Status ofbeamtransport lines
SuperKEKB review

2019.7.9
T. Mori, BT group

Contents• Modification for Phase-3• Septum leakage field suppression• Wire scanner (WS) update• Fiber loss monitor (LM) installation

Arc1• Issues found in Phase-3
LM(𝑒 + )ECS𝑒+WS𝑒−• DR extraction septum PS trouble• BPM• Rejection of Linac 1-pulse modulation• Emittance increase• Future planWS• Modification of radiation safety system
for getting more Linac&BT study time
• Construction of beam diagnostics line

Beam transport line
2019.07.09

SuperKEKB Review2

Modification for Phase-3• Leakage field suppression for MR injection septum• Wire scanner update• Fiber loss monitor installation
2019.07.09

SuperKEKB Review

3Effect of septum leakage field• It was found that septum leakage field from fringes might not be negligible for MR
LER (sler_1689.sad), 1000 positrons, 50 Hz injection, RFSW, RAD, FLUC, NOINTRA

Without leakage field from septum

Y. OhnishiWith leakage field from septum• Assumption for leakage: 𝐵𝐿 ~ 1.0 × 10−4 Tm , 𝐵′ 𝐿 ~ 0.014 [T]2019.07.09

SuperKEKB Review

4Septum leakage field measurement
Septum region
Injection beamStored beamSUSO

Carbon steelO𝑥O𝑧

Septum leakage field measurement

Horizontal scanLongitudinal scan

• 𝐵𝐿max ~ 2.8 × 10−4 Tm/fringe , 𝐵′ 𝐿max ~ 0.018 [T/fringe]• Both of LER/HER MR-ducts on septa was replaced with new ducts made ofcarbon steel overall
Vacuum group2019.07.09

SuperKEKB Review6

Leakage field on new beam duct

• 𝐵𝐿max ~ 1.35 × 10−5 Tm/fringe , 𝐵′ 𝐿max ~ 0.0006 [T/fringe]• 20 times smaller than that of previous measurement• If it not enough, there is the way that the beam duct wrapped by magnetic shield

2019.07.09

SuperKEKB Review

7Fiber installation

WSLMLM• Fibers for WS and LM• LM: both sides connected to OE
module• WS: single side connected to OE
module, opposite side is blank

WSOE moduleWS2019.07.09

SuperKEKB Review

8Wire scanner update

Wire scanner is tilted by 45
degrees from a horizontal
plane
All the wires of 11 WSs
were replaced

Wiring jig

2019.07.09• Wire diameter: 200 → 60 𝜇m• Wire tension: 200 gf• PMT → fiber loss monitor as detector• DAQ system• VME event receiver, ADC, scaler• Pulsed motor controllers (LAN based connection)• Software updated
SuperKEKB Review9

Beam loss measurement with fiber loss monitor• Beam status• Electron: 1bunch 12.5Hz 0.7nC• Positron: 1bunch 12.5Hz 0.6nC
5.85e-5 C/hour in total• N: 0.02 μSv/h,γ: BG @ BT escape door
• N: 0.016 - 0.02 μSv/h, γ: BG @ ARS cable introducing port

• Currently 5.76E-4 C/hour is allowed by radiation safety; about 10 timeslarger• 2-bunch, 25Hz, 2nC/bunch injection → 12 times larger if linearly scaled• Loss rate should be kept less than threshold value
2019.07.09

SuperKEKB Review

10Fiber loss monitor
T. Mimashi• Beam loss could be successfully reduced by BT orbit tuning• Ready for 2-bunch, 25Hz, 2nC/bunch injection
2019.07.09

SuperKEKB Review

11Issues found in Phase-3••••

DR extraction septum PS trouble
BPMRejection of Linac 1-pulse modulation
Emittance increase• Will be reported in next presentation (N. Iida for Y. Seimiya)

2019.07.09

SuperKEKB Review

12

DR Extraction Septum PS trouble

M. TawadaDR extraction septum
Deflection angle (mrad)
Max. current (kA)Max. voltage (kV)
Voltage stability (%)
Current waveformMax. Repetition (Hz)Full sin wave width(usec)
2019.07.09
Magnet inductance (uH)

103
12.5
2.0
< ±0.01
full sine wave
50
250
SuperKEKB Review
5.9

13M. Tawada

DR Extraction septum PS trouble

Septum magnet

Main capacitor (C0)- DR extraction septum PS had been in trouble.
- The voltage of the main capacitor couldn’t be controlled
precisely.
- This failure had been disappeared during the investigation.
- It will be checked during this summer maintenance.

