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

More documents

Recommendations

Info

Thepurposeofmeasuringthetransverseresponseoftheopticallatticeistogetsomeinsightsonthe 3.3.1TheoreticalBackground validity,accordinglyto: traryposition0,ispropagatedtoanotherposition,undertheassumptionofrstordertransportcitation,opticalelementsmisaligned.Wehaveperformedtwotypesofmeasurement:(1)response ofthelatticeforagivenangularexcitationbymeanofcorrectorsand(2)energydependenceofthe latticei.e.measurementofthedispersion. Inadispersion-freeregion,thepositionanddivergencecentroidofabeam(x(0);y(0))atanarbirstordertransportandpotentiallyndoutproblemswiththelatticei.e.magnetscorruptedex- anevent,the\perturbed"beampositiondownstreamnowwrites: bativeangularkickonthebeamtrajectoryatthepositionx(0)i.e.x0(0)!x0(0)+x0.Insuch Theobservablethatcaneasilybemeasuredisabeamcentroidpositionatthedownstreamlocation x(s).Henceatechniquetomeasurethetransverseresponseisdistorttheorbitbyusingapertur- x0(s)!= x(s) R0!s 11R0!s 21R0!s 12 22! x0(0)! x(0) (3.1) Moreover,foradipolewecanrelatetheangularkicktothebeammomentum:x0=1=(3:3356 ontheangularperturbationat0: Thatisthedisplacementofthebeampositionats,x(s)def xperturb(s)=R0!s x(s)=R0!s 11x(0)+R0!s 12x0 12(x0(0)+x0) =xperturb(s)x(s)isonlydependent (3.3) (3.2) ofR11requiresmoreelaboration:oneneedstocreateaperturbationthatisexactly90degoutof betatronphasewithrespecttothekickintendedtomeasuretheR12;insuchwayonecancompute p)RBdlwhereRBdlrepresentstheeldintegral(inT.m),andpisthebeammomentum(in towhatpositiondisplacementitcorresponds. ordertransfermatrixmodel,istomeasurethebeampositionalongthebeamlinefordierentperturbations(angularkickvaluesbutalsopositionofthekickermagnetused).Itisworthmentioning thatthistechniqueallowsdirectlytomeasuretheR12transfermatrixelement.Themeasurement GeV). Henceaverysimplewaytocheckifthe\realworld"machineisperformingaspredictedbyrst wecangetanestimateofthedispersionfunction. totheorbit.Notethat(s)R0!s asx(s)=x(s)+(s)(0),wherex(s)isapurebetatroninducedpositionandtheproductof Theothertypeofmeasurementistheenergydependenceoftheopticallattice.Thismeasurementis verysimilartothetransfermatrixresponseaforementioned:itisknowthataftermagneticelement systemssuchasdipolestherecanbepositiondependenceonenergy,i.e.thepositionx(s)writes (s),dispersionfunctionats,with(0),energyosetat0,representthedispersivecontribution !+)andmeasuringtheassociatedpositionchangedownstreamthebeamlinex= 16.Thereforebyvaryingtheenergyofthebunchcentroid(i.e.
3.3.2ExperimentalMethod Todetermineexperimentallythelatticeresponseduetoeitherkickexcitation(puretransverse pickupcalledbeampositionmonitors(BPMs)[25].TheseBPMsconsistofanumberofpick-up response)orenergychange(dispersion),weonlyhavetomeasurethebeamposition,theonly observablewecaneasilyaccess.Thebeampositionismeasuredbymeansofelectromagnetic antennaedistributedaroundthediameterofthevacuumchamberthatdetecttheCoulombeld associatedwithanelectronbunchasitpropagatesalongthebeamline.Basedontheasymmetry ofthesignaloneachantenna,thebeamcentroidcoordinatescanbeinferred.TwotypesofBPMs areinstalledintheIRFELaccelerator.Inthemeasurementpresentedhereafter,wehaveonly wakeeld.Thebeamcentroidcoordinateisasimplefunctionoftheelectricpotential(VR,VL,VD, usedtheso-calledstriplineBPMswhosecrosssectionisdepictedingure3.3.ThistypeofBPM