Ring Commissioning
Y. Funakoshi
KEKB Review
2013. 03. 05

Commissioning schedule• Start‐up Dme of SuperKEKB– SuperKEKB commissioning is expected to start in January
2015.

• QCS schedule– Due to the background issues, the fabricaDon schedule ofQCS’s on the right side of IP will be delayed.
– SuperKEKB commissioning will start w/o QCS magnets.

• Linac commissioning– Linac beams are expected to be ready by the SuperKEKB
ring commissioning.

• Damping ring

– Commissioning of damping ring will start someDme aRer
commissioning of SuperKEKB rings. (May or June 2015)• RF system reinforcement– Works for reinforcements will conDnue in FY2015 andFY2016 due to budget constraint.

Two possible scenarios

First target luminosity
1 x 1034 cm‐2s‐1

Scenario A

First target luminosity
1 x 1034 cm‐2s‐1

Scenario B

Consensus between SuperKEKBaccelerator group and Belle II group• To proceed with Scenario A (phase 2commissioning with QCS and Belle II solenoid)• To keep Scenario B (phase 2 commissioning withQCS without Belle II solenoid) as a backup opDon
for some unexpected situaDons.

This proposal by the accelerator group was accepted at theBelle II EB meeDng on Sep. 27th.

Procedures of machine commissioning• Commissioning I :Basic commissioning of machine (~ 1.5 month)– Linac tuning– Damping Ring tuning (new at SuperKEKB)– BT tuning– InjecDon tuning (including beam Dming and simultaneous injecDon)– COD correcDon, OpDcs correcDon (rough correcDon)– Tuning on beam abort system– Tuning on beam monitor system (including beam feedback)– Tuning and measurement on radiaDon safety– Tuning on other hardware systems– Test and debugging various kinds of control soRwares• Commissioning II : Vacuum scrubbing (>~3 months)• Commissioning III : More sophisDcated tuning– OpDcs measurements and correcDons• Squeezing IP beta funcDon (more diﬃcult than KEKB)• Achieving a small x‐y coupling (more diﬃcult than KEKB)– Beam collision tuning and luminosity tuning (more diﬃcult than KEKB)– Belle II beam background: study and tuning (more diﬃcult than KEKB)– Increasing beam currents (ﬁnal target is higher than KEKB)– Study on the other beam dynamics issues

Vacuum scrubbing at KEKB （HER/LER）

HER

LER

HERLER

SuperKEKB Commissioning Meeting2011.11.08 Kikuchi, M.

DR Commissioning•LTR commissioning
2 days•BPM commission•First turn1 day•COD meas. and correcDon 2 day•BPM commission•OpDcs meas.
2 days•RTL commissioning
2 days•InjecDon to LER•25 Hz operaDon•SR commission•Vacuum scrubbing~14 days~ 9 days~ 3 weeks
by wishful thinking

M. KikuchiCommissioning phase 1 (2015 Jan. ~ May)
• Machine condiDon– No QCS, No solenoid (no Belle II)• Tuning items– Special opDcs for phase 1– Commissioning item I (basic commissioning)– Commissioning item II (vacuum scrubbing)• HER beam current ( ~< 1A)• LER beam current (~ <0.5A with low emikance beam)• Belle II people request enough vacuum scrubbing in this phase (beforeBelle II roll‐in).
– At least one month with beam currents of 0.5 ~ 1 A.

– Damping ring commissioning (from May or June)• If possible, we hope to check LER injecDon of the e+ beam from DR.

– Commissioning III• Belle II Background study with Beast II Detector• Achieving a small x‐y coupling– In phase 1, we can study without IR.
– Beam size monitor will have to work (with low beam current ~30mA?).

Phase 1 ‐ Linear OpDcs ‐H. Sugimoto• OpDcs W/O QCS and solenoid has been designed• QCS and solenoid is replaced by driR space.
• Machine tuning except for IR is expected to be done in this phase.

03/04/2013

LER

HER

Dri(Dri(The 18th KEKB Accelerator Review Commikee9H. Sugimoto

Phase 1 ‐ Dynamic Aperture ‐• DA example assuming,‐ Design bunch current.
‐ 2% emikance raDo.
• Beam loss esDmaDon is ongoing from view point of radiaDon protecDon.
Funakoshi‐san’s talkHER Touscheck Life
~6.3 hours

LER Touscheck Life
~1.4 hours

RF Bucket

Physical Aperture

03/04/2013

The 18th KEKB Accelerator Review Commikee

10SuperKEKB beam‐beam simulaDon
Laqce non‐linearity and space charge eﬀect is not considered.
SuperKEKB design

1.2e+36

0.25x
0.5x
1.25x
2x1x!yL (cm-2s-1)

1e+36
8e+35

LERHERεx [nm]3.2

4.6

εy [pm]8.64

11.5κ [%]

0.27

0.25

6e+35

K. Ohmi4e+35

Strong‐strong method (PIC)
For the long‐rage force, the gaussian
distribuDon was assumed.

