scholarly journals Experimental investigation of size broadening of a Kα x-ray source produced by high intensity laser pulses

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Gambari ◽  
R. Clady ◽  
L. Videau ◽  
O. Utéza ◽  
A. Ferré ◽  
...  
Keyword(s):  
High Intensity ◽  
Laser Intensity ◽  
Contrast Ratio ◽  
Spot Size ◽  
Source Size ◽  
Hot Electron ◽  
Temporal Contrast ◽  
X Ray ◽  
Wide Range ◽  
The Impact

AbstractThe size of a hard Kα x-ray source ($${\mathrm{E}}_{{\rm{K}}_{\rm{\alpha }}}$$ E K α = 17.48 keV) produced by a high intensity femtosecond laser interacting with a solid molybdenum target is experimentally investigated for a wide range of laser intensity (I ~ 1017–2.8 × 1019 W/cm2) and for four values of the temporal contrast ratio (6.7 × 107 < CR < 3.3 × 1010). Results point out the size enlargement of the x-ray source with the increase of laser intensity and with the deterioration of temporal contrast. It amounts up to sixteen times the laser spot size at the highest laser intensity and for the lowest temporal contrast ratio. Using hydrodynamic simulations, we evaluate the density scale length of the pre-plasma L/λ just before the main pulse peak. This allows us to show that a direct correlation with the laser absorption mechanisms is not relevant to explain the large size broadening. By varying the thickness of the molybdenum target down to 4 µm, the impact of hot electron scattering inside the solid is also proved irrelevant to explain the evolution of both the x-ray source size and the Kα photon number. We deduce that the most probable mechanism yielding to the broadening of the source size is linked to the creation of surface electromagnetic fields which confine the hot electrons at the solid surface. This assumption is supported by dedicated experiments where the evolution of the size enlargement of the x-ray source is carefully studied as a function of the laser focal spot size for the highest contrast ratio.

Improvement of the Detection Sensitivity of Edxrf Trace Element Analysis by Means of Efficient X-Ray Focusing Based on Strongly Curved Hopg Crystals

1995 ◽  
Vol 39 ◽  
pp. 109-117
Author(s):  
Burkhard Beckhoff ◽  
Birgit Kanngießer
Keyword(s):  
High Intensity ◽  
Focal Plane ◽  
Bragg Reflection ◽  
Pyrolytic Graphite ◽  
Trace Element Analysis ◽  
Detection Sensitivity ◽  
Element Analysis ◽  
X Ray ◽  
Wide Range ◽  
Very High

X-ray focusing based on Bragg reflection at curved crystals allows collection of a large solid angle of incident radiation, monochromatization of this radiation, and condensation of the beam reflected at the crystal into a small spatial cross-section in a pre-selected focal plane. Thus, for the Bragg reflected radiation, one can achieve higher intensities than for the radiation passing directly to the same small area in the focal plane. In that case one can profit considerably from X-ray focusing in an EDXRF arrangement. The 00 2 reflection at Highly Oriented Pyrolytic Graphite (HOPG) crystals offers a very high intensity of the Bragg reflected beam for a wide range of photon energies. Furthermore, curvature radii smaller than 10 mm can be achieved for HOPG crystals ensuring efficient X-ray focusing in EDXRF applications. For the trace analysis of very small amounts of specimen material deposited on small areas of thin-filter backings, HOPG based X-ray focusing may be used to achieve a very high intensity of monochromatic excitation radiation.

High-Intensity Rotating Anode X-Ray Tubes

1965 ◽  
Vol 9 ◽  
pp. 194-201
Author(s):  
A. Taylor
Keyword(s):  
Power Dissipation ◽  
Rotational Speed ◽  
High Intensity ◽  
High Pressures ◽  
Focal Spot ◽  
Spot Size ◽  
Focal Spot Size ◽  
X Ray

AbstractDemountable rotating anode X-ray tubes with a 7½ kW power dissipation have been built for conventional diffraction work with powder cameras and equi-inclination Weissenberg goniometers, and for use with a tetrahedral press for studying crystalline matter at ultra-high pressures. The tubes employ a highly compact cooling and sealing arrangement on the rotating anode which enables four windows to be used with the focal spot close to the specimen. A rotational speed of 1750 rpm with a focal spot size of 10 × 1 mm enables the tubes to be operated at 250–275 mA at 30 kV DC or at 150 mA, 50 kV DC.

