A simple method of determining the relative efiiciency of thin Ge(Li) x- ray detectors in the vicinity of the K absorption edge of Ge is given. (auth)
Energy Citations Database
... Abstract : The effect of the Burstein-Moss shift of the absorption edge on the spectral response of Pb/SnTe detectors is calculated. ...
DTIC Science & Technology
The determination of the efficiency curve of Ge(Li) detectors near the germanium K edge by the K/sub alpha //K/sub BETA / X-ray intensity ratio is discussed. It turns out that the use of arsenic X rays emitted by fiuorescence from a GaAs crystal as suggested by Forcinal causes a small error due to the different functional dependence of the ...
Non-linearities in the energy response of gas detectors in the regions of the absorption edges of the detection medium are well documented. Monte Carlo calculations show that the non-linearity results from differences in efficiencies for converting absorbed radiation into ionisation for different atomic sub-shells. Energy non-linearity ...
PubMed
Dispersion corrections to the atomic scattering factors for the copper K edge have been measured by a new technique, Fresnel diffraction. Fresnel diffraction fringes were measured at several sample-detector distances as a function of energy across the copper K-absorption edge. The dispersion corrections were ...
... Title : THE SHAPE OF THE ABSORPTION EDGE OF AMORPHOUS GERMANIUM, SILICON, INDIUM ANTIMONIDE, GALLIUM ANTIMONIDE ...
... Title : Scattering Coefficients and the Absorption Edge of Longitudinal Coherent Sound Waves in Selected Inhomogeneous Materials. ...
We describe in this paper a new method for measuring the K shell photoelectric cross sections of high-Z elemental targets at a K absorption edge. In this method the external bremsstrahlung (EB) photons produced in the Ni target foil by beta particles from a weak 90Sr-90Y beta source are passed through an elemental target and the spectrum of transmitted EB ...
NASA Astrophysics Data System (ADS)
We report the first measurement of an EXAFS signal from an L edge in the intermediate-energy range 200--1000 eV, obtained using synchrotron radiation and by the use of a specially designed multielement detector system. Observations of the near-edge absorption fine structure show the hole-state spin-orbit splitting ...
... x rays with en- ergy E less than the K-edge EK, the ... of: 1 the number of pho- tons m originally created after absorption of an x ray of energy E is ...
... p i e quency dependent DQE, which is mainly determined by five X-ray K-edge Filter Shotomulltipoi ... A. X-ray absorption and Swank factor ...
... electron beam de-excitation photon emissions from the K-edge ... The photoelectric absorption can cause a characteristic x-ray of the silicon to ...
... materials carried on pods. Also a K-edge detector. ... SJI-151, 152). Thin foil calorimeter for total x ray yield was rocket-borneafrom ... Noise Absorption. ...
Fluorescent-yield X-ray absorption spectroscopy (XAS) taken with a superconducting tunnel junction (STJ) detector has been employed to study the oxygen K-edge structure of Hf Al oxide gate insulators for next-generation metal-oxide-semiconductor (MOS) devices. Thermal stability is a critical issue in the MOS fabrication processes. We ...
Image reconstruction for computerized x-ray tomography requires exact evaluation of the optimum quantum energy E/sub 0/. If E/sub 0/ lies in the region of the absorption edges, where ..mu..(E) is nonmonotone, one can use energy-dispersive detectors. The nonlinear corrections are estimated. Measurements have been made with Si(Li) ...
... of this systematic investigation is to gain further understanding of the details of various absorption features in the vicinity of the K absorption edge of ...
We present the results from newly designed and fabricated double window photon detector to improve the overall energy resolution for inverse photoemission spectroscopy (IPES). This simple design allows us to introduce an absorption gas (Krypton) to decrease the band-width of the energy selective photon detector and thus improve the ...
In this paper we compare different edge detectors based on peak signal to noise ratio on Echocardiographic images. Edge detection is a critical element in image processing, since edges contain a major function of image information. The function of edge detection is to identify the boundaries of ...
