INTERACTION OF HIGHLY CHARGED Xeq+ (q = 26, 27, 30) IONS WITH MOLYBDENUM SURFACE

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2443-2451 ◽  
Author(s):  
ZHAOYUAN LIU ◽  
HONGQIANG ZHANG ◽  
XIMENG CHEN ◽  
ZHIHU YANG ◽  
JINZHANG XU ◽  
...  
Keyword(s):  
Energy Range ◽  
Charge State ◽  
Incident Energy ◽  
Target Atom ◽  
Simple Explanation ◽  
Electron Configuration ◽  
X Rays ◽  
X Ray ◽  
Initial Charge ◽  
The Difference

Experimental investigation of Molybdenum L-shell X-ray emission is reported in the collision of highly charged Xe q+ (q = 26,27,30) ions with Molybdenum surface in the energy range 400 to 600 keV. Based on the X-ray spectra obtained and by the extrapolation of experimental data to the lower incident energy range, a limit was found for the energy of the incident ions. The influence of initial charge state on X-ray emission from the target L-shell was observed. The difference of the initial charge state and electron configuration of the incident ions may lead to observably different contribution to the target atom vacancy production and L-shell X-rays emission. Based on COB model, a simple explanation was presented to interpret the features of the experimental results.

THE MAXIMUM ENERGY OF ħω INDUCED BY N+, N2+ AND N3+ IONS

1996 ◽  
Vol 06 (01n02) ◽  
pp. 59-63
Author(s):  
C.C. Hsu ◽  
T.C. Chu ◽  
Y.C. Chang ◽  
H.H. Hsu
Keyword(s):  
Charge State ◽  
Atomic Number ◽  
Maximum Energy ◽  
Target Atom ◽  
X Rays ◽  
X Ray ◽  
Relationship Of ◽  
The Relationship

The continuous X-ray of Be, Ni, and Cd targets induced by N +, N 2+, N 3+ ions were measured at the projectile energies of 50-, 70-, 100-, 150-, and 200-keV. Since the energy of the projectile is so low and the detecting limit of the detector is about one keV, the continuous X-ray would be the X-rays of nuclear and atomic bremsstrahlung (NB, AB). From the result of maximum energy of ħω. the relationship of a maximum energy ħω of below: [Formula: see text] Which indicates that the maximum energy of ħω depends on (-3/5) power of the atomic number of projectile, Zp. and on (-1/3q) power of the atomic number of target atom, Zt, and on the energy of projectile. Where q expresses the number of charge state of the projectile.

scholarly journals NSLS-II MX beamlines FMX for micro-crystallography & AMX for highly automated MX

2014 ◽  
Vol 70 (a1) ◽  
pp. C1733-C1733
Author(s):  
Martin Fuchs ◽  
Robert Sweet ◽  
Lonny Berman ◽  
Dileep Bhogadi ◽  
Wayne Hendrickson ◽  
...  
Keyword(s):  
Energy Range ◽  
Structure Determination ◽  
Optical Systems ◽  
Photon Flux ◽  
X Rays ◽  
Macromolecular Crystallography ◽  
Binding Studies ◽  
X Ray ◽  
Array Detectors ◽  
Broad Energy Range

We present the final design of the x-ray optical systems and experimental stations of the two macromolecular crystallography (MX) beamlines, FMX and AMX, at the National Synchrotron Light Source-II (NSLS-II). Along with its companion x-ray scattering beamline, LIX, this suite of Advanced Beamlines for Biological Investigations with X-rays (ABBIX, [1]) will begin user operation in 2016. The pair of MX beamlines with complementary and overlapping capabilities is located at canted undulators (IVU21) in sector 17-ID. The Frontier Microfocusing Macromolecular Crystallography beamline (FMX) will deliver a photon flux of ~5x10^12 ph/s at a wavelength of 1 Å into a spot of 1 - 50 µm size. It will cover a broad energy range from 5 - 30 keV, corresponding to wavelengths from 0.4 - 2.5 Å. The highly Automated Macromolecular Crystallography beamline (AMX) will be optimized for high throughput applications, with beam sizes from 4 - 100 µm, an energy range of 5 - 18 keV (0.7 - 2.5 Å), and a flux at 1 Å of ~10^13 ph/s. Central components of the in-house-developed experimental stations are a 100 nm sphere of confusion goniometer with a horizontal axis, piezo-slits to provide dynamic beam size changes during diffraction experiments, a dedicated secondary goniometer for crystallization plates, and sample- and plate-changing robots. FMX and AMX will support a broad range of biomedical structure determination methods from serial crystallography on micron-sized crystals, to structure determination of complexes in large unit cells, to rapid sample screening and data collection of crystals in trays, for instance to characterize membrane protein crystals and to conduct ligand-binding studies. Together with the solution scattering program at LIX, the new beamlines will offer unique opportunities for advanced diffraction experiments with micro- and mini-beams, with next generation hybrid pixel array detectors and emerging crystal delivery methods such as acoustic droplet ejection. This work is supported by the US National Institutes of Health.

