Progress of Injector Linac
Kazuro Furukawa
for Injector Linac

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

1

!!入射器の復習!!今期の運転!!Alignment!!陽電子発生装置!!RF 電子銃!!Commissioning!!Phase-1 定常運転

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

2

Linac Overview

Mission of electron/positron Injector in SuperKEKB!!40-times higher Luminosity"!Twice larger storage beam
! Higher beam current at Linac"!20-times higher collision rate with nano-beam scheme#!! Low-emittance even at first turn#!! Shorter storage lifetime! Low-emittance beam from Linac! Higher Linac beam current!!Linac challenges"!Low emittance e#!with high-charge RF-gun"!Low emittance e+#!with damping ring"!Higher e+ beam current#!with new capture section"!Emittance preservation#!with precise beam control"!4+1 ring simultaneous injection
Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

3

Linac Overview

電子ビームパラメタ
SuperKEKB

KEKB

エネルギー (GeV)

7.0

8.0

HER蓄積電流値 (A)

2.6

1.1

HERビーム寿命 (min.)6200

最大ビーム繰り返し (Hz)50

50

最大バンチ数 (rfパルス当たり)2

2

エミッタンス (mm!mrad)50/20 (Hor./Ver.)100

バンチ電荷量 (nC)51

エネルギー広がり (%)

0.1

0.05

バンチ長 "z (mm)

1.3

1.3

ダンピングリングn/a

n/a

同時トップアップ入射

4 rings (SuperKEKB
e-/e+, PF, PF-AR)

3 rings (KEKB e-/e+, PF)

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

Linac Overview

陽電子ビームパラメタ
SuperKEKB

KEKB

エネルギー (GeV)

4

3.5

LER蓄積電流値 (A)

3.6

1.6

LERビーム寿命 (min.)6133

最大ビーム繰り返し (Hz)50

50

最大バンチ数 (rfパルス当たり)2

2

エミッタンス (mm!mrad)

100/20 (Hor./Ver.)2100

バンチ電荷量 (nC)41エネルギー広がり (%)

0.1

0.125

バンチ長 "z (mm)

0.7

2.6

ダンピングリング〇n/a

同時トップアップ入射

4 rings (SuperKEKB
e-/e+, PF, PF-AR)

3 rings (KEKB e-/e+, PF)

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

Schedule

RF-Gun e- beamcommissioning
at A,B-sector

Linac Schedule Overview (tentative A)
e- commiss.
at A,B,J,C,1

e+ commiss.
at 1,2 sector (FC, DCS, Qe- 50%)e- commiss.
at 1,2,3,4,5 sector

Phase1: high emittance beam for vacuum scrub
Phase2,3: low emittance beam for collision

Time →

Location↓

1 nC
Phase1: Electron: Positron: Low current electron

Linac Upgrade Status towards SuperKEKB

non dad e+ cos.
s
at 1,2, 3,4,5 sectors
e- commiss. at A→5 sectors

2 nC
Phase2ped e+ commiss
commiss.
a
at 1→5 Qe+ = 1~4nC
e- commiss.
at A→5 Qe- = 1~5nC

4 nC
Phase3PF-AR ecommiss.

K.Furukawa, KEK, Jan.2015.

6

Schedule

RF-Gun e- beamcommissioning
at A,B-sector

Linac Schedule Overview (tentative B)
e- commiss.
at A,B,J,C,1

e+ commiss.
at 1,2 sector (FC, DCS, Qe- 50%)e- commiss.
at 1,2,3,4,5 sector

Phase1: high emittance beam for vacuum scrub
Phase2,3: low emittance beam for collision

Time →

Location↓

1 nC
Phase1: Electron: Positron: Low current electron

Linac Upgrade Status towards SuperKEKB

non d
da
a
d e+ cos.
s
at 1,2, 3,4,5 sectors
e- commiss. at A→5 sectors

2 nC
Phase2

damped e+ commiss.
miiss.
at 1→5 Qe+ = 1~4nC
e- commiss.
at A→5 Qe- = 1~5nC

K.Furukawa, KEK, Jan.2015.