The spectrum of angle-integrated undulator radiation displays a sharp edge at every harmonic photon energy. A technique utilizing this feature to measure minute changes in K-parameters of an undulator in a free-electron laser has been proposed. To date, t...
National Technical Information Service (NTIS)
�10587, Berlin, Germany Abstract As part of the program to calibrate X�ray CCD detectors for the AXAF mission we have performed high�spectral resolution, absolute measurements of CCD quantum efficiency using to resonant absorption in the oxide layers of the CCD gate structure. The amplitude of edge structures
E-print Network
The spectrum of angle-integrated undulator radiation displays a sharp edge at every harmonic photon energy. A technique utilizing this feature to measure minute changes in K-parameters of an undulator in a free-electron laser has been proposed. To date, this technique requires the use of crystal monochromators as bandpass filters whose energy centroid depends on the incident ...
DOE Information Bridge
In x-ray and gamma-ray spectroscopy, it is desirable to have detectors with high energy resolution and high absorption efficiency. At LLNL, we have developed superconducting tunnel junction-based single photon x-ray detectors with thin film absorbers that...
We demonstrate the simultaneous acquisition of high-resolution x-ray absorption spectra and scattering data, using a combination of energy-dispersive optics and a two-dimensional CCD detector. Results are presented on the optical constants of Pt and on the reflectivity of a platinum-carbon multilayer at the L/sub III/ absorption ...
... Title : SHIFT OF THE EDGE OF SELF-ABSORPTION IN AN ELECTRIC FIELD OF CdTe SINGLE CRYSTALS AND FILMS,. ...
... Accession Number : AD0261240. Title : OPTICAL TRANSITIONS NEAR THE ABSORPTION EDGE IN CDS. I. - BAND STRUCTURE IN CDS. ...
... Accession Number : AD0624534. Title : ABSORPTION EDGE SPECTRUM OF SCANDIUM OXIDE,. Corporate Author : AEROSPACE ...
... ionized air vs. photon energy. The absorption edge is at the energy of the K absorption edge of nitrogen. effective mass ...
An x-ray spectrometer devoted to dynamical studies of transient systems using the x-ray absorption fine spectroscopy technique is presented in this article. Using an ultrafast laser-induced x-ray source, this optical device based on a set of two potassium acid phthalate conical crystals allows the extraction of x-ray absorption ...
We present a new edge detector for automatic extraction of oceanographic (mesoscale) features in infrared (IR) images obtained from the Advanced Very High Resolution Radiometer (AVHRR). Conventional edge detectors are very sensitive to edge fine structure...
We are using the Monte Carlo Program PENELOPE and the cylindrical geometry program PENCYL to develop a model of the detector efficiency of a planar Ge detector. The detector is used for x-ray measurements in an ongoing experiment to measure electron bremsstrahlung. While we are mainly interested in the efficiency up to 60 keV, the ...
One of the difficulties in X-ray imaging is the need to record a wide dynamic range of intensities on the detector. For example, some rays may miss the object being imaged entirely while others may suffer many orders of magnitude attenuation in passing through. In K-edge subtraction (KES) [E. Rubenstein, et al., Trans. Am. Clin. Climatol. Assoc. 97 (1985) ...
Oxygen implantation in ZnTe may be used to obtain optical absorption at wavelengths higher than 0.55 ..mu..m, which is the normal absorption edge in this compound semiconductor. Optical waveguides obtained by boron implantation in this material are associated with detectors using that extrinsic ...
We have investigated a technique for measuring stable iodine concentrations by absorption-edge transmission measurements using a /sup 139/Ce radiation source. The lanthanum daughter emits characteristic x rays whose energies just bracket the absorption edge of iodine at 33.2 keV. relative transmission of these x rays is sensitive to ...
... Accession Number : ADA471353. Title : Microfluidic Integration on Detector Array for Absorption and Fluorescence Micro-Spectrometers. ...