Magnetic Structure of Multilayers from Soft-X-Ray Magnetic Circular Dichroism

1994 ◽  
Vol 375 ◽  
Author(s):  
C. T. Chen ◽  
Y. U. Idzerda ◽  
C.-C. Kao ◽  
L. H. Tjeng ◽  
H.-J. Lin ◽  
...  
Keyword(s):  
Thin Films ◽  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
Magnetic Thin Films ◽  
X Rays ◽  
X Ray ◽  
Specific Manner ◽  
Left And Right ◽  
The Difference ◽  
Circular Dichroïsm

AbstractSoft-x-ray magnetic circular dichroism (MCD) is the difference between the absorptivity or reflectivity of left and right circularly polarized soft-x-rays at the magnetically interesting L2,3- edges of 3d transition metals or the M4,5-edges of the 4f rare earth elements. Thanks to its large absorption cross-section and strong MCD effect, this technique has become a powerful new means for probing, in an element- and site-specific manner, the magnetic properties of ultra-thin films and multilayers. Soft-x-ray MCD experiments, recently conducted at the Dragon beamline, are utilized to demonstrate the recent progress in this technique and its applications in the research of magnetic thin films.

scholarly journals The sensitivity of atomic analysis by X-rays

1932 ◽  
Vol 135 (828) ◽  
pp. 637-656 ◽  
Keyword(s):  
Atomic Number ◽  
Target Material ◽  
High Sensitivity ◽  
Major Constituent ◽  
X Rays ◽  
Depth Of Penetration ◽  
X Ray ◽  
Constituent Element ◽  
The Difference ◽  
Atomic Analysis

In a previous paper it was shown that 0·0007 per cent, of 29 Cu and 0·0003 per cent, of 26 Fe could be detected in 30 Zn by atomic analysis by X-ray spectroscopy. This sensitivity is greater than that which was claimed by Noddack, Tacke, and Berg, who set the limit at about 0·1 per cent, for non-metals, and by Hevesy, who stated it to be about 0·01 per cent, for an element present in an alloy. It was later suggested by Hevesy that the high value of the sensitivity which we found might result from the fact that some of the alloys we had used were composed of elements of almost equal atomic number, and that the sensitivity would be smaller for a constituent of low atomic number mixed with a major constituent of high atomic number. To elucidate these disagreements we have made further observations of the sensitivity with elements of different atomic number and have investigated the conditions which can influence the sensitivity. The Factors Determining Sensitivity . The detection of one element in a mixture of elements depends upon the identification of its K or L lines in the general spectrum emitted by the mixture under examination. The intensity with which these lines are excited in the target (“excited intensity”) is proportional to the number of atoms of the constituent element excited, i. e ., to its concentration and to the volume of the target in which the cathode ray energy is absorbed. The depth of penetration of the cathode rays is determined by the density of the target material and by their velocity ( i. e ., by the voltage applied to the X-ray tube). Schonland has shown that the range of homogeneous cathode rays in different elements, expressed as a mass per unit area, is approximately constant and is independent of the atomic number of the absorbing element. When their velocity is increased, the cathode rays will penetrate to a greater depth, and therefore a greater number of atoms of all constituents will be ionised. This will increase the “excited intensity” of the lines due to the particular constituent sought equally with those lines of the other elements present. The intensity of a line further depends upon the difference between the voltage applied to the X-ray tube and that necessary to excite the series. For these reasons, a high applied voltage is required for a high sensitivity.

scholarly journals A Method to Optimize the Electron Spectrum for Simulating Thermo-Mechanical Response to X-ray Radiation

Symmetry ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 59
Author(s):  
Xianwen Ran ◽  
Bo Wang ◽  
Kun Zhang ◽  
Wenhui Tang
Keyword(s):  
Electron Spectrum ◽  
Mechanical Response ◽  
Least Squares Method ◽  
Mechanical Deformation ◽  
X Rays ◽  
Linear Least Squares ◽  
X Ray ◽  
Relativistic Electron Beams ◽  
Transport Code ◽  
The Difference

