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SimulationsanddesignforsoftX-raybeamlinesatMAXIV
RamiSankari
SoftwareforOpticalSimulations,WorkshopTrieste,3-7October2016
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Outline● MAXIVLaboratory● Descriptionofthebeamlines● Needsinsimulations
– Performance– Power,coolingandstability– Thesource– Coherence
● Resultsandconclusions
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March2014
Overwiew
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March2014
Injection
XRM2016,Yngve Cerenius
TwoinjectionsystemThermionicRFGun1nC @10Hz
PhotocathodeRFGun100pC @100Hz
Status:Inoperation≠Fullycommissioned
Photocathode RF Gun
Thermionic RF Gun
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March2014
Linac
XRM2016,Yngve Cerenius
Thelinac• Length:300m(39sections)• 3.5GeV• 2transferpoints
Status:Inoperation
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March2014
The1.5GeVring
XRM2016,Yngve Cerenius
The1.5GeVring• Circumference:96m• Ringlattice:doublebendachromat(DBA)• Storedcurrent:500mA• Straightsections:12(3.5m)• Emittance(hor):6nmrad
Status:Commissioning
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March2014
The3.0GeVring
XRM2016,Yngve Cerenius
The3.0GeVring• Circumference:528m• Ringlattice:7bendachromat(MBA)• Storedcurrent:500mA• Straightsections:20(5m)• Emittance(hor):0.2-0.3nmrad
Status:Inoperation
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March2014
TheSPF
XRM2016,Yngve Cerenius
TheShortPulseFacility• Pulses>≈100fs• Repetitionrate:100Hz
FemtoMAX beamline• Energyrange:1.8– 20keV• Photons/pulse:107
Status:Commissioning
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March2014
Beamlines
XRM2016,Yngve Cerenius
BeamlinesBl fundedonthe3GeVring:8(19)Bl fundedonthe1.5GeVring:5(11)Bl fundedontheSPF:1(3)
Status:Variousdegreesofcompletion
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XRM2016,Yngve cerenius
1. FemtoMAXfsdynamicsinsolid
2. NanoMAXNano-imaging&- spectroscopy
3. BioMAXProteinCrystallography
4. BalderChemicalspectroscopy:real-time&-condition
5. VeritasElectronic&magneticexcitations:solids
6. HippiePhotoemission:mBar gaspressure
7. ARPESElectronicstructure:solids
8. FinEstBeaMSElectronicstructure:gases,aerosols
9. SPECIESElectronic&magneticexcitations:surfaces
10. MAX-PEEMMicroscopy:surfaces
11. FlexPESElectronicstructure:surfaces&gases
12. CoSAXSGeometricstructure&correlation:(bio)liquids
13. SoftiMAXMicroscopy&methoddevelopment
14. DanMAXPowderdiffraction&imaging:materialsscience
20162017
20172018
Beamlines
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DescriptionofthesoftX-raybeamlines
● VERITAS,3.0GeV ring– VeryhighresolutionRIXSspectroscopy– 275-1600eV– R=50000,500eV,1x1012 ph/s– Smallspot,always,
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DescriptionofthesoftX-raybeamlines
● SoftiMAX,3.0GeVring– STXMandCXI– 275-2500eV– R≈5000– Spotca.20-30nmatSTXMbranchand
ca.20x20µm2 atCXIbranch
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DescriptionofthesoftX-raybeamlines● ARPES,1.5GeVring
– VeryhighresolutionARPES– 10-200(1000)eV– R<1meV upto100eV– Mediumsizespot
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DescriptionofthesoftX-raybeamlines
● SPECIES,1.5GeVring– RIXSandAP-XPS– 27-1500eV– R≈10000– SpotatRIXS<5x20µm2– SpotatAP-XPS60x100µm2
– PrototypeforMAXIVbeamlines– Complementary,lowenergybeamlinefor
HIPPIE
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DescriptionofthesoftX-raybeamlines
● INSERTIONDEVICES– 3.0GeVring:ca.3.75mlongEPUs– 1.5GeVring:ca.2.5mlongEPUs
● Otherspecifications– 3.0GeV ring:ca.50mbeamlines– 1.5GeV ring:ca.30…40mbeamlines– Horizontalbeamatsample(!)– Experimentatreasonableheight(!)– Highflux,lowflux,highresolution,low
resolution,mediumspotwhichcanbereduced,orinsomecasesexpanded
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DesignofthesoftX-raybeamlines
– Collectinginputfromtheusercommunities;convergencetofinalparameters
– Comparisonofvariousdesigns– aiminfindinglocaloptimum
– Extensivemodelingcorrespondingtofinaldesign• Reliableestimateofperformance• Tolerancesdefinedforopticalelements• Stability/vibrationsincludedforcheckingtheeffect
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DesignofthesoftX-raybeamlines
- monochromator/gratings
- focusingtoslit
- refocusing
- source
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DesignofthesoftX-raybeamlines
PracticallyallVUV- softX-raymonochromatorsatMAX-labwerebasedonplanegratings
– Experienceonworkingwiththem– Blazedplanegratingsavailableforreuse– Flexibleandyeteasytouse
PlanegratingmonochromatorilluminatedwithcollimatedlightchosenintheendforallpresentsoftX-raybeamlines.
