Author: Hirlaender, S.
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TUPAF020 Performance of the CERN Low Energy Ion Ring (LEIR) with Xenon beams 705
 
  • R. Alemany-Fernández, S.C.P. Albright, O. Andujar, M.E. Angoletta, J. Axensalva, H. Bartosik, G. Baud, N. Biancacci, M. Bozzolan, S. Cettour Cave, K. Cornelis, J. Dalla-Costa, M. Delrieux, A. Dworak, A. Findlay, F. Follin, A. Frassier, M. Gabriel, A. Guerrero, M. Haase, S. Hirlaender, S. Jensen, V. Kain, L.V. Kolbeck, Y. Le Borgne, D. Manglunki, O. Marqversen, S. Massot, D. Moreno Garcia, D.J.P. Nicosia, S. Pasinelli, L. Pereira, D. Perez, A. Rey, J.P. Ridewood, F. Roncarolo, Á. Saá Hernández, R. Scrivens, O.G. Sveen, G. Tranquille, E. Veyrunes
    CERN, Geneva, Switzerland
 
  In 2017 the CERN Low Energy Ion Ring demonstrated once more the feasibility of injecting, accumulating, cooling and accelerating a new nuclei, 129Xe39 . The operation of this new ion species started at the beginning of March with the start up of the xenon ion source and the Linac3. Ten weeks later the beam arrived to the Low Energy Ion Ring (LEIR) triggering the start of several weeks of beam commissioning in view of providing the injector complex with Xenon beams for different experiments and a series of machine development experiments in LEIR. Two types of beams were setup, the so called EARLY beam, with a single injection into LEIR from Linac3, and the NOMINAL beam with up to seven injections. 2017 was as well an interesting year for LEIR because several improvements in the control system of the accelerator and in the beam instrumentation were done in view of increasing the machine reliability. This paper summarises the beam commissioning phase and all the improvements carried out during 2017.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF020  
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TUPAF024 Impedance and Instability Studies in LEIR with Xenon 720
 
  • N. Biancacci, H. Bartosik, M. Gąsior, S. Hirlaender, V. Kain, T.E. Levens, E. Métral
    CERN, Geneva, Switzerland
  • M. Migliorati
    Rome University La Sapienza, Roma, Italy
 
  In 2017, the LEIR accelerator has been operated with Xe39+ beam for fixed target experiments in the SPS North Area. The different ion species, with respect to the usually operated Pb54+, allowed for additional comparative measurements of tune shift versus intensity at injection energy both in coasting and bunched beams. The fast transverse instability observed for high accumulated intensities has been as well characterized and additional observations relevant to impedance have been collected from longitudinal Schottky signal and BTF measurements. The results of these measurements are summarised and compared to the currently developed machine impedance model.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF024  
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TUPAF034 LEIR Injection Efficiency Studies as a Function of the Beam Energy Distribution from Linac3 758
 
  • S. Hirlaender, R. Alemany-Fernández, H. Bartosik, G. Bellodi, N. Biancacci, V. Kain, R. Scrivens
    CERN, Geneva, Switzerland
 
  High intensities in the CERN Low Energy Ion Ring (LEIR) are achieved using multi-turn injections from the pre-accelerator Linac3 combined with simultaneous stacking in momentum and transverse phase spaces. Up to seven consecutive 200 μs long, 200 ms spaced pulses are injected from Linac3 into LEIR by stacking each of them into the six-dimensional phase-space over 70 turns. An inclined septum magnet allows proper filling of the transverse phase-space plane, while longitudinal stacking requires momentum variation achieved by a shift of mean momentum over time provided by phase shifting a combination of 2 RF cavities at the exit of Linac3. The achievable maximum accumulated intensity depends strongly on the longitudinal beam quality of the injected beam. The longitudinal Schottky signal is used to measure the received energy distribution of the circulating beam which is then correlated with the obtained injection efficiency. This paper presents the experimental studies to understand and further improve the injection reliability and the longitudinal stacking.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF034  
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TUPAF035 Observations of SPS Slow-Extracted Spill Quality Degradation and Possible Improvements 761
 