Overview of polycapillary X-ray optics

2002 ◽  
Vol 17 (2) ◽  
pp. 70-80 ◽  
Author(s):  
Paul J. Schields ◽  
David M. Gibson ◽  
Walter M. Gibson ◽  
Ning Gao ◽  
Huapeng Huang ◽  
...  
Keyword(s):  
Focal Spot ◽  
State Of The Art ◽  
Substantial Reduction ◽  
Spot Size ◽  
Source Size ◽  
Total External Reflection ◽  
X Rays ◽  
Focal Spot Size ◽  
Polycapillary Optics ◽  
X Ray

Polycapillary optics are utilized in a wide variety of applications and are integral components in many state of the art instruments. Polycapillary optics operate by collecting X-rays and efficiently propagating them by total external reflection to form focused and parallel beams. We discuss the general parameters for designing these optics and provide specific examples on balancing the interrelations of beam flux, source size, focal spot-size, and beam divergence. The development of compact X-ray sources with characteristics tailored to match the requirements of polycapillary optics allows substantial reduction in size, weight, and power of complete X-ray systems. These compact systems have enabled the development of portable, remote, and in-line sensors for applications in industry, science and medicine. We present examples of the utility and potential of these optics for enhancing a wide variety of X-ray analyses.

scholarly journals INVESTIGATING THE MULTIPLE RECOLLISION OF THE NONSEQUENTIAL DOUBLE IONIZATION PROCESS

2017 ◽  
Vol 126 (1B) ◽  
pp. 63
Author(s):  
Pham Nguyen Thanh Vinh
Keyword(s):  
Significant Contribution ◽  
Laser Intensity ◽  
Double Ionization ◽  
Ionization Process ◽  
Wide Range ◽  
The Impact ◽  
Nonsequential Double Ionization

<p>We systematically investigate the contribution of recollision dynamics to the nonsequential double ionization process (NSDI) of Ar atom for a wide range of laser intensity. The result shows that the first- and second-recollision scenarios have significant contribution to the NSDI events. Moreover, we figure out that the impact of double-recollision trajectories decreases as the laser intensity increases. Besides, many details of multiple recollisions are also investigated in this paper.</p>

Impact of X-ray induced radiation damage on FD-MAPS of the ARCADIA project

2022 ◽  
Vol 17 (01) ◽  
pp. C01035
Author(s):  
C. Neubüser ◽  
T. Corradino ◽  
S. Mattiazzo ◽  
L. Pancheri
Keyword(s):  
Power Consumption ◽  
Radiation Damage ◽  
High Energy ◽  
Full Potential ◽  
Sensor Design ◽  
Charge Collection Efficiency ◽  
X Ray ◽  
Active Pixel ◽  
Wide Range ◽  
The Impact

Abstract Recent advancements in Monolithic Active Pixel Sensors (MAPS) demonstrated the ability to operate in high radiation environments of up to multiple kGy’s, which increased their appeal as sensors for high-energy physics detectors. The most recent example in such application is the new ALICE inner tracking system, entirely instrumented with CMOS MAPS, that covers an area of about 10 m2. However, the full potential of such devices has not yet been fully exploited, especially in respect of the size of the active area, power consumption, and timing capabilities. The ARCADIA project is developing Fully Depleted (FD) MAPS with an innovative sensor design, that uses a proprietary processing of the backside to improve the charge collection efficiency and timing over a wide range of operational and environmental conditions. The innovative sensor design targets very low power consumption, of the order of 20 mW cm−2 at 100 MHz cm−2 hit flux, to enable air-cooled operations of the sensors. Another key design parameter is the ability to further reduce the power regime of the sensor, down to 5 mW cm−2 or better, for low hit rates like e.g. expected in space experiments. In this contribution, we present a comparison between the detector characteristics predicted with Technology Computer Aided Design (TCAD) simulations and the ones measured experimentally. The comparison focuses on the current-voltage (IV) and capacitance-voltage (CV) characteristics, as well as noise estimated from in-pixel capacitances of passive/active pixel matrices. In view of the targeted applications of this technology, an emphasis is set on the modeling of X-ray induced radiation damage at the Si-SiO2 interface and the impact on the in-pixel sensor capacitance. The so-called new Perugia model has been used in the simulations to predict the sensor performance after total ionizing doses of up to 10 Mrad.