7

Operation

Operation Status!!FY2014 の運転"!運転時間: 3900 hours (FY2013 -27%)#!PF/PF-AR Injection (and Commissioning for SuperKEKB)#!Apr.11 – Apr.25#!May.7 – Jul.1#!Sep.24 – Dec.26#!5 days in Jan, Feb"!故障 (FY2013 0.43%)#!偏向電磁石コイル発熱 (May)#!マイクロ波パルス電源デスパイカー発熱 (May)#!フラックスコンセントレータ電源側ケーブル発熱 (Dec)#!マイクロ波パルス電源トランス端末発熱 (Dec)
Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

8

Utility

Facility for Electric Power and Cooling Water!!Linac needs electricity and cooling water extensions, especially for
positron generator upgrade!!Separate building construction in FY2013 not to impact PF/PF-AR!!Facility extensions performed during summer 2014
50 Hz (e+ or e-)pulse-by-pulse
mode switching SuperKEKB injector
1.1 GeV
Damping Ringcirc. 136 m

low emittancegunRF gun3.5 GeV
10nC x 2 (prim. e-)
5nC x 2 (inj. e-)Bunch
Compressor

S-bandlinac

Energy-spread
Compression System
3T
RF gunPF

AR

2.5 GeV e6.5 GeV e- 
0.1nC x 1LER

4.0 GeV e+
4nC x 2
ECS
ECS

HER

e+ target &LAS capture section
[1] Sector 1,2
Electricity and coolingwater addition for new
positron generator+920 kVA, +900 L/min
Linac Upgrade Status towards SuperKEKB

7.0 GeV e5nC x 2[2] Sector 2,3
Electricity addition for
new damping ring
+310 kVA[3] Sector 5Electricity and cooling water
addition for energy compression,
beam diag., injection beamlines+300 kVA, +460L/min
K.Furukawa, KEK, Jan.2015.

Alignment

Alignment!!High-precision alignment was not necessary in PF and KEKB
injections, and it was much damaged by earthquake in 2011.
!!Instead of flexible-structure girder before earthquake, rigidstructure was adopted with jack-volts and fixed supports.
!!Reflector pedestals are developed and mounted onto quadmagnets and accelerating cavities for laser-tracker measurement.
!!Iterative measurement and adjustment with 500-m straight laser
and position sensors should enable 0.3-mm global alignment.
!!Laser tracker should enable 0.1-mm measurement within 10-m
girder unit.
!!Displacement gauges, hydrostatic leveling, inclinometer are also
employed.
!!Remote measurement system and girder mover system will benecessary for longer term, and are under development.
Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

10

Alignment

Alignment progress in 2014!!For the first time at 3-5 sectors!!Horizontal axis: sensor number from sector C, 1-4, to sector 5(~80 m/sector)!!Vertical axis: voltage (~displacement at 0.25~0.5mm/mV)!!Some girders were not yet upgraded!!Moved up to 3 mm not to break vaccuum

Displacement / mV

Sector C

Linac Upgrade Status towards SuperKEKB

Sector 5

K.Furukawa, KEK, Jan.2015.

11

Alignment

Alignment progress in 2014!!For the first time after earthquake at downstream sectors!!Several measurements during summer!!Measurement reproducibility was confirmed up to ~0.2 mm!!While there existed
several conflicting
measurements,
consistent scheme~5mm
has been established!!Movement of tunnel
by several 10’s of
micrometer wasobserved (→ mover)~10mm!!Further work necessary
in 2015, for alignmentand girder replacement
Linac Upgrade Status towards SuperKEKB

Higo et al.

K.Furukawa, KEK, Jan.2015.

