Author: Schmitz, M.
Paper Title Page
WEPF05 An Electron Beam Detector for the FLASH II Beam Dump 814
 
  • F. Perlick, J.D. Good, N. Leuschner, M. Sachwitz
    DESY Zeuthen, Zeuthen, Germany
  • G. Kube, M. Schmitz, K. Wittenburg, T. Wohlenberg
    DESY, Hamburg, Germany
  
  For the elec­tron ab­sorber at FLASH II a de­tec­tor is de­vel­oped to con­trol the po­si­tion, di­men­sions and pro­file of the elec­tron beam. Scin­til­la­tion light, emit­ted from a lu­mi­nes­cent screen in front of the dump win­dow, is re­flected by a mir­ror, lo­cated in 2 m dis­tance from the screen, and passes through a vac­uum win­dow. Two dif­fer­ent op­ti­cal sys­tems will be in­stalled re­dun­dantly for beam image trans­fer: a con­ven­tional lens-mir­ror-sys­tem and a sys­tem using a ra­di­a­tion-hard op­ti­cal fibre bun­dle. A CCD cam­era, lo­cated in one and a half meter dis­tance from the beam line, is used for the op­ti­cal analy­sis. An ex­per­i­men­tal setup, where the terms of in­stal­la­tion of the com­po­nents cor­re­spond to the FLASH ac­cel­er­a­tor, has been built up in a lab to co­or­di­nate the in­ter­ac­tion of the screen with the com­po­nents of the op­ti­cal sys­tem. It was shown that the res­o­lu­tion of the lens-mir­ror-sys­tem is about one line pair per mil­lime­ter. An ex­per­i­ment is set up to test the im­pact of ra­di­a­tion on the op­ti­cal qual­i­ties of the fibre optic bun­dle by in­stalling it onto a “ra­dioac­tive hot spot” at the bunch com­pres­sor in the FLASH ac­cel­er­a­tor.  
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