Author: Martí, Z.
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MOPOR007 Local Impedance Measurements at ALBA from Turn-by-Turn Acquisition 598
  • M. Carlà, G. Benedetti, T.F.G. Günzel, U. Iriso, Z. Martí
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  A transverse impedance source manifests itself, among other ways, by producing a small defocusing kick which depends on the beam bunch charge. By repeating optics measurements for different bunch charges, it is possible to disentangle the contribution produced by each impedance source from the dominating focusing effects given by the machine optics. But hunting for such faint defocusing effects poses strong requirements on the precision and sensibility of the measurements, and slow machine drifts or different thermal conditions shall be avoided. In this report, we present a novel method to assess in a fast and precise manner machine optics for different bunch charges using BPM turn-by-turn data and hybrid filling patterns. Finally, measurements for different ALBA machine components like scrapers and In-vacuum undulators are compared with simulation results.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOR007  
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WEPOW033 Commissioning of the Alba Injector With 67 Mev Single Klystron Linac 2905
  • G. Benedetti, U. Iriso, J. Marcos, Z. Martí, V. Massana, R. Muñoz Horta, F. Pérez, M. Pont
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  The 3 GeV ALBA booster normally accelerates an injected beam of 110 MeV, delivered by the linac operating with two independent klystrons. On 2014, the linac waveguide system was upgraded and commissioned to allow operating with either klystron and providing a reduced beam energy of 67 MeV. The commissioning of the booster to capture the beam at a reduced energy and ramp it up to 3 GeV has required a long set-up process of the magnets at 67 MeV beam energy. Due to the dominant effect of the remnant magnetic field in the low energy regime, the scaling of the magnet settings at the beginning of the ramp did not allow to capture the beam, and more precise calibrations were measured on spare quadrupoles to ease its fine tuning. The effect of higher eddy currents induced when the dipoles start ramping, combined with the lower beam rigidity, has been also an issue to tune the dipole waveforms for the 67 MeV - 3 GeV cycle. The encountered problems and their solutions to commission the ALBA injector in this new mode of operation are here presented.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW033  
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THPMR035 Low Horizontal Beta Optics for ALBA 3461
  • G. Benedetti, J. Campmany, Z. Martí
    ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
  The ALBA insertion device beamlines have a horizontal and vertical rms source size of 130 and 5.5 microns. Protein crystallography beamlines (Xaloc) would benefit from a reduction of the horizontal and increase of the vertical beam size, to gain spatial resolution and avoid anisotropy effects. A modified lattice with horizontal and vertical beam size of 74 and 9 microns has been setup and tested, breaking the ring symmetry, with different setting of the six neightbouring quadrupoles at each side of the Xaloc insertion device. Such configuration keeps the nominal emittance almost unvaried and the working point is recovered by small changes in the quadrupole strengths of the four symmetric matching sections. A dedicated setting of the nine available sextupole families has been obtained by numerical optimization of the dynamical apertures and tune shifts. The lattice settings have been satisfactorily tested. The measured lifetime is reduced a factor two and the injection efficiency decreases to 60%. Finally, the option of increasing the number of sextupole families, to recover the dynamic aperture and guarantee the injection efficiency, has been studied.  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMR035  
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