Mid-long term plan at the injector linac
Supplement to Masanori Satoh’s injector presentation

Kazuro Furukawa
for Injector Linac Group<http://www-linac.kek.jp/linac-paper/general/>< kazuro.furukawa @ kek.jp >Injector linac plan

K.Furukawa, Sep.2021

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Injector Linac Upgrade Items 2022 - 2026
Thermionic gun with 10 nC

BJ-arc

ARF gun with 4 nC

PF ring
2.5 GeV
0.2 nC

1.1 GeV positron
damping ring

1.5 GeV
Bunch compression

3.2 GeV, 10nC x 2C

1 Positron
generation 2LER positron
4.0 GeV
Energy compression 4 nC x 2

Energy compression

345PF-AR
6.5 GeV
0.2 nCHER electron
7.0 GeV
4 nC x 2

Pulsed magnets/kickers High precision movers PCB capacitor renewal New energy compressor

RF gunInjector linac plan

Positron capture section

Accelerating structure
K.Furukawa, Sep.2021

Linac Beam Property Requirements

Linac Beam Parameters for KEKB/SuperKEKB
Stage

KEKB (final)

Beame+e–e+e–e+e–e+e–e+e–

EnergyStoredcurrent
Life time(min.)

3.5 GeV

8.0 GeV

4.0 GeV

7.0 GeV

4.0 GeV

7.0 GeV

4.0 GeV

7.0 GeV

4.0 GeV

7.0 GeV

1.6 A

1.1 A

1.0 A

1.0 A

––

1.8 A

1.3 A

3.6 A

2.6 A

150

200

100

100––––

66

primary e- 10

Bunchcharge (nC)
Norm.
Emittance

1

Simultaneous top-up
injection
(PPM)

0.5

1310

1000

Phase-III (final)2

2

150/30100/40100/1540/20(Hor./Ver.)(Hor./Ver.)(Hor./Ver.)(Hor./Ver.)→ 0.4

200/401400

Phase-III (interim)

primary e- 10130(γβε) (mrad)
EnergyspreadBunch /Pulse
Repetition
rate

Phase-II (achieved)

primary e- 8

1→1

Phase-I (achieved)

4→4150(Hor./Ver.)

0.13%

0.13%

0.50%

0.50%

0.16%

0.10%

0.16%

0.10%

0.16%

0.07%

222222222250 Hz

25 Hz

25 Hz

3 rings(LER, HER, PF)

No top-up

Partially

50 Hz

50 Hz

4+1 rings (LER, HER, DR, 4+1 rings (LER, HER, DR,PF, PF-AR)
PF, PF-AR)

u Gradual improvements
Injector linac plan

K.Furukawa, Sep.2021

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Challenges in Linac upgradeu Achieving the both of higher injection beam charge and lower
transverse/longitudinal emittanceu Maintaining higher availability and stability
u Establishing injection energy for higher resonances
u Solutions with upgraded hardware
v Precise pulsed magnets and kickers
v Movable girders for quads and structures
v Energy compression system (ECS)v Accelerating structures to replace aged onesv Low emittance and high charge RF gun
v High efficiency positron capturing
v Replacement of capacitors including PCB at power converters

u Polarized electron beam design for the future

Injector linac plan

K.Furukawa, Sep.2021

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Pulsed Magnet, Kicker and Mover
Injector linac injects beams into SuperKEKB HER, LER as well as light sources PF, PFAR with adequate beam properties at 50 Hz maximum in simultaneous top-up injection
scheme. Pulsed magnets, kicker magnets and girder movers will be installed in orderto suppress emittance blow-up caused by wakefield in accelerator structure with 4 nC
per bunch. Kicker magnets may correct beam orbits separated by only 96 ns. Girders
may adjust girders at less than 10 microns.
Ceramics chamber integrated
kicker development

Pulsed magnets andpower supplies
High-precision girder movers

Injector linac planK.Furukawa, Sep.2021

RF gun and positron capture section
Further improvements at the high-charge
low-emittance RF gun and high-efficiency
positron capture section are planned.

Flux concentrator (FC)primarye- beam

Cavities and photo cathodepositronproduction
Target

Flux
Concentrator
Laser shaping and stabilization with DOE optical element

BridgeCoils
Positron capture sectionwith FC

Injector linac plane+ beamK.Furukawa, Sep.2021

New accelerating structuresand ECS for electron beam
7% of 230 accelerating structures will bereplaced for mitigation of 40-years ofdegradation by discharges and water leaks.

Energy compression system (ECS) for
electron beam will be installed at thebeginning of the beam transport line.

電子銃空洞と光陰極回折光学素子による形状補正

Additional replacement will benecessary in nearfuture.

EEHHEHEEHEE
H

Injector linac plan

EK.Furukawa, Sep.2021

Capacitors with PCB contamination
Capacitors (up to 1200) in power modulatorswith low-level PCB produced before 1991 will
be replaced following the law.
Summary:
Capacitors in high-power
Injector linac continues to improve
klystron modulatorswith hardware upgrade in above 7
category regions from 2022 to 2026.

Injector linac plan

K.Furukawa, Sep.2021

Injector linac plan

K.Furukawa, Sep.2021

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