scholarly journals Changing mass liner system for generation of soft X rays

1997 ◽  
Vol 15 (1) ◽  
pp. 133-138 ◽  
Author(s):  
A.M. Buyko ◽  
O.M. Burenkov ◽  
V.K. Chernyshev ◽  
S.F. Garanin ◽  
S.D. Kuznetsov ◽  
...  
Keyword(s):  
Current Pulse ◽  
High Precision ◽  
X Rays ◽  
Stored Energy ◽  
Single Experiment ◽  
X Ray ◽  
Liner System ◽  
The Cost

Powerful pulse installations are usually used to produce large yields of X-ray radiation. With an increase of the stored energy up to 100 MJ, the costof a single experiment on these installations becomes comparable to the cost of a shot with explosive magnetic generators (EMG), according to expert estimates. The physical scheme of a device with a changeable mass liner forlarge soft X-ray (in the range of 0.3 to 0.5 keV) yields eneration is investigated. The scheme investigated is substantially free from difficulties connected with high precision liners and fast switches for current pulse sharpening.

scholarly journals X-Ray Analysis for Electron Beam Enhancement in the Plasma Focus Device*

1974 ◽  
Vol 18 ◽  
pp. 184-196 ◽  
Author(s):  
R. L. Gullickson ◽  
R. H. Barlett
Keyword(s):  
Electric Fields ◽  
Plasma Focus ◽  
Average Energy ◽  
High Energy ◽  
Plasma Focus Device ◽  
X Rays ◽  
Stored Energy ◽  
Power Law Distribution ◽  
X Ray ◽  
Thermoluminescent Dosimeters

AbstractThe plasma focus device, a form of linear pinch discharge, produces an intense x-ray and neutron (D2) burst from a magnetically heated dense plasma. Rapidly changing magnetic fields at pinch time generate large axial electric fields which accelerate electrons and ions. In the experiments reported here the x-ray production during the plasma pinch of a 96 kilojoule (at 20 kV) plasma focus device was measured.The purpose of these experiments was to evaluate the energy in accelerated electrons in the plasma focus device and to learn how to enhance these electron hursts. Well focused, megampere electron beams at a few hundred kilovolts, lasting less than 10 nanoseconds have applications in fusionable pellet heating experiments. (1) X-rays were monitored to evaluate these electron bursts using a defocusing bent crystal spectrometer, doubly diffused silicon (PIN) detectors, with Ross filters, thermoluminescent dosimeters (TLDs) with filters, and x-ray pinhole photography.Thermoluminescent dosimeters indicated maximum x-ray yields of 140 joules above 3 keV at 57.3 kilojoules stored energy (16 kV) for a conversion efficiency to x-rays of 0.2%. 40 joules are above 60 keV and 15 joules above 80 keV. The hard x-ray pulse typically rises in 3 ns and frequently has a pulse width less than 10 ns. The low energy x-ray spectrum consists almost entirely of lines from the high Z anode insert, and the high energy spectrum is characteristic of a nonthermal power law distribution with an exponent of 2.2 ± 0.8. Peak hard x-ray production is obtained at 1 torr deuterium in contrast to peak neutron production (3 x 1010) at 5 torr. The addition of argon reduces total x-ray yield and increases the relative fraction of soft x-rays.These measurements suggest that the plasma focus produces 1200 joules of electrons with an average energy of 150 keV, in 10 nanoseconds with a stored energy of 57.3 kilojoules. This is a power of 1.2 × 1011 watts and power density of 1.5 × 1013 watts cm−2.

scholarly journals High-Precision X-ray Total Scattering Measurements Using a High-Accuracy Detector System

2021 ◽  
Vol 7 (1) ◽  
pp. 2
Author(s):  
Kenichi Kato ◽  
Kazuya Shigeta
Keyword(s):  
High Precision ◽  
Dynamic Range ◽  
Atomic Displacement ◽  
High Accuracy ◽  
Detector System ◽  
Scattering Method ◽  
X Rays ◽  
Total Scattering ◽  
X Ray ◽  
Scattering Measurements

The total scattering method, which is based on measurements of both Bragg and diffuse scattering on an equal basis, has been still challenging even by means of synchrotron X-rays. This is because such measurements require a wide coverage in scattering vector Q, high Q resolution, and a wide dynamic range for X-ray detectors. There is a trade-off relationship between the coverage and resolution in Q, whereas the dynamic range is defined by differences in X-ray response between detector channels (X-ray response non-uniformity: XRNU). XRNU is one of the systematic errors for individual channels, while it appears to be a random error for different channels. In the present study, taking advantage of the randomness, the true sensitivity for each channel has been statistically estimated. Results indicate that the dynamic range of microstrip modules (MYTHEN, Dectris, Baden-Daettwil, Switzerland), which have been assembled for a total scattering measurement system (OHGI), has been successfully restored from 104 to 106. Furthermore, the correction algorithm has been optimized to increase time efficiencies. As a result, the correcting time has been reduced from half a day to half an hour, which enables on-demand correction for XRNU according to experimental settings. High-precision X-ray total scattering measurements, which has been achieved by a high-accuracy detector system, have demonstrated valence density studies from powder and PDF studies for atomic displacement parameters.

