Modelling of a nitrogen x-ray laser pumped by capillary discharge

Open Physics ◽  
2005 ◽  
Vol 3 (4) ◽  
Author(s):  
Pavel Vrba ◽  
Miroslava Vrbová ◽  
Nadezhda Bobrova ◽  
Pavel Sasorov
Keyword(s):  
Computer Modelling ◽  
Energy Levels ◽  
Initial Pressure ◽  
Gain Factor ◽  
Time Interval ◽  
Discharge System ◽  
Peak Current ◽  
X Ray ◽  
Capillary Radius ◽  
Nitrogen Ions

AbstractWe performed computer modelling of a fast electrical discharge in a nitrogen-filled alumina capillary in order to discover discharge system parameters that may lead to efficient recombination pumping of soft X-ray laser with active medium created by H-like nitrogen ions. The space-time dependences of pinch plasma quantities were found by means of a one-dimensional MHD code. Time dependences of populations of all ionisation states and populations of selected energy levels of lithium-, helium- and hydrogen-like nitrogen ions were evaluated using the FLY code as a post-processor. The population inversion was found at the quantum transition corresponding to the Balmer α-line of N6+ ions and the resulting gain factor was evaluated for different capillary radii, initial pressure, electric current peaks and periods. A gain factor of 1 cm−1 spanning the time interval of 1 ns was found for an optimised arrangement with capillary radius 1.5 mm, peak current 50 kA, quarter period 40 ns and filling gas pressure 0.5 kPa. It is pointed out that even higher values of the gain factor may be achieved with thinner capillaries and shorter current pulses, e.g. a gain factor of 6 cm−1 is achieved if the capillary radius is 0.5 mm, peak current 56 kA, quarter period 15 ns, and filling nitrogen pressure 3.9 kPa.

scholarly journals CN Com: a Typical RS Canum Venaticorum Star

1995 ◽  
Vol 151 ◽  
pp. 106-107
Author(s):  
G.A. Richter ◽  
J. Greiner
Keyword(s):  
Time Interval ◽  
Optical Counterpart ◽  
X Ray ◽  
Sky Survey ◽  
Error Circle

CN Com = CSV 6907 was dicovered by Romano (1958). First we note that the GCVS (and Simbad) coordinates are wrong by ≈2′. Using the finding chart of Romano (1958) and the APM data (digitized POSS), the correct coordinates of CN Com are R.A.(2000.0) = 12h19m47s.0, DEC(2000.0) = +16°30′50″.CN Com is only 8″ distant from the ROSAT X-ray source RX J1219.7+1630 detected during the All-Sky-Survey at a PSPC countrate of 0.022 cts/s. Due to the positional proximity and the absence of other optical objects brighter than 20rmm within the about 30″ error circle, CN Com is very probably the optical counterpart of RX J1219.7+1630.CN Com was investigated on some 600 photographic plates (Sonneberg astrographs 400/1600 mm and 400/2000 mm) of the fields 26 Com and 5 Com, covering the time interval from 1962 to 1994 (with only a very few plates from the years 1967-1974).

scholarly journals Transient Formation of Super-Explosives under High Pressure for Fast Ignition

2008 ◽  
Vol 63 (1-2) ◽  
pp. 35-41 ◽  
Author(s):  
Friedwardt Winterberg
Keyword(s):  
High Pressure ◽  
Energy Levels ◽  
Strong Shock ◽  
Dense Matter ◽  
Fast Ignition ◽  
Molecular Configuration ◽  
Exploding Wire ◽  
X Ray ◽  
Wire Arrays ◽  
Thermonuclear Target

Dense matter, if put under high pressure, can undergo a transformation from an atomic to a molecular configuration, where the electron orbits go into lower energy levels. If the rise in pressure is very sudden, for example by a strong shock wave, the electrons change their orbits rapidly under the emission of photons, which for more than 100 Mbar can reach keV energies. With the opacity of dense matter going in proportion to the density, the photons can be efficiently released from the surface of the compressed matter by a rarefaction wave. The so produced X-ray photons can be used for the fast ignition of a thermonuclear target.The proposed mechanism may be also responsible for the large keV X-ray bursts observed in exploding wire arrays, which can not be explained by conversion of kinetic into thermal energy.

scholarly journals X-ray laser lines in nickel-like erbium

2016 ◽  
Vol 94 (8) ◽  
pp. 705-711
Author(s):  
Wessameldin S. Abdelaziz
Keyword(s):  
Ionization Potential ◽  
Excited States ◽  
Ground State ◽  
Energy Levels ◽  
Single Electron ◽  
Electron Densities ◽  
X Ray ◽  
Electron Excited States