  • F.M. Velotti, H. Bartosik, K. Cornelis, M.A. Fraser, B. Goddard, S. Hirlaender, V. Kain, O. Michels, M. Pari
    CERN, Geneva, Switzerland
 
  The SPS delivers slow extracted proton and heavy ion spills of several seconds to the North Area fixed target experiments with a very high duty factor. Reduced machine reproducibility due to magnetic history and power supply ripples on the main circuits lead however to frequent degradation of the spill duty factor. In this paper, the measured effect of the SPS magnetic history on spill quality and principal machine parameters is presented. Another detailed measurement campaign was aimed at characterising the frequency content and response of the spill to noise on the main power supplies ripples. The main findings of this study will also be reported. Finally, simulations of possible improvements based on the data acquired are discussed, as well as an extrapolation to the possible spill quality after the implementation of the improvements.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF035  
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TUPAF036 Studies of the Injection and Cooling Efficiency in LEIR Using the Longitudinal Schottky Spectrum 765
 
  • S. Hirlaender, R. Alemany-Fernández, H. Bartosik, N. Biancacci, V. Kain
    CERN, Geneva, Switzerland
 
  The CERN Low Energy Ion Ring (LEIR) has two main operational beams with their associated cycles, the so-called EARLY and the NOMINAL beam. The EARLY beam consists of a single injected pulse from the LINAC3 accelerator, whereas seven consecutive injections are accumulated, and electron cooled for the NOMINAL beam. In both cases, the longitudinal Schottky monitor allows assessing the longitudinal particle distribution during the cooling process on the injection plateau. A method has been established to analyze the Schottky signal, reconstruct the initial particle momentum distribution and derive relevant parameters such as the cooling time, energy off-set of injected and stacked beam or the momentum distribution of the lost beam. The variations of the obtained parameters and the impact on the LEIR performance will be addressed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF036  
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TUPAF039 Electron Cooling Simulation and Experimental Benchmarks at LEIR 776
 
  • A. Latina, H. Bartosik, N. Biancacci, R. Corsini, D. Gamba, S. Hirlaender, A. Huschauer
    CERN, Geneva, Switzerland
 
  A fast and accurate simulation of Electron Cooling has recently been implemented in the tracking code RF-Track. The implementation, which is based on a "hybrid kinetic" model, enables the simulation of a large variety of realistic scenarios, including imperfections such as gradients in the electron density, misalignments of electrons / ions / solenoidal fields, both in the static and in the dynamic regimes. Benchmarks of the simulations against measurements performed at LEIR, using Lead and Xenon ions, are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPAF039  
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WEYGBD3 The CERN Gamma Factory Initiative: An Ultra-High Intensity Gamma Source 1780
 
  • M.W. Krasny
    LPNHE, Paris, France
  • R. Alemany-Fernández, H. Bartosik, N. Biancacci, P. Czodrowski, B. Goddard, S. Hirlaender, J.M. Jowett, R. Kersevan, M. Kowalska, M.W. Krasny, M. Lamont, D. Manglunki, A.V. Petrenko, M. Schaumann, C. Yin Vallgren, F. Zimmermann
    CERN, Geneva, Switzerland
  • P.S. Antsifarov
    Institute of Spectroscopy, Russian Academy of Science, Troitsk, Moscow, Russia
  • A. Apyan
    ANSL, Yerevan, Armenia
  • E.G. Bessonov
    LPI, Moscow, Russia
  • J. Bieron, K. Dzierzega, W. Placzek, S. Pustelny
    Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków, Poland
  • D. Budker
    Johannes Gutenberg University Mainz, Institut für Physik, Mainz, Germany
  • K. Cassou, I. Chaikovska, R. Chehab, K. Dupraz, A. Martens, Z.F. Zomer
    LAL, Orsay, France
  • F. Castelli
    Università degli Studi di Milano, Milano, Italy
  • C. Curatolo, L. Serafini
    Istituto Nazionale di Fisica Nucleare, Milano, Italy
  • K. Kroeger
    FSU Jena, Jena, Germany
  • V. Petrillo
    Universita' degli Studi di Milano & INFN, Milano, Italy
  • V.P. Shevelko
    LPI RAS, Moscow, Russia
  • T. Stöhlker
    HIJ, Jena, Germany
  • G. Weber
    IOQ, Jena, Germany
  • Y.K. Wu
    FEL/Duke University, Durham, North Carolina, USA
  • M.S. Zolotorev
    LBNL, Berkeley, California, USA
 