12

Positron Enhancement

Positron Generation!!4-times more positron is required at
SuperKEKB than KEKB"!Safety measure was taken after cable fire during thetest of Flux Concentrator (FC)"!New components in
100-m capture section
were tested in steps"!High voltage tests intunnel in April"!Beam tests with electron
in MayLinac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

13

Positron Enhancement

Positron generation for SuperKEKB!"#$%&"$'
10 nC
primary e-bridge coils

DC QM spoilertargetsolenoid

LAS Accel.
structure

primary
e- beame+ positron
beam
hole

5 nC injection e-production
Target

Flux
Concentrator

pulsed ST

Flux
Concentrator

pulsed QM
BridgeCoils

e+ beam

New positron capture section after target with
Flux concentrator (FC) and large-aperture S-band structure (LAS)
Satellite bunch (beam loss) elimination with velocity bunching
Pinhole (2mm) for electrons beside target (3.5mm)
Beam spoiler for target protection
Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

14

Positron Enhancement

陽電子捕獲部@Linacトンネル
この中にFC、標的
ブリッジコイルが収められている。

T.Kamitani

DCソレノイド

2014年4月に陽電子捕獲部
をビームラインの設置し、5月より陽電子のコミッショニングを開始した。
Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

Positron Enhancement

Positron from New Positron Capture Section!!Generated positron ~0.1nC wastransferred to the entrance of
damping ring!!With higher magnetic and electricfield, 4-nC positron will be
generated!!Target shield(40cm x 6m long)
Beam position
will be finalized
Horizontal!!Alignment will be
Vertical
improved
3mm ! 0.1mm
Beam charge

Linac Upgrade Status towards SuperKEKB

Flux
concentrator
and structure
Large
aperture S-band
following
beforesolenoidsolenoid/quad& quad installation

400 m~0.1 nC

PositronPrimary Electron
W target
K.Furukawa, KEK, Jan.2015.

16

Positron Enhancement

T.Kamitani(1) FC current

6kAより大きな電流値でもまだsaturationせずに順調に伸びていくと期待される新型電源では12kAまで上がる予定。
伝送路の inductance も下げる予定。
FC currentがzeroでもある程度のyieldがあるFCでの実電流値は1.07倍
plot上の6kA => 6.42 kA

CT測定値
Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

Positron Enhancement

T.Kamitani

Positron Generation

1)! Installation of positron generator for SuperKEKB in April 2014
(Beamline construction since summer 2013)(positron target, spoiler, Flux Concentrator, bridge coils, LAS structures [x6], DC solenoids [16+13],
e+/e- separator, quads [>90])

2)! Commissioning of positron beam, observation of the first
positron after reconstruction for SuperKEKB, further
improvements expected
Primary e- [nC] Positron [nC]
June 2014
Specification(at SY2)

0.6

0.12

x17

10.0

DR injection(2017?)
3)!

Oct.~Dec.2014 : Linac commissioning
Jan.~Mar.2015 : Construction
Jul.~Sep.2015 : Construction

Linac Upgrade Status towards SuperKEKB

5.0
4.0

x42

Efficiency

Parameters

20%

FC 6.4kA, Solenoids 370A,
LAS capture field 10 MV/m

50%
40%

x2.5

FC 12kA, Solenoids 650A,
LAS capture field 14 MV/m
Energy spread acceptance0.5%

Apr.~Jun. : Linac commissioning
Oct (?) : LER injection
K.Furukawa, KEK, Jan.2015.

Positron Enhancement

陽電子生成装置遮蔽体
1-5 陽電子ターゲット下流の加速器上空に鉄を主体としたシールドを設置する．
遮蔽体の全体図

Linac Upgrade Status towards SuperKEKB

S. Matsumoto

K.Furukawa, KEK, Jan.2015.

