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Simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI) can provide both functional and structural information about disease. However, for quantitative PET measurements all sources of scatter and absorption that photons undergo on their trajectory between source and detector must be assessed. In simultaneous PET/MR, this includes the scatter and absorption undergone in...
Modern x-ray CT systems measure the total energy of all photons incident to detectors, and thus it is very difficult to identify a medium with an x-ray CT image. We proposed a new method to identify a medium with an x-ray CT system, in which we used a detector that could measure photons with several energy windows. Our method identifies an object with a set of linear attenuation coefficients of the...
ICx Radiation has developed a novel method to determine the direction of radiation with a device containing only two detectors by comparing and analyzing the paired-energy distributions of coincident events. The method does not require complex image reconstruction but rather extracts the directionality from the means and skewness of the two coincidence spectra. All energy data contribute to the energy...
Decommissioning of nuclear power plant will increase a number of radioactive wastes near future. In Japan, some of the radioactive wastes will show high intensity of radiation and must be disposed in underground that deep enough from human activities. Therefore, it is important to estimate the inventory of such intense radioactive wastes. But it is difficult to verify the inventory of such radioactive...
CdTe is a promising sensor material for the detection of γ-Rays and X-Rays as it offers an absorption efficiency higher than 50 % for photon energies up to 120 keV for 1 mm thick sensors. Connected to the pixilated, single-photon counting readout electronics Timepix, its application at a synchrotron source was investigated. The focus of the investigations was on the high flux behavior of the CdTe-Timepix...
ChromAIX is an ASIC for fast single photon-counting designed to study the feasibility of energy-resolved photon-counting human Spectral CT. It allows for reading out 4 × 16 pixels of a direct converting sensor made of Cd[Zn]Te with a pixel pitch of about 300μm. It supports K-edge imaging [3]. After thorough electrical testing reported in [6] characterization under g- and X-rays was done giving promising...
Direct conversion detectors are increasingly used in digital mammography. Investigation of new breast imaging techniques such as digital breast tomosynthesis that provide information in three dimensions has thus been made possible. Amorphous Selenium is currently the most common direct converting digital detector material The prospect of optimum energy weighting and photon counting to improve detector...
This paper presents multi dimensional approaches for material identification applied on experimental X-ray measurements obtained with CdTe spectrometric detector. LETI has been developing a 16 channels fast read-out electronics capable to perform spectrometric measurements at count rates above 107 counts/s. The read-out electronics was coupled to CdTe linear array pixel detectors. A multidimensional...
We present in this paper the study ofspecial nuclear materials(SNM) detection method based on Pair production and Compton scattering Atomic Number Identification (PCANI) technique. PCANI, a technique that uses the information of annihilation and Compton scattered photons from target is applied at first to achieve the atomic number(Z) identification. Because of the Z2 and Z1 relationship of pair production...
Photon counting detectors with electronic spectrum splitting, such as cadmium telluride (CdTe) and cadmium zinc telluride (CZT) detectors have been widely used in x-ray imaging. We research the feasibility of material discrimination using dual energy imaging with CZT photon counting detector. The initial x-ray spectrum is from the X-ray tube with a voltage of 160 kVp, and the x-ray spectrum is calculated...
Thomson scattering is a phenomenon taking place for low energy X and gamma ray photons. It is known as the basis of photon reflection from surfaces at grazing angle of incidence. Using existing data on terahertz reflection coefficient, it is shown that Thompson scattering is a plausible explanation for terahertz reflection from surfaces. In the present work, preliminary computation shows that the...
A new generation of ultra-narrow band gap materials made from trapped atoms enables the velocity dependence of the force of radiation pressure to be greatly enhanced. Estimates for an array of trapped 87Rb show a significant effect for velocities ~ ms-1.
We calculated isotropic and anisotropic Bragg interaction geometry in silicon based 2D photonic crystals with square and triangle lattice. Bragg angle vs. acoustic wave frequency dependencies are presented and compared for both structures. Further research aims and expected effects are defined.
An excellent agreement is achieved between calculated and experimental performances for published designs. By optimization of gain saturation in the structure, wall plug efficiency can be increased by more than 50%.
This paper reviews our recent activities on nanophotonics based on a photonic crystal (PC)/quantum dot (QD)-combined structure for an all-optical device and a metal/semiconductor composite structure using surface plasmon (SP) and negative refractive index material (NIM). The former structure contributes to an ultrafast signal processing component by virtue of new PC design and QD selective-area-growth...
In this paper, we present experimental results showing how appropriately designed and constructed artificial materials can be used to refract negatively terahertz frequency light without the need for the materials to have both a negative permeability and a negative permittivity.
We have investigated the light-current characteristics of terahertz quantum cascade lasers using an external light whose energy is below the bandgap energy of the host material. It is found that light injection induces a large modulation depth, up to 100%.
Besides several other factors, radiometric differences between a reference and a floating image greatly influence the achievable accuracy of image registration. In this work we derive the magnitude of registration inaccuracy coming from changes in radiometric properties. This is done for the example of medical X-ray image registration. We therefore estimate the change of image intensity with respect...
In this paper propagation of electromagnetic waves in self-organized eutectic structures with SRR-like inclusions is studied through modelling. The focus is to examine the electromagnetic response of two different-size SRRs in close proximity with each other, and how their interaction affects this response. Under certain conditions a double non-disturbed resonance has been observed in a material containing...
Microthermophotovoltaic (micro-TPV) systems are generators currently being extensively developed to convert radiation heat energy from hydrocarbon fuel combustion into useful electricity by using low band-gap photovoltaic cell for microelectromechanical systems (MEMS). Micro-TPV systems consist of a heat source (microcombustor), a thermal emitter (microcombustor surfaces), a dielectric/optical filter,...
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