  This contribution discusses the possibility of broadening the present CERN research programme making use of a novel concept of light source. The proposed, Partially Stripped Ion beam driven, light source is the backbone of the Gamma Factory (GF) initiative. It could be realized at CERN by using the infrastructure of the already existing accelerators. It could push the intensity limits of the presently operating light-sources by up to 7 orders of magnitude, reaching fluxes of 1017 photons/s in the interesting gamma-ray energy domain between 1 MeV and 400 MeV. The GF light-source cannot be replaced, in this energy domain, by a FEL source as long as the multi TeV electron beams are not available. Its intensity is beyond the reach of the Inverse Compton Scattering sources. The unprecedented-intensity, energy-tuned gamma beams, together with the gamma-beams-driven secondary beams of polarized leptons, neutrinos, neutrons and radioactive ions are the basic research tools of the proposed Gamma Factory. A broad spectrum of new opportunities, in a vast domain of uncharted fundamental and applied physics territories, could be opened by the Gamma Factory research programme.  
slides icon Slides WEYGBD3 [7.531 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEYGBD3  
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THPAF055 Space Charge Studies on LEIR 3095
 
  • Á. Saá Hernández, H. Bartosik, N. Biancacci, S. Hirlaender, A. Huschauer, D. Moreno Garcia
    CERN, Geneva, Switzerland
 
  The performance of the CERN Low Energy Ion Ring with electron cooled ion beams is presently limited by losses occurring once the beam has been captured in the RF buckets. An intense machine study program was started by the end of 2015 to mitigate the losses and improve the performance of the accelerator. The measurements pointed to the interplay of direct space charge forces and excited betatron resonances as the most plausible driving mechanism of these losses. In this paper, we present the systematic space-charge measurements performed in 2017 and compare them to space-charge tracking simulations based on an adaptive frozen potential.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF055  
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THPMF015 Lifetime and Beam Losses Studies of Partially Strip Ions in the SPS (129Xe39+) 4070
 
  • S. Hirlaender, R. Alemany-Fernández, H. Bartosik, N. Biancacci, T. Bohl, S. Cettour Cave, K. Cornelis, B. Goddard, V. Kain, M.W. Krasny, M. Lamont, D. Manglunki, G. Papotti, M. Schaumann, F. Zimmermann
    CERN, Geneva, Switzerland
  • K. Kroeger
    FSU Jena, Jena, Germany
  • V.P. Shevelko
    LPI RAS, Moscow, Russia
  • T. Stöhlker, G. Weber
    IOQ, Jena, Germany
 
  The CERN multipurpose Gamma Factory proposal relies on using Partially Stripped Ion (PSI) beams, instead of electron beams, as the drivers of its light source. If such beams could be successfully stored in the LHC ring, fluxes of the order of 1017 photons/s, in the gamma-ray energy domain between 1 MeV and 400 MeV could be achieved. This energy domain is out of reach for the FEL-based light sources as long as the multi TeV electron beams are not available. The CERN Gamma Factory proposal has the potential of increasing by 7 orders of magnitude the intensity limits of the present Inverse Compton Scattering sources. In 2017 the CERN accelerator complex demonstrated its flexibility by producing a new, xenon, ion beam. The Gamma Factory study group, based on this achievement, requested special studies. Its aim was to inject and to accelerate, in the SPS, partially stripped xenon ions Xe39+ measure their life time, and determine the relative strength of the processes responsible for the PSI beam losses. This study, the results of which are presented in this contribution, was an initial step in view of the the future studies programmed for 2018 with lead PSI beams.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF015  
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