Author: Wolski, A.
Paper Title Page
TUPC149 Measurements at the ALICE Tomography Section 1377
 
  • M.G. Ibison, K.M. Hock, D.J. Holder, B.D. Muratori, A. Wolski
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
  • M. Korostelev
    The University of Liverpool, Liverpool, United Kingdom
 
  Funding: STFC
This paper reports the results of tomography measurements of the electron beam transverse phase space distribution in the ALICE accelerator at Daresbury Laboratory. These measurements have two main aims. The first is to give a detailed picture of the phase space distribution of the electron beam injected from ALICE into the EMMA prototype non-scaling FFAG accelerator. The second is to provide data for the development and testing of a variety of techniques for tomographic reconstruction. We summarize the measurement results which we have obtained and discuss the advantages and disadvantages of some different tomography methods.
 
 
TUPC150 The Effect of Space-Charge on the Tomographic Measurement of Transverse Phase-Space in the EMMA Injection Line 1380
 
  • M.G. Ibison, M. Korostelev
    The University of Liverpool, Liverpool, United Kingdom
  • K.M. Hock, D.J. Holder, B.D. Muratori, A. Wolski
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: STFC
Phase-space tomography for particle beams depends upon detailed knowledge of the particle transport through specified sections of a beam line. In the simplest case, only the effects of magnets (such as quadrupoles) and drift spaces need to be taken into account; however, in certain parameter regimes (high charge density and low energy) space charge forces may play a significant role. The ALICE accelerator is the electron source for EMMA, a prototype ns-FFAG machine. Results are presented of investigations into these effects on phase-space tomography in the injection line between ALICE and EMMA. The application of suitable correction techniques* to the EMMA injection line tomography measurements in the presence of space-charge is also discussed.
* D. Stratakis et al., Phys. Rev. ST Accel. Beams 9, 112801 (2006).
 
 
TUPC151 Cherenkov Fibre Optic Beam Loss Monitor at ALICE 1383
 
  • A. Intermite
    The University of Liverpool, Liverpool, United Kingdom
  • A. Intermite, M. Putignano, A. Wolski
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  The need for real-time monitoring of beam losses, including evaluation of their intensity and the localization of their exact position, together with the possibility to overcome the limitations due to the reduced space for the diagnostics, makes optical fibres (using the Cherenkov Effect) one of the most suitable and explored candidate for beam loss monitoring. In this contribution, we report on an optical fibre beam loss monitor based on large numerical aperture pure silicon fibres and silicon photomultipliers, tested at ALICE, Daresbury Laboratories, UK. The original design of the sensor has the advantage to combine the functions of a real time detector and a transmission line. It also allows reading the signals independently and determining the time and position of the losses without the use of an external trigger.  
 
TUPC152 Comparative Study of Performance of Silicon Photomultipliers for Use in Cherenkov Fibre Optic Beam Loss Monitors 1386
 
  • A. Intermite
    The University of Liverpool, Liverpool, United Kingdom
  • A. Intermite, M. Putignano, A. Wolski
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Silicon Photomultipliers (SiPMs) are semiconductor photo-sensitive devices built from a matrix of Single Photon Avalanche Diodes (SPADs) on a common silicon substrate, working in the limited Geiger mode and with a common readout. The fast counting ability, high timing resolution, immunity to magnetic field up to 15 T, low power consumption and relative small temperature dependence together with the small dimensions make SiPMs excellent candidates as commercially available solid state detectors, and a promising alternative to traditional photomultiplier tubes for single photon detection. Nevertheless, SiPMs do suffer from erroneous counting due to noise effects that can deteriorate their performances. These effects are, in general, heavily dependent on manufacturing quality. In this contribution, results are reported of the characterization of different models of SiPMs in terms of noise spectra and response to light, and a procedure for determining quality manufacturing parameters is described.  
 
TUPC052 Normal Mode BPM Calibration for Ultralow-Emittance Tuning in Lepton Storage Rings 1114
 
  • A. Wolski
    The University of Liverpool, Liverpool, United Kingdom
  • D. L. Rubin, D. Sagan, J.P. Shanks
    CLASSE, Ithaca, New York, USA
 
  BPMs capable of high-resolution turn-by-turn measurements offer the possibility of new techniques for tuning for ultra-low beam emittance. In this paper, we describe how signals collected from individual buttons during resonant beam excitation can be used to calibrate BPMs to read the beam position in a normal mode coordinate system. This allows for rapid minimization of the mode II emittance, simply by correcting the mode II dispersion. Simulations indicate that the technique is effective and robust, and has the benefit of being insensitive to BPM gain and alignment errors that can limit the effectiveness of other techniques.  
 
WEPC128 Application of Dynamical Maps to the FFAG EMMA Commissioning* 2304
 
  • Y. Giboudot, R. Nilavalan
    Brunel University, Middlesex, United Kingdom
  • A. Wolski
    The University of Liverpool, Liverpool, United Kingdom
 
  Funding: Work supported by the Engineering and Physical Sciences Research Council, UK.
The lattice of the Non Scaling FFAG EMMA has four degrees of freedom (strengths and transverse positions of each of the two quadrupoles in each periodic cell). Dynamical maps computed from an analytical representation of the magnetic field may be used to predict the beam dynamics in any configuration of the lattice. An interpolation technique using a mixed variable generating function representation for the map provides an efficient way to generate the map for any required lattice configuration, while ensuring symplecticity of the map. The interpolation technique is used in an optimisation routine, to identify the lattice configuration most closely machine specified dynamical properties, including the variation of time of flight with beam energy (a key characteristic for acceleration in EMMA).
yoel.giboudot@stfc.ac.uk
 
 
TUODA03 The Status of the ALICE Accelerator R&D Facility at STFC Daresbury Laboratory 934
 
  • F. Jackson, D. Angal-Kalinin, R. Bate, R.K. Buckley, S.R. Buckley, J.A. Clarke, P.A. Corlett, D.J. Dunning, J.-L. Fernández-Hernando, A.R. Goulden, S.F. Hill, D.J. Holder, S.P. Jamison, J.K. Jones, L.B. Jones, A. Kalinin, S. Leonard, P.A. McIntosh, J.W. McKenzie, K.J. Middleman, A.J. Moss, B.D. Muratori, T.T. Ng, J.F. Orrett, S.M. Pattalwar, Y.M. Saveliev, D.J. Scott, B.J.A. Shepherd, A.D. Smith, R.J. Smith, S.L. Smith, N. Thompson, A.E. Wheelhouse, P.H. Williams
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
  • P. Harrison, G.M. Holder, A.L. Schofield, P. Weightman, R.L. Williams, A. Wolski
    The University of Liverpool, Liverpool, United Kingdom
  • M.D. Roper
    STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
  • M. Surman
    STFC/DL/SRD, Daresbury, Warrington, Cheshire, United Kingdom
 
  Funding: Science and Technology Facilities Council
The ALICE accelerator, the first energy recovery machine in Europe, has recently demonstrated lasing of an infra-red free electron laser (IR-FEL). The current status of the machine and recent developments are described. These include: lasing of the IR-FEL, a programme of powerful coherent terahertz radiation research, electro-optic diagnostic techniques, development of high precision timing and distribution system, implementation of digital low level RF control. ALICE also serves as an injector for the EMMA non-scaling FFAG machine.
 
slides icon Slides TUODA03 [1.648 MB]