Precise voltage control unit
2019.07.09- Spare circuit board will be available in Jan. next year
because of the global shortage of MLCC.
SuperKEKB Review

14Issues for BPM: BT end feedback and bpm resolution

●
●
●
●

Radius of target circle: 0.3 mm; larger target had induced beam abort
Full width of BPM resolution: > 0.5 mm
Asynchronous BPM readout: feedback delayed
Difficult to keep orbit in target range
Maybe situation is severer for tighter MR optics

15

Issues for BPM• Other problem• Old oscilloscopes (Windows XP) are still in use• ~10 channel of BPM signals combined and read by a oscilloscope channel• Installation of cables corresponding 1 to 1 BPM channel is difficult for budgetaryrestriction• Solution under consideration• For BT end feedback (8-BPM): Libera• The rest of BPMs: Tektronix 12-bit ADC osc after command 'CURVESTREAM' implemented

2019.07.09

SuperKEKB Review

16Rejection of Linac 1-pulse modulation
This type of beams induce MR abort• Energy modulation ~ 50 Mev• Impossible to reject modulated beams by collimators on BT-line• Planning to relocation of collimators where dispersion exists• Middle of ECS@SY3 for positrons• Near vertical bend on end of slope for electrons
2019.07.09

SuperKEKB Review

17Future plan
• Modification of radiation safety system for getting more Linac&BT study time
• Construction of beam diagnostics line

2019.07.09

SuperKEKB Review

18Modification of radiation safety• Beam operation of BT is not allowed even if
there are men only at opposite side of
injection point (IR, BelleII)• Divided management allows BT-dump mode
operation when Tsukuba, Nikko, Oho is 'limit'
or 'free' state• Linac&BT need more study time
• Also important to reduce injection BG• Task force organized, decided to do,
detail specification development on going• Fastest implementation: 2020 fall
• Safety is most important; we should be patient2019.07.09

SuperKEKB Review

19Construction of beam diagnostics line
• Importance of keeping stable injection increases day by day• Some people consider diagnostics system separately• Task force will be organized2019.07.09

SuperKEKB Review

20Summary• Modification for Phase-3: successfully• Septum leakage field suppression• Overall carbon steel ducts were installed for LER/HER• Wire scanner• Fiber loss monitor installed• Issues found in Phase-3: need breakthrough• Power supply trouble on DR extraction septum• Under investigation• BPM• Resolution and synchronization• Solution under consideration; Libera for BT-end feedback BPMs, 12-bit ADC osc for others• Rejection of Linac 1-pulse modulation• Collimator will be relocated to reject modulated beams• Future plan

• Modification of radiation safety system• Specific development on going• Construction of beam diagnostics line• Task force will be organized2019.07.09

