scholarly journals Method and application of fast estimating particle background level for space-based focusing X-ray instruments

2020 ◽  
Vol 69 (15) ◽  
pp. 150701
Author(s):  
Wen-Li Jiang ◽  
Li-Qiang Qi ◽  
Da-Wei Han ◽  
Ze-Yu Song ◽  
Ai-Mei Zhang ◽  
...  
Keyword(s):  
Background Level ◽  
X Ray ◽  
Particle Background

ANALYSIS OF MULTI-ELEMENT POWDERS AND SOLUTIONS OF METALS WITH A PYROELECTRIC X-RAY GENERATOR

2005 ◽  
Vol 15 (01n02) ◽  
pp. 19-25 ◽  
Author(s):  
TETSUYA KOYAMA ◽  
JUN KAWAI
Keyword(s):  
Low Power ◽  
Background Level ◽  
Solid Samples ◽  
Portable Xrf ◽  
X Ray ◽  
Metal Elements ◽  
Xrf Analysis ◽  
Liquid Samples

Applications of X-ray fluorescence (XRF) analysis to solid and liquid samples with a pyroelectric X-ray generator are described. The X-ray generator is driven by a 9 V dry electric battery and small dimensions. It enables compact and portable XRF spectrometer. It has disadvantages in low power and periodically changing X-ray flux. Measured solid samples are briquettes from powdery oxides of Ti , V , Cr , Mn , Fe , Co , Ni and Cu , and sulfide of Zn . Each sample is prepared to contain equal molar metal elements. Liquid samples are solutions of Fe , Cr , Zn , Pb , Bi , Cd . K α and K β lines of all metals in solid samples are detected. Although background level was relatively high for liquids, all metals in the measured samples were detected within 70 seconds, except for Cd . The capability of XRF with the pyroelectric X-ray generator is discussed.

scholarly journals Techniques for X-Ray Diffraction Studies of Radioactive Materials

1958 ◽  
Vol 2 ◽  
pp. 261-274
Author(s):  
W. V. Cummings ◽  
W. J. Gruber
Keyword(s):  
Energy Spectrum ◽  
Radiation Damage ◽  
Background Level ◽  
Operating Conditions ◽  
Limiting Factor ◽  
X Ray Diffraction ◽  
Radioactive Materials ◽  
High Background ◽  
X Ray

AbstractMany materials, both fissionable and non-fissionable, become very radioactive when subjected to nuclear radiations. This radioactivity results in a high background level in X-ray diffraction studies and becomes a limiting factor in an analysis of radiation damage. A description is given of special techniques that are used to minimize this background and produce optimum diffraction conditions. The radioactive intensity of irradiated X-ray specimens varies from levels that are only mildly troublesome to levels that are extremely hazardous to personnel. The diffraction methods employed at the various levels are explained. An example of the radioactive energy spectrum of a specimen is given to show the method of selecting the best operating conditions and techniques.

scholarly journals Reproducibility and monitoring of the instrumental particle background for the X-ray Integral Field Unit

2018 ◽  
Author(s):  
Edoardo Cucchetti ◽  
Etienne Pointecouteau ◽  
Didier Barret ◽  
Simone Lotti ◽  
Claudio Macculi ◽  
...  
Keyword(s):  
X Ray ◽  
Particle Background ◽  
Field Unit ◽  
Integral Field

scholarly journals JoXSZ: Joint X-SZ fitting code for galaxy clusters

2020 ◽  
Vol 639 ◽  
pp. A73 ◽  
Author(s):  
Fabio Castagna ◽  
Stefano Andreon
Keyword(s):  
Galaxy Clusters ◽  
Missing Values ◽  
High Redshift ◽  
Background Level ◽  
X Ray ◽  
Calibration Uncertainty ◽  
User Request ◽  
Mass Profile ◽  
X Ray Background ◽  
Fully Bayesian

The thermal Sunyaev-Zeldovich (SZ) effect and the X-ray emission offer separate and highly complementary probes of the thermodynamics of the intracluster medium. We present JoXSZ, the first publicly available code designed to jointly fit SZ and X-ray data coming from various instruments to derive the thermodynamic profiles of galaxy clusters. JoXSZ follows a fully Bayesian forward-modelling approach, accounts for the SZ calibration uncertainty, and for the X-ray background level systematic. It improves upon most current and not publicly available analyses because it adopts the correct Poisson-Gauss expression for the joint likelihood, makes full use of the information contained in the observations, even in the case of missing values within the datasets, has a more inclusive error budget, and adopts a consistent temperature in the various parts of the code, allowing for differences between X-ray and SZ gas-mass weighted temperatures when required by the user. JoXSZ accounts for beam smearing and data analysis transfer function, accounts for the temperature and metallicity dependencies of the SZ and X-ray conversion factors, adopts flexible parametrisation for the thermodynamic profiles, and on user request, allows either adopting or relaxing the assumption of hydrostatic equilibrium (HE). When HE holds, JoXSZ uses a physical (positive) prior on the radial derivative of the enclosed mass and derives the mass profile and overdensity radii rΔ. For these reasons, JoXSZ goes beyond simple SZ and electron density fits. We illustrate the use of JoXSZ by combining Chandra and NIKA data of the high-redshift cluster CL J1226.9+3332. The code is written in Python, it is fully documented, and the users are free to customise their analysis in accordance with their needs and requirements. JoXSZ is publicly available on GitHub.

