232 research outputs found

    A Non-Scaling FFAG Gantry Design for the PAMELA Project

    Get PDF
    A gantry is re­quired for the PAMELA pro­ject using non-scal­ing Fixed Field Al­ter­nat­ing Gra­di­ent (NS-FFAG) mag­nets. The NS-FFAG prin­ci­ple of­fers the pos­si­bil­i­ty of a gantry much small­er, lighter and cheap­er than con­ven­tion­al de­signs, with the added abil­i­ty to ac­cept a wide range of fast chang­ing en­er­gies. This paper will build on pre­vi­ous work to in­ves­ti­gate a de­sign which could be used for the PAMELA pro­ject

    An FFAG Transport Line for the PAMELA Project

    Get PDF
    The PAMELA project to design an accelerator for hadron therapy using non-scaling Fixed Field Alternating Gradient (NS-FFAG) magnets requires a transport line and gantry to take the beam to the patient. The NS-FFAG principle offers the possibility of a gantry much smaller, lighter and cheaper than conventional designs, with the added ability to accept a wide range of fast changing energies. This paper will build on previous work to investigate a transport line which could be used for the PAMELA project. The design is presented along with a study and optimisation of its acceptance

    Effective lifetimes exceeding 300 μs in gettered p-type epitaxial kerfless silicon for photovoltaics

    Get PDF
    We evaluate defect concentrations and investigate the lifetime potential of p-type single-crystal kerfless silicon produced via epitaxy for photovoltaics. In gettered material, low interstitial iron concentrations (as low as (3.2 ± 2.2) × 10[superscript 9] cm[superscript −3]) suggest that minority-carrier lifetime is not limited by dissolved iron. An increase in gettered lifetime from 300 μs is observed after increasing growth cleanliness. This improvement coincides with reductions in the concentration of Mo, V, Nb, and Cr impurities, but negligible change in the low area-fraction (23%.United States. Dept. of Energy (Contract DE-EE0005314)National Science Foundation (U.S.) (United States. Dept. of Energy NSF CA EEC-1041895)American Society for Engineering Education. National Defense Science and Engineering Graduate FellowshipAlexander von Humboldt-Stiftung (Feodor Lynen Postdoctoral Fellowship

    Pamela: development of the RF system for a non-relativistic non-scaling FFAG

    Get PDF
    The PAMELA project(Particle Accelerator For MEdical Applications) currently consists of the design of a particle therapy facility. The project, which is in the design phase, contains Non-Scaling FFAG, particle accelerator capable of rapid beam acceleration, giving a pulse repetition rate of 1kHz, far beyond that of a conventional synchrotron. To realise the repetition rate, a key component of the accelerator is the rf accelerating system. The combination of a high energy gain per turn and a high repetition rate is a significant challenge. In this paper, options for the rf system of the proton ring and the status of development are presented

    Clarifying the role of three-dimensional transvaginal sonography in reproductive medicine: an evidenced-based appraisal

    Get PDF
    This overview describes and illustrates the clinical applications of three-dimensional transvaginal sonography in reproductive medicine. Its main applications include assessment of uterine anomalies, intrauterine pathology, tubal patency, polycystic ovaries, ovarian follicular monitoring and endometrial receptivity. It is also useful for detailed evaluation of failed and/or ectopic pregnancy. Three-dimensional color Doppler sonography provides enhanced depiction of uterine, endometrial, and ovarian vascularity

    Conceptual design of a nonscaling fixed field alternating gradient accelerator for protons and carbon ions for charged particle therapy

    Get PDF
    Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.The conceptual design for a nonscaling fixed field alternating gradient accelerator suitable for charged particle therapy (the use of protons and other light ions to treat some forms of cancer) is described.EPSR

    Homogenization of Halide Distribution and Carrier Dynamics in Alloyed Organic-Inorganic Perovskites

    Get PDF
    Perovskite solar cells have shown remarkable efficiencies beyond 22%, through organic and inorganic cation alloying. However, the role of alkali-metal cations is not well-understood. By using synchrotron-based nano-X-ray fluorescence and complementary measurements, we show that when adding RbI and/or CsI the halide distribution becomes homogenous. This homogenization translates into long-lived charge carrier decays, spatially homogenous carrier dynamics visualized by ultrafast microscopy, as well as improved photovoltaic device performance. We find that Rb and K phase-segregate in highly concentrated aggregates. Synchrotron-based X-ray-beam-induced current and electron-beam-induced current of solar cells show that Rb clusters do not contribute to the current and are recombination active. Our findings bring light to the beneficial effects of alkali metal halides in perovskites, and point at areas of weakness in the elemental composition of these complex perovskites, paving the way to improved performance in this rapidly growing family of materials for solar cell applications.Comment: updated author metadat

    Reproducibility of fetal heart volume by 3D-sonography using the XI VOCAL method

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>To assess the reliability of fetal heart volume measurement by three-dimensional sonography (3DUS) using the eXtended Imaging Virtual Organ Computer-aided AnaLysis (XI VOCAL) method.</p> <p>Methods</p> <p>This reliability study enrolled 30 pregnant women with singleton healthy pregnancies between 19 and 34 weeks of gestation. All volume acquirements were performed with a convex volumetric transducer (C3-7ED) coupled to an Accuvix XQ sonography device (Medison, Korea). The XI VOCAL 10 planes was the method of choice for volumetric measurement. 3D datasets were analyzed by two observers (EQSB and HJFM); fetal heart volume was measured twice by the first and once by the second observer to calculate intra and interobserver reproducibility. Statistical analysis used pareated Student's t test (p) and calculated Intraclass correlation coefficients (ICC). Bland-Altman plots were also constructed.</p> <p>Results</p> <p>We observed an excellent intra- and interobserver reliability for fetal cardiac volume assessed by XI VOCAL. For the intraobserver the ICC was 0.998 (95% CI: 0.997; 0.999), with mean of differences of 0.12 cm<sup>3 </sup>(95% limits of agreement: -0.84; +0.84; p = 0.130). For interobserver the ICC was 0.899 (95%CI: 0.996; 0.998), mean of differences 0.05 cm<sup>3 </sup>(95% limits of agreement: -0.84; +0.84; p = 0.175).</p> <p>Conclusion</p> <p>Fetal cardiac volume assessed by 3DUS using XI VOCAL method is highly reproducible between 19 to 34 gestational weeks.</p
    corecore