Energy levels of 249 excited levels in nickel-like erbium are calculated using the 3s23p63d10 as a ground state and the single electron excited states from n = 3 to n = 4, 5 orbitals, calculations have been performed using FAC code (Gu. Astrophys. J. 582, 1241 (2003). doi:10.1086/344745 ). The populations are calculated over electron densities from 1020 to 1023 cm−3 and electron temperatures 1/2, 3/4 of the ionization potential of Ni-like Er. The gain coefficients of the transitions are calculated.

about chemical bonding and molecular structure. This information can be used to detect th e types of organic materials present on the surface. 4.3.2.2. Raman spectroscopy (RS) [7, 8] It is used to examine the energy levels of molecules that cannot be well character-ized via infrared spectroscopy. Th e two techniques, however, are complimentary. In the RS, a sample is irradiated with a strong monochromatic light source (usu-ally a laser). Most of the radiation will scatter or "reflect off' the sample at the same energy as the incoming laser radiation. However, a small amount will scat-ter from the sample at a wavelength slightly shifted from the original wavelength. It is possible to study the molecular structure or determine the chemical identity of the sample. It is quite straightforward to identify compounds by spectral library search. Due to extensive library spectral information, the unique spectral finger-print of every compound, and the ease with which such analyses can be per-formed, the RS is a very useful technique for various applications. An important application of the RS is the rapid, nondestructive characterization of diamond, diamond-like, and amorphous-carbon films. 4.3.2.3. Scanning electron microscopy (SEM) / energy dispersive X-ra y analysis (EDX) [7, 8] The SEM produce s detailed photographs that provide important information about the surface structure and morphology of almost any kind of sample. Image analy-sis is often the first and most important step in problem solving and failure analy-sis. With SEM, a focused beam of high-energy electrons is scanned over the sur-face of a material, causing a variety of signals, secondary electrons, X-rays, photons, etc. - each of which may be used to characterize the material with re-spect to specific properties . The signals are used to modulate the brightness on a CRT display, thereb y providing a high-resolution map of the selected material property. It is a surface imaging technique, but with Energy Dispersive X-ray (EDX) it can identify elements in the near-surface region. This technique is most useful for imaging particles. 4.3.2.4. X-ray fluorescence (XRF) [7, 8] Incident X-rays are used to excite surface atoms. The atoms relax through the emission of an X-ray with energy characteristic of the parent atoms and the inten-sity proportional to the amount of the element present. It is a bulk or "total mate-rials" characterization technique for rapid, simultaneous, and nondestructive analysis of elements having an atomic number higher than that of boron. Tradi-tional bulk analysis applications include identifying metals and alloys, detecting trace elements in liquids, and identifying residues and deposits. 4.3.2.5. Total-reflection X-ray fluorescence (TXRF) [7, 8] It is a special XRF technique that provides extremely sensitive measures of the elements present in a material's outer surface. Applications include searching for metal contamination in thin films on silicon wafers and detecting picogram-levels o f arsenic, lead, mercury and cadmium on hazardous, chemical fume hoods.

2003 ◽  
pp. 43-45
Keyword(s):  
Molecular Structure ◽  
Energy Levels ◽  
Monochromatic Light ◽  
Surface Region ◽  
Carbon Films ◽  
Energy Dispersive ◽  
X Rays ◽  
Bulk Analysis ◽  
X Ray ◽  
High Resolution Map

scholarly journals Typhoid ileal perforation in Shisong, Northwestern Cameroon

2019 ◽  
pp. 08-24
Author(s):  
Bamidele Johnson Alegbeleye
Keyword(s):  
Computer Software ◽  
Operation Time ◽  
Time Interval ◽  
Female Ratio ◽  
Ileal Perforation ◽  
X Ray ◽  
Dismal Prognosis ◽  
Northwestern Region ◽  
Male To Female ◽  
Prompt Diagnosis

