High Brightness Electron Beam Diagnostics and their ... - CASA
High Brightness Electron Beam Diagnostics and their ... - CASA
High Brightness Electron Beam Diagnostics and their ... - CASA
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FromthesebothmeasurementitispossibletodeducetheR56oftheby-passchicanes:Usingthe nominalsettingsmeasurementwend:Rchic trimquadrupoleinarc1bothpowered<strong>and</strong>turnedo.Itisseenthelevelofagreementisexcellent. TypicalR56measured<strong>and</strong>expectedforthewholerecirculation,i.e.fromthecryomoduleexitup toitsentranceisapproximately-20cmforthenominalsetupusedatthattime(February1999). themagneticopticcodedimad.Wehaveperformedthemeasurementatbothlocationwiththe formed<strong>and</strong>iscomparedinthisgurewiththeexpectedmomentumcompactioncomputedusing<br />
mentumcompactionfromthelinacexituptothepickupcavity#3.Theresultsarepresentedinexcitationbysystematicallyvaryingthequadrupolesstrength<strong>and</strong>eachtimemeasuringthemo- valuesof28cm.WehaveattemptedtoquantifytheR56dependenceonthetrimquadrupoles thecodeseemstobeaverygoodtooltopredicttheR56evolutionaroundtherecirculation. theverygoodagreement,with2cmbetweenthemeasuredR56forthechicanes<strong>and</strong>itsdesign gure3.19wherewecomparedthemeasurementwithnumericalsimulationusingthedimadcode; 56'29:60cm<strong>and</strong>Rarc 56'23:51cm,againwecannote<br />
Wehavecarriedaqualitativestudyofthesextupoleeectontheenergy-phasetransferfunction. EectsoftheSextupoles Theexperimentconsistedofmeasuringthehinjoutitransferfunctionusingthepickupcavity number3.Duringthemeasurementthetrimquadareun-powered.Ingure3.20,wepresentthe<br />
3.4.8ConcludingRemarksontheLongitudinalResponseMeasurement tointroducedapositivenon-linear(quadratic)curvature.Againonecanusethesameschemeas weusedbefore<strong>and</strong>comparenottheabsolutetransfermap,butrelativetransfermapi.e.compare thealgebraicdierencehinjoutionhinjoutioffforthesimulated<strong>and</strong>measuredset. measuredtransferfunctions.Quantitativelythereissomedisagreementbetweenthesimulated<strong>and</strong> measureddata.Howeveritisseenthatthesextupolehavethesameeect:whenturnontheytend<br />
Inthissectionwehaveshowedthat:<br />
2.phase-phasemapcanbeusedtosetthelatticei.e.tooperateinisochronousmode,e.g.by 1.phase-phaserstordermap<strong>and</strong>nonlinearitiesmeasuredcanberatherwellreproducedwith spacechargeforce. makingsurethemapbefore<strong>and</strong>afterasectionisapproximatelythesame latticecompressionrate,practically,<strong>and</strong>especiallyinthelowenergyregion,wherethebeam isinaspace-charge-dominatedregime,thecompressionisstronglyinuencedbycollective theparmelacode.Alsoitcanbeusedtodeduceboththecompressionratebetweenthepoint ofmeasurement(pickupcavitylocations)<strong>and</strong>thephoto-cathodesurface;ofcoursethisisa<br />
4.energy-phasetransfermapcanalsobeusedtocharacterize,withhighaccuracytheeect 3.energy-phasetransfermap,cangivewithfairlygoodaccuracythemomentumcompactionofa ofthesextupoleonthelongitudinaldynamics,alsointhepresentworkwewerenotable<br />
R56'12cmfromthecryomoduleexittothearc3F.Whichgivetheforthesectionwiggler tolinacentranceR56'+16cmveryclosetothedesiredvalueof20cm. section.Wehavemeasuredthemomentumcompactionoftherecirculationtoapproximately
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