19

Positron Enhancement

鳥瞰図：南東方向から見た図． トンネル1-5 陽電子
ターゲットの60cm上流から６ｍの範囲に設置．今年度は、遮蔽鉄の厚みは200mm（図中の赤＋灰色部）．
200mm角柱 6本が現場通路上ビームラインよりに設置される．鉛カーテンを設置すると、通路の幅が現場では1400mm．3 月末までに建設.
Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

20

RF gun for low-emittance electron

Photo cathode RF gun development

Cascaded frequency doublers
Quasi traveling wave side couple cavity
Yb fiber and Yb:YAG think disk laser

Ir5Ce
CathodeIr5Ce photo cathode
Linac Upgrade Status towards SuperKEKB!! 5.6 nC / bunch was confirmed!! Next step: 50-Hz beam generation &Radiation control
K.Furukawa, KEK, Jan.2015.

21

RF gun for low-emittance electron

RF-Gun development strategy for SuperKEKB!!Cavity : Strong electric field focusing structure"!Disk And Washer (DAW)=> 3-2, A-1(test)"!Quasi Traveling Wave Side Couple=> A-1=> Reduce beam divergence and projected emittance dilution!!Cathode : Long term stable cathode"!Middle QE (QE=10-4〜10-3 @266nm)"!Solid material (no thin film) => Metal composite cathode=> Started from LaB6 (short life time)=> Ir5Ce has very long life time and QE>10-4 @266nm!!Laser : Stable laser with temporal manipulation"!LD pumped laser medium => Nd / Yb doped"!Temporal manipulation => Yb doped=> Minimum energy spread

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

RF gun for low-emittance electron

Design of a quasi traveling wave side couple RF gun
M. Yoshida et al

Normal side couple
structure

Quasi traveling wave sidecouple
structure

Quasi traveling wave side couple has stronger focusing field
Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

RF gun for low-emittance electron

Beam tracking simulation result
5 nC

Gun
Exit

()"*+,-$%./.%))0)1+#

M. Yoshida

10 nC

2"3$%4/5%))(,$167%!81$+#%
4/9:;<,-=%!=+8$
Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

RF gun for low-emittance electron

RF-Gun comparison

M. Yoshida

Quasi traveling wave side couple RF gun(100 MV/m, 6mm-mrad, 13.5 MeV)
DAW-type RF gun(90 MV/m, 5 mm-mrad, 3.2 MeV)
BNL-type RF gun(120 MV/m, 11.0 mm-mrad, 5.5 MeV)
Beam Size

Quasi traveling wave side couple cavity

BNL (3.8 mm)
DAW (1.7 mm)
QTW (0.2 mm)

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

25

RF gun for low-emittance electron

Ir5Ce Cathode!"#$%"&'()*+($*,'+&-./0(&($%'
1,'2#3(.'*4(#$+$5

AB'$1%$,$167%#$,!"C7%%"!%$,B<6=%CB%+-D&+C$%%E1.F$

6#.1/$
78+5($

2(>0(?@

M. Yoshida2(>0(?@
6#.1/$

No oxidization
is observed

QE lifetime

QE Enhancement of IrCe cathode

Ir5Ce
Cathode
Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

26

RF gun for low-emittance electron

Energy spread reduction using temporal manipulation
M. Yoshida

Energy spread of 0.1% is required for SuperKEKB
synchrotron injection.
15nC

t

5nC10nC

20nC

Gaussiant

Square 5nC
10nC
15nC
20nC

5nC electron
Linac Upgrade Status towards SuperKEKB

15nC
Primary beam for positron production
K.Furukawa, KEK, Jan.2015.