consistsoffourstrip-likepickupantennaeorientedat90degfromeachother.Thistypeofgeometry forthepickupantennaehastheadvantagetominimizethebeamqualitydeteriorationbecauseof VU)inducedbythebeamoneachantenna[19]oftheBPM(R,L,D,Uongure3.3): Figure3.3:schematiccutofabeampositionmonitor(BPM). Theelectronicsystemusedtoprocessthesignalistheso-calledSwitchedElectrodeElectronics system.Andthebeampositionisinferredusingthestandardtechniquefromthissignal.An (SEE)[24].Thesignalofperiphericalelectrodesismultiplexedtothesameprocessingelectronics y/VUVD x/VRVL VU+VD VR+VL typically30Hztostudypotentialtimedependentbeampositionuctuation. advantageofthiselectronicisthatitcanbeusedtoacquirebeampositionatveryhighrate (3.4) Thepracticalmethodtomeasuretheresponseofthelatticeisasfollows:(1)Forthenominal condition,measurethebeampositiononallthedesiredBPMsfx0;y0gi=1:::N(thesubscriptiisthe angularkickforR12measurement);(3)measurethenewbeampositionontheNBPMsfx;ygi=1:::N BPMindex);(2)impressthedesireddistortion(i.e.energychangefordispersionmeasurementor andcomputethedisplacement(ordierenceorbit)ofthebeamcentroidalongthebeamlineatthe L Vacuum Chamber U y y O D x Beam cross-section R Pickup Antenna x
Page 1 and 2: HighBrightnessElectronBeamDiagnosti
Page 3 and 4: eratedupto48MeVpriortothelasingsyst
Page 5 and 6: IthanktheCEBAFmachineoperators,with
Page 7 and 8: 3.4MeasurementoftheLongitudinalResp
Page 9 and 10: 5.6ZerophasingTechniqueforBunchLeng
Page 11 and 12: ListofTables 3.2Comparisonofcoecien
Page 13 and 14: ListofFigures 1.1Comparisonoftheexp
Page 15 and 16: 3.11Momentumcompactionandnonlinearm
Page 17 and 18: 4.18Overviewofthephasespacesampling
Page 19 and 20: 5.16Interferogrammeasuredfordierent
Page 21 and 22: 6.10Comparisonofthermstransversehor
Page 23 and 24: Chapter1 UVdomainandareplannedtogen
Page 25 and 26: space-chargeinthelowenergyregime,an
Page 27 and 28: !Vjitsthevelocity,and!Xjisthepositi
Page 29 and 30: equation boundarybetweenvacuumandam
Page 31 and 32: 10 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.
Page 33 and 34: 1.0 0.8 0.6 0.4 0.2 E=10 MeV E=42 M
Page 35 and 36: 00000000000000000000000000000000000
Page 37 and 38: harmonicwithproperchoiceoftheKvalue
Page 39 and 40: Bu(rms)0.28T ParameterValueUnit Nu
Page 41: 2.7TheJeersonLabIRproject usedasexp
Page 44 and 45: Study TheFELdriveraccelerator:Latti
Page 46 and 47: ParameterValue x -0.178 x(m) 8.331
Page 50 and 51: computedusingthelatticeset-upuseddu
Page 52 and 53: etatronexcitationaspicturedingure3.
Page 54 and 55: ∆ x (mm), Corrector 0F00H ∆ x (
Page 56 and 57: 1 0.5 0 spreadoftheparticlewassetto
Page 58 and 59: 2 1 −5 −3 −1 1 3 5 k (m q −
Page 60 and 61: Experimentallythecalibrationcoecien
Page 62 and 63: tioned.FromthetransferfunctioninFig
Page 64 and 65: Pickup Experiment #2 #3 #4 Simulati
Page 66 and 67: Fromthesebothmeasurementitispossibl
Page 68 and 69: . . . . . . . . . . . . . . . . . .
Page 70 and 71: 10 5 Sext. ON Figure3.20:Eectofthes
Page 72 and 73: spaceabeamthatconsistsofNparticles,
Page 74 and 75: Asforthegeometricemittanceonecanden
Page 76 and 77: (a) ceramic radiator beam x-wire be
Page 78 and 79: and validundertheassumptionofaunifo
Page 80 and 81: 1000 900 800 700 Figure4.4:Steadyst
Page 82 and 83: Fraction of Beam enclosed within (%
Page 84 and 85: 5 2 2 3 4 5 6 7 8 9 10 0 10 5 2 Foi
Page 86 and 87: Actuator Inserts Foil and Mirror CI
