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Basilio, R.

Paper Title Page
THPCH132 EPU Assembly Based on Sub-cassettes Magnetic Characterization 3107
 
  • G. Tosin, R. Basilio, J.F. Citadini, M. Potye
    LNLS, Campinas
 
  A procedure to speed up the magnetic field correction of an EPU type undulator is proposed and its results are shown. Such procedure consists in segmenting each one of the four magnetic blocks linear arrays (cassettes) in seven sub-cassettes and making their individual magnetic and mechanical characterization. One theoretical perfect sub-cassette, which is composed of four segments per period in Halbach configuration, is taken as the standard field profile. The peak fields and the fields integrated in each semi-period of one sub-cassette are chosen to be the optimization parameters. The magnetic blocks are displaced (virtual shims) to minimize the difference of the optimization parameters between the sub-cassette magnetic measurement and the standard profile. The sub-cassette magnetic measurements are performed with Hall probes, using the same bench employed in insertion devices characterization.  
THPCH133 Conceptual Design of an EPU for VUV Radiation Production at LNLS 3110
 
  • G. Tosin, R. Basilio, J.F. Citadini, R.T. Neuenschwander, M. Potye, X.R. Resende, M. Rocha, P.F. Tavares
    LNLS, Campinas
 
  We describe the magnetic and mechanical design of an elliptically polarizing undulator (EPU) currently under construction at the (Brazilian Synchrotron Light Source - LNLS). The device is designed to cover the photon flux in the range from 100eV to 1000eV (124Å a 12.4 Å), allowing linear, elliptical and circular polarizations. With this device it is possible to reach absorption edges of several elements such as Si, S, Br, C, N, O, Fe, F, Cl and to measure magnetic dichroism. The EPU's magnetic design is conventional, and field corrections are done by means of virtual shims, with horizontal and vertical displacements. Each one of the four magnetic blocks linear arrays (cassettes) is segmented in seven sub-cassettes. The separate magnetic measurement of each sub-cassette allows corrections of the magnetic field profile to be made before final assembly and makes the verification of mechanical tolerances easier and faster, decreasing the expected time that will be spent in the magnetic tuning of the device. The mechanical structure is composed of a C-Frame, gap and phase actuators. The gaps actuators and phase actuators use absolute encoders and bias with springs to eliminate backlash.  
THPCH134 Development of Insertion Device Magnetic Characterization Systems at LNLS 3113
 
  • G. Tosin, R. Basilio, J.F. Citadini, M. Potye
    LNLS, Campinas
 
  This paper describes a set of magnetic measurement systems employed in the development of insertion devices at LNLS (Brazilian Synchrotron Light Source). They are: rotating coil (which can also operate as a flip-coil), spatial field mapping using Hall probes and parallel coils (Helmholtz configuration) for magnetic blocks characterization. Although such techniques are well established, strict specifications imposed by the beam dynamics on the magnetic field quality, led to a detailed analysis of their sources of error and their minimization. All three systems have already been tested and showed excellent accuracy and repeatability when compared to typical values found in the literature.