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DesignofthesoftX-raybeamlines
Havingalsothehorizontalfocusattheexitslitplaneincreasesachievableresolvingpower.
– Focusingwithfirstmirrorresultsinhighestresolvingpowerbutlowestdemagnification
– Focusinghorizontally(andvertically)withthefocusingmirrorincreasesdemagnification
– Havingacollimation-focusingpairbyfirstmirrorandfocusingmirrorgivesabitofbothadvantages
– Stigmaticfocusatexitslitallowsusingellipsoidalrefocusingmirrors
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DesignofthesoftX-raybeamlines
Singlerefocusingmirror,ellipsoidalortoroidalusedforallexceptcoherentscatteringbeamline
– Singlereflection,lesslosses– Easytokeepbeamhorizontalatexperiment– Sagittalfocusinginverticaldirection– Aberrations(low)
– Rotationaroundthenormalofatoroidalmirror(yaw)allowstoenlargethebeam
– Beampositioncanbechangedalonghorizon(pitch)andperpendiculartoit(roll)
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DesignofthesoftX-raybeamlines
Astigmaticfocusforrefocusingtoroidalmirrorallowstochangeitssourcesize(exitslitopening)withoutaffectingtheimagesizewhichisnowdictatedbythebeamdivergence.
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DesignofthesoftX-raybeamlines
- power
- stability
- coherence
Mainfocusareas
- source
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PowerfromasoftX-rayundulatorEllipticallypolarizingundulatorat3.0GeVring:
● EPU48– 48mmperiodlength,81periods,L=3905.5mm– Kmax =4.506,limitedtoK=3.30(6.2kW)– 275– 1500(1st harmonic)
Ellipticallypolarizingundulatorat1.5GeVring:
● EPU95p2– 95.2mmperiodlength,25periods,L=2380mm– Kmax =10.065(2.6kW)– 4– 1000– Experimentsupto1486.295eV(AlKa)
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PowerfromasoftX-rayundulatorEPU48 EPU95.2
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Max.powerdensityat10m:26.6W/mm2 Max.powerdensityat10m:0.9W/mm2
Calculations with SPECTRAv10.
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PowerfromasoftX-rayundulatorHeatloadinducedstructuralchanges,M1
Calculations with COMSOL,v3.5,www.comsol.com
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PowerfromasoftX-rayundulatorHeatloadinducedstructuralchanges,apertureeffect
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0.150.100.050.00-0.05-0.10-0.15M1 length (m)
6σ illumination 9σ illumination
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PowerfromasoftX-rayundulatorHeatbumpprofilescanbeinsertedintoraytracing
– SHADOW1,RAY2,RAY-UI3,XRT4,…– Mostheatbumpscanberegardedasadditionalconvexmirrors,radiusdefinesimagingeffect
– Densemeshorinterpolatingimportant– Loopingautomatizedfiniteelementanalysisintoraytracingpossible,andwithpresentcomputersthatisalsofeasible
1M.SanchezdelRio,N.Canestrari,F.JiangandF.Cerrina,J.Synchrotron Rad.18,708(2011);http://www.esrf.eu/Instrumentation/software/data-analysis/OurSoftware/raytracing2F.Schäfers in:ModernDevelopmentsinX- RayandNeutronOptics,(2008).3https://www.helmholtz-berlin.de/forschung/oe/fg/nanometeroptik/science/layout/ray_en.html4K.Klementiev andR.Chernikov,Proc.SPIE9209,92090A(2014);http://pythonhosted.org/xrt/
POSTERS:RAY-UI/PeterBaumgärtel/HZBMASH/PeterSondhaus/MAXIV
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StabilityThecoolingsolutionpresentedearlierreliesonturbulent
flowinthenarrowcoolingchannelsundersurfaceofthemirror.
