!"#$%&'#()*+'&%,-(")%.+'%/0*"'121!!
34562!57838%
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3F! G")-D(%+.%"B%H"#$%,-(")%
!!
"!
#!
$!

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L;9ME%I%G#$*-(D%'-(D%KLC?N%
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G#$*-(D%'-(D%I%L2?%

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!!

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BT!
%!

!%"B%C#'D"&%I%&>"%"(<%+.%)"J&+'%7%
Tracking simulation!
C'#J:-(D%)-$0,#P+(!

/-&"%.+'%&>"%<#$*-(D%'-(D!

"B%C#'D"&!

!!

Initial parameters of e+ capture section!
T.Kamitani!

Present KEKB!

SuperKEKB!

present capt. section

L-band capt. section

accelerating structures

1m x 2 + 2m x 22m x 2 + 2m x 4

RF frequency

2856 MHz1298 MHz

aperture of the structures

20 mm in diameter

30 mm in diameter

accel. field gradient14.0 ~ 13.2 MV/m

10.0 MV/m

accel. phase-30 deg-30 degsolenoid field （strong）

2.0 T x 45 mm QWT

6.0 T x 220 mm AMD

solenoid field （weak）

0.4 T x 7.9 m

0.4 T x 13.1 m

energy after capt. sec.

~ 80 MeV~ 120 MeV(!=10.5cm)(!=23.1cm)

Increase e+ capture efficiency by enlarging these acceptances !

!! longitudinal acceptance by longer wave length of L-band RF!
!! transverse acceptance by larger aperture of L-band structure!! energy acceptance by adiabatic matching device

Qe+ = 1 nC!

4 nC!

prelim. simulation result by N. Iidasuggests
Qe+ ~ 8 nC @ DR! 3Present KEKB!

Q*PJ)% SuperKEKB!

S-band!&= !y=75e-6m
Momentum=85.7GeV

L-band!&= !y=100e-6m
Momentum=120GeV

Quad( '-band
60mm"! 40mm"

Quad(S-band
30mm"! 20mm"

S-band20mm"

This section is crowded with quads.!
34562!57838!

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)!

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Present KEKB!
/RH#(<%90$H"'%+.%*#'PJ,")(%38888KS'-$#'T%"RN%%%%%I%U3VUK#W"'%J#*&0'"%)"JP+(N%%%%%I%3X33K"(<%+.%7%)"J&+'N%%%% %%%%%%%%K3XYN%
After Capture
section!

34562!57838!

The end of
sector 2!

SuperKEKB!
LRH#(<%90$H"'%+.%*#'PJ,")(%
X(E!
3888KS'-$#'T%"RN%%%%%I%7==7K#W"'%J#*&0'"%)"JP+(N%%%%%I%3Z87K"(<%+.%7%)"J&+'N%%%% %%%%%%%%K3Z8YN%
After Capture
section!

The end of
sector 2!

33F7(E%%I%38(E!

1GeV!x=0.824µm!y=0.672µm

1GeV!x=2.17µm!y=2.12µm#!x=1610µm#!y=1320µm#!x=4250µm+#!y=4150µm

3=&>%121!%?"@-"AO%9#+:+%;-<#!

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-!

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LTR Entrance!

LTR after ECS!

2E/!

c3F=Y%

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ECS!
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e- bypass line!

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ion lin

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Cavity!

Dampingring!

%0!

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Double kickers!

BCS!

Double kickers!
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LER!

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%3!

e+ injection beam seems to be in the LER dynamic aperture.!
34562!57838!

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%-!

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300ns
RTL

DR'(34562!57838!

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10!

M. Kikuchi!

•! Shift the energy of the injection beam : #0(•!%M<e0)&%&>"%-(e"JP+(%#$*,-&0<"%&+%&>"%J,+)"<%+'H-&%+.%&>"%-(e"JP+(%"("'DTF%•!%Q)J-,,#P(D%-(%&>"%)T(J>'+&'+(%*>#)"%)*#J"F%%!

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1%!