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When a photon interacts in a PCD, the amplitude of the resulting electrical pulse is roughly proportional to the photon energy. By comparing each pulse produced in a pixel with a suitable low-energy threshold, contributions from low-energy events (resulting from both photon interactions and electronic noise) can be filtered out. This ...
Modeling photon propagation with Monte Carlo methods is a flexible yet rigorous approach to simulate photon transport. In the method, local rules of photon transport are expressed as probability distributions which describe the step size of photon movement between sites of photon-matter interaction and the angles of deflection in a photon's trajectory when a scattering event occurs.
Dual-energy imaging, i.e. imaging at two energy levels, is a special case of spectral imaging and is still the most widely used terminology, but the terms "spectral imaging" and "spectral CT" have been coined to acknowledge the fact that photon-counting detectors have the potential for measurements at a larger number of energy levels.
Photon statistics is the theoretical and experimental study of the statistical distributions produced in photon counting experiments, which use photodetectors to analyze the intrinsic statistical nature of photons in a light source.
Comparing the energy of a neutron, electron or photon with a wavelength of the order of the relevant length scale in a solid - as given by the de Broglie equation considering the interatomic lattice spacing is in the order of Ångströms - it derives from the relativistic energy–momentum relation that an X-ray photon has more energy than a ...
Fluorescence-lifetime imaging microscopy or FLIM is an imaging technique based on the differences in the exponential decay rate of the photon emission of a fluorophore from a sample. It can be used as an imaging technique in confocal microscopy , two-photon excitation microscopy , and multiphoton tomography.
Shot noise is easily observable in the case of photomultipliers and avalanche photodiodes used in the Geiger mode, where individual photon detections are observed. However the same noise source is present with higher light intensities measured by any photo detector , and is directly measurable when it dominates the noise of the subsequent ...
where N is the number of collected photons, a is the pixel size of the imaging detector, is the average background signal and is the standard deviation of the point spread function. [10] The requirement of localizing at the same time multiple fluorophores simultaneously over an extended area determines the reason why these methods are wide ...