Author: Saa Hernandez, A.     [Saá Hernández, Á.]
Paper Title Page
MOPWA041 The New SLS Beam Size Monitor, First Results 759
  • Á. Saá Hernández, N. Milas, M. Rohrer, V. Schlott, A. Streun
    PSI, Villigen PSI, Switzerland
  • Å. Andersson, J. Breunlin
    MAX-lab, Lund, Sweden
  Funding: This research has received funding from the European Commission under the FP7-INFRASTRUCTURES-2010-1/INFRA-2010-2.2.11 project TIARA (CNI-PP). Grant agreement no. 261905.
An extremely small vertical beam size of 3.6 μm, corresponding to a vertical emittance of 0.9 pm, only about five times bigger than the quantum limit, has been achieved at the storage ring of the Swiss Light Source (SLS). The measurement was performed by means of a beam size monitor based on the imaging of the vertically polarized synchrotron radiation in the visible and UV spectral ranges. However, the resolution limit of the monitor was reached during the last measurement campaign and prevented further emittance minimization. In the context of the work package “SLS Vertical Emittance Tuning” of the TIARA collaboration, a new improved monitor was built. It provides larger magnification, an increase of resolution and enables two complementary methods of measurement: imaging and interferometry. In this paper we present the design, installation, commissioning, performance studies and first results obtained with the new monitor.
WEPWA051 Extraction Beam Line for Light Sources 2232
  • M. Aiba, M. Böge, T. Garvey, N. Milas, Á. Saá Hernández, A. Streun
    PSI, Villigen PSI, Switzerland
  Most of measurements, with circulating beam in a ring, to determine transverse and longitudinal phase space volume are rather indirect although it is of importance to characterize these beam parameters for better understanding the machine. Direct measurements may be performed when the beam is extracted to a beam line, where destructive methods are available. However, light sources can tolerate internal beam dumping and thus do not have an extraction line in general. We, therefore, propose a diagnostic dedicated extraction line, motivated by precise determination of the geometrical vertical emittance, which can be a few pm or even less and general comparisons of direct and indirect measurements. Such an extraction beam line has been realized in several accelerator facilities, e.g. KEK-ATF. The idea is, however, to equip a compact beam line, which fits into the existing tunnel and allows us to measure transverse and longitudinal emittances. We present possible design of an extraction beam line assuming typical light source parameters.  
WEPME047 Identification of Sources of Orbital Distortions in Corrector Space 3034
  • M. Böge, M. Aiba, Á. Saá Hernández, A. Streun
    PSI, Villigen PSI, Switzerland
  Since modern ring and linear accelerator based light sources feature fast orbit feedback (FOFB) systems which transform orbital oscillations in beam position monitor (BPM) space into corrector (C) space over a wide frequency range, most perturbations can be directly analyzed utilizing the C pattern. In C space the localization of sources of distortions is facilitated since the large (per unit phase) number of BPMs and Cs involved provides a good spatial resolution. Applications of this technique include the beam-assisted girder alignment where changes in the C pattern are interactively analyzed while girder positions are remotely altered or the beam-based alignment of quadrupole/BPM pairs where the variation of C values as the result of quadrupole variations are observed. In both cases large oscillations in BPM space are completely surpressed by the FOFB leading to well controlled and stable conditions during the measurement.