Testing of gadolinium oxy-sulphide phosphors for use in CCD-based X-ray detectors for macromolecular crystallography

The resolution and detective quantum efficiency of CCD-based detectors used for X-ray diffraction is primarily affected by the layer of phosphor that converts incident X-ray photons into visible photons. The optimum thickness of this phosphor layer is strongly dependent on the fraction of absorbed incident X-ray photons and required spatial resolution. A range of terbium doped gadolinium oxy-sulphide (Gd2O2S:Tb) phosphor samples, provided by Applied Scintillation Technologies, have been evaluated for spatial resolution, light output and uniformity. The phosphor samples varied in coating weight (10-25 mg/cm2), grain size (2.5, 4, 10 μm), and applied coating (no coating, reflectors and absorbers). In addition, a non-uniform layer was introduced to some samples in order to provide an inherent diffusion layer. The experimental results showed that the introduction of a reflector increases the point spread function (PSF) and increases light yield up to 30%, while an absorber reduces the PSF tails and decreases the light yield up to 35%. The PSF linearly increases with thickness, while the greatest light yield was obtained with phosphor samples of 4 μm particle size. © 2002 Elsevier Science B.V. All rights reserved

ekoNET - Environmental Monitoring using Low-cost Sensors for Detecting Gases, Particulate Matter and Meteorological Parameters

This paper presents the environmental monitoring solution ekoNET, developed for a real-time monitoring of air pollution and other atmospheric condition parameters such as temperature, air pressure and humidity. The system is based on low-cost gas, PM and meteorological sensors providing cost-efficient, simple to deploy, use and maintain solution targeted for the usage within the Internet of Things domain of smart cities and smart enterprises. The paper gives an overview of the system architecture, encompassing the ekoNET device, back-end cloud infrastructure, data handling and visualization engine as well as the application-level components and modules. Furthermore, initial field trial data of twelve ekoNET devices is presented, enabling the overall system operation performance testing.International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing., 8th International Conference on Innovative Mobile and Internet Services in Ubiquitous Computing (IMIS), Jul 02-04, 2014, Birmingham City Univ, Birmingham, Englan

Testing of gadolinium oxy-sulphide phosphors for use in CCD-based X-ray detectors for macromolecular crystallography

The resolution and detective quantum efficiency of CCD-based detectors used for X-ray diffraction is primarily affected by the layer of phosphor that converts incident X-ray photons into visible photons. The optimum thickness of this phosphor layer is strongly dependent on the fraction of absorbed incident X-ray photons and required spatial resolution. A range of terbium doped gadolinium oxy-sulphide (Gd2O2S:Tb) phosphor samples, provided by Applied Scintillation Technologies, have been evaluated for spatial resolution, light output and uniformity. The phosphor samples varied in coating weight (10-25 mg/cm2), grain size (2.5, 4, 10 ?m), and applied coating (no coating, reflectors and absorbers). In addition, a non-uniform layer was introduced to some samples in order to provide an inherent diffusion layer. The experimental results showed that the introduction of a reflector increases the point spread function (PSF) and increases light yield up to 30%, while an absorber reduces the PSF tails and decreases the light yield up to 35%. The PSF linearly increases with thickness, while the greatest light yield was obtained with phosphor samples of 4 ?m particle size. © 2002 Elsevier Science B.V. All rights reserved.</p

Large area high-resolution CCD-based X-ray detector for macromolecular crystallography

An X-ray detector system for macromolecular crystallography based on a large area charge-coupled device (CCD) sensor has been developed as part of a large research and development programme for advanced X-ray sensor technology, funded by industry and the Particle Physics and Astronomy Research Council (PPARC) in the UK. The prototype detector consists of two large area three-sides buttable charge-coupled devices (CCD 46-62 EEV), where the single CCD area is 55.3mm41.5 mm. Overall detector imaging area is easily extendable to 85mm110 mm. The detector consists of an optically coupled X-ray sensitive phosphor, skewed fibre-optic studs and CCDs. The crystallographic measurement requirements at synchrotron sources are met through a high spatial resolution (20481536 pixel array), high dynamic range (B105), a fast readout (B1 s), low noise (o10e) and much reduced parallax error. Additionally, the prototype detector system has been optimised by increasingits efficiency at low X-ray energies for use at conventional lab sources. The system design of the prototype detector is discussed and the proposed method for crystallographic data processing is briefly outlined