scholarly journals Feasibility Study of a New Cherenkov Detector for Improving Volcano Muography

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1183 ◽  
Author(s):  
Domenico Lo Presti ◽  
Giuseppe Gallo ◽  
Danilo Bonanno ◽  
Daniele Bongiovanni ◽  
Fabio Longhitano ◽  
...  
Keyword(s):  
Feasibility Study ◽  
Background Noise ◽  
Cherenkov Radiation ◽  
Background Level ◽  
Cosmic Ray ◽  
Muon Flux ◽  
Arrival Direction ◽  
High Background ◽  
X Ray ◽  
Preliminary Study

Muography is an expanding technique for internal structure investigation of large volume object, such as pyramids, volcanoes and also underground cavities. It is based on the attenuation of muon flux through the target in a way similar to the attenuation of X-ray flux through the human body for standard radiography. Muon imaging have to face with high background level, especially compared with the tiny near horizontal muon flux. In this paper the authors propose an innovative technique based on the measurement of Cherenkov radiation by Silicon photo-multipliers arrays to be integrated in a standard telescope for muography applications. Its feasibility study was accomplished by means of Geant4 simulations for the measurement of the directionality of cosmic-ray muons. This technique could be particularly useful for the suppression of background noise due to back-scattered particles whose incoming direction is likely to be wrongly reconstructed. The results obtained during the validation study of the technique principle confirm the ability to distinguish the arrival direction of muons with an efficiency higher than 98% above 1 GeV. In addition, a preliminary study on the tracking performance of the presented technique was introduced.

scholarly journals OSO-8 X-Ray Polarimeter and Bragg Crystal Spectrometer Observations

1977 ◽  
Vol 4 (1) ◽  
pp. 95-97
Author(s):  
R. Novick ◽  
H.L. Kestenbaum ◽  
K.S. Long ◽  
E.H. Silver ◽  
M.C. Weisskopf ◽  
...  
Keyword(s):  
Charged Particle ◽  
Counting Rate ◽  
Crab Nebula ◽  
Position Angle ◽  
Crystal Spectrometer ◽  
X Ray ◽  
Particle Background ◽  
The Crab Nebula ◽  
Satellite Spin

The OSO-8 satellite contains a focusing mosaic graphite crystal X-ray polarimeter that is oriented along the spin axis of the wheel section of the satellite. The polarimeter operates at 2.6 and 5.2 keV. Polarization in a source appears as a modulation of the counting rate at twice the satellite spin frequency. The amplitude and phase of the modulation are simply related to the polarization and position angle, respectively. Two independent polarimeters are employed, and their axes are offset by 128°. Focusing is achieved by mounting the crystals on a parabolic sector, which reduces the background without reducing the sensitivity. The low background that results from the focusing not only improves the statistical quality of the data but also substantially reduces the danger that an asymmetry in the charged particle background may produce a spurious polarization result. This is particularly important in the case of weak sources. The instrument has been described in detail elsewhere (Novick 1975); here we will briefly discuss the results obtained on the Crab Nebula, Cyg X-l, and Cyg X-2.

Measuring Performance of EDX Systems

1998 ◽  
Vol 4 (S2) ◽  
pp. 210-211
Author(s):  
Peter Statham
Keyword(s):  
Performance Measures ◽  
Radiation Source ◽  
Background Level ◽  
Peak Height ◽  
Radioactive Source ◽  
Charge Collection ◽  
Intended Application ◽  
X Ray ◽  
Economic Considerations

There are no “absolutes” in terms of performance and wherever possible, performance measures need to reflect conditions similar to those in the intended application. Unfortunately, measurements are frequently constrained by practical and economic considerations. For example, the most convenient radiation source for testing EDX systems is the Fe55 radioactive source which produces Mn Kα radiation at 5.9keV and can be used with an air path between source and detector. However, the fwhm resolution at 5.9keV is a rather poor measure of what the resolution will be for x-ray energies below 0.5 keV. Furthermore, “P/B”, the ratio of Mn Kα peak height to background level at IkeV, is only a crude indication of incomplete charge collection ICC, and does not reveal problems that may give rise to shift and broadening of the C Kα peak for example.