Background: The study aims to provide an overview of the spectrum of perforated typhoid fever cases and their outcome that were managed in resource constrained rural mission hospital, Northwestern of Cameroon. Methods: This was a retrospective observational study which was conducted in St Elizabeth Catholic General Hospital, Shisong, Northwestern region of Cameroon over a two year period covering January 2016 and December 2018. The patients included were those admitted and diagnosed of typhoid ileal perforation. Data collected were analyzed using SPSS computer software version 22. Results: During the study period, thirty-eight patients underwent surgery for typhoid ileal perforation. They included 26 (68.43%) males and 12 (31.57%) females with Male to Female ratio of 2.2: 1. Sixty -five percent of cases occurred between the months of July and September. The most common presentations were with abdominal pains (92.11%), and abdominal distention (92.11%). X-ray abdomen revealed pneumo -peritoneum in 26 (68.4%) cases, while ultrasound detected free peritoneal collection in 34 (90%) cases. Perforations were surgically treated depending upon the number of perforations, general health status of patient and degree of fecal contamination. Perforated typhoid still carries dismal prognosis. The mortality was associated with duration of delay in obtaining blood pre - operatively for patients requiring transfusion (p=0.018) and duration of presentation to operation time interval (p=0.026). Conclusion: Typhoid intestinal perforation is still endemic in our setting with dismal prognosis. Urgent public health concerted effort is required with emphasis on preventive measures such as safe drinking water, appropriate sewage disposal, and typhoid vaccination. Educating the populace on early and prompt diagnosis, adequate resuscitation as well as early surgery in patients with typhoid ileal perforation to keep the mortality low.

Characterization of Melting and Solidification Phenomena in Electromagnetic Punching of Aluminum Tubes

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
De Waele Wim ◽  
Faes Koen ◽  
Van Haver Wim
Keyword(s):  
Plastic Deformation ◽  
Energy Levels ◽  
High Energy ◽  
Effect Of Temperature ◽  
Fracture Mechanisms ◽  
Time Interval ◽  
Short Time Interval ◽  
Total Width ◽  
Premature Failure ◽  
Charging Energy

Electromagnetic punching of tubular products is considered to be a promising innovative perforating process. The required punching energy decreases when using high velocities. Also, less tools are required when compared to conventional mechanical punching. However, the increase in punching speed can involve new strain and fracture mechanisms which are characteristic of the dynamic loading. In high energy rate forming processes the effect of temperature versus time gradient on the material properties becomes important due to the heat accumulated from plastic deformation and friction. The deformation induced heating will promote strain localization in it, possibly degrade its formability and cause premature failure in the regions of high localized strain. The feasibility of the electromagnetic pulse forming process for punching holes in aluminum cylindrical specimens has been investigated on an experimental trial-and-error basis. Experiments were performed using a Pulsar system (model 50/25) with a maximum charging energy of 50 kJ and a discharge circuit frequency of 14 kHz. Microscopic and metallographic inspection of the punched workpieces, together with hardness measurements, was performed to critically evaluate the quality of the cuts. It was observed that damage occurred at part of the edge of the punched hole during some of the perforation experiments. It was evidenced that in most workpieces, especially those performed at higher charging energy levels, a considerably high temperature must have been reached in the regions near the punched hole. The aluminum in this region was assumed to have melted and resolidified. These assumptions were affirmed by the following observations. Microscopic-size precipitates present in the unaffected base metal microstructure, had completely dissolved in that region; shrinkage cavities and dendrite rich regions were clearly visible. Next to this region, a heat affected zone was present where the grain boundaries had partially melted and precipitates partially disappeared. Considerably high temperatures, in the order of 520 to 660 °C, were reached in the regions around the punched holes, leading to melting and resolidification of the material. The total width of the thermally affected regions appeared to be larger at higher energy levels. The combination of heat generated by ohmic heating and by plastic deformation in a very short time interval is the most probable cause of the high peak temperatures that have occurred during the electromagnetic punching process.

EFFECT OF ION-ENERGY ON THE PROPERTIES OF AMORPHOUS GaN FILMS PRODUCED BY ION-ASSISTED DEPOSITION

2001 ◽  
Vol 15 (28n29) ◽  
pp. 1355-1360 ◽  
Author(s):  
UDAY LANKE ◽  
ANNETTE KOO ◽  
SIMON GRANVILLE ◽  
JOE TRODAHL ◽  
ANDREAS MARKWITZ ◽  
...  
Keyword(s):  
Room Temperature ◽  
Single Phase ◽  
Thermal Evaporation ◽  
Ion Beam ◽  
Atomic Ratio ◽  
Nuclear Reaction Analysis ◽  
Ion Energy ◽  
X Ray ◽  
Nitrogen Ions ◽  
Nitrogen Ion

Amorphous GaN films were deposited on various substrates viz. Si (100), quartz, glass, Al, stainless steel and glassy carbon by thermal evaporation of gallium in the presence of energetic nitrogen ions from a Kaufman source. The films were deposited at room temperature and 5 × 10-4 mbar nitrogen partial pressure. The effect of a low energy nitrogen ion beam during the synthesis of films was investigated for energies 40 eV and 90 eV. The N:Ga atomic ratio, bonding state, microstructure, surface morphology, and electrical properties of the deposited a-GaN films were studied by different characterisation techniques. The films are found to be X-ray amorphous in nature, which is confirmed by Raman spectroscopy. Rutherford Backscattering Spectroscopy (RBS) and Nuclear Reaction Analysis (NRA) indicate the N:Ga atomic ratio in the films. The 400-750 eV energy range is thought to be optimal for the production of single-phase amorphous GaN . The effect of ion-energy on optical, Raman, and electrical conductivity measurements of the films is also presented.