The X-ray pulse originating from high altitude nuclear detonation (HAND) is mainly soft X-ray and its intensity is high enough to gasify the penetrated material and then lead to the severe thermo-mechanical deformation of unpenetrated material from the gasified blow-off effect. This effect cannot be directly reproduced in a lab for the lack of the X-ray source like HAND. At present, the low-energy relativistic electron beams resulting from an electron accelerator are usually used to approximately reproduce this effect, but the difference in the energy-deposited profile in materials between the electron and X-ray cannot be eliminated. In this paper, the symmetric linear least squares method was used to optimize the electron spectrum, and the general Monte Carlo N-Particle Transport Code calculations showed the optimized spectrum can produce the same energy-deposited profile in aluminum, copper, and tantalum with the soft X-rays like 1 keV or 3 keV spectrums. This indicates that it is possible to simulate the severe thermo-mechanical deformation resulting from HAND using the optimized electron spectrums.

A scanning transmission X-ray microscope at the Pohang Light Source

2018 ◽  
Vol 25 (3) ◽  
pp. 878-884 ◽  
Author(s):  
Hyun-Joon Shin ◽  
Namdong Kim ◽  
Hee-Seob Kim ◽  
Wol-Woo Lee ◽  
Chae-Soon Lee ◽  
...  
Keyword(s):  
Energy Range ◽  
Light Source ◽  
Photon Energy ◽  
Chemical State ◽  
Photon Energy Range ◽  
X Rays ◽  
X Ray ◽  
Space Resolution ◽  
Scanning Transmission ◽  
Pohang Light Source

A scanning transmission X-ray microscope is operational at the 10A beamline at the Pohang Light Source. The 10A beamline provides soft X-rays in the photon energy range 100–2000 eV using an elliptically polarized undulator. The practically usable photon energy range of the scanning transmission X-ray microscopy (STXM) setup is from ∼150 to ∼1600 eV. With a zone plate of 25 nm outermost zone width, the diffraction-limited space resolution, ∼30 nm, is achieved in the photon energy range up to ∼850 eV. In transmission mode for thin samples, STXM provides the element, chemical state and magnetic moment specific distributions, based on absorption spectroscopy. A soft X-ray fluorescence measurement setup has been implemented in order to provide the elemental distribution of thicker samples as well as chemical state information with a space resolution of ∼50 nm. A ptychography setup has been implemented in order to improve the space resolution down to 10 nm. Hardware setups and application activities of the STXM are presented.

Destruction of C2H4O2 isomers in ice-phase by X-rays: Implication on the abundance of acetic acid and methyl formate in the interstellar medium

2017 ◽  
Vol 13 (S332) ◽  
pp. 418-424
Author(s):  
Marina G. Rachid ◽  
K. Faquine ◽  
S. Pilling
Keyword(s):  
Acetic Acid ◽  
Cross Sections ◽  
Methyl Formate ◽  
X Rays ◽  
Formation Cross Section ◽  
X Ray ◽  
Synchrotron Light ◽  
The Difference ◽  
Astrophysical Ices

AbstractC2H4O2 isomers, methyl formate (HCOOCH3), acetic acid (CH3COOH) and glycoaldehyde (HOCH2CHO), have been detected in a lot of sources in ISM. However, their abundances are very different, with methyl formate much more abundant than the other two isomers. This fact may be related to the different destruction by ionizing radiation of these molecules. The goal of this work is experimentally study the photodissociation processes of methyl formate and acetic acid ices when exposed to broadband soft X-ray from 6 up to 2000 eV. The experiments were performed coupled to the SGM beamline in the Brazilian Synchrotron Light Source (LNLS/CNPEM) at Campinas, Brazil. The simulated astrophysical ices (12K) were monitored throughout the experiment using infrared vibrational spectroscopy. The analysis of processed ices allowed the determination of the effective destruction cross sections of the parent molecules as well as the effective formation cross section of daughter molecular species. The relative abundance between acetic acid and methyl formate (NCH3COOH/NHCOOCH3) in different astronomical scenarios and their column density evolution in the presence of X-rays were calculated and our results suggests that such radiation field can be one of the factors that explain the difference in the isomers C2H4O2 abundances. We also quantified the daugther species after the establishment of a chemical equilibrium in the samples.

scholarly journals Iron Line Emission from NGC1068

1989 ◽  
Vol 134 ◽  
pp. 167-172
Author(s):  
Katsuji Koyama
Keyword(s):  
Energy Range ◽  
Power Law ◽  
Equivalent Width ◽  
Line Emission ◽  
X Rays ◽  
Iron Line ◽  
X Ray ◽  
Central Engine ◽  
Photon Index ◽  
The Continuum

