Global hybrid simulations of soft X-ray emissions in the Earth’s magnetosheath

Earth’s magnetopause is a thin boundary separating the shocked solar wind plasma from the magnetospheric plasmas,and it is also the boundary of the solar wind energy transport to the magnetosphere.Soft X-ray imaging allows investigation of the large-scale magnetopause by providing a two-dimensional(2-D)global view from a satellite.By performing 3-D global hybrid-particle-in-cell(hybrid-PIC)simulations,we obtain soft X-ray images of Earth’s magnetopause under different solar wind conditions,such as different plasma densities and directions of the southward interplanetary magnetic field.In all cases,magnetic reconnection occurs at low latitude magnetopause.The soft X-ray images observed by a hypothetical satellite are shown,with all of the following identified:the boundary of the magnetopause,the cusps,and the magnetosheath.Local X-ray emissivity in the magnetosheath is characterized by large amplitude fluctuations(up to 160%);however,the maximum line-of-sight-integrated X-ray intensity matches the tangent directions of the magnetopause well,indicating that these fluctuations have limited impact on identifying the magnetopause boundary in the X-ray images.Moreover,the magnetopause boundary can be identified using multiple viewing geometries.We also find that solar wind conditions have little effect on the magnetopause identification.The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will provide X-ray images of the magnetopause for the first time,and our global hybrid-PIC simulation results can help better understand the 2-D X-ray images of the magnetopause from a 3-D perspective,with particle kinetic effects considered.

Hybrid-Vlasov simulation of soft X-ray emissions at the Earth’s dayside magnetospheric boundaries

Solar wind charge exchange produces emissions in the soft X-ray energy range which can enable the study of near-Earth space regions such as the magnetopause,the magnetosheath and the polar cusps by remote sensing techniques.The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)and Lunar Environment heliospheric X-ray Imager(LEXI)missions aim to obtain soft Xray images of near-Earth space thanks to their Soft X-ray Imager(SXI)instruments.While earlier modeling works have already simulated soft X-ray images as might be obtained by SMILE SXI during its mission,the numerical models used so far are all based on the magnetohydrodynamics description of the space plasma.To investigate the possible signatures of ion-kinetic-scale processes in soft Xray images,we use for the first time a global hybrid-Vlasov simulation of the geospace from the Vlasiator model.The simulation is driven by fast and tenuous solar wind conditions and purely southward interplanetary magnetic field.We first produce global X-ray images of the dayside near-Earth space by placing a virtual imaging satellite at two different locations,providing meridional and equatorial views.We then analyze regional features present in the images and show that they correspond to signatures in soft X-ray emissions of mirrormode wave structures in the magnetosheath and flux transfer events(FTEs)at the magnetopause.Our results suggest that,although the time scales associated with the motion of those transient phenomena will likely be significantly smaller than the integration time of the SMILE and LEXI imagers,mirror-mode structures and FTEs can cumulatively produce detectable signatures in the soft X-ray images.For instance,a local increase by 30%in the proton density at the dayside magnetopause resulting from the transit of multiple FTEs leads to a 12%enhancement in the line-of-sight-and time-integrated soft X-ray emissivity originating from this region.Likewise,a proton density increase by 14%in the magnetosheath associated with mirror-mode structures can result in an enhancement in the soft X-ray signal by 4%.These are likely conservative estimates,given that the solar wind conditions used in the Vlasiator run can be expected to generate weaker soft X-ray emissions than the more common denser solar wind.These results will contribute to the preparatory work for the SMILE and LEXI missions by providing the community with quantitative estimates of the effects of small-scale,transient phenomena occurring on the dayside.

Thermal Diffusion of Si Atoms at the Interface of Mo/Si Bilayers Studied with a Soft X-ray Emission Microscope

Thermal diffusion of Si atoms at the interface in Mo/Si multilayers was observed with an imaging type soft X ray emission microscope developed by us. It was possible to observe the diffusion with 0.2nm depth resolution in the direction normal to the interface by comparing the emission intensity for exactly the same position. The diffusion coefficient of Si atoms in Mo at 600℃ was roughly estimated to be 6.0×10 17 cm 2/s.

