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Tanaka, T.

Paper Title Page
WEPEB068 Feasibility Tests of the Beam Halo Monitoring System for Protecting Undulator Permanent Magnets against Radiation Damage at XFEL/SPring-8 2851
 
  • H. Aoyagi, T. Bizen, N. Nariyama
    JASRI/SPring-8, Hyogo-ken
  • Y. Asano, T. Itoga, H. Kitamura, T. Tanaka
    RIKEN/SPring-8, Hyogo
  
 

A beam halo re­gion of an elec­tron beam at a lin­ear ac­cel­er­a­tor might hit the un­du­la­tor mag­nets and de­grade un­du­la­tor per­ma­nent mag­nets. An in­ter­lock sen­sor is in­dis­pens­able to pro­tect the mag­nets against ra­di­a­tion dam­age. We have been de­vel­op­ing an elec­tron beam halo mon­i­tor using di­a­mond de­tec­tors for an in­ter­lock sen­sor at the X-ray free elec­tron laser fa­cil­i­ty at SPring-8 (XFEL/SPring-8). The di­a­mond de­tec­tors are op­er­at­ed in pho­to­con­duc­tive mode. Pulse-by-pulse mea­sure­ments are adopt­ed to sup­press the back­ground noise ef­fi­cient­ly. The fea­si­bil­i­ty tests of this mon­i­tor have been per­formed at the SPring-8 com­pact SASE source (SCSS) test ac­cel­er­a­tor for XFEL/SPring-8, and the re­sults will be sum­ma­rized.

  
WEPD026 In-situ Magnetic Correction for Cryogenic Undulators 3147
 
  • T. Tanaka, H. Kitamura
    RIKEN/SPring-8, Hyogo
  • A. Anghel, M. Bruegger, W. Bulgheroni, B. Jakob, T. Schmidt
    PSI, Villigen
  • A. Kagamihata, T. Seike
    JASRI/SPring-8, Hyogo-ken
  
 

The cryo­genic per­ma­nent mag­net un­du­la­tor (CPMU) is an in­ser­tion de­vice in which per­ma­nent mag­nets are cooled down to cryo­genic tem­per­a­ture (CT) to im­prove the mag­net­ic per­for­mances. Al­though CPMUs are re­al­ized by a slight mod­i­fi­ca­tion of in-vac­u­um un­du­la­tors (IVUs), we have sev­er­al tech­ni­cal chal­lenges to be over­come. Among them, the most im­por­tant one is how to en­sure the mag­net­ic per­for­mance, in other words, how to mea­sure the mag­net­ic field at CT, and how to cor­rect it if nec­es­sary. A new method of the phase-er­ror cor­rec­tion has been pro­posed at SPring-8, in which the gap vari­a­tion is cor­rect­ed by ad­just­ing me­chan­i­cal­ly the in-vac­u­um beam. What is im­por­tant in this method is that the cor­rec­tion can be done at CT with­out break­ing the vac­u­um, i.e., an 'in-situ' field cor­rec­tion is pos­si­ble. The cor­rec­tion method has been test­ed to check the fea­si­bil­i­ty using the new CPMU with a mag­net­ic pe­ri­od of 14 mm and a mag­net­ic length of 1.7 m con­struct­ed for Swiss Light Source. In this paper, the prin­ci­ple and re­sults are de­scribed to­geth­er with the de­tails of the new mea­sure­ment sys­tem SAFALI (self aligned field an­a­lyz­er with laser in­stru­men­ta­tion) for the field mea­sure­ment of CPMUs.