scholarly journals X-ray diffraction broadening analysis

2015 ◽  
Vol 34 (1) ◽  
pp. 39
Author(s):  
Stanko Popović ◽  
Željko Skoko
Keyword(s):  
Crystallite Size ◽  
Line Profile ◽  
Chemical Properties ◽  
Background Level ◽  
X Ray Diffraction ◽  
Transform Method ◽  
Diffraction Profile ◽  
X Ray ◽  
Microstructural Parameters ◽  
Integral Width

The microstructure is very important in research aimed to the development of new materials. The microstructural parameters, crystallite size, crystallite size distribution, crystallite strain, dislocation density and stacking fault probability, play a major role in physical and chemical properties of the material. These parameters can be determined by a proper analysis of X-ray diffraction line profile broadening. The observed XRD line profile of the studied sample, <em>h</em>(<em>ε</em>), is the convolution of the instrumental profile, <em>g</em>(<em>ε</em>), inherent in diffraction, and pure diffraction profile, <em>f</em>(<em>ε</em>), caused by small crystallite (coherent domain) sizes, by faultings in the sequence of the crystal lattice planes, and by the strains in the crystallites. That is, <em>f</em>(<em>ε</em>) is the convolution of the crystallite size/faulting profile, <em>p</em>(<em>ε</em>), and the strain profile, <em>s</em>(<em>ε</em>). The derivation of <em>f</em>(<em>ε</em>) can be performed from the measured <em>h</em>(<em>ε</em>) and <em>g</em>(<em>ε</em>) by the Fourier transform method, usually referred to as the Stokes method. That method does not require assumptions in the mathematical description of <em>h</em>(<em>ε</em>) and <em>g</em>(<em>ε</em>). The analysis of <em>f</em>(<em>ε</em>) can be done by the Warren-Averbach method, which is applied to the Fourier coefficients obtained by the deconvolution. On the other hand, simplified methods (which may bypass the deconvolution) based on integral widths may be used, especially in studies where a good relative accuracy suffices. In order to obtain the relation among integral widths of <em>f</em>(<em>ε</em>), <em>p</em>(<em>ε</em>) and <em>s</em>(<em>ε</em>), one assumes bell-shaped functions for <em>p</em>(<em>ε</em>) and <em>s</em>(<em>ε</em>). These functions are routinely used in the profile fitting of the XRD pattern and in the Rietveld refinement of the crystal structure. The derived crystallite size and strain parameters depend on the assumptions for the profiles <em>p</em>(<em>ε</em>) and <em>s</em>(<em>ε</em>). Integral width methods overestimate both strain and crystallite size parameters in comparison to the Warren-Averbach-Stokes method. Also, the crystallite size parameter is more dependent on the accuracy, with which the profile tails are measured and how they are truncated, than it is the strain parameter. The integral width also depends on the background level error of the pure diffraction profile. The steps and precautions, which are necessary in order to minimize the errors, are suggested through simple examples. The values of the crystallite size and strain parameters, obtained from integral widths derived by the Stokes deconvolution, are compared with those which followed from the Warren-Averbach treatment of broadening. Recent approaches in derivation of microstructure are also mentioned in short.

scholarly journals Microwave, EUV, and X-ray Observations of Active Region Loops and Filaments

1980 ◽  
Vol 86 ◽  
pp. 71-85
Author(s):  
E. Schmahl
Keyword(s):  
High Resolution ◽  
Background Level ◽  
Early Years ◽  
Apparent Brightness ◽  
X Ray ◽  
Brightness Temperatures ◽  
Eclipse Observations ◽  
Apparent Brightness Temperature ◽  
Bright Area ◽  
Full Disk

In the early years of centimetric radio astronomy, even before high resolution techniques were available, it was found that the apparent brightness temperature of the full disk is made up of a background level (the so-called quiet sun temperature) added to which is a contribution roughly proportional to the sum of the sunspot areas on the disk (Smerd 1964, Pawsey and Smerd 1953). Eclipse observations in 1946 at a wavelength of 10.7 cm (Covington 1947) and in 1948 at 10 cm (Piddington and Hindman 1949) and at 3.2 cm (Hagen et al. 1948) showed that the average bright area occupied about 4-thousandths of the disk, and had brightness temperatures of about 5 million degrees. Subsequent interferometric observations have extended and amplified these early studies in several ways. Kundu (1965) has reviewed the literature up to the early 1960's.

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