X-ray emission from 424-MeV/u C ions impacting on selected target

The K-shell x-rays of Ti, V, Fe, Co, Ni, Cu, and Zn induced by 424-MeV/u C^（6＋） ion impact are measured. It is found that the K x-ray shifts to the high energy side and the intensity ratio of Kβ/Kα is larger than the atomic data, owing to the L-shell multiple-ionization. The x-ray production cross sections are deduced from the experimental counts and compared with the binary encounter approximation（BEA）, plane wave approximation（PWBA） and energy-loss Coulomb-repulsion perturbed-stationary-state relativistic（ECPSSR） theoretical predictions. The BEA model with considering the multipleionization fluorescence yield is in better consistence with the experimental results. In addition, the cross section as a function of target atomic K-shell binding energy is presented.

Comparison Between X-rays Absorption and Emission Spectroscopy Measurements on a Ceramic Envelop Lamp

Burners of metal halide lamps used for illumination are generally made of polycrystalline alumina ceramic （PCA） which is translucent to visible light. We show that the difficulty of selecting a line of sight through the lamp prevents the use of optical emission diagnostic. X-rays photons are mainly absorbed and not scattered by PCA. Absorption by mercury atoms contributing to the discharge allowed us to determine the density of mercury in the lamp. By comparing diagnostic methods, we put in evidence the difficulty of taking into account the scattering of light mathematically.

Application of methods of X-ray diffraction analysis and acoustic emission on research of plastic deformation in steels

Results of researches on plastic deformation of steels were obtained by acoustic emission and X-ray methods.The new numerical-analytical method of the thin structure parameter determination on one diffraction line was offered.It is supposed that with a growth of the deformation the cubic lattice will be transformed in the orthorhombic lattice.It is shown that changes of a condition of crystal structure of austenitic steel occur in four stages and of carbonaceous steel occur in six stages.Existence of two types of acoustic emission sources in carbonaceous steel and one type of acoustic emission source in austenitic steel was proposed.

Blue-shift of Nano-Y_2O_3 : Eu^(3+) Emission Spectra Excited by X-ray

Nano-Y_2O_3:Eu^(3+) powder was prepared by the homogeneous precipitation. With controlling the conditions of the reaction, nano powders with different grain size were obtained. It is found that the blue-shift phenomena exist in the nano-Y2O3:Eu3+ emission spectra excited by X-ray. The wave lengths of the peak (5D0→7F2) are related with the grain size of the powder

Design and calibration of an elliptical crystal spectrometer for the diagnosis of proton-induced x-ray emission(PIXE)

Laser-driven proton-induced x-ray emission(laser-PIXE) is a nuclear analysis method based on the compact laser ion accelerator. Due to the transient process of ion acceleration, the laser-PIXE signals are usually spurted within nanoseconds and accompanied by strong electromagnetic pulses(EMP), so traditional multi-channel detectors are no longer applicable.In this work, we designed a reflective elliptical crystal spectrometer for the diagnosis of laser-PIXE. The device can detect the energy range of 1 keV–11 ke V with a high resolution. A calibration experiment was completed on the electrostatic accelerator of Peking University using samples of Al, Ti, Cu, and ceramic artifacts. The detection efficiency of the elliptical crystal spectrometer was obtained in the order of 10-9.

Research into Excited Long Lived 0.6-6.0 keV Energy Levels in the Cathode Solid Medium of Glow Discharge by X-Ray Emission Registration

X-ray emission from metal cathodes in glow discharge （current is up to 300 mA, voltage is 1,500-4,300 V） experiments in the spectral range from 700 eV to 6 keV has been observed. The effect has been seen with a variety of different metal cathodes （including AI, Sc, Ti, V, Ni, Nb, Zr, Mo, Pd, Ta, W, and Pt）, as well as with different gasses （including D2, H2, Kr, Ar, and Xe） at low pressure （3-10 Torr）. We present results from a variety of diagnostics, including： pinhole camera imaging; thermo luminescent detector measurements; time-resolved scintillator measurements; and a curved mica spectrometer to register X-ray spectra. Both diffuse and collimated X-ray emission have been observed.. Diffuse emission occurs in bursts of X-rays; with up to 10^5 bursts per second, with up to 10^6 photons per burst during the discharge. Collimated X-ray emission appears in the form of beamlets directed normal to the cathodes surface with a very small angular divergence; with up to 104 bursts per second, and up to 1013 photons overall up to 20 h after discharge switch off. Based on these experimental results we propose a phenomenological model of processes.