We describe in this paper a new method for measuring the K shell photoelectric cross sections of high-Z elemental targets at a K absorption edge. In this method the external bremsstrahlung (EB) photons produced in the Ni target foil by beta particles from a weak[superscript 90]Sr-[superscript 90]Y beta source are passed through an elemental target and the ...
ERIC Educational Resources Information Center
... the x-ray absorption edges. Tungsten and carbon have edges about 7 and 44 A corresponding to the tungsten M edges and the carbon K edge ...
Both the K absorption edge and the K-shell photoelectric cross section have been determined for Hf, Ta, Au, and Pb by using a continuous external bremsstrahlung (EB) radiation from a weak {beta} source. In this method the EB photons produced in a nickel foil by the {beta} particles from a weak {sup 90}Sr-{sup 90}Y {beta} source are incident on a target and ...
GaAs Blocked-Impurity-Band (BIB) photoconductor detectors have the potential to become the most sensitive, low noise detectors in the far-infrared below 45.5 cm{sup -1} (220 {micro}m). We have studied the characteristics of liquid phase epitaxial GaAs films relevant to BIB production, including impurity band formation and the infrared ...
... Descriptors : *LAYERS, *INFRARED DETECTORS, *ABSORPTION, MATHEMATICAL MODELS, OPTICAL PROPERTIES, THIN FILMS ...
A method is presented whereby the intrinsic efficiency of Ge is utilized to calculate the expected peak efficiency of detectors having a wide range of sizes. The intrinsic efficiency of Ge, which is the probability for total absorption, was measured at 122 and 136 keV in Ge(Li) coaxial detectors and HPGe planar ...
A system for the measurement of fluorescence EXAFS using 6 NaI (Tl) scintillation detectors has been commissioned on the Wiggler line of the Daresbury Synchrotron Radiation Source (SRS). Results at the copper and molybdenum K-edges are presented to illust...
Fluorescence extended x-ray absorption fine structure spectroscopy (EXAFS) is a commonly used technique in conjunction with x-ray synchrotron radiation for studying the local atomic structure of dilute elements in biological, geological and materials systems. Due to the nature of the EXAFS technique, and the difficulties associated with the detection of low energy x-rays, ...
The effects of UV irradiation (?=254 nm) on polyester nuclear track detector have been investigated employing bulk-etch technique, UV-visible spectrophotometry and infra-red spectrometry (FTIR). The activation energy values for bulk-etching were found to decrease with the UV-irradiation time indicating the scission of the polymer. Not much shift in the ...
In this article we present a setup of a spectrometer for near edge x-ray absorption spectroscopy at the carbon K-edge (284 eV). The spectrometer works with a laser produced plasma as x-ray source and a single x-ray optical element in grazing incidence configuration called off-axis reflection zone plate. Using different sample foils we ...
The Monte-Carlo method is used to model perturbation to the dose response of solid-state detectors and biological systems in the vicinity of the K-edge of constituent elements. Diamond detectors are examined where silver-based (Ag) solders are used to form electrical contact with the diamond crystal. Perturbation from photoelectric ...
We have surveyed the chemical utility of the near-edge structure of molybdenum X-ray absorption edges from the hard X-ray K-edge at 20,000eV down to the soft X-ray M(4,5)-edges at approximately 230eV. We compared, for each edge, the spectra of two tetrahedral anions, ...
The chemical short-range structure was studied in liquid Al-Ni alloys by x-ray absorption spectroscopy as a function of temperature and composition. A containerless technique, combining aerodynamic levitation and inductive heating, was used to position and melt the samples. The fluorescence yield x-ray absorption at the Ni K edge was ...
The blue curve gives the fractional excess when trailing edge detectors are included. Any excess seen in this curve isn't due to photons incident on leading ...