X-ray emission in the 2–10 keV energy range was observed with the Ginga satellite from the Seyfert 2 galaxy NGC1068. The continuum spectrum can be described by a power-law of photon index about 1.5. An intense iron line at 6.5 keV with an equivalent width of 1.3 keV was clearly noticed. The X-ray flux was about 6 × 10 −12 erg/sec/cm2 or 3 × 1041 erg/sec, assuming a distance of 22 Mpc. The observed spectrum is consistent with the scattering and reprocessing of X-rays by the gas surrounding the central engine. With this picture we estimate that the X-ray flux of the central engine is about 1043 - 1044 erg/sec, a typical value for a Seyfert 1 galaxy.

Low-energy cosmic X-ray measurements

1969 ◽  
Vol 47 (23) ◽  
pp. 2651-2666 ◽  
Author(s):  
A. J. Baxter ◽  
B. G. Wilson ◽  
D. W. Green
Keyword(s):  
Spectral Analysis ◽  
Energy Range ◽  
Crab Nebula ◽  
Spectral Characteristics ◽  
Low Energy ◽  
Data Recovery ◽  
X Rays ◽  
X Ray ◽  
Recovery System ◽  
The Crab Nebula

An experiment is described to investigate cosmic X rays in the energy range 0.25–12 keV. The data-recovery system and methods of spectral analysis are considered. Results are presented for the energy spectrum of the diffuse X-ray component and its distribution over the northern sky down to 1.6 keV with a limited extension at 0.27 keV.In the energy range 1.6 to 12 keV, the spectrum is represented by:[Formula: see text]although separate analyses indicate a flattening below 4.5 keV to give:[Formula: see text]and[Formula: see text]At the lowest energies, the flux appears to increase more rapidly and exhibits some anisotropy in arrival directions related to the gross galactic structure. Spectral characteristics of the Crab Nebula and Cygnus X-2 have also been determined.

5d and 4f electron configuration of CeB6 at 340 and 535 K

2008 ◽  
Vol 64 (5) ◽  
pp. 534-549 ◽  
Author(s):  
Ryoko Makita ◽  
Kiyoaki Tanaka ◽  
Yoshichika Ōnuki
Keyword(s):  
Electron Transfer ◽  
Crystal Field ◽  
Ground State ◽  
Room Temperature ◽  
Atomic Orbital ◽  
Energy Levels ◽  
Electron Configuration ◽  
Acta Cryst ◽  
X Ray ◽  
The Difference

X-ray atomic orbital (XAO) analysis revealed that at both temperatures the electrons are transferred from B 2px (= py ) to Ce 5d and 4f orbitals. At 340 K 5d(j = 5/2)Γ8 orbitals are occupied partially, but 4f(j = 5/2)Γ8 orbitals are more populated than 4f(j = 5/2)Γ7 orbitals, in contrast to our observation at 430 K [Makita et al. (2007). Acta Cryst. B63, 683–692]. At 535 K the XAO analysis revealed clearly that the order of the energy levels of 4f(j = 5/2)Γ8 and Γ7 states reversed again and is the same as that at room temperature. It also limited the possible 5d configurations to three models among the nine possible ones. However, the XAO analysis could not decide which of the three models was the best with the present accuracy of the measurement. Two of them have partially and fully occupied 5d(j = 5/2)Γ7 orbitals and the remaining one has a fully occupied 5d(j = 3/2)Γ8 orbital. Since the lobes of 5d(j = 3/2)Γ8 or 5d(j = 5/2)Γ7 orbitals do not overlap with the 4f(j = 5/2)Γ8 orbitals as well as the 5d(j = 5/2)Γ8 orbitals, the order of the energy levels of the 4f(j = 5/2) orbitals became the same as that at room temperature. These results indicate that the crystal field varies with temperature due to the electron transfer from B 2p to Ce 5d orbitals. The difference densities after the spherical-atom refinement at the three temperatures clearly revealed the different combinations of 4f and 5d orbitals which are occupied. In the present study positive peaks due to the 4f electrons appear near the Ce nucleus and those due to 5d orbitals are found in the area outside the 4f peaks. Between the two areas there is a negative area distributed spherically at 340 K. The negative area produced by the contraction of 4f(j = 5/2)Γ8 orbitals seems to reduce the electron repulsion of the 5d(j = 5/2)Γ8 orbitals and helps the 4f(j = 5/2)Γ8 orbitals to remain as the ground state.

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