Solar Impulsive Hard X-Ray Emission and Two-Stage Electron Acceleration

Heating and acceleration of electrons in solar impulsive hard X-ray （HXR） flares are studied according to the two-stage acceleration model developed by Zhang for solar ^3Herich events. It is shown that electrostatic H-cyclotron waves can be excited at a parallel phase velocity less than about the electron thermal velocity and thus can significantly heat the electrons （up to 40 MK） through landau resonance. The preheated electrons with velocities above a threshold are further accelerated to high energies in the flare-acceleration process. The flareproduced electron spectrum is obtained and shown to be thermal at low energies and power law at high energies. In the non-thermal energy range, the spectrum can be double power law if the spectral power index is energy dependent or related. The electron energy spectrum obtained by this study agrees quantitatively with the result derived from the Reuven Ramaty High Energy Solar Spectroscopic Imager （RHESSI） HXR observations in the flare of 2002 July 23. The total flux and energy flux of electrons accelerated in the solar flare also agree with the measurements.

Relations between the IR-UV-X-ray Continuum and Emission Lines for a Large Composite Sample of Narrow Line and Normal Seyfert 1 Galaxies

We report on our research on the UV, optical line parameters and the infrared through UV to soft X-ray continuum parameters for a composite sample of narrow line and normal Seyfert 1 galaxies. The strong correlations among the line width of HB, optical line strength of Fell and the soft X-ray slope are confirmed. We found no correlations between the UV line parameters, the equivalent widths of Lya and CIV and their ratio on one hand and the optical line parameters on the other. The UV and X-ray luminosities strongly correlate with the line widths of HB and the Fe II/HB ratio. No significant correlation is found between the infrared-soft X-my continuum slope aix and the line width of HB.

Mechanical properties and acoustic emission characteristics of thick hard roof sandstone in Shendong coal field

The mechanical properties and acoustic emission characteristics of thick hard roof sandstone were investigated. Samples were taken from the 30.87-m thick sandstone roof in a mine in the Shengdong coal field, China. Firstly, the composition and microscopic characteristics were analyzed by XRD and FE-SEM, respectively. Moreover, the indirect tensile test, uniaxial compression test, three axis compression experiment and AE test are carried out by using RMT-150C mechanics experiment system with DSS-8B AE test system. The experiment results indicate that the main framework particles of sandstone are quartz and feldspar, and mainly quartz. Cements are mainly pyrite, kaolinite, chlorite and zeolite cross needle, clinochlore, and clay minerals. The microstructure of sandstone is very dense, with few pores and high cementation degree. The tensile strength, compressive strength and elastic modulus of sandstone are 4.825, 85.313 MPa, 13.814 GPa, respectively, so the sandstone belongs to hard rock. The AE cumulative counts of sandstone can be divided into three phases： relatively flat growth period, rapid growth period and spurt period. The signal strength of AE waveform can be used as a warning signal. In the tensile fracture zone, the warning value is 0.4 mV, and in the compression shear failure zone, it is 4 mV. The numbers of cumulative counts of AE under different stress conditions have obvious difference. Moreover, the growth of cumulative counts of acoustic emission is more obvious when the stress is more than 60% of the peak stress.

