44 research outputs found

    Anisotropy of charge and spin motion in arene radical cation salts

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    We summarize our attempts to derive the intrinsic anisotropy of the electrical conductivity and the spin diffusion coefficient in the metallic phase above the Peierls transition of the highly anisotropic radical cation salts of arenes

    THE LINE FOCUS X-RAY TUBE: AN X-RAY SOURCE FOR FLASH AND SPATIALLY FRACTIONATED RADIATION THERAPY

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    Background and Aims: FLASH and spatially fractionated radiationtherapy (SFRT) demonstrated reduced side effects at equal tumourcontrol compared to conventional radiotherapy. Currently onlylarge synchrotrons may facilitate clinical x-ray FLASH or SFRTtreatments. We are constructing a prototype of an innovative, table-top x-ray source that will allow FLASH and SFRT treatments. Thesource is based on the line focus x-ray tube (LFxT) concept and willeventually deliver dose rates of up to 200 Gy/s.Methods: We designed a thermionic electron gun that generatesa low-emittance, high-current electron beam at 300 keV. Twoquadrupole magnets focus the electrons onto a 50 micrometer wide focalspot on a tungsten-molybdenum target that spins at 250 Hz. Weassessed the radiation field, temperature and mechanical stressconditions with finite-element and Monte Carlo simulations. Theseparation tube equipped motor drive and liquid metal bearings fitfor operation in ultra-high vacuum. We developed a high-voltagesupply based on modular multi-level converter (MMC) technologyfor increased power in a future clinical source.Results: Finite element simulations showed an operation of theLFxT in the heat capacity limit permitting substantially enhanceddose rates at small focal spot sizes. Thermal and mechanical stressesare tolerated by the target design. An MMC based DCDC converterwith 320 battery-powered units can store enough energy to supplythe source with 2 MW electrical power in a duty cycle of 2%
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