27

RF gun for low-emittance electron

Properties of laser medium
Nd-doped

Nd laser system for 3-2 RF-Gun

τ〜200μs, 40%&  $  
SHG(532nm) 40%
Nd:YVO4& High power pump LD is available. LD Pump
FHG(266nm) 20%(808nm)Nd:YAG& $ "
5HG(213nm) 3%%Pulse width is determined by SESAM.
808nm
1064nm(Gaussian)Yb-doped&# !τ〜900μs, 40%& !   #
SHG(520nm) 40%&   
LD Pump Yb-glass
FHG(260nm) 20%&   Yb:YAG(941/976nm)
5HG(208nm) 3%% 
Yb:BOYS
941/976nm
1040nm% Ti-doped Pump τ=200μs, 40%Pump(808nm)40%

Best for Linac RF-Gun

τ〜3μs, 40%
SHG(400nm) 40%
THG(266nm) 20%
FHG(200nm) 10%

Nd:YAG
SHG
Ti:Sapphire
808nm 1064nm
800nm
532nm
Ti:Sapphire laser system.
& $## & # 
TW laser is based on Ti-Sapphire%Low cross section%Short fluorescent time => Q-switched laser is required for pumping

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

28

A-1 RF gun results
5.6 nC bunch charge
was observed.

RF gunA1 sector at KEK linac

beam size measurement for Q-scanx32.7 3.1 mm-mrad
Linac Upgrade Status towards SuperKEKB

Q-scan emittance measurementy10.7 1.4 mm-mrad
K.Furukawa, KEK, Jan.2015.

29

RF gun for low-emittance electron

Photo cathode RF gun development

Cascaded frequency doublers
Yb fiber and Yb:YAG think disk laser

Ir5Ce photo cathode
Linac Upgrade Status towards SuperKEKB

Quasi traveling wave side
couplecavityPartof multi-pass
Ampliﬁer!! 5.6 nC / bunch was confirmed!! Next step: 50-Hz beam generation &Radiation control
K.Furukawa, KEK, Jan.2015.

30

RF gun for low-emittance electron

GU_A1 Laser Configuration as of Nov.2014

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

31

RF gun for low-emittance electron

GU_A1 Laser Configuration as of Dec.2014

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

32

RF gun for low-emittance electron

Photo cathode RF gun improvement!!Crucial for high-current low-emmittance beam!!New Ir5Ce cathode and new cavity QTWSC weresuccessful!!Basic features were confirmed at 2 ~ 5 Hz!!Expect beam parameter and stability performanceat 50 Hz, with multi-pass amplifiers and coolingsystem!!Resolved the issue of oscillator synchronization!!Staged laser system improvements with beammeasurement system
Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

33

Commissioning

バンチ電荷量の履歴
最大達成電荷量!
電子銃下流：5 nC!
J-ARC出口：
2 nC!
入射器終端： 0.74 nC

SP_A1_C5: 電子銃直後!
SP_B7_4:
Bセクタ
終端
SP_R0_63: J-ARC出口
SP_58_0: 入射器終端

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

34

Commissioning

バンチ電荷量安定性の改善

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

35

Commissioning

ビーム軌道の例
PFトップアップ入射を継続しつつ，RF電子銃スタディをおこなっている。3セクタ以降は，PFビーム用パラメタを使
用。

X軌道

y軌道

電荷量

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

36

Commissioning

A1 部 Dispersion (2014/11/26) の測定結果

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

37

Commissioning

シミュレーション２
測定値を再現するようなBMA*の曲げ角をSADのマッチングで探す。
４点でフィット

K0/K0⌘x [m]•!

•!

うまく収束しない。

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

38

Commissioning

入射部のアライメント測定（RF-Gun〜A2）
QM̲A1̲1

QF̲A1̲C5 QD̲A1̲C5

QM̲A1̲1 QM̲A1̲C5

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

39

Commissioning

2014.10.10

A1-A2 測量結果 [PD_A2_U - PD_A2-D 基準]

PD平均 [A2]QM測定 1回目 [A2]QM測定 [A1]

加速管 [A2]

加速管 [A1]

基準レール [A1]A1架台東端 [A1]

RF-Gun [A1]

-1.5

-1

QM̲A1̲M

基準レールに当てた後
測量した

-0.5
15000

10000

5000

0

-10000-5000-15000西

0→

QM̲A1̲C5

東QM̲A2̲3

0.5

QM̲A2̲1

QM̲A1̲2[mm]

QM̲A2̲4

RF-Gun1
QM̲A1̲1

1.5

2

2.5

Horizontal
3

下流

Linac Upgrade Status towards SuperKEKB←

上流

K.Furukawa, KEK, Jan.2015.