Acoustic Emission Studies on Weld Bead Defects in Nuclear Grade SS 316L Materials

This paper contributes about the behaviour of Acoustic Emission (AE) signatures of implanted weld defects of SS 316L materials. Lack of penetration and lack of side fusion defects were implanted in weld bead region of the materials. Tungsten Inert Gas Welding (TIG) is adopted to weld the Stainless Steel (SS316L) nuclear grade materials. The material is fabricated with dimensions of 140 × 16 × 10 mm and AE signatures are studied under preload conditions. Mechanical Jig is fabricated to maintain constant load in concentrated weld region. When external load is applied on the weld region, the deformed specimen experiences acoustic emission signals form the weld defect region which are potential source of releasing stress energy. Liner Location Technique (LLT) is adopted for AE singal studies and the generated signal is processed by 2-channel USB—AE node and AE-WIN software. The tests are conducted on two different samples having each defect. A conventional NDT method i.e. X-ray Radiography is conducted on the samples to know the defect ranging and correlated with AE signatures. This study will be helpful to standardize the AE signals for different implanted weld defects of SS 316L materials and it is found that, the parameter “counts vs. amplitude” has given the widest distinction with respect to the type of defects.

Electron emission induced by keV protons from tungsten surface at different temperatures

The electron emission yield is measured from the tungsten surface bombarded by the protons in an energy range of 50keV–250keV at different temperatures.In our experimental results,the total electron emission yield,which contains mainly the kinetic electron emission yield,has a very similar change trend to the electronic stopping power.At the same time,it is found that the ratio of total electron emission yield to electronic stopping power becomes smaller as the incident ion energy increases.The experimental result is explained by the ionization competition mechanism between electrons in different shells of the target atom.The explanation is verified by the opposite trends to the incident energy between the ionization cross section of M and outer shells.

Optical Emission Spectroscopic Study During the Evaporation of Aluminium in the Thermal Plasma Reactor

The oxidation of aluminium was studied using optical emission spectroscopy （OES） during the evaporation of aluminium in traces of oxygen in a thermal plasma reactor. The ratio of the measured line intensities of Al-O with that of Al follows the exact trend as of that obtained from the corresponding line intensities in X-ray diffraction spectra of the synthesized samples. In this paper the inherent capacity of emission spectroscopy in evaluating the growth processes under plasma induced reactions is presented.

Pancreatic neuroendocrine tumor detected by technetium-99m methoxy-2-isobutylisonitrile single photon emission computed tomography/computed tomography:A case report

BACKGROUND Pancreatic neuroendocrine tumors(NETs)account for about 1%–2%of pancreatic tumors and about 8%of all NETs.Computed tomography(CT),magnetic resonance imaging,and endoscopic ultrasound are common imaging modalities for the diagnosis of pancreatic NETs.Furthermore,somatostatin receptor imaging is of great value for diagnosing pancreatic NETs.Herein,we report the efficacy of technetium-99m methoxy-2-isobutylisonitrile(99mTc-MIBI)single photon emission CT(SPECT)/CT for detecting pancreatic NETs.CASE SUMMARY A 57-year-old woman presented to our hospital with a 1-d history of persistent upper abdominal distending pain.The distending pain in the upper abdomen was aggravated after eating,with nausea and retching.Routine blood test results showed a high neutrophil percentage,low leukomonocyte and monocyte percentages,and low leukomonocyte and eosinophil counts.Amylase,liver and kidney function,and tumor markers alpha-fetoprotein,carcinoembryonic antigen,and cancer antigen(CA)125,CA72-4,CA19-9,and CA153 were normal.Abdominal CT showed a mass,with multiple calcifications between the pancreas and the spleen.The boundary between the mass and the pancreas and spleen was poorly defined.Contrast-enhanced CT revealed that the upper abdominal mass was unevenly and gradually enhanced.99mTc-MIBI SPECT/CT revealed that a focal radioactive concentration,with mild radioactive concentration extending into the upper abdominal mass,was present at the pancreatic body and tail.The 99mTc-MIBI SPECT/CT manifestations were consistent with the final pathological diagnosis of pancreatic NET.CONCLUSION 99mTc-MIBI SPECT/CT appears to be a valuable tool for detecting pancreatic NETs.