Fabrication and Characterization of LaOBr:Eu3+ Luminescent Nanofibers

2015 ◽  
Vol 1118 ◽  
pp. 92-96 ◽  
Author(s):  
Wen Sheng Yu ◽  
Chun Song Zhu ◽  
Qian Li Ma ◽  
Wen Wen Ma ◽  
Jin Xian Wang ◽  
...  
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Fluorescence Spectra ◽  
Energy Levels ◽  
Energy Dispersion Spectroscopy ◽  
Spectra Analysis ◽  
Red Emission ◽  
X Ray ◽  
Double Crucible ◽  
Fabrication And Characterization

LaOBr:Eu3+ nanofibers have been successfully fabricated by electrospinning combined with a double-crucible bromination technique using cetyltrimethylammonium bromide (CTAB) powers as bromine source. The products were characterized in detail by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS) and fluorescence spectroscopy. The results indicate that LaOBr:Eu3+ luminescent nanofibers are tetragonal in structure with space group P4/nmm. The diameter of LaOBr:Eu3+ luminescent nanofibers is ca. 150 nm. Fluorescence spectra analysis shows that under the excitation of 302-nm ultraviolet light, the LaOBr:Eu3+ nanofibers exhibit red emission centering at 620 nm, which is attributed to the 5D0→7F2 energy levels transitions of Eu3+ ions.

Observations of Lattice Distortions near Silicon Surfaces Implanted with Low-Energy Nitrogen Ions by Reflection X-ray Topography

2005 ◽  
Vol 44 (8) ◽  
pp. 6277-6282
Author(s):  
Koji Futagami ◽  
Taichiro Fukumori ◽  
Noboru Tsukuda ◽  
Kiyohiro Kuroki
Keyword(s):  
Low Energy ◽  
Silicon Surfaces ◽  
X Ray ◽  
Nitrogen Ions ◽  
Lattice Distortions

scholarly journals Gaseous combustion at high pressures. Part IV.—The influence of varying initial pressures upon the rate of pressure development and the activation of nitrogen in carbon monoxide-air explosions

1924 ◽  
Vol 105 (732) ◽  
pp. 406-433
Keyword(s):  
Carbon Monoxide ◽  
High Pressures ◽  
Vibrational Energy ◽  
Initial Pressure ◽  
Maximum Pressure ◽  
Time Interval ◽  
Pressure Development ◽  
The One ◽  
Air Explosion ◽  
Energy Absorbing

In the previous paper of this series it was shown :— (1) that when nitrogen is added as a diluent to a mixture of 2CO+O 2 undergoing combustion in a bomb at an initial pressure of 50 atmospheres, it exerts a peculiar energy-absorbing influence upon the system, far beyond that of other diatomic gases, or of argon; (2) that by virtue of such influence, it retards the attainment of maximum pressure in a much greater degree than can be accounted for on the supposition of its acting merely as a diatomic diluent; (3) that the energy so absorbed by the nitrogen during the combustion period, which extends right up to the attainment of maximum pressure, is slowly liberated thereafter as the system cools down ; and that consequently the rate of cooling is greatly retarded for a considerable time interval after the attainment of maximum pressure; (4) that there is no such energy-absorbing effect ( i. e ., other than a purely "diluent" one) when nitrogen is present in a 2H 2 +O 2 mixture similarly undergoing combustion ; but that, on the contrary, the presence of hydrogen in a CO-air mixture undergoing combustion at such high pressures so strongly counteracts the said " energy-absorbing " influence of the nitrogen, that it must be excluded as far as possible from the system before any large nitrogen-effect can be observed. These facts were explained on the supposition that there is some constitutional correspondence between CO and N 2 molecules (whose densities are identical) whereby the vibrational energy (radiation) emitted when the one burns is of such a quality as can be readily absorbed by the other, the two thus acting in resonance. It was further supposed that, in consequence of such resonance, nitrogen becomes chemically " activated " when present during the combustion of carbon monoxide at such high pressures ; and in conformity with this supposition, it was shown that such "activated" nitrogen is able to combine with oxygen more readily than does nitrogen which has merely been raised to a correspondingly high temperature in a hydrogen-air explosion.

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