39 results match your criteria: "Institute for Radiation Physics[Affiliation]"
Entropy (Basel)
December 2024
Institute for Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany.
We present a synchronization transition study of the locally coupled Kuramoto model on extremely large graphs. We compare regular 405 and 1004 lattice results with those of 12,0002 lattice substrates with power-law decaying long links (ll). The latter heterogeneous network exhibits ds>4 spectral dimensions.
View Article and Find Full Text PDFPhys Rev E
February 2024
Institute of Theoretical Physics, University of Wroclaw, 50-204 Wroclaw, Poland.
The properties of plasmas in the low-density limit are described by virial expansions. Analytical expressions are known from Green's function approaches only for the first three virial coefficients. Accurate path-integral Monte Carlo (PIMC) simulations have recently been performed for the uniform electron gas, allowing the virial expansions to be analyzed and interpolation formulas to be derived.
View Article and Find Full Text PDFSci Rep
July 2021
Department of Physics, The University of Texas at Austin, Austin, TX, 78712-1081, USA.
We reconstruct spectra of secondary X-rays from a tunable 250-350 MeV laser wakefield electron accelerator from single-shot X-ray depth-energy measurements in a compact (7.5 × 7.5 × 15 cm), modular X-ray calorimeter made of alternating layers of absorbing materials and imaging plates.
View Article and Find Full Text PDFJACC Clin Electrophysiol
February 2021
Department of Cardiology, University Hospital Centre Vaudois, Lausanne, Switzerland. Electronic address:
Objectives: This study sought to investigate the RADPAD No Brainer (Worldwide Innovation and Technologies, Overland Park, Kansas) efficiency in reducing brain exposure to scattered radiation.
Background: Cranial radioprotective caps such as the RADPAD No Brainer are being marketed as devices that significantly reduce operator's brain exposure to scattered radiation. However, the efficiency of the RADPAD No Brainer in reducing brain exposure in clinical practice remains unknown to date.
Appl Radiat Isot
February 2021
European Council for Nuclear Research (CERN), Esplanade des Particules, CH-1211, Meyrin, Switzerland; Institute for Radiation Physics, Lausanne University Hospital, Rue du Grand-Pré, CH-1007, Lausanne, Switzerland.
We determined the distribution of activation products inside the magnet coils of a medical cyclotron that has been operational for fifteen years. Besides FLUKA, we based our approach on new software tools (RAW and ActiWiz) developed for high-energy accelerators at CERN. A combined analysis of measurements on the coils with Monte-Carlo simulations resulted in a detailed three-dimensional radiological characterisation of the coils.
View Article and Find Full Text PDFSci Rep
November 2020
Department of Mechanical and Aerospace Engineering, University of California at San Diego, La Jolla, CA, 92093, USA.
We present the first 3D fully kinetic simulations of laser driven sheath-based ion acceleration with a kilotesla-level applied magnetic field. The application of a strong magnetic field significantly and beneficially alters sheath based ion acceleration and creates two distinct stages in the acceleration process associated with the time-evolving magnetization of the hot electron sheath. The first stage delivers dramatically enhanced acceleration, and the second reverses the typical outward-directed topology of the sheath electric field into a focusing configuration.
View Article and Find Full Text PDFPhys Rev E
July 2020
Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093, USA.
A high-intensity laser beam propagating through a dense plasma drives a strong current that robustly sustains a strong quasistatic azimuthal magnetic field. The laser field efficiently accelerates electrons in such a field that confines the transverse motion and deflects the electrons in the forward direction. Its advantage is a threshold rather than resonant behavior, accelerating electrons to high energies for sufficiently strong laser-driven currents.
View Article and Find Full Text PDFRSC Adv
April 2020
Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen Lotharstr. 1 47057 Duisburg Germany
Atomic scale defects generated using focused ion as well as laser beams can activate ferromagnetism in initially non-ferromagnetic B2 ordered alloy thin film templates. Such defects can be induced locally, confining the ferromagnetic objects within well-defined nanoscale regions. The characterization of these atomic scale defects is challenging, and the mechanism for the emergence of ferromagnetism due to sensitive lattice disordering is unclear.
View Article and Find Full Text PDFRadiother Oncol
May 2020
OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany; German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), Germany; Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Germany; Department of Medical Physics, Faculty of Physics, TU Dort-mund University, Germany. Electronic address:
Background And Purpose: Proton radiotherapy offers the potential to reduce normal tissue toxicity. However, clinical safety margins, range uncertainties, and varying relative biological effectiveness (RBE) may result in a critical dose in tumor-surrounding normal tissue. To assess potential adverse effects in preclinical studies, image-guided proton mouse brain irradiation and analysis of DNA damage repair was established.
