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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Fraction of <strong>Beam</strong> enclosed within (%)<br />
100<br />
90<br />
80<br />
t=0.25 m<br />
t=0.8 m<br />
t=1.5 m<br />
70<br />
60<br />
Figure4.6:Angularscatteringdistributionexperimentallymeasuredforthreedierentthicknesses<br />
50<br />
ofAluminumfoil.<br />
40<br />
30<br />
20<br />
10<br />
0<br />
numberofcollisionisafunctionoftheatomicweightA,theatomicnumberZ,<strong>and</strong>thethickness foragivenmeannumberofcollisionsasafunctionofthereducedanglesisgivenby: wherethecoecentsc1<strong>and</strong>c2areconstantthatwheredeterminedfromexperiment.Themean F(;s)=eXk=0mk Xl=0CkmCmk l bk1Bl2((c1l+c2k)2+2s)3=2 lc1kc2 (4.20)<br />
0.0 0.0002 0.0004 0.0006 0.0008 0.001<br />
(rad)<br />
ofthefoil: whereisthereducedvelocity. Thereducedangle,s,inthelatterequationisrelatedtotheprojectedangleviatherelation: =8:83103tAZ4=3 2 (4.21)<br />
inMeV.ItisworthwhiletonotethattheworkofKeil(asMoliere)wastoshowthattheangular scatteringdistributioninthepluralscatteringregimedoesnotexactlyfollowagaussi<strong>and</strong>istribution<br />
wherethecriticalangleisdenedas=4:23Z1=3 E,Ebeingtheenergyoftheincidentelectrons<br />
s= (4.22)
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