000317338 001__ 317338
000317338 005__ 20211110140713.0
000317338 0247_ $$2datacite_doi$$a10.3204/PUBDB-2017-00617
000317338 037__ $$aPUBDB-2017-00617
000317338 041__ $$aEnglish
000317338 0881_ $$aDESY-THESIS-2017-001
000317338 088__ $$2DESY$$aDESY-THESIS-2017-001
000317338 1001_ $$0P:(DE-H253)PIP1019178$$aTamashevich, Yegor$$b0$$eCorresponding author$$gmale
000317338 245__ $$aDiagnostics and treatment of 1.3 GHz Nb cavities$$f2013-03-13 - 2016-06-30
000317338 260__ $$aHamburg$$bVerlag Deutsches Elektronen-Synchrotron$$c2017
000317338 300__ $$a207
000317338 3367_ $$2DataCite$$aOutput Types/Dissertation
000317338 3367_ $$0PUB:(DE-HGF)3$$2PUB:(DE-HGF)$$aBook$$mbook
000317338 3367_ $$2ORCID$$aDISSERTATION
000317338 3367_ $$2BibTeX$$aPHDTHESIS
000317338 3367_ $$02$$2EndNote$$aThesis
000317338 3367_ $$0PUB:(DE-HGF)29$$2PUB:(DE-HGF)$$aReport$$mreport
000317338 3367_ $$0PUB:(DE-HGF)11$$2PUB:(DE-HGF)$$aDissertation / PhD Thesis$$bphd$$mphd$$s1526646960_10975
000317338 3367_ $$2DRIVER$$adoctoralThesis
000317338 4900_ $$0PERI:(DE-600)1437131-5$$aDESY-THESIS$$x1435-8085
000317338 502__ $$aDissertation, Universität Hamburg, 2016$$bDissertation$$cUniversität Hamburg$$d2016$$o2016-11-28
000317338 520__ $$aThe European XFEL and the International Linear Collider are based on superconductingrf cavities.  In order to reach the theoretical gradient limits of the superconducting cavitiesit is necessary to increase the mechanical quality and chemical composition of the innersurface as well as to understand the reason for performance limitations. This work is basedon the diagnosis of over 100 XFEL and HiGrade cavities whose performance was limitedby several factors:  eld emission on dust or surface defects, low-eld thermal breakdowncaused by the defects, Q-slope etc.It was found that some defects were produced during the mechanical production of thecavity and were not removed by electro-chemical polishing, a standard processing tech-nique of the inner cavity surface.  On the other hand, some of the defects were producedduring the electro-chemical polishing process as the surface initially had imperfections orinclusions of foreign material.One  of  the  opportunities  to  overcome  the  aforementioned  drawbacks  is  to  replace  the\bulk" electro-chemical polishing process by mechanical centrifugal barrel polishing.  Theparameters of the surface after each polishing step were studied using small samples, so-called coupons.  An undersurface layer was investigated using metallographic techniquesand cross sectioning.  The inuence of centrifugal polishing on the specic parameters ofa 9-cell cavity (eld atness, eccentricity etc.)  was investigated.  As a result, a single-stepcentrifugal  barrel  polishing  process  followed  by  a  standard  \light"  electropolishing  wasproposed for industrial application.Although the performance-limiting mechanisms are understood in general, the origin ofthe quench of the cavity is often unclear. To determine the quench locations, a localisationtool for thermal breakdown using the \second sound" in superuid helium has been used.All components of this tool were improved to increase the accuracy of the measurements.A  new  program  code  for  quench  localisation  calculating  the  path  of  the  second-soundwave  was  developed.   This  allows  the  signals  from  all  sensors  to  be  used,  regardlessof  their  position  relative  to  the  quench  site.   The  new  approach  was  validated  usingadditional  techniques  such  as  a  temperature  mapping  and  an  optical  inspection  of  theinner cavity surface.  Furthermore, a new multi-sensor for second-sound wave detection inthe helium vessel of a cavity was developed and successfully tested on a serial-productionXFEL cavity.  The determined quench site location was conrmed by subsequent opticalinspection.  The algorithm localises the quench without mode measurements i.e.  thereis  no  need  to  dismount  HOM-antennas  which  requires  special  procedures  and  must  beperformed in a clean-room.The mathematical approach described in this paper can be applied for second-sound testsof superconductive cavities of various shapes and dimensions.
000317338 536__ $$0G:(DE-HGF)POF3-611$$a611 - Fundamental Particles and Forces (POF3-611)$$cPOF3-611$$fPOF III$$x0
000317338 650_7 $$xDiss.
000317338 693__ $$0EXP:(DE-H253)ILC(machine)-20150101$$1EXP:(DE-H253)ILC-20150101$$5EXP:(DE-H253)ILC(machine)-20150101$$aILC$$eFacility (machine) ILC$$x0
000317338 7001_ $$0P:(DE-H253)PIP1002713$$aElsen, Eckhard$$b1$$eThesis advisor$$udesy
000317338 7001_ $$0P:(DE-H253)PIP1003141$$aFoster, Brian$$b2$$eThesis advisor
000317338 8564_ $$uhttps://bib-pubdb1.desy.de/record/317338/files/Tamashevich_thesis_20160927_2.pdf$$yOpenAccess
000317338 8564_ $$uhttps://bib-pubdb1.desy.de/record/317338/files/desy-thesis-17-001.title.pdf$$yOpenAccess
000317338 8564_ $$uhttps://bib-pubdb1.desy.de/record/317338/files/Tamashevich_thesis_20160927_2.gif?subformat=icon$$xicon$$yOpenAccess
000317338 8564_ $$uhttps://bib-pubdb1.desy.de/record/317338/files/Tamashevich_thesis_20160927_2.jpg?subformat=icon-1440$$xicon-1440$$yOpenAccess
000317338 8564_ $$uhttps://bib-pubdb1.desy.de/record/317338/files/Tamashevich_thesis_20160927_2.jpg?subformat=icon-180$$xicon-180$$yOpenAccess
000317338 8564_ $$uhttps://bib-pubdb1.desy.de/record/317338/files/Tamashevich_thesis_20160927_2.jpg?subformat=icon-640$$xicon-640$$yOpenAccess
000317338 8564_ $$uhttps://bib-pubdb1.desy.de/record/317338/files/desy-thesis-17-001.title.gif?subformat=icon$$xicon$$yOpenAccess
000317338 8564_ $$uhttps://bib-pubdb1.desy.de/record/317338/files/desy-thesis-17-001.title.jpg?subformat=icon-180$$xicon-180$$yOpenAccess
000317338 8564_ $$uhttps://bib-pubdb1.desy.de/record/317338/files/desy-thesis-17-001.title.jpg?subformat=icon-700$$xicon-700$$yOpenAccess
000317338 909CO $$ooai:bib-pubdb1.desy.de:317338$$pdnbdelivery$$pdriver$$pVDB$$popen_access$$popenaire
000317338 9101_ $$0I:(DE-HGF)0$$6P:(DE-H253)PIP1019178$$aExternes Institut$$b0$$kExtern
000317338 9101_ $$0I:(DE-588b)2008985-5$$6P:(DE-H253)PIP1002713$$aDeutsches Elektronen-Synchrotron$$b1$$kDESY
000317338 9101_ $$0I:(DE-HGF)0$$6P:(DE-H253)PIP1003141$$aExternes Institut$$b2$$kExtern
000317338 9131_ $$0G:(DE-HGF)POF3-611$$1G:(DE-HGF)POF3-610$$2G:(DE-HGF)POF3-600$$3G:(DE-HGF)POF3$$4G:(DE-HGF)POF$$aDE-HGF$$bForschungsbereich Materie$$lMaterie und Universum$$vFundamental Particles and Forces$$x0
000317338 9141_ $$y2016
000317338 915__ $$0StatID:(DE-HGF)0510$$2StatID$$aOpenAccess
000317338 920__ $$lyes
000317338 9201_ $$0I:(DE-H253)FLA-20120731$$kFLA$$lForschung Linear Accelerator$$x0
000317338 980__ $$aphd
000317338 980__ $$aVDB
000317338 980__ $$abook
000317338 980__ $$areport
000317338 980__ $$aI:(DE-H253)FLA-20120731
000317338 980__ $$aUNRESTRICTED
000317338 9801_ $$aFullTexts