NASA Website
Automation of x-ray absorption spectroscopic (XAS) data reduction is essential to cope with high-throughput data collection becoming available at an increasing number of synchrotron radiation centers. A flexible script called KEMP has been developed and implemented at the XAS beamline at EMBL Hamburg. It automatically processes fluorescence XAS data. The pipeline includes dead ...
Transition edge sensors (TESs) have been developed to be used as high-resolution x-ray detectors. They show excellent energy resolution and can be used in many applications. TESs are a special kind of calorimeters that can determine small temperature changes after x-ray absorption. Such a temperature change causes a strong resistance ...
The goal of this paper was to investigate the benefits that could be realistically achieved on a microCT imaging system with an energy-resolved photon-counting x-ray detector. To this end, we built and evaluated a prototype microCT system based on such a detector. The detector is based on cadmium telluride (CdTe) radiation sensors and ...
Contents: TASC detectors for 'electromagnetic' or Type A particles; Performance of TASC detectors; TANC detectors for 'strongly interacting' or Type B particles; Outlook for the future.
Regions of incomplete charge collection, or dead layers'', are compared for Si(Li) detectors fabricated with Au and Pd entrance window electrodes. The dead layers were measured by characterizing the detector spectral response to x-ray energies above and below the Si K{alpha} absorption edge. It ...
The authors are developing x-ray and gamma-ray spectrometers with high absorption efficiency and high energy-resolution for x-ray and gamma-ray spectroscopy. They are microcalorimeters consisting of a bulk Sn absorber coupled to a Mo/Cu multilayer superconducting transition edge sensor (TES). The authors have measured an energy resolution of 70 eV FWHM for ...
Under the Characterization, Monitoring, and Sensor Technology Crosscutting Program, the authors have designed and built a K-edge heavy metal detector that measures the level of heavy metal contamination inside closed containers in a nondestructive, non-invasive way. The device employs a volumetric technique that takes advantage of the X-ray ...
The contribution of scattering effects to the X-ray fluorescence intensity was studied for pure element samples, BaB binary samples and fused disk samples by theoretic calculation and experiment. Three scattering effects were considered in the present study, i. e. coherent scattering effect, incoherent scattering effect, and primary fluorescence that was scattered into the direction of ...
The total mass attenuation coefficient for Potassium dichromate, Potassium chromate and Manganese acetate compounds are measured at different photon energies 5.895, 6.404, 6.490, 7.058, 8.041 and 14.390 keV using Fe-55, Co-57 and 241Am source with Copper target, radioactive sources. The photon intensity is analyzed using a high resolution HPGe detector system coupled to MCA ...
The charge-collection efficiency of beveled-edge-type silicon avalanche photodiodes has been determined for soft x rays in the 50--300-eV range. An efficiency of greater than 80% is measured for energies below the Si {ital L} absorption edge. The measured efficiency is well described by a model that accounts for ...
The objective of this article is to describe the capability of a two-dimensional (2D) approach to X-ray absorption near-edge structure (XANES) measurement by means of a partial fluorescence yield (PFY) method. 2D-XANES measurements were achieved by using a silicon drift detector as an energy-dispersive fluorescence ...
Polycrystalline thin films of CrSi2, LaSi2, and ReSi2 were grown on silicon substrates. Normal incidence optical transmittance and reflectance measurements were made as a function of wavelength. It was demonstrated that LaSi2 is a metallic conductor, but that CrSi2 and ReSi2 are, in fact, narrow bandgap semiconductors. For CrSi2, the complex index of refraction was determined by computer analysis ...
iron K absorption edge. This decline is too broad for a single edge, and instead ... constrain the iron K absorption feature evident in Figure 6. ...
... K-edge and L-edge absorptions are the only ... dichroism (MCD), or more specifically x-ray MCD (XMCD ... of the difference between the absorption of left ...
... Title : STRUCTURE OF K X-RAY ABSORPTION EDGES OF ARGON AND KRYPTON IN GASEOUS AND SOLID STATES. ...
