Search results for "CHAMBER"
showing 10 items of 359 documents
Measurement of the production of charged pions by protons on a tantalum target
2007
38 páginas, 31 figuras, 4 tablas.-- PACS nrs.: 13.75.Cs; 13.85.Ni.-- El Pdf del artículo es la versión pre-print: arXiv:0706.1600v1.-- HARP Collaboration: et al.
International Scoping Study (ISS) for a future neutrino factory and Super-Beam facility. Detectors and flux instrumentation for future neutrino facil…
2009
Technical report by The ISS Detector Working Group; This report summarises the conclusions from the detector group of the International Scoping Study of a future Neutrino Factory and Super-Beam neutrino facility. The baseline detector options for each possible neutrino beam are defined as follows: 1. A very massive (Megaton) water Cherenkov detector is the baseline option for a sub-GeV Beta Beam and Super Beam facility. 2. There are a number of possibilities for either a Beta Beam or Super Beam (SB) medium energy facility between 1-5 GeV. These include a totally active scintillating detector (TASD), a liquid argon TPC or a water Cherenkov detector. 3. A 100 kton magnetized iron neutrino det…
Evaluation of Galantamine transbuccal absorption by reconstituted human oral epithelium and porcine tissue as buccal mucosa models: Part I
2008
Over the last decade, interest in delivering drugs through buccal mucosa has increased. As a major limitation in buccal drug delivery could be the low permeability of the epithelium, the aim of this study was to evaluate the aptitude of galantamine, useful in Alzheimer's disease, to penetrate the buccal mucosa. The evaluation of the ability of galantamine to permeate through the buccal epithelium was investigated using two permeation models. Firstly, in vitro permeation experiments were carried out using reconstituted human oral non-keratinised epithelium and Transwell diffusion cells system. Results were validated by ex vivo experiments using porcine buccal mucosa as membrane and Franz typ…
Modulation transfer function: Rigid versus foldable phakic intraocular lenses
2008
Purpose To study in a standard eye model the changes in modulation transfer function (MTF) of a monofocal intraocular lens (IOL) when a phakic IOL (pIOL) is placed in the anterior chamber, compare the MTFs of the rigid Artisan pIOL and foldable Artiflex pIOL, and evaluate the temporal evolution of the MTF of the foldable pIOL after the mechanical stress the pIOL undergoes when injected. Setting Fundacion Oftalmologica del Mediterraneo, Valencia, Spain. Methods The MTF values of the IOLs were calculated from the cross-line spread function recorded with the Opal Vector System. The measurements were taken using an eye model following the British and EN-ISO standards with 2.0 mm, 3.0 mm, 4.0 mm…
The posterior chamber phakic refractive lens (PRL): a review
2012
Implantation of phakic intraocular lenses (pIOLs) is a reversible refractive procedure, preserving the patient’s accommodative function with minimal induction of higher order aberrations compared with corneal photoablative procedures. Despite this, as an intraocular procedure, it has potential risks such as cataracts, chronic uveitis, pupil ovalization, corneal endothelial cell loss, pigmentary dispersion syndrome, pupillary block glaucoma, astigmatism, or endophthalmitis. Currently, only two models of posterior chamber pIOLs are commercially available, the implantable collammer lens (STAAR Surgical Co.) and the phakic refractive lens (PRL; Zeiss Meditec). The number of published reports on…
Acute exposure to 50ppm toluene does not increase sleepiness
2005
Abstract The Pupillographic Sleepiness Test (PST) is a new neurophysiological method to assess sleepiness. In an exposure study to a constant exposure level of 50 ppm toluene on 20 healthy men, our aim was to find out, if increased sleepiness could be seen with PST. PST was performed before and after 4.5 h of exposure. General complaints were assessed with the Swedish Performance Evaluation System (SPES) self-assessment questionnaire, once before and during exposure. Values obtained during exposure were related to pre-exposure values. Parametric cross-over analysis of logarithmic Pupillary Unrest Index (PUI) values did not show an effect of toluene exposure. In a nonparametric cross-over an…
Gradients in physical parameters in zoned felsic magma bodies: Implications for evolution and eruptive withdrawal
1990
Abstract Five diverse, well documented, chemically zoned magmas have been chosen from the literature to demonstrate the extent and patterns of density and viscosity gradients in zoned magma chambers. The patterns are used to assess implications for development of zonation, and withdrawal dynamics and preservation of systematic chemical variations in the final pyroclastic deposit. These examples are: Bishop Tuff, California (high-silica rhyolite); Los Humeros, Mexico (calc-alkaline rhyolite to andesite); Fogo A, Azores (trachyte); Laacher See, Eifel (phonolite) and Tenerife, Canary Islands (phonolite). It was necessary to make several simplifying assumptions in order to calculate viscosity a…
Operation and first results of the NEXT-DEMO prototype using a silicon photomultiplier tracking array
2013
NEXT-DEMO is a high-pressure xenon gas TPC which acts as a technological test-bed and demonstrator for the NEXT-100 neutrinoless double beta decay experiment. In its current configuration the apparatus fully implements the NEXT-100 design concept. This is an asymmetric TPC, with an energy plane made of photomultipliers and a tracking plane made of silicon photomultipliers (SiPM) coated with TPB. The detector in this new configuration has been used to reconstruct the characteristic signature of electrons in dense gas, demonstrating the ability to identify the MIP and "blob" regions. Moreover, the SiPM tracking plane allows for the definition of a large fiducial region in which an excellent e…
Investigation of correction factors for non-reference conditions in ion chamber photon dosimetry with Monte-Carlo simulations.
2009
Current dosimetry protocols require geometrical reference conditions for the determination of absorbed dose in external radiotherapy. Whenever these geometrical conditions cannot be maintained the application of additional corrections becomes necessary, in principle. The current DIN6800-2 protocol includes a corresponding factor k(NR), but numerical values are lacking and no definite information about the magnitude of this correction is available yet. This study presents Monte-Carlo based calculations within the 6 MV-X photon field of a linear accelerator for a common used ion chamber (PTW31010) employing the EGSnrc code system. The linear accelerator model was matched to measurements, show…
Characterization of PTW-31015 PinPoint ionization chambers in photon and proton beams
2018
The increased use of complex forms of radiotherapy using small-field photon and proton beams has invoked a growing interest in the use of micro-ionization chambers. In this study, 48 PTW-TM31015 PinPoint-type micro-ionization chambers that are used in the commissioning and patient specific QA of a proton pencil beam scanning (PBS) delivery system have been characterized in proton and high-energy photon beams. In both beam modalities, the entire set of PinPoint chambers was characterized by imaging them, by evaluating their stability using check source measurements, by experimentally determining the ion recombination, polarity effect and by cross calibrating them in terms of absorbed dose to…