Theoretical and Experimental X-Ray Peak/Background Ratios and Implications for Energy-Dispersive Spectrometry in the Next-Generation Analytical Electron Microscope

2016 ◽  
Vol 22 (1) ◽  
pp. 230-236 ◽  
Author(s):  
Nestor J. Zaluzec
Keyword(s):  
Theoretical Calculations ◽  
Detection Sensitivity ◽  
X Ray ◽  
Background Ratio ◽  
Exit Surface ◽  
Wide Range ◽  
Analytical Electron ◽  
Solid Angles ◽  
Electron Microscopes ◽  
The Impact

AbstractModern analytical electron microscopes equipped with silicon drift detectors now allow for a wide range of geometrical configurations capable of performing quantitative X-ray spectrometry. Recent work has improved the collection solid angles of these detectors, however, the impact of increasing the solid angle on detection sensitivity as measured by the peak/background ratio has not been addressed. This work compares theoretical and experimental peak/background ratios for incident electron energies in the range of 20–200 keV, with X-ray detectors in both conventional orientations (on the electron entrance surface) as well as new geometries (the electron exit surface). The implications of these parameters on detectability limits for the next generations of “Lab-in-the-Gap” analytical microscope are also considered. It was found that theoretical calculations of the angular distribution of bremsstrahlung and their effects on the peak/background ratio match well with experimental measurements, and indicate that new geometries which can result in large solid angles provided an added benefit in addition to increased characteristic signal, namely increased sensitivity for the analyst.

scholarly journals Nikola Tesla and medicine: 160th anniversary of the birth of the genius who gave light to the world - part I

2016 ◽  
Vol 69 (9-10) ◽  
pp. 313-322
Author(s):  
Danijela Vucevic ◽  
Drago Djordjevic ◽  
Tatjana Radosavljevic
Keyword(s):  
High Frequency ◽  
X Rays ◽  
X Ray ◽  
Nikola Tesla ◽  
Wide Range ◽  
The World ◽  
Biologic Effects ◽  
History Of ◽  
The Impact ◽  
Harmful Effects

Introduction. The interest in Nikola Tesla, a scientist, physicist, engineer and inventor, is constantly growing. In the millennia-long history of human civilization, it is almost impossible to find another person whose life and work has been under so much scrutiny of such a wide range of researchers, medical professionals included. Although Tesla was not primarily dedicated to biomedical research, his work significantly contributed to the development of radiology, and high frequency electrotherapy. This paper deals with the impact of Tesla?s work on the development of a new medical branch - radiology. Nikola Tesla and the Discovery of X-ray radiation. Tesla pioneered the use of X-rays for medical purposes, practically laying the foundations of radiology. Namely, since 1887, Tesla periodically experimented with X-rays, at that time still unknown and unnamed, which he called "shadowgraphs". Moreover, at the end of 1894, he conducted extensive research focusing on X-rays, but unfortunately it was interrupted after the fire burning down his laboratory in 1895. In 1896 and 1897, Tesla published ten papers on the biologic effects of X-ray radiation. All his studies on X-rays were experimental. During 1896 and 1897, Tesla continued improving X-ray devices. Apart from this, Tesla was the first to point out the harmful effects of exposure to X-ray radiation on human body. Conclusion. Nikola Tesla was a visionary genius of the future. Tesla?s pioneer steps, made more than a century ago in the domain of radiology, are still being used today.

