Keyword: scattering
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MOPB06 DAΦNE Luminosity Monitor luminosity, detector, simulation, experiment 81
  • A. De Santis, C. Bisegni, O.R. Blanco-García, O. Coiro, A. Michelotti, C. Milardi, A. Stecchi
    INFN/LNF, Frascati (Roma), Italy
  The DAΦNE collider instantaneous luminosity has been measured identifying Bhabha scattering events at low polar angle (∼10°) around the beam axis by using two small crystal calorimeters shared with the KLOE-2 experiment. Independent DAQ setup based on !CHAOS, a novel Control System architecture, has been designed and realized in order to implement a fast luminosity monitor, also in view of the DAΦNE future physics runs. The realized setup allows for measurement of Bunch-by-Bunch (BBB) luminosity that allows to investigate the beam-beam interaction for the Crab-Waist collisions at DAΦNE and luminosity dependence on the bunch train structure.  
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WEOC03 A Simple Model to Describe Smoke Ring Shaped Beam Profile Measurements With Scintillating Screens at the European XFEL FEL, electron, diagnostics, ECR 366
  • G. Kube, S. Liu, A.I. Novokshonov, M. Scholz
    DESY, Hamburg, Germany
  Standard beam profile measurements of high-brightness electron beams based on OTR may be hampered by coherence effects. Therefore it was decided for the European XFEL to measure transverse beam profiles based on scintillating screen monitors using LYSO:Ce. While it is possible to resolve beam sizes down to a few micrometers with this scintillator, the experience during the XFEL commissioning showed that the measured emittance values were significantly larger than the expected ones. In addition, beam profiles measured at bunch charges of a few hundred pC showed a 'smoke ring' structure. While coherent OTR emission and beam dynamical influence can be excluded, it is assumed that the profile distortions are caused by effects from the scintillator material. Following the experience in high energy physics, a simple model was developed which takes into account quenching effects of excitonic carriers inside a scintillator in a heuristic way. Based on this model, the observed beam profiles can be understood qualitatively. Together with the model description, first comparisons with experiments will be presented, and new scintillators suitable for beam profile diagnostics will be discussed.  
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THOA03 Progress on Transverse Beam Profile Measurement Using the Heterodyne Near Field Speckles Method at ALBA radiation, undulator, target, experiment 538
  • S. Mazzoni, F. Roncarolo, G. Trad
    CERN, Geneva, Switzerland
  • U. Iriso, C. Kamma-Lorger, A.A. Nosych
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  • M.A.C. Potenza
    Universita' degli Studi di Milano & INFN, Milano, Italy
  • M. Siano
    Università degli Studi di Milano, Milano, Italy
  We present the recent developments of a study aiming at measuring the transverse beam profile using the Heterodyne Near Field Speckles (HNFS) method. The HNFS technique consists of a suspension of nanoparticles suspended in a liquid and illuminated by synchrotron radiation (either in the visible or in X-ray wavelength range). The transverse coherence of the source, and therefore, under the conditions of validity of the Van Cittert and Zernike theorem, the transverse electron beam size is retrieved from the interference between the transmitted beam and the spherical waves scattered by each nanoparticle. We here describe the fundamentals of this technique, as well as the recent experimental results obtained with 12 keV radiation at the NCD beamline at ALBA. The applicability of such technique for future accelerators (e.g. CLIC or FCC) is also discussed.  
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THOB03 Long Term Investigation of the Degradation of Coaxial Cables radiation, insertion, operation, pick-up 552
  • M. Kuntzsch, R. Schurig
    HZDR, Dresden, Germany
  • S.J. Burger
    Delta Gamma RF-Expert, Melbourne, Australia
  • T. Weber
    el-spec GmbH, Geretsried, Germany
  For the transport of RF signals coaxial cables with PTFE ('Teflon') as dielectric medium are widely used because they offer a wide bandwidth and low insertion loss. Coaxial cables that are routed in immediate vicinity to the beamline are exposed to ionizing radiation that is mainly generated by beam-loss. In this radiative environment cables change their electrical properties which directly affects the signal on the receiver side and in turn the measured beam parameters. This contribution describes a measurement setup at the superconducting CW accelerator ELBE that was used to investigate the degradation of coaxial cables under well-controlled conditions up to an accumulated dose of 94 kGy. Furthermore the acquired data up to 40 GHz of two coaxial cable samples are presented and the results are discussed.  
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