Author: Jebramcik, M.A.
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TUPVA013 Lifetime of Asymmetric Colliding Beams in the LHC 2067
 
  • J.M. Jowett, R. Alemany-Fernández, M.A. Jebramcik, T. Mertens, M. Schaumann
    CERN, Geneva, Switzerland
 
  In the 2013 proton-nucleus (p-Pb) run of the LHC, the lifetime of the lead beam was significantly shorter than could be accounted for by luminosity burn-off. These effects were observed at a lower level in 2016 and studied in more detail. The beams were not only asymmetric but the differences in the bunch filling schemes between protons and Pb nuclei led to a wide variety of beam-beam interaction sequences in the bunch trains. The colliding bunches were also of different sizes. We present an analysis of the data and an interpretation in terms of theoretical models.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA013  
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TUPVA014 The 2016 Proton-Nucleus Run of the LHC 2071
 
  • J.M. Jowett, R. Alemany-Fernández, G. Baud, P. Baudrenghien, R. De Maria, R. De Maria, D. Jacquet, M.A. Jebramcik, A. Mereghetti, T. Mertens, M. Schaumann, H. Timko, M. Wendt, J. Wenninger
    CERN, Geneva, Switzerland
 
  For five of the LHC experiments the second p-Pb collision run planned in 2016 offered the opportunity to answer a range of important physics questions arising from the surprise discoveries (e.g., flow-like collective phenomena in small systems) made in earlier Pb-Pb, p-Pb and p-p runs. However the diversity of the physics and their respective capabilities led them to request very different operating conditions, in terms of collision energy, luminosity and pile-up. These appeared mutually incompatible within the available one month of operation. Nevertheless, a plan to satisfy most requirements was developed and implemented successfully. It exploited different beam lifetimes at two beam energies of 4 Z TeV and 6.5 Z TeV, a variety of luminosity sharing and bunch filling schemes, and varying beam directions. The outcome of this very complex strategy for repeated re-commissioning and operation of the LHC included the longest ever LHC fill with luminosity levelled for almost 38 h. The peak luminosity achieved exceeded the design value by a factor 7.8 and integrated luminosity substantially exceeded the experiments' requests.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA014  
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TUPVA128 Performance of the CERN Injector Complex and Transmission Studies into the LHC during the Second Proton-Lead Run 2395
 
  • R. Alemany-Fernández, S.C.P. Albright, M.E. Angoletta, J. Axensalva, W. Bartmann, H. Bartosik, P. Baudrenghien, G. Bellodi, A. Blas, T. Bohl, E. Carlier, S. Cettour-Cave, K. Cornelis, H. Damerau, A. Findlay, S.S. Gilardoni, S. Hancock, A. Huschauer, M.A. Jebramcik, S. Jensen, J.M. Jowett, V. Kain, D. Küchler, A.M. Lombardi, D. Manglunki, T. Mertens, M. O'Neil, S. Pasinelli, Á. Saá Hernández, M. Schaumann, R. Scrivens, R. Steerenberg, H. Timko, V. Toivanen, G. Tranquille, F.M. Velotti, F.J.C. Wenander, J. Wenninger
    CERN, Geneva, Switzerland
 
  The LHC performance during the proton-lead run in 2016 fully relied on a permanent monitoring and systematic improvement of the beam quality in all the injectors. The beam production and characteristics are explained in this paper, together with the improvements realized during the run from the source up to the flat top of the LHC. Transmission studies from one accelerator to the next as well as beam quality evolution studies during the cycle at each accelerator, have been carried out and are summarized in this paper. In 2016, the LHC had to deliver the beams to the experiments at two different energies, 4 Z TeV and 6.5 Z TeV. The properties of the beams at these two energies are also presented  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA128  
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WEPAB009 Pilot Experiments and New Developments at the DELTA Short-Pulse Facility 2578
 
  • S. Khan, B. Büsing, F. Götz, M.A. Jebramcik, N.M. Lockmann, C. Mai, A. Meyer auf der Heide, R. Niemczyk, B. Riemann, G. Shayeganrad, M. Suski, P. Ungelenk, D. Zimmermann
    DELTA, Dortmund, Germany
  • U. Bovensiepen, S. Döring, A. Eschenlohr, M. Ligges, L. Plucinski, M. Plötzing, C.M. Schneider, S. Xiao
    Universität Duisburg-Essen, Duisburg, Germany
  • S. Cramm
    Forschungszentrum Jülich, Peter-Gruenberg-Institut-6, Jülich, Germany
  • M. Gehlmann
    Forschungszentrum Jülich, Peter Gruenberg Institut, Jülich, Germany
 
  Funding: BMBF 05K16PEA, BMBF 05K16PEB, Mercur Pr-2014-0047
At the 1.5-GeV synchrotron light source DELTA operated by the TU Dortmund University, ultrashort radiation pulses in the vacuum ultraviolet (VUV) and terahertz (THz) regime are routinely generated by the interaction of electron bunches with femtosecond laser pulses. A laser-induced energy modulation is converted into a density modulation (microbunching) by a magnetic chicane, leading to coherent emission at harmonics of the initial laser wavelength (coherent harmonic generation, CHG). Path length differences of the energy-modulated electrons along the magnetic lattice lead to a dip in the longitudinal charge distribution, which gives rise to the coherent emission of THz radiation. In first pump-probe photoemission experiments, the spatial and temporal overlap of laser pump and CHG probe pulse on the sample was demonstrated. Furthermore, the effect of two temporally separated seed pulses was studied in the VUV and (sub-)THz regime.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB009  
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WEPAB010 Progress Towards an EEHG-Based Short-Pulse Source at DELTA 2582
 
  • A. Meyer auf der Heide, F.H. Bahnsen, B. Büsing, F. Götz, S. Hilbrich, M.A. Jebramcik, S. Khan, N.M. Lockmann, C. Mai, R. Niemczyk, B. Riemann, G. Shayeganrad, M. Suski, P. Ungelenk, D. Zimmermann
    DELTA, Dortmund, Germany
 
  Funding: Work supported by the accelerator initiative (ARD) of the Helmholtz society, BMBF 05K13PE3, BMBF 05K16PEA.
The short-pulse source at the 1.5-GeV synchrotron light source DELTA, operated by the TU Dortmund University, enables the generation of sub-ps radiation pulses in the VUV regime based on coherent harmonic generation (CHG). As an upgrade, the employment of echo-enabled harmonic generation (EEHG) is planned which allows to produce shorter wavelengths. Recent developments and measurements regarding the twofold energy modulation required for EEHG are presented.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPAB010  
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