The 6.7 keV Line Emission from the Stellar Flare of Algol

We present spectral analysis of Algol stellar flare data. The 2-day observation of Algol in our Galaxy was done by Suzaku Satellite. Algol binary system consists of two component stars that eclipse one another periodically. The stellar magnetic field activities and Roche Lobe overflow/mass transfer mechanisms during rapid rotation of the component stars generate an X-ray emission. The variation in brightness of the stellar flare from epoch to epoch provides useful information of stellar properties of the component stars. The atomic physics of the Kα line emission process in the vicinities of chromospherically active and X-ray flare stars, and binaries is well understood. The photo ionization/collisional excitation in the Algol’s corona produces 6.7 keV line emission. The accumulated spectra in X-ray Imaging Spectrometer (XIS) sensors fitted combined with bremsstrahlung model and Gaussian line show a strong fixed X-ray energy of 6.7 keV.

Variation of Radiation Emission with Argon Gas Pressure in UM Plasma Focus with the Hollow Anode

A Plasma Focus device (2.2 kJ, 12 kV) is studied as a pulsed X-ray source, operated with Argon at a filling pressure in the range of 0.7 to 2.5 mbar. The time resolved X-ray signals are measured with an array of PIN diode detectors. The X-ray emission produced by the plasma focus discharge at various pressures is investigated and compared. It is found that at the high pressure regime of more than 1.5 mbar, very consistent and high output of X-ray radiation is obtained, at the peak of the discharge current. A remarkable increase of about five times of the average X-ray yield is achieved at optimum pressure 1.7 mbar compared to that obtained at other pressures. An indirect method to determine the electron temperature of the plasma is achieved by using the array of 5 channel PIN diode detector coupled with Al foil of different thicknesses. The result shows that the electron temperature of the plasma is 7 keV, when the operating pressure is at 1.7 mbar. The maximum total X-ray yield is about 2.53 mJ per shot at optimum pressure, equivalent to the efficiency of 0.00012%.

A seven-crystal spectrometer for high-energy resolution X-ray spectroscopy at Shanghai Synchrotron Radiation Facility

A Johann-type X-ray spectrometer was successfully developed at the hard X-ray branch(in-vacuum undulator with a 24-mm periodic length)of the energy material beamline(E-line)at the Shanghai Synchrotron Radiation Facility(SSRF).This spectrometer was utilized to implement X-ray emission spectroscopy(XES),high-energy resolution fluorescence-detected X-ray absorption spectroscopy(HERFD-XAS),and resonant inelastic X-ray scattering.Seven spherically bent crystals were positioned on the respective vertical 500-mm-diameter Rowland circles,adopting an area detector to increase the solid angle to 1.75%of 4πsr,facilitating the study of low-concentrate systems under complex reaction conditions.Operated under the atmosphere pressure,the spectrometer covers the energy region from 3.5 to 18 keV,with the Bragg angle ranging from 73°to 86°during vertical scanning.It offers a promised energy resolution of sub-eV(XES)and super-eV(HERFD-XAS).Generally,these comprehensive core-level spectroscopy methods based on hard X-rays at the E-line with an extremely high photon flux can meet the crucial requirements of a green energy strategy.Moreover,they provide substantial support for scientific advances in fundamental research.

X and γ-rays emission probabilities of ^(131)I and ^(133)Xe

Radioactive nuclides as 131I and 133Xe are increasingly used for both clinical diagnosis and therapeutic treatment of the patient. For example, 131I is used for the treatment of thyroid gland cancer. Otherwise, 133Xe is used in ventilation studies to assess and evaluate pulmonary function and to provide images of the lungs in both cardiac and pulmonary diseases, such as asthma, pulmonary emphysema, bronchiectasis, carcinoma of the lung, and pulmonary embolism [1,2]. Furthermore, cerebral blood flow is measured using 133Xe inhalation. In this study, the X and γ-rays emission probabilities in the decay of 131I and 133Xe were precisely measured with a calibrated Si(Li) detector. Results of this study were compared using available results in the literature. Good agreement was observed between our results and available results in the literature.