Commissioning

2014.10.10

A1-A2 測量結果 [PD_A2_U - PD_A2-D 基準]

PD平均 [A2]QM測定 1回目 [A2]QM測定 [A1]

加速管 [A2]

加速管 [A1]

基準レール [A1]A1架台東端 [A1]

RF-Gun [A1]1

0.8
RF-Gun0.6
QM̲A2̲1

QM̲A2̲3

QM̲A1̲2

0.4

上QM̲A1̲1

→
下
[mm]

15000

0.2

QM̲A1̲C5

QM̲A2̲4

0
10000

5000

0

-5000

-10000-15000-0.2
QM̲A1̲M

-0.4

-0.6

-0.8

Vertical-1

下流

Linac Upgrade Status towards SuperKEKB←

上流

K.Furukawa, KEK, Jan.2015.

Cathode 面の影響
F. Miyahara
初期分布：
横方向：
カソード面で一様
縦方向：
矩形、
パルス幅 30 ps、入射角度60・初期位相が10°変わると横方向の位相空間分布が変わる=レーザーのタイミングに敏感（電子銃内部での収束
力は位置、時刻によって変動するので分布が変化すれば出口での 位相空間分布も変化してしまう）
Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

42

Commissioning

ターゲット周辺の軌道

不自然な水平軌道（要アライメント確認）

43

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

43

Commissioning

R0 ARC Dispersion測定： Trackingとの比較

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

44

Commissioning

電子ビームコミッショニング
項目

設計値

現状

バンチ電荷量 (nC)55.01 (電子銃直後)
0.58 (入射器終端)

ビームエネルギー

77.5

入射器終端でのエミッタンス(mm!mrad)50/20 (Hor./Ver.)

20/7 (Hor./Ver.) (@A1 unit)

2.5 (KEKB)

10 ~ 20

バンチ圧縮 (A1ユニット） (ps)30 -> 1010 ~ 15

バンチ圧縮 (J-ARC) (ps)

10 -> 5n/a

ビーム分布 （縦方向）

一様分布

n/a

エミッタンス保存“J-ARCバンチ圧縮” +“オフセットインジェクション”

n/a

最大ビーム繰り返し (Hz)50

25

最大バンチ数(rfパルス当たり)

2

2

ビーム入射

Simultaneous top-upn/a

電荷量安定性(%)

45

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

45

Commissioning

今季の Commissioning!!コミッショニングツール群の整備"!ワイヤスキャナ"!トリガ同期カメラおよびスクリーンモニタによるQス
キャン測定"!マッチングソフトウェア!!課題"!入射部のアライメント"!A1シケイン，J-ARCでのビームロス低減（アライメン
ト再確認）

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

Electron gun rearrangement

入射運転に向けて!!現状で定常運転向けの Beam が完成しているわ
けではない!!開発は継続する必要があるが、運転向けの体制を考える!!Phase-1 では Beam requirement は厳しくない!!放射線施設検査を 5-6 月に控えている!!RF 電子銃と熱電子銃の併用を進める

Linac Upgrade Status towards SuperKEKB

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47

Electron gun rearrangement

Staged Radiation Control License towards SuperKEKB!!Two licenses were approved in June 2014!![1] Beam diagnostic station at #A2 just after gun"!for 1250nC/s at 50Hz 2bunches!![2] Beam dump at #28 just before damping ring"!for 10nC/s with positrons!!Radiation measurements especially at positron
generator"!Indispensable to estimate radiation at >100 times higher beam!!Both approved!!Soon apply for the next license at ~May.2015

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48

Electron gun rearrangement

現状

KL-A1-B

KL-A1-A

移相器・減衰器

第2加速管

Linac Upgrade Status towards SuperKEKB

RF-gun（Pre-buncher）

K.Furukawa, KEK, Jan.2015.