X-ray spectroscopy codes were applied to achieve quantitative interpretation of x-ray absorption near edge structure
X-ray absorption edge observation by transmittance measurements through thin unbacked metal films in
NASA Technical Reports Server (NTRS)
... Descriptive Note : Final technical rept., 1 Feb 64-31 Jan 66. ... of the sensitivity of absorption edge position to valence in a series of iron compounds. ...
X-ray fluorescence spectroscopy is a widely used method for determining the electronic configuration and local structure of dilute species with high sensitivity. In the dilute limit, and for thin films, the X-ray fluorescence signal is directly proportional to the atomic sub-shell absorption coefficient. However, for concentrated samples, the well-documented ...
We evaluate experimentally the intrinsic detection efficiency (IDE) of superconducting NbN nanowire single-photon detectors in the range of wire thicknesses from 4 to 12 nm. The study is performed in the broad spectral interval between near-ultraviolet (wavelength 400 nm) and near-infrared (wavelength 2000 nm) light with plane waves at normal incidence. For visible light the ...
... measurements demonstrate that the particles are superparamagnetic with a blocking temperature T about 55 K. The optical absorption edge of the ...
... Title : IMPURITY ABSORPTION DUE TO TRANSITIONS TO CONDUCTION BAND EDGE REGION IN PHOSPHORUS-DOPED SILICON. ...
This paper presents an evaluation of edge detector performance. We use the task of structure from motion (SFM) as a "black box" through which to evaluate the performance of edge detection algorithms. Edge detector goodness is measured by how accurately the SFM could recover the known structure ...
We present a derivation of the main contrast mechanisms accessible in scanning transmission x-ray microscopy with a pixel-array detector. We consider the effect of the probe defocus and show that it can produce strong differential absorption contrast. The effect of noise is derived and used to compare the relative merits of absorption ...
PubMed Central
Qualitative phase contrast (QPC) imaging is a powerful tool to assess objects or composites with low or nearly the same attenuation coefficient resulting in a low absorption contrast. QPC imaging provides additional information like enhanced contrast at edges and interfaces as well as the possibility to separate materials with similar attenuation ...
... Corporate Author : STANFORD UNIV CALIF HIGH ENERGY PHYSICS LAB. ... detectors for 'electromagnetic' or Type A particles; Performance of ...
... Descriptors : *INFRARED DETECTORS, *GERMANIUM ALLOYS, *SILICON ALLOYS, LASER BEAMS, RADIATION ABSORPTION, CRYSTAL ...
... conductor detectors offer significant advantages for multielement analyses in fields such as atomic absorption and atomic emission spectroscopy. ...
The measurements of the piezo-absorption in the absorption edge region for germanium and silicon was concluded. A theoretical calculation of the matrix elements for these indirect transitions at the center of the Brillouin Zone in silicon was published in...
... IMPROVING SPECTRAL FITS OF ABSORPTION DATA TAKEN WITH AN ARRAY DETECTOR: WAVELENGTH "LINEARIZATION" ... w Wavelength ...
... ANALYSIS, CROSS SECTIONS, REMOTE DETECTORS, SPACE SHUTTLES, ABSORPTION, CARBON MONOXIDE, ABSORPTION SPECTRA ...
The reflectivity of the gold-coating on the XRT mirrors is a decreasing function of energy with a number of additional (minor) absorption edges. ...
... Title : INFLUENCE OF THE ION-IMPLANTED OXYGEN ON THE ABSORPTION EDGE AND ELECTRICAL PROPERTIES OF AMORPHOUS ...
... STRUCTURAL GEOMETRIES: THE EFFECTS OF EDGE ... of strength, energy absorption and transition ... difference in transition temperature for the ...
Edges characterize the boundaries of objects in images and are informative structural cues for computer vision and target/object detection and recognition systems. The Canny edge detector is widely regarded as the edge detection standard. It is fairly adaptable to different environments, as its parametric nature ...
