Scintillation

About: Scintillation is a research topic. Over the lifetime, 14022 publications have been published within this topic receiving 187694 citations.

Lithium-doped two-dimensional perovskite scintillator for wide-range radiation detection

Abstract: Two-dimensional lead halide perovskites have demonstrated their potential as high-performance scintillators for X- and gamma-ray detection, while also being low-cost Here we adopt lithium chemical doping in two-dimensional phenethylammonium lead bromide (PEA)2PbBr4 perovskite crystals to improve the properties and add functionalities with other radiation detections Li doping is confirmed by X-ray photoemission spectroscopy and the scintillation mechanisms are explored via temperature dependent X-ray and thermoluminescence measurements Our 1:1 Li-doped (PEA)2PbBr4 demonstrates a fast decay time of 11 ns (80%), a clear photopeak with an energy resolution of 124%, and a scintillation yield of 11,000 photons per MeV under 662 keV gamma-ray radiation Additionally, our Li-doped crystal shows a clear alpha particle/gamma-ray discrimination and promising thermal neutron detection through 6Li enrichment X-ray imaging pictures with (PEA)2PbBr4 are also presented All results demonstrate the potential of Li-doped (PEA)2PbBr4 as a versatile scintillator covering a wide radiation energy range for various applications Two-dimensional lead halide perovskites have shown great potential as X- and γ-ray scintillators due to their high light yield, fast decay rate, and low fabrication cost Here, their versatility is expanded by achieving, via Li-doping, α-particle/γ-ray discrimination and thermal neutron detection

Energy resolution of scintillation detectors

Abstract: According to current knowledge, the non-proportionality of the light yield of scintillators appears to be a fundamental limitation of energy resolution. A good energy resolution is of great importance for most applications of scintillation detectors. Thus, its limitations are discussed below; which arise from the non-proportional response of scintillators to gamma rays and electrons, being of crucial importance to the intrinsic energy resolution of crystals. The important influence of Landau fluctuations and the scattering of secondary electrons (δ-rays) on intrinsic resolution is pointed out here. The study on undoped NaI and CsI at liquid nitrogen temperature with a light readout by avalanche photodiodes strongly suggests that the non-proportionality of many crystals is not their intrinsic property and may be improved by selective co-doping. Finally, several observations that have been collected in the last 15 years on the influence of the slow components of light pulses on energy resolution suggest that more complex processes are taking place in the scintillators. This was observed with CsI(Tl), CsI(Na), ZnSe(Te), and undoped NaI at liquid nitrogen temperature and, finally, for NaI(Tl) at temperatures reduced below 0 °C. A common conclusion of these observations is that the highest energy resolution, and particularly intrinsic resolution measured with the scintillators, characterized by two or more components of the light pulse decay, is obtainable when the spectrometry equipment integrates the whole light of the components. In contrast, the slow components observed in many other crystals degrade the intrinsic resolution. In the limiting case, afterglow could also be considered as a very slow component that spoils the energy resolution. The aim of this work is to summarize all of the above observations by looking for their origin.

High energy x-y neutron detector and radiographic/tomographic device

Abstract: An improved fast neutron x-y detector and radiographic/tomographic device utilizing a white neutron probe (4). The invention includes a multiple scattering filter (44), radiographic and tomographic imaging of the number densities of atoms in small volume increments through a sample 32 and the atomic, chemical and physical structure of a sample, (32), and neural net analysis techniques, where the neural net is trained through use of simulated volume increments. The invention detects fast neutrons over a two dimensional plane, measures the energy of the neutrons, and discriminates against gamma rays. In a preferred embodiment, the detector face is constructed by stacking separate bundles (6) of scintillating fiber optic strands (20) one on top of the other. The first x-y coordinate is determined by which bundle (6) the neutron strikes. The other x-y coordinate is calculated by measuring the difference in time of flight for the scintillation photon to travel to the opposite ends of the fiber optic strand 20. In another embodiment, the detector is constructed of discrete scintillator sections (48) connected to fiber optic strands (52) by couplers (50) functioning as lens. The fiber optic strands (52) are connected to a multi-anode photomultiplier (100) tube (56). The x-y coordinate of a neutron interaction is determined by the row and column of the affected scintillation section (48). Neutron energy for both detectors is calculated by measuring the flight time of a neutron from a point source (2) to the detector face.