured to explain the experimental observations.

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