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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hor.<br />
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ver.<br />
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-20<br />
-100 -80 -60 -40 -20 0 20 40 60 80 100<br />
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Energy .<br />
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7<br />
Figure6.5:Focallengthoftherst(cavity#4)<strong>and</strong>second(cavity#3)cryounitcavitiesversus<br />
6<br />
.<br />
5<br />
.<br />
4<br />
Energy<br />
duetothefactthatthekickisdependentontheparticlepositioninsidethebunch,<strong>and</strong>therefore yieldsadierentialmotionbetweenthehead<strong>and</strong>thetailofthebunch.Thisinturnreultsin<br />
3<br />
.<br />
anincreaseofthebunch(projected)emittance.Itisstraightforwardtoestimatetheemittance<br />
hor. 2<br />
growthduetothiseect:itdependsonthebunchlength<strong>and</strong>thebeamparametersatthelocation<br />
.<br />
oftheconsideredcoupler.Thegeneralexpressionfortheemittancegrowthis[62]: ,thephasedierencew.r.t.themaximumenergyphase(so-called\crestphase")<br />
1 ver. .<br />
0<br />
~"x'z<br />
-200 -150 -100 -50 0 50 100 150 200<br />
2~"x0A2x+B02 x (6.13)<br />
(RF-deg)<br />
thecorrespondingeectonemittancegrowthissmallerthanthehead-taileectinduceddilution emittanceistheskewcouplingeectinducedbytheskewquadrupolemomentoftheelectriceldin thecavity:itintroducesacouplingbetweenthevertical<strong>and</strong>horizontaltransverseplane.Generally <strong>and</strong>itcanbereducedwithapropercorrectionscheme[62];thislattereectwillbeignoredinthe forthcomingdiscussion. atthecouplerlocation,<strong>and</strong>A<strong>and</strong>Baccountsforthesteeringeectsofthecavity,theselattertwo termscanbeestimatedusingtrackingcode.Theothercontributionthatcanspoilthetransverse where~"0istheinitialemittance,z,x<strong>and</strong>0xarerespectivelythermsbeamsize<strong>and</strong>divergence<br />
6.1.4The10MeVRegion Aspreviouslymentioned,wehaveinstrumentedthe10MeVregionwithavarietyofdiagnostics devices:beamdensitymonitors,emittancemeasurementdevices,atime-of-ightpickup<strong>and</strong>a<br />
Focal Length (m)<br />
Cav #4<br />
Cav #3<br />
10<br />
E out (MeV)
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