Nanostructure Fabrication: Dry Etching Damage

1991 ◽  
Vol 236 ◽  
Author(s):  
G.F. Doughty ◽  
R. Cheung ◽  
M.A. Foad ◽  
M. Rahman ◽  
N.I. Cameron ◽  
...  
Keyword(s):  
Chemical Reactivity ◽  
Compound Semiconductors ◽  
Dry Etching ◽  
Schottky Junction ◽  
Nanostructure Fabrication ◽  
X Ray ◽  
Wide Range ◽  
Directed Energy ◽  
The Impact ◽  
Surface Changes

AbstractAlthough the directed energy and chemical reactivity of dry etching permits the fabrication of nanostructures with precise geometries, it also causes unwanted electrical and optical changes to the surface, changes generally referred to as “damage”.This paper discusses the extent and the impact of dry-etching damage on rI-V and I[-VI compound semiconductors as assessed by a very wide range of techniques: the performance of devices such as MESFETs, and measurements of other properties - surface uniformly and precisely, Schottky junction characteristics, cut-off of epitaxial wire conductance, integrated photoluminescence, X-ray reflectivity, DLTS, TEM imaging and Raman scattering.We distinguish an important difference between the nature of damage on sidewalls and on surfaces normal to the directed ions, and report on progress towards establishing a model of the nature of dry etching damage. This model is applied to indicate what kinds of processes are likely to give etching with low damage.

scholarly journals Upgrading Existing Diffractometers with State-of-the-art Microfocus Sources

2014 ◽  
Vol 70 (a1) ◽  
pp. C1724-C1724
Author(s):  
André Beerlink ◽  
Jürgen Graf ◽  
Jörg Wiesmann ◽  
Carsten Michaelsen
Keyword(s):  
State Of The Art ◽  
Spot Size ◽  
Spare Parts ◽  
Attractive Alternative ◽  
Detector Performance ◽  
X Ray ◽  
Service Support ◽  
Angle Scattering ◽  
Wide Range ◽  
Beam Delivery

Modern microfocus X-ray sources define the state-of-the-art for a broad spectrum of applications in home laboratories, such as protein and small molecule crystallography, and small-angle scattering. These sources are combined with multilayer optics to image the source spot onto the sample. The optics provides a parallel or focused monochromatic X-ray beam, magnified to a suitable size. Low power sealed microfocus sources, such as Incoatec's IµS represent an attractive alternative to rotating anodes, with a significant reduction in cost and maintenance. Power loads of a few kW/mm2 in anode spot sizes below 50µm deliver a compact brilliant beam. For example, the IµSHighBrilliance delivers up to 1010 photons/s/mm2 in a spot size in the 100µm range. It is available for Cu, Mo, Ag, Cr and Co anodes. Since the launch in 2006 more than 400 IµS are now in operation worldwide for a large variety of applications in biology, chemistry, physics and material science. Are you tired of getting spare parts for an ancient rotating anode or is your detector performance only limited by your beam delivery system? We will demonstrate how to bring former high end diffractometers back to a superb performance for cutting edge science after an upgrade with an IµS source. Incoatec ensures full software and safety integration, and an installation hand in hand with the local service, providing a constant service support from your partners on site. In addition to all Bruker or Nonius systems, Incoatec also offers integrations into a wide range of instruments from Rigaku, Marresearch or STOE, also with Dectris or Huber components.

Shock-produced mosaicism in plagioclase, Charlevoix structure, Quebec

1977 ◽  
Vol 14 (1) ◽  
pp. 74-81 ◽  
Author(s):  
Michael J. Walawender
Keyword(s):  
Impact Crater ◽  
Morphological Character ◽  
Shock Metamorphism ◽  
Complex Nature ◽  
Impact Event ◽  
X Ray ◽  
Shock Process ◽  
Wide Range ◽  
Differential Uplift ◽  
The Impact

The Charlevoix structure, Quebec, Canada, is generally accepted as a Paleozoic meteorite impact site. Plagioclase grains from samples in and around this structure were examined via X-ray (oscillation) techniques to determine the maximum range of angular misorientation between crystal subdomains (mosaicism) within a given sample (ηmax), and its usefulness as an index of shock metamorphism at Charlevoix. The complex morphological character of the impact crater can be divided into five concentric zones, which exhibit alternately high and low values of ηmax. This distribution appears to be the result of differential uplift and subsidence that followed the impact event, in that blocks which have undergone different shock histories during the impact event have been brought into juxtaposition. The wide range in ηmax within as well as between samples attests to the complex nature of the shock process and the hazards of using mosaicism as the sole index of shock metamorphism.

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