Electron gun rearrangement

現状

KL-A1-B
KL-A1-A

第2加速管

Linac Upgrade Status towards SuperKEKB

移相器・減衰器

RF-gunK.Furukawa, KEK, Jan.2015.

Electron gun rearrangement

M. Yoshida

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K.Furukawa, KEK, Jan.2015.

51

Electron gun rearrangement

M. Yoshida

Linac Upgrade Status towards SuperKEKB

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52

Electron gun rearrangement

S.Ohsawa

改造案

KL-A1-A

KL-A1-B

3dB DC
復元

移相器・減衰器（移設）
他のWG新規製作
又は流用

加速管１本

(第2RF-gun)

第1RF-gun

WG 1本

新規製作

移相器・減衰器
（移設）

加速管2本

BuncherPre-buncher

WG 3本を600mmつめる(第2RF-gun用パルスベンドと予備スペース)

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

Electron gun rearrangement

改造案2

S.Ohsawa

KL-A1-A

KL-A1-B

3dB DC
復元

移相器・減衰器
（移設）

WG 1本

他のWG新規製作
又は流用

加速管１本

(第2RF-gun)

第1RF-gun

新規製作

移相器・減衰器
（移設）

加速管2本

BuncherPre-buncher

WG 3本を600mmつめる(第2RF-gun用パルスベンドと予備スペース)

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

Summary!!Steady progress towards first MR injection in 2015!!Finishing earthquake disaster recovery in 2014!!Will make staged improvements before 2017!!Will balance between final beam quality andstaged operation!!Will select optimized route depending on available
resources"!Incorporate thermionic gun as well as RF gun

Linac Upgrade Status towards SuperKEKB

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55

Mt. Tsukuba

Thank you
SuperKEKB
dual rings
PF-AR
PF

Linac Upgrade Status towards SuperKEKB

Injector
Linac

K.Furukawa, KEK, Jan.2015.

56

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

57

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

58

Emittance Preservation and Alignment!!If Device is off center of the beam"!Focusing magnet (quad) kicks the beam bunch"!Accelerating structure (cavity) excites wakefield, to bend the tail!!Distorted bunch in banana shape"!Emittance dilution or blow-up, even 100 times larger#!Depending on the beam optics and the beam charge!!Alignment and orbit correction is crucial to preserve theemittance
Sugimoto et al.

Beam
Focusing
MagnetAccelerating
Structure
Transverse beam distribution in time direction

Linac Upgrade Status towards SuperKEKB

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59

Emittance Preservation!!Offset injection may solve the issue!!Orbit have to be maintained precisely!!Mis-alignment should be <0.1mm locally, <0.3mm globally
Mis-alignment leads to Emittance blow-up

Orbit manipulation compensates it

100 samples
Sugimoto et al.
Linac Upgrade Status towards SuperKEKB

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60

Pulse-to-pulse modulation!!Four PPM virtual accelerators
for SuperKEKB projectmaybe withadditional PPM VAs
for stealth beammeasurements
based onDual-tier controls withEPICS and event-system

Event-based
Control System

Every
20 ms

F.B
e" Gunn
ARCF.B

PF Injectione– ((2.5GeV,
2 5G V
2.5GeVV,, 00.2nC)
2

F.B
e" Gun
ARC

Dam

rring
ing

F.B

SuperKEKB-LER Injectione– (3.5GeV, 10nC)

F.B

e+ Target

e+

V,
V 4
4nC)
nC)

e" GunARC

SuperKEKB-HER Injection

F.Be" GunARC

PF-AR Injection

F.B

e– (7GeV, 5nC)
F.B
e– (6
((6.5G
6.5G
65G

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

5nC)
C)
61

Linac Upgrade Status towards SuperKEKB

K.Furukawa, KEK, Jan.2015.

62