2e+35
0

SuperKEKB design luminosity

01000

2000

3000
turn4000

5000

Smaller (single beam ) verDcal emikance gives higher luminosity. Much lower verDcal
emikance than the design (about half) will be needed to achieve the designluminosity. A tentaDve target of x‐y coupling w/o beam‐beam is 0.15%.
At SuperKEKB, low emikance tuning will be very important.

Comparison of emikances of colliders

Future colliders

LEP3
ExisDng colliders

TLEP‐HFrom Beam Dynamics Newsleker No. 31
Courtesy of F. Zimmermann, H. Burkhardt and Q. Qin

Comparison of emikances of colliders[cont’d]Future colliders
ExisDng colliders
LEP3
TLEP‐HA
Possible
BEASTII
Strategy
Modular design, where we can easily add/remove sub detectors as required• Perhaps grouped into Inner BEAST, Outer BEAST• Three conﬁguraDon: T0, T1, T2
All scenario

Scenario B

Scenario A

BEASTII‐T0

BEASTII‐T1

BEASTII‐T2

w/o QCS, w/osolenoid

w/ QCS, w/osoldenoid

Phase 1Phase 2

w/QCS, w/solenoid ,No SVD, PXD

ECL shielding

NNNDiodes & beamabort

YYY

Micro‐TPCs

YY

Y, in dock

BGONY?

CDC prototype

NY

N

SVD, PXD
ladders &monitors

NY

YDiamonds

YY

YY. SakaiPhase 2

 For BEASTII_T2, place some sub system in PXD DOCK space Keep up development of all BEAST sub systems.

Outer Beast

Inner Beast

Commissioning phase 2 (2016 Jan. ~ April)• Machine condiDon– With QCS, with Belle II (no VXD)
– Full accelerator tuning, no physics run– Target luminosity at the end of this phase: 1 x 1034 cm‐2 s‐1• Tuning items– InjecDon tuning w/ Belle II detector starDng from detunedopDcs– Commissioning item II (vacuum scrubbing)• ConDnue to increase beam currents– Commissioning III• Belle II Background study with Belle II (and with Beast II)• Achieving a small x‐y coupling with IR• Squeezing IP beta funcDons• Collision tuning with the nano‐beam scheme– Establishment of collision feedback• Other beam dynamics issues• Luminosity tuningDetuned OpDcs (4x8)
Example of Parameters for 1034 cm-2s-1

16βx*: x4, βy*: x8, coupling =2 %, ξy ~ 0.025, ILER = 1 A.
The effect of intra-beam scattering is decreased in LER.

Commissioning phase 3 (2016 Oct. ~ )• Machine condiDon– With QCS, with Belle II including VXD– ConDnue full accelerator tuning. Physics run will
start aRer some detector tuning period.

• Tuning items– Commissioning item II (vacuum scrubbing)• ConDnue to increase beam currents– Commissioning III• Achieving a small x‐y coupling with IR?
• Squeezing IP beta funcDons• Other beam dynamic issues• ConDnue luminosity tuning

Summary• The SuperKEKB accelerator ground and Belle II ground agreed thatthe ring commissioning will be done with 3 phases. There are twopossible scenarios. Scenario A has the ﬁrst priority. Scenario B is
kept for the situaDon where Belle II schedule delays.
• Phase 1 (scenario A) (2015 Jan. ~ May)
– No QCS, No Belle II– Basic commissioning, vacuum scrubbing, low emikance tuning,detector background (Beast II), DR commissioning• Phase 2 (scenario A) (2016 Jan. ~ April)– w/ QCS, w/ Belle II (no VXD)– Full accelerator tuning, no physics run, detector background (Beast II)– Target luminosity = 1 x 1034 cm‐2 s‐1• Phase 3 (scenario A) (2016 Oct. ~ )– w/ Belle II (w/ VXD)
– ConDnue accelerator tuning, Belle II tuning, physics run will start.

Future prospects• Tasks to be done (from summer 2013)– More concrete and detailed scenarios for beamcommissioning– Development of operaDon soRware• Ask for your cooperaDon– SuperKEKB is an extremely diﬃcult machine• Low‐beta, Low‐emikance, nano‐beam scheme, high beamcurrents, high luminosity– Pioneer for new accelerator physics– Experiences in other laboratories are extremely
helpful• SLAC, BINP, DAFNE, , SuperB, Cornell….

Spare slides

Detailed Schedule 1

Scenario A

Scenario B

Detailed Schedule 2

Scenario A

Scenario BComparison of two scenarios
during commissioning phase 2
Scenario A (w/ solenoid)

Scenario B (w/o solenoid)

OpDcs correcDon(1)Squeezing IP beta
funcDons

We can do full tuning.

We can do something. But we will
have to do tuning w/ Belle II
solenoid almost from scratch.

OpDcs correcDon(2)Achieving a small x‐ycoupling

We can do full tuning.

We can do something. But we will
have to do tuning w/ Belle II
solenoid again anyway.

Collision tuning

We can do full tuning.

The beam collision may not bepossible w/o Belle II solenoid.

Belle II background
Study and tuning

The real beam background can bestudied. Also some test detectors
can be installed at the place of VXD.