scholarly journals High Precision X-Ray Measurements

2019 ◽  
Vol 4 (2) ◽  
pp. 59 ◽  
Author(s):  
Alessandro Scordo
Keyword(s):  
High Precision ◽  
Human Life ◽  
Strong Impact ◽  
X Rays ◽  
X Ray

Since their discovery in 1895, the detection of X-rays has had a strong impact and various applications in several fields of science and human life [...]

Direct and indirect actions of radiation on viruses and enzymes

Parasitology ◽  
1944 ◽  
Vol 36 (1-2) ◽  
pp. 110-118 ◽  
Author(s):  
Douglas Lea ◽  
Kenneth M. Smith ◽  
Barbara Holmes ◽  
Roy Markham
Keyword(s):  
British Empire ◽  
X Rays ◽  
X Ray ◽  
Low Concentrations ◽  
Biochemical Laboratory ◽  
Γ Rays ◽  
High Concentrations ◽  
Concentrated Solution ◽  
The Cost ◽  
Indirect Action

1. The inactivation by γ-rays of tobacco mosaic virus is studied at various concentrations. It is found that the inactivation dose is independent of concentration at high concentrations, and at low concentrations also attains a constant, but lower, value. Over an intermediate range the inactivation dose increases with increase of concentration.2. These facts are explained on the basis that when irradiated dry or in concentrated solution the inactivation is direct and due to ionization produced inside the virus particle. At lower concentrations the inactivation is largely indirect and due to ionization of the water.3. Gelatin added to the solution protects the virus against the indirect action of radiation.4. Curves are given of the inactivation of dry preparations of ribonuclease and adenylpyro-phosphatase (myosin) by X-rays.5. It is shown that on the assumption that a single ionization in an enzyme molecule leads to its inactivation, measurement of the inactivation dose leads to a rough estimate of the molecular weight of the enzyme.6. There appears to be no fundamental difference in the mechanism of radiation-inactivation of viruses and enzymes.All irradiations were carried out at the Strangeways Laboratory. The virus was prepared and tested at the Plant Virus Station and the Molteno Institute. The enzymes were prepared and estimated at the Biochemical Laboratory. We are indebted to the British Empire Cancer Campaign for defraying the cost of the X-ray equipment at the Strangeways Laboratory.

Surface Finishing Method Using Plasma Chemical Vaporization Machining for Narrow Channel Walls of X-Ray Crystal Monochromators

2019 ◽  
Vol 13 (2) ◽  
pp. 246-253 ◽  
Author(s):  
Takashi Hirano ◽  
Yuki Morioka ◽  
Shotaro Matsumura ◽  
Yasuhisa Sano ◽  
Taito Osaka ◽  
...  
Keyword(s):  
High Precision ◽  
Atmospheric Pressure Plasma ◽  
Narrow Channel ◽  
Surface Finishing ◽  
Process Conditions ◽  
X Rays ◽  
Plasma Chemical ◽  
Etching Technique ◽  
X Ray ◽  
Surface Flatness

Channel-cut Si crystals are useful optical devices for providing monochromatic X-ray beams with extreme angular stability. Owing to difficulties in the high-precision surface finishing of narrow-channel inner walls of the crystals, typical channel-cut crystals have considerable residual subsurface crystal damage and/or roughness on their channel-wall reflection surfaces that decrease intensity and distort the wavefronts of the reflected X-rays. This paper proposes a high-precision surface finishing method for the narrow-channel inner walls based on plasma chemical vaporization machining, which is a local etching technique using atmospheric-pressure plasma. Cylinder- and nozzle-shaped electrodes were designed for channel widths of more than 5 and 3 mm, respectively. We optimized process conditions for each electrode using commercial Si wafers, and obtained a removal depth of 10 μm with a surface flatness and roughness of less than 1 μm and 1 nmRMS, respectively, which should allow the damaged layers to be fully removed while maintaining the wavefront of coherent X-rays.