SuperKEKB Review

21Thank you

2019.07.09

SuperKEKB Review

22Backup slides

2019.07.09

SuperKEKB Review

23

LER1 Septum Leakage Field

T. Mori2017.11.06

測定方法

O𝑥O𝑧

z軸方向に測定

𝑥 = 0.0 mm

𝑥 = 15.0 mm

x軸方向に測定

最大で20Gauss程度
𝐵𝐿 = 0.5 × 0.28 × 20 × 10−4 = 2.8 × 10−4 Tm

磁気遮蔽
⚫

SUS430 filmを用意した− 2種類: 2 μm, 5 μm⚫

5 μmはうまく巻けなかった⚫

2 μmを巻いて、アルミテープで留めた− 本当は6 μm程度ほしいところ− 3枚くらい重ねて巻けばよかったかも？

SUS430-film あり/なし

SUS430-film あり/なしセプタム導体板の端MR duct reproduction⚫

作り直すとして、どのくらい磁性体部を延長するか⚫

D8側のMR ductも作り直すか− HER2部分⚫

磁性体にできるならしたほうが安心− 末次氏によると可能とのこと− 上流側短管⚫

ここは磁性体のカバーを取り付ければよい⚫

作り直して入れる場合、上流側セプタムをどける必要がある漏れ磁場：磁性体ダクト効果

小玉さんのスライドより

ー：磁性体ダクトなし
ー：磁性体ダクトをセプタム銅板端から25 mm突き出し
ー：磁性体ダクトをセプタム銅板端から100 mm突き出し（上流側の磁性体ダクト突き出し量）

Magnetic Field [T]

もれ磁場が最大の場所で測定(コア端から90 mm，セプタム板端から20 mm)

0.8-30.6x10

Magnetic Field [T]

1.00.40.20.0-200-150-100-50050100150200250

Longitudinal coordinate z [mm]Time × 10-3 [sec]漏れ磁場は磁性体ダクトによって十分に小さい信号値まで減少．
*菊池さんの計算によると1 Gauss程度の磁場では周回ビームへの影響は少ない

ダクト突き出し量と漏れ磁場磁性体ダクト突き出し量と漏れ磁場の関係
DR出射セプタム⚫

プローブの位置まで磁性体ダクトが来ていると半分程度に落ちる

プローブの位置

MRダクト磁性体部をセプタム導体板の端から150mm程度延ばす セプタム導体板の端Design ofreproduced
beam duct(LER)R10.2: Cross-calibrate the field measurements of magnets between LTR,RTL, DR, and Linac.

IRトンネル入域中のBT dump mode化
2019.3.29
SuperKEKB Commissioning打ち合わせ
N. Iida
これは、MRの富士周辺のみをキープアウトにすることにより、筑波地区などリングの他の場所での作業中でも、BTラインでのビーム調整、ビームスタディを可能にするためにシステム変更をお願いしたいという趣旨に基づくものです。
----船越 義裕 (KEK)BT dump modeでの調整について
1.

BT調整の必要性
A)
B)

2.

Emittance 増大問題
入射ビーム調整としてLINAC modeA) 電子、陽電子をPulse-to-pulseでDumpできない。
B) Energy profileは、BTと同等。
C) Straight dump？

3.

IR作業
1.

4.

どれくらいあるか？

BT安全システム変更
1.
2.

予算はどれくらい？
作業量は？

Request of injection beam from SuperKEKB

1. BT調整の必要性
A) Emittance増大問題

Phase 2Phase3 Goal

2018

2019〜202?

< 200< 100< 40

gey [mm]< 40< 15< 20sd [%]

0.16

0.16

0.07

Charge [nC]

1.5

4.0

4.0e-電子源

RTLLTRSector2

Sector3

Jarc

SectorA

SectorC

Sector1

Sector4

Sector5

Beam Transport lines(BT)

e+陽電子源＋フラックス・コンセントレーター（FC）

2018/9/6

e-gex [mm]DR 1.1GeV

SectorB

e+38

393. Injection
Feb.
4, 2019, beam
32nd B2GM
for the beginning of Phase 3

Emittance blowup in Phase 2
YX

There is no question thatthe emittance blowup
affects the BG.

Final Request from MR
Phase2---------Phase3 final ----------

1.2nC

eMeasurement
at the upstreamof BT

B C

5 BT

B C

5 BT
40 ---15 ----

0.7nC

e+

DR designed value
B C5 BTB C

More beam studies at BT will be needed.

