BEAM TRANSPORT,INJECTION
13/Jun/2016
21th SuperKEKB Review
N.Iida for KEKB/BT GroupContents• Introduction• Upgrades for SuperKEKB
1.
2.

Changes of the beam energies
New septum magnets• Phase1 Commissioning and status
1.
2.

Orbit, charge, and Injection
Optics measurement with wire scanners• Issues
1. Water interlock
2. X-Y Coupling in e+ line

• SummeryIntroduction

BT for AR

The half of BT lines have double-story structure of e- and e+ lines

0th Arc

1st Arc

2nd Arc
3rd Arcard 3YgnihctSwi(SY3)

4th Arce- Dump/BTe+KEKB

4th Arce-/e+
LINAC

New
AR/ B
Te-PF/B
Te-Introduction

Components of BT lines
Magnet, PS

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e-e+MagnetPower Supply

MagnetPower Supply

Dipole

65

1858

16

Quadrupole

53

2353

53

Sextrupole (Phase2)

2222

Steering

45

45

50

50

Backleg

25

25

16

16

Injection Septum

4422

Injection Kicker

3+33+33+33+3

Monitor, Collimator

e-e+

BPM

60

60

Screen monitor

20

20

Wire scanner

56

Collimator

49

Beam shutter

21

21th SuperKEKB Review

3Upgrades for SuperKEKB
1.
2.

Changes of the beam energiesNew septum magnets

13/Jun/2016

21th SuperKEKB Review

4Upgrades for SuperKEKB

1. Change of the Beam Energy• e- : 8 GeV to 7 GeV, and e+: 3.5 GeV to 4 GeV• The layout of Switching Yard 3 (SY3) has been reconstructed.

• Increase of e+ energy• Some dipoles :The power supplies are upgraded.
• Dipoles in 2nd and 3rd Arc :The gaps have been made narrower, which increase magnetic ﬁelds
without upgrading their power supplies nor the water cooling of magnets.

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21th SuperKEKB Review

5Upgrades for SuperKEKBEnergy Compression System(ECS) at SY3from KEKB to SuperKEKB

Chicane of ECS
e+/e-Cavitis of ECS

e+e1st Dipole of ECS(Separation dipole)e+873.54e-

The 1st dipole of Energy Compression System(ECS),
whose magnetic ﬁeld is static, is also used as aseparator of e- and e+.
The orbits are changed from KEKB operation.
The dipoles other than 1st one are renewed.

Upgrades for SuperKEKB

SY3 Construction changed

20/Jul/12

N. Iida, 18th MAC

New Energy Compression
System(ECS) of positron line at theend of LINAC is under construction,which is needed to change theenergy of positron from 3.5 GeV to 4GeV.

Magnets of ECS were removed
and the new ones will be installedin this summer.

DRChicane of ECS

SY3

Upgrades for SuperKEKB

1. Change of the Beam Energy• e- : 8 GeV to 7 GeV, and e+: 3.5 GeV to 4 GeV• The layout of Switching Yard 3 (SY3) has been reconstructed.

• Increase of e+ energy• Some dipoles :The power supplies are upgraded.
• Dipoles in 2nd and 3rd Arc :The gaps have been made narrower, which increase magnetic ﬁelds
without upgrading their power supplies nor the water cooling of magnets.

13/Jun/2016

21th SuperKEKB Review

8Upgrades for SuperKEKB

2. New Septum Magnets

T. Mori, 19th MAC• For smaller injection error, the eﬀective septum thickness isnarrowed from 5mm to 3.5mm.
(only HER in Phase1, and LER in Phase2)
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21th SuperKEKB Review

9Phase 1 Commissioning and Status
1.
2.

Orbit, charge, and Injection
Optics measurement and matching with wire scanners

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21th SuperKEKB Review

10Phase 1 Commissioning and Status

1. Orbit, Charge
The e+ beam with hugeemittance comes from theFlux Concentrator without
Damping ring now.
We use the collimators toguard the cavities.

LINACBTe+ Simulation

LINACBT

Collimation
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e+ Target

F. Miyahara,
T. Miura,
N. Iida21th SuperKEKB Review

Collimatione+ Target

0.45 (nc)γεx=1400µm
γεy=1590µm

11Phase 1 Commissioning and Status

1. Injection

The injection eﬃciencies are good for the both rings.
Orbit FB Panel atthe end of BT

Y. Ohnishi

Horizontal positionof 2 BPMs

Vertical positionof 2 BPMs

13/Jun/2016

The vertical jitter of the electron
beam is large, which aﬀects theinjection eﬃciency.