Page 88 and 89: shortterm,touseasbeamdensitymonitor
Page 90 and 91: Alongwiththeseimplementedoperations
Page 92 and 93: whereiistheerrorontheithbeamsizemea
Page 94 and 95: Let'sassumethethinlensapproximation
Page 96 and 97: obtainedviathestatisticalanalysis.T
Page 98 and 99:
20 18 16 . 14 . 12 . Figure4.14:Rel
Page 100 and 101:
100 10 −3 10 −2 10 −1 10 that
Page 102 and 103:
multislits mask (copper) Aluminum F
Page 104:
TheReductionoftheSpaceChargeconditi
Page 107 and 108:
. . . . . . . . . . . . . . . . . .
Page 109 and 110:
Table4.7:Typicalsystematicerroronem
Page 111 and 112:
180 8 160 6 Figure4.22:Anexampleof2
Page 113 and 114:
4.0 3.5 3.0 2.5 Figure4.24:Emittanc
Page 115 and 116:
Characterization LongitudinalPhaseS
Page 117 and 118:
concentrateonthebeamparametersinthe
Page 119 and 120:
1.1 1 mrad 0.9 5 mrad mainlyduetoth
Page 121 and 122:
Population Population 100000 90000
Page 123 and 124:
Theequation5.8yields: f()=jZ+1 11Xn
Page 125 and 126:
presentanoutlineofthisproofbelow,an
Page 127 and 128:
contrastintheCEBAFmachine,varyingas
Page 129 and 130:
1.5 1 correspondtothevarianceofveco
Page 131 and 132:
Ε’ 2 B Mirror M 2 Ε2 Polarizer
Page 133 and 134:
FinallyitisinterestingtonotethatFou
Page 135 and 136:
Itsautocorrelationis:S(z)=8>:(1=w2)
Page 137 and 138:
drivelaserwhereasin(A),suchoperatio
Page 139 and 140:
expansionoftheBFFderivedinthischapt
Page 141 and 142:
Asarstapproximation,wecanestimatetr
Page 143 and 144:
errorpropagation8theoryappliedonEqn
Page 145 and 146:
inducedbyspacechargeisnotaconcernin
Page 147 and 148:
Golay Cell Signal (V) Golay Cell Si
Page 149 and 150:
Golay Cell Ouput (V) Golay Cell Oup
Page 151 and 152:
150 100 5 4 Figure5.19:Energyspectr
Page 153 and 154:
Figure5.23:picturaleectoflongitudin
Page 155 and 156:
. .. .. . .. . . .. . .. . . .. . .
Page 157 and 158:
σ x (m) x 10−3 5 4 3 2 1 0 0 5 1
Page 159 and 160:
BeamDynamicsStudies Chapter6 undula
Page 161 and 162:
x,y (mm) 6.0 4.8 3.6 2.4 1.2 x y 0.
Page 163 and 164:
Space Charge over Emittance Ratio (
Page 165 and 166:
numericalsolution[56].Thisapproxima
Page 167 and 168:
0.03 . .... . .. ... . .. ..... . .
Page 169 and 170:
ε x (mm−mrad) Nominal 6 4 2 cryo
Page 171 and 172:
2.2 2 1.8 Figure6.10:Comparisonofth
Page 173 and 174:
6 4 2 Figure6.12:\R55"transfermapfo
Page 175 and 176:
10 1 5 10 0 500 1000 1500 2000 2500
Page 177 and 178:
EnergySpread(%) BunchLength(mm) Par
Page 179 and 180:
15 Effect of RMS energy Spread 10 F
Page 181 and 182:
6.4.4BunchSelfInteractionviaCoheren
Page 183 and 184:
100 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0
Page 185 and 186:
Inthesecondseriesofrun,wewereableto
Page 187 and 188:
Conclusion Chapter7 Therecirculator
Page 189 and 190:
[2]Y.Shibata,T.Takahashi,T.Kanai,K.
Page 191 and 192:
[29]J.-C.Denard,C.Bochetta,G.Traomb
Page 193 and 194:
[65]B.C.Yunn,\ImpedancesintheIRFEL"
Page 195 and 196:
TEM:transverseelectricmagnetic. TOF
Page 197 and 198:
B.2Anoteonspacecharge Wedenetheslop
Page 199 and 200:
B.3.3PARMELA FeaturesofJeersonLabVe
Page 201 and 202:
Initialization MAIN Stop INPUT DECK
Page 203 and 204:
C.0.6TheDispersionRelationsfor^S(!)
Page 205 and 206:
have: Howeveritshouldbenotedthatweh
Page 207:
FigureD.1:OverviewoftheRF-controlsy
show all

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

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?