Totalwaterflowwillbeseverallitersperminute→largediameterfeedinglineneeded,withpracticalsizestheflowwillnotbelaminarthereeither.
Turbulenceinducedvibrationsbythecoolingchannelsandlinesisoneofthefutureforthestabilitygroup.
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Stability
“Forestimatingvibrations,thetransitionpointsfromlaminartoturbulentflowneedstobeknown– measurementsneededtofixthosepoints.”
?
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R&DPresentation,BrianNorsk Jensen,MAXIVLaboratory,calculationsbyKarlÅhnberg
Stability
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Stability
R&DPresentation,BrianNorsk Jensen,MAXIVLaboratory,calculationsbyKarlÅhnberg
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Gaussianapproximationiswidelyusedindescribingtheundulatorlightsource.However,precisecalculations*predictcleardeviationfromit,resultingin
i.e sourcesizeisabouttwiceaslargeastheonegivenbyGaussianapproximation.Withlowemittancestorageringsthisstartstodominatethesourcesizeanddivergence.
Anotherquestioncomeswithusingtheundulatoraswigglerforhighphotonenergies.
*P.Elleaume in:Undulators,wigglersandtheirapplications,eds.H.Onuki andP.Elleaume,Taylor&Francis,69-108(2003).
Thesource
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ThesourceEPU48onaxis EPU481/Ndetuning
EPU95.2closedgap,1000eV
These calculations withSPECTRAv10,SRWalsoused forthese.
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ThesourceForraytracingthesourcecharacteristicsweremodeledin
SPECTRA1 andSRW2 – thosevalueswereusedasinputparametersine.g.RAY.
Atpresent,theraytracing/wavepropagationprogramXRTisused.Itincludesalsonearfieldcalculationsforundulators,andcanuseelectrontrajectoriescalculatedwithRADIA3
1T.TanakaandH.Kitamura,J.SynchrotronRad.8,1221(2001).2O.Chubar andP.Elleaume,Proc.EPAC-98,1177(1998).3O.Chubar,P.Elleaume,andJ.Chavanne,J.SynchrotronRad.,5,481(1998).
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PartialcoherenceLowemittancesynchrotronsprovidelightwithhighdegree
oftransversecoherence,sometensofpercentatfewhundredeV
Forapplicationsutilizingcoherence,likecoherentX-rayimaging,preservingandrefiningcoherencefortheexperimentiscrucial– thisappliesalsotodiffractionlimitedimagingwithzoneplates
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PartialcoherenceChosetobemadebetweentwophilosophies:using
secondarysource,orundisturbedexpansionuntilfinal,acceptancelimited,refocusingmirror?
Lookingatpropertiesatfocus (andaround)– Size,divergence,flux– Coherencelength– Degreeofcoherence– flexibility
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●where to put FZP?●what is the result if finite beam emittance?●what are the coherence properties?●how to isolate the coherent part?
image by K. Schulte
Partialcoherence
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Partialcoherence
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Partialcoherence
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Partialcoherence
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Partialcoherence
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Partialcoherence
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PartialcoherencePerformanceestimationfortheSTXMbranch;raytracinguntilgrating,wavefront propagationuntilsample
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Partialcoherence
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Finalsimulations,softX-raybeamlines
– Includerealopticsintosimulationswhendelivered– Possibleeffectofshapeoutsidetolerances– Slopeerrormapsinsteadofstatisticalslopeerrordistributions(collaborationwithHZB)
– Analysisoffinalperformance• Real-timemodellingassistedtuningwithinreach
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Resultsandconclusions● Classicalraytracingstillthemaintoolforgeneraldesignwork
● Precisemodelingofthesourcemoreimportantforlowemittancerings
● Stabilityisvitalpartoftransportingthebeam– vibrationsneedtobeincludedintosimulation
● Partialcoherencerequireswavefront-basedapproach
● Toolsneedtobeeasytousebutmosttoolsexist
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Acknowledgementstocolleaguesat