5 BT

LINAC Beam Studies (Oct.-Dec.,2018)⚫

RF Gun (M. Yoshida, X. Zhou, R. Zhang )⚫

Thermionic Gun••⚫

24 degree Line•••⚫

Measurement and Correction of Dispersion（Y. Seimiya）
Bunch Compress（M. Yoshida)
OctoPos BPM (F. Miyahara)

秋、冬のLINAC Studyでは、Beam jitter, Energy jitter, OctoPos開発等、様々な理解を進めることができた。

Measurement of Beam Position Jitter and Fluctuation (Y. Seimiya)••

Binarization from Pulsed Magnet (T. Natsuim Y. Enomoto, M. Satoh, I. Satake)Monitors of RF Phase and RF Induced wave⚫

Monitors of RF Phase and RF Induced wave (T. Miura, et al.)⚫

Primary side power fluctuation (T. Miura, T. Natsui)⚫

Investigation around Dummy Target (Y. Enomoto, H. Sugimura, T. Kamitani, Y. Ohnishi, Y. Funakoshi, N. Iida)•Feb. 4, 2019,32nd B2GM

Measurement and Correction of Dispersion（Y. Seimiya）
Measurement of Response and Aperture (Y. Seimiya)Consistency Measurement of BPM (F. Miyahara)

Jarc•••⚫

… Studies especially related to the BG:
Core subjects

Tuning of Buncher (T. Natsui)
Q-Scan、10nC（T. Natsui and Y. Seimiya）

Beam Based Aligment ( Ballistic Orbit、QuadBPM )⚫

Investigation of Solenoid magnet after Positron Target (T. Kamitani, Y. Ohnishi)⚫

Measurement of RF Energy Gain (T. Kamitani, Y. Ohnishi, T. Natsui, Y. Seimiya, M. Satoh)⚫

SY2 (N. Iida, H. Koiso)⚫

しかし、BT dump modeはMRがReadyでないとできないので、• Measurement of Dispersion
BTの調整時間を確保するには、MR運転中にもかかわらず入Sector 3-5
射を止めなければならない。
• Offset Injection (Y. Seimiya, N. Iida, T. Mimashi, T. Kawamoto, K. Yokoyama)→少しでもBT調整の時間が取れないか？
• Fudge Factor Measurement of Quad (Y. Seimiya, M. Satoh)• QuadBPM (H. Sugimura), Mover Alignment (Y. Enomoto, T. Kamitani)
40→IR作業中にBTDump modeにできないか？

⚫

Coexistence with PF and PF-AR

1. BT調整の必要性B) 入射ビーム調整
LINACビームの診断ラインとしてのBT
LINAC BTe+ Optics

BT dump

LINAC BTe- Optics

当然LINACとBTは繋がっていて、LINAC-BT全長の約４割を占める。
BT dumpまで調整しておけば、入射までは100ｍ以下である。
LINACの診断ラインとしても重要。

BT dump2. LINAC modeA) 電子、陽電子をPulse-to-pulseでDumpできない。

ECS MagnetSY3/ECS第１Bendを転極してDumpに導いているため、電子、陽電子は同時に捨てられない。
東側Dump2. LINAC mode

LINAC
end

Dump lineB) Energy profileは、BTと同等
Dump line でも、Dispersionは十分大きい（-3ｍ）

electron BT

positron BT

hx〜４ｍ

LINAC
end

hx〜４ｍ

LINAC
end

2. LINAC modeC) Straight dump ?

•••Dispersionが発生しないので、Energy Spread調整ができない。
しかも、• AR停止中しか使えない• Dump前のBend内のChamberをクロス管に入れ替えないといけない等の困難がある。

Straight Dump

3. IR作業⚫

今後どれくらいあるか？
• 2020年（2021年？）夏、Belle2の作業で8ヶ月トンネル入域がある。
• ８ヶ月間の最後の何日間かは、IR以外の作業がないことも考えられる。

• IR関係の作業は、トラブル等により日常的に１〜２時間程度の作業はあり得る。
（不吉なのであまり考えたくありませんが）4. BT dump mode

e+Dump magnet
BH4P.5eDump magnet
BV2E.45-6月運転中の筑波入域
2019.6.19
N. Iida木曜メンテ：5/16, 30, 6/13
メンテ日以外の筑波入域を調べた。

27分
112分
29分
4分
34分

28分

37分

60分

7分
20分
137分

5/7-6/8：
434+61=495分

QCS Quench時
5分
18分

24分
6分

7分

14分

29分
5分
93分

30分
43分
34分
13分

5/7-6/8：
434+61=495分

6/9-6/19：
320+44=364分

43分
5/7-6/19：
495+364=859分=14時間32分