THE DENSITOMETRIC RESPONSE OF THE HIGH SENSITIVE GAFCHROMIC FILM EXPOSED TO X-RAYS

2002 ◽  
Vol 02 (01) ◽  
pp. 29-36 ◽  
Author(s):  
D. O. ODERO
Keyword(s):  
Energy Dependence ◽  
High Precision ◽  
Optical Density ◽  
Irradiation Time ◽  
X Rays ◽  
X Ray ◽  
Post Irradiation ◽  
Gafchromic Film ◽  
Sensitivity Curves ◽  
Gafchromic Films

Tests have been performed on the high sensitive (HS) GAFChromic film to evaluate its densitometric response to external X-rays (photon beam). Several 2 cm by 2 cm pieces of HS and MD-55-2 GAFChromic films were prepared and irradiated for sensitivity comparison, and X-rays energy dependence study. The optical densities of three irradiated pieces of HS film were measured as a function of time to establish the time taken for the optical density to stabilize. The densitometric sensitivity curves comparison showed that the HS film is twice as sensitive as its predecessor, MD-55-2, more spatially uniform and dosimetric measurements can be made with high precision. Its sensitivity is independent of 6 MV and 15 MV X-ray beam energies and its optical density is stable after about 36 hours post-irradiation time.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

Chemical Species Identification in an SEM by Changes in Emitted X-Ray Energies

1974 ◽  
Vol 32 ◽  
pp. 570-571
Author(s):  
R. H. Duff
Keyword(s):  
Species Identification ◽  
Valence Electron ◽  
Chemical Species ◽  
X Rays ◽  
Chemical Bonds ◽  
Small Shift ◽  
X Ray ◽  
Electron Transitions ◽  
Peak Energy ◽  
Chemical Combination

A material irradiated with electrons emits x-rays having energies characteristic of the elements present. Chemical combination between elements results in a small shift of the peak energies of these characteristic x-rays because chemical bonds between different elements have different energies. The energy differences of the characteristic x-rays resulting from valence electron transitions can be used to identify the chemical species present and to obtain information about the chemical bond itself. Although these peak-energy shifts have been well known for a number of years, their use for chemical-species identification in small volumes of material was not realized until the development of the electron microprobe.

Influence of X-Ray Induced Fluorescence on Energy Dispersive X-Ray Analysis of Thin Foils

1977 ◽  
Vol 35 ◽  
pp. 328-329
Author(s):  
E. A. Kenik ◽  
J. Bentley
Keyword(s):  
Thin Foil ◽  
Electron Excitation ◽  
Simple Approach ◽  
Foil Thickness ◽  
X Rays ◽  
X Ray ◽  
Hole Spectrum ◽  
Illumination System ◽  
Thin Foils ◽  
Intensity Ratios

Cliff and Lorimer (1) have proposed a simple approach to thin foil x-ray analy sis based on the ratio of x-ray peak intensities. However, there are several experimental pitfalls which must be recognized in obtaining the desired x-ray intensities. Undesirable x-ray induced fluorescence of the specimen can result from various mechanisms and leads to x-ray intensities not characteristic of electron excitation and further results in incorrect intensity ratios.In measuring the x-ray intensity ratio for NiAl as a function of foil thickness, Zaluzec and Fraser (2) found the ratio was not constant for thicknesses where absorption could be neglected. They demonstrated that this effect originated from x-ray induced fluorescence by blocking the beam with lead foil. The primary x-rays arise in the illumination system and result in varying intensity ratios and a finite x-ray spectrum even when the specimen is not intercepting the electron beam, an ‘in-hole’ spectrum. We have developed a second technique for detecting x-ray induced fluorescence based on the magnitude of the ‘in-hole’ spectrum with different filament emission currents and condenser apertures.

X-ray micro tomography in the scanning electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 106-107 ◽  
Author(s):  
W. Brünger
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Target Surface ◽  
The Body ◽  
X Rays ◽  
Cross Sectional ◽  
X Ray ◽  
Micro Tomography ◽  
Scanning Electron

Reconstructive tomography is a new technique in diagnostic radiology for imaging cross-sectional planes of the human body /1/. A collimated beam of X-rays is scanned through a thin slice of the body and the transmitted intensity is recorded by a detector giving a linear shadow graph or projection (see fig. 1). Many of these projections at different angles are used to reconstruct the body-layer, usually with the aid of a computer. The picture element size of present tomographic scanners is approximately 1.1 mm2.Micro tomography can be realized using the very fine X-ray source generated by the focused electron beam of a scanning electron microscope (see fig. 2). The translation of the X-ray source is done by a line scan of the electron beam on a polished target surface /2/. Projections at different angles are produced by rotating the object.During the registration of a single scan the electron beam is deflected in one direction only, while both deflections are operating in the display tube.

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