Author: Breede, H.F.
Paper Title Page
MOP015 A Power Switching Ionization Profile Monitor (3D-IPM) 47
 
  • H.F. Breede, H.-J. Grabosch, M. Sachwitz, L.V. Vu
    DESY Zeuthen, Zeuthen, Germany
  
  FLASH at DESY in Ham­burg is a lin­ear ac­cel­er­a­tor to pro­duce soft x-ray laser light rang­ing from 4.1 to 45 nm. To en­sure the op­er­a­tion sta­bil­ity of FLASH, mon­i­tor­ing of the beam is manda­tory. Two Ion­iza­tion Pro­file Mon­i­tors (IPM) de­tect the lat­eral x and y po­si­tion and pro­file changes of the beam. The func­tional prin­ci­ple of the IPM is based on the de­tec­tion of par­ti­cles, gen­er­ated by in­ter­ac­tion of the beam with the resid­ual gas in the beam line. The newly de­signed IPM en­ables the com­bined eval­u­a­tion of the hor­i­zon­tal and ver­ti­cal po­si­tion as well as the pro­file. A com­pact mon­i­tor, con­sist­ing of two mi­cro-chan­nel plates (MCP) is as­sem­bled on a con­duct­ing cage along with tog­gled elec­tric fields in a rec­tan­gu­lar vac­uum cham­ber. The par­ti­cles cre­ated by the pho­ton beam, drift in the ho­moge­nous elec­tri­cal field to­wards the re­spec­tive MCP, which pro­duces an image of the beam pro­file on an at­tached phos­phor screen. A cam­era for each MCP is used for as­sess­ment. This in­di­rect de­tec­tion scheme op­er­ates over a wide dy­namic range and al­lows the live de­tec­tion of the clear po­si­tion and the shape of the beam. The final de­sign is pre­sented.  
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