Phase 1 Commissioning and Status

F. Miyahara, Y. Yano, N. Iida

2. Optics Measurement with Wire scanners (WS’s)
Several wire scanners are in LINAC and BT.
A set of 4 wires is installed at each location.
KEKB Ring

BT e-(4)SectorC(4)Sector2(4)Sector5(4) Sector3(4)LINAC

SectorB(4)SectorA(1)BT e+(4)Detector:
Optical Fiber
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21th SuperKEKB Review13

Phase 1 Commissioning and Status

Beam size measurements of e- at upstream of BTe- from the Thermal gun

e- from the RF-gun

jitter fromLINAC
YX

YX

Leak ofDispersion of BTYXYXYX

YXYX

YX

The beam sizes of RF-gun is small than those of Thermal gun.
T. Mori
V. Phase space at QXD6E

Thermal gun

RF gunThe measured vertical jitters for 20min. of e- beam in the vertical phasespace are almost same for the both of guns. (All scales are same)Phase 1 Commissioning and Statuse- from RF-gun

Phase spaces at the 1st Wire scanner
Beam size X by WS

T. Mori, N. Iida

Jitter X

The red circle shows emittance coresponding to1σ of beam size.

The vertical jitter is large and comparable with 1σ of the beam distribution.
Beam size Y by WS
Jitter Y

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21th SuperKEKB Review15

Phase 1 Commissioning and Status

Measured Emittances by WS
The emittance of RF
gun is smaller thanthermal gun.

These blow-up
caused by leak ofthe dispersion at BT

SectorC

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Sector5BT

BTend

21th SuperKEKB Review

SectorC

Sector5

BT

BTend

16

Issues• Water interlock
1.

The dipoles are down due to the water interlock 2-3 times for a week.
• The water of the cooling system is polluted by CuO. The Cu is dissolved from thecooling-water pipes.

2.

The water interlocks of some dipoles whose gap is narrowed work by
the leaked magnetic ﬁeld (20~30Gauss) from the dipoles.

• The iron cans are covered over the ﬂow meter.
• The reason is thought the interlock switches became older.

• X-Y Coupling in e+ line

〜450mm13/Jun/2016

21th SuperKEKB Review

17Issues

Abnormal X-Y Coupling in the e+ BT
H. Sugimoto
Horizontal position/kickWhen the beam is kicked horizontallythe vertical orbit distortion appears.

Vertical position/kick

A large vertical dispersion exits aroundthe same place where the verticaldesign dispersion is zero andhorizontal dispersion exits.

13/Jun/2016

Between 2nd and 3rd Arc

21th SuperKEKB Review

18IssuesY. Onishi, N. Iida

Abnormal X-Y Coupling in the e+ BT (Cont’d)
Measurement

Simulation• Some hypothesis can be thought to explain the dispersion pattern.
1.
2.
3.

The quadrupole, QCD2P, is rotated -107 mrad.
Some of the quadrupoles around the 3rd Arc are rotated ~10mrad.
The dipoles of the 3rd Arc, BH3P, have sextupole components.

• K2=0.1 at ΔY=10mm.
• The magnetic measurements of the dipoles were not so large.
• The interference from the neighbor magnets are also suspended.

• All of them are not realistic.
• We will study more.
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21th SuperKEKB Review

19Summery• The performance of BT is almost well.
• Some issues are not serious in Phase 1, but they should be improvedby the beginning of Phase 2.

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21th SuperKEKB Review

20Thank you.

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21th SuperKEKB Review

21Phase 1 Commissioning and Status

Charge at the end of BT
e- injection
from RF Gun

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21th SuperKEKB Review

22e- Orbit from RF-Gun

e+ Orbit

Phase 1 Commissioning and Status

Collimation

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21th SuperKEKB Review

25〜450mm13/Jun/2016

21th SuperKEKB Review

26Phase 1 Commissioning and Status

Measured Emittances
The emittance of RF
gun is smaller thanthermal gun.

These blow-up
caused by leak ofthe dispersion at BT

SectorC

13/Jun/2016

Sector5

SectorC

BT

21th SuperKEKB Review

Sector5

BT27