View Article and Find Full Text PDFStruct Dyn
July 2019
Elettra Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5 in Area Science Park, I-34149 Basovizza, Trieste, Italy.
The rapid development of extreme ultraviolet (EUV) and x-ray ultrafast coherent light sources such as free electron lasers (FELs) has triggered the extension of wave-mixing techniques to short wavelengths. This class of experiments, based on the interaction of matter with multiple light pulses through the th order susceptibility, holds the promise of combining intrinsic ultrafast time resolution and background-free signal detection with nanometer spatial resolution and chemical specificity. A successful approach in this direction has been the combination of the unique characteristics of the seeded FEL FERMI with dedicated four-wave-mixing (FWM) setups, which leads to the demonstration of EUV-based transient grating (TG) spectroscopy.
View Article and Find Full Text PDFActa Oncol
October 2019
OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine , Dresden , Germany.
Phys Med
January 2019
Institute for Radiation Physics, Lausanne University Hospital, Lausanne, Switzerland; CERN, European Organization for Nuclear Research, Switzerland; Department of Radiology, University of Otago, Christchurch, New Zealand.
Epidemiological studies indicate that radiation damages to the eye lens occurs at lower dose values than previously considered (Worgul et al., 2007; Chodick et al., 2008; Ciraj-Bjelac et al.
View Article and Find Full Text PDFRev Sci Instrum
August 2018
Institute for Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.
This article describes the design and presents recent results from testing and calibration of a forward Compton scattering high energy X-ray spectrometer. The calibration was performed using a bremsstrahlung source on the photon scattering facility at the Electron linac for beams with high brilliance and low emittance accelerator at Helmholtz-Zentrum Dresden-Rossendorf, which provides high energy X-ray photons with energies up to 18 MeV. The calibration was conducted at different bremsstrahlung end point energies-10.
View Article and Find Full Text PDFRadiother Oncol
December 2017
OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany; Helmholtz-Zentrum Dresden - Rossendorf, Institute of Radiooncology - OncoRay, Dresden, Germany; Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; German Cancer Consortium (DKTK), partner site Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany. Electronic address:
Background And Purpose: A prompt-gamma imaging (PGI) slit-camera was recently applied successfully in clinical proton treatments using pencil beam scanning (PBS) and double scattering (DS). However, its full capability under clinical conditions has still to be systematically evaluated. Here, the performance of the slit-camera is systematically assessed in well-defined error scenarios using realistic treatment deliveries to an anthropomorphic head phantom.
View Article and Find Full Text PDFSci Rep
March 2017
The College of William and Mary, Department of Physics, Williamsburg, VA, 23187, USA.
Metallic gratings can support Fano resonances when illuminated with EM radiation, and their characteristic reflectivity versus incident angle lineshape can be greatly affected by the surrounding dielectric environment and the grating geometry. By using conformal oblique incidence thin film deposition onto an optical grating substrate, it is possible to increase the grating amplitude due to shadowing effects, thereby enabling tailoring of the damping processes and electromagnetic field couplings of the Fano resonances, hence optimizing the associated localized electric field intensity. To investigate these effects we compare the optical reflectivity under resonance excitation in samples prepared by oblique angle deposition (OAD) and under normal deposition (ND) onto the same patterned surfaces.
View Article and Find Full Text PDFZ Med Phys
September 2014
Radiotherapy Hirslanden, Hirslanden Medical Center, Aarau, Switzerland.
Purpose: Late toxicities such as second cancer induction become more important as treatment outcome improves. Often the dose distribution calculated with a commercial treatment planning system (TPS) is used to estimate radiation carcinogenesis for the radiotherapy patient. However, for locations beyond the treatment field borders, the accuracy is not well known.
View Article and Find Full Text PDFPhys Med
May 2014
Department of Radiation Oncology, Technische Universität Munchen, Klinikum rechts der isar, D-81675 Munchen, Germany.
Suitable instrumentation for laser-accelerated proton (ion) beams is critical for development of integrated, laser-driven ion accelerator systems. Instrumentation aimed at beam diagnostics and control must be applied to the driving laser pulse, the laser-plasma that forms at the target and the emergent proton (ion) bunch in a correlated way to develop these novel accelerators. This report is a brief overview of established diagnostic techniques and new developments based on material presented at the first workshop on 'Instrumentation for Diagnostics and Control of Laser-accelerated Proton (Ion) Beams' in Abingdon, UK.
View Article and Find Full Text PDFPhys Med Biol
August 2011
University Institute for Radiation Physics, CHUV and University of Lausanne, Grand-Pré 1, CH-1007 Lausanne, Switzerland.
Second cancer risk assessment for radiotherapy is controversial due to the large uncertainties of the dose-response relationship. This could be improved by a better assessment of the peripheral doses to healthy organs in future epidemiological studies. In this framework, we developed a simple Monte Carlo (MC) model of the Siemens Primus 6 MV linac for both open and wedged fields that we then validated with dose profiles measured in a water tank up to 30 cm from the central axis.
View Article and Find Full Text PDFEnviron Sci Technol
November 2010
Institute for Radiation Physics, University Hospital Center, and Institute of Mineralogy and Geochemistry, University of Lausanne, Switzerland.
Colloidal transport has been shown to enhance the migration of plutonium in groundwater downstream from contaminated sites, but little is known about the adsorption of ⁹⁰Sr and plutonium onto colloids in the soil solution of natural soils. We sampled soil solutions using suction cups, and separated colloids using ultrafiltration to determine the distribution of ²³⁹Pu and ⁹⁰Sr between the truly dissolved fraction and the colloidal fraction of the solutions of three Alpine soils contaminated only by global fallout from the nuclear weapon tests. Plutonium was essentially found in the colloidal fraction (>80%) and probably associated with organic matter.
View Article and Find Full Text PDFRadiat Prot Dosimetry
March 2011
University Institute for Radiation Physics, University Hospital of Lausanne, 1007 Lausanne, Switzerland.
Monte Carlo simulations were carried out to study the response of a thyroid monitor for measuring intake activities of (125)I and (131)I. The aim of the study was 3-fold: to cross-validate the Monte Carlo simulation programs, to study the response of the detector using different phantoms and to study the effects of anatomical variations. Simulations were performed using the Swiss reference phantom and several voxelised phantoms.
View Article and Find Full Text PDFChemosphere
July 2010
University Institute for Radiation Physics, University Hospital Center, University of Lausanne, Switzerland.
Plutonium and (90)Sr are considered to be among the most radiotoxic nuclides produced by the nuclear fission process. In spite of numerous studies on mammals and humans there is still no general agreement on the retention half time of both radionuclides in the skeleton in the general population. Here we determined plutonium and (90)Sr in human vertebrae in individuals deceased between 1960 and 2004 in Switzerland.
View Article and Find Full Text PDFSci Total Environ
July 2010
University Institute for Radiation Physics, University Hospital Center, University of Lausanne, Switzerland.
Artificial radionuclides ((137)Cs, (90)Sr, Pu, and (241)Am) are present in soils because of Nuclear Weapon Tests and accidents in nuclear facilities. Their distribution in soil depth varies according to soil characteristics, their own chemical properties, and their deposition history. For this project, we studied the atmospheric deposition of (137)Cs, (90)Sr, Pu, (241)Am, (210)Pb, and stable Pb.
View Article and Find Full Text PDFRadiat Prot Dosimetry
August 2010
Institute for Radiation Physics IRA, CHUV - UNIL, Grand Pré 1, 1007 Lausanne, Switzerland.
A method of objectively determining imaging performance for a mammography quality assurance programme for digital systems was developed. The method is based on the assessment of the visibility of a spherical microcalcification of 0.2 mm using a quasi-ideal observer model.
View Article and Find Full Text PDFPhys Rev Lett
February 2010
Forschungzentrum Dresden-Rossendorf, Institute for Radiation Physics, 01328 Dresden, Germany.
Laser-plasma wakefield-based electron accelerators are expected to deliver ultrashort electron bunches with unprecedented peak currents. However, their actual pulse duration has never been directly measured in a single-shot experiment. We present measurements of the ultrashort duration of such electron bunches by means of THz time-domain interferometry.
View Article and Find Full Text PDFAppl Radiat Isot
August 2010
University Institute for Radiation Physics, Lausanne, Switzerland.
Since the 1990s, regular comparisons of gamma-ray spectrometry in Switzerland were organized to improve laboratory abilities to measure the radioactivity in the environment and food stuffs at typical routine levels. The activity concentration of the test samples and the evaluation of the associated uncertainties remained each year the main required test result. Over the years, the comparisons used certified reference solutions as well as environmental samples.
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