High Brightness Electron Beam Diagnostics and their ... - CASA

∆ x (mm), Corrector 0F00H
∆ x (mm), Corrector 0F04H
x 10−3
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x 10−3
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∆ y (mm), Corrector 0F00V
x 10−3
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x 10−3
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x 10−3
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problemfortheoperatingenergiesoftheIRFEL:simulationsindicatestheinduceddeectiondueto gradientchangeissignicantandcanbeoftheorderoffewtensofmrad.Wehaveexperimentally Figure3.6:Comparisonbetweenthemeasuredandsimulatedlatticeresponseforthesixcorrectors
veriedsuchresultinourpreliminarymeasurementofdispersionintheback-legtransferlineby usedduringthedierenceorbitmeasurement(100meterscorrespondsapproximatelytotheendof thebacklegbeamline). beam6.BecausethisRF-induceddeectionisinverselyproportionaltothebeamenergyitcanbea
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andcompareitwiththecasewhereweoperatethecavityattheirnominalgradientanduseda
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(whichisinfacttheR12-inducedpattern)isreproduced.Thisresultconrmsoursuspicionthat varyingthecavitygradient.Wepresentingure3.8thebeampositionosetalongthebeamline correctoratthelinacexittosimulatepotentialRF-inducedsteering:thesametypeofpattern
Distance (meters)
Distance (meters)
approximately500100mforamagneticeldvariationof1%insuringthespuriousdispersion therecirculationarc.Wenotethatthemaximumtraversedisplacementofthebeamcentroidis islowerthan5cminabsolutevalue.Thisisanimportantresultforemittancemeasurementaswe shallseeinChapter4. dispersionmeasurementsperformedusingRF-gradientvariationisnotvalid.Nextwepresent,in gure3.9,ameasurementofdispersionobtainedbyvaryingthemagneticeldinallthedipolesof 6AdetailedstudyofthiseectispresentedinChapter6
∆ x (mm), Corrector 0F08H
∆ y (mm), Corrector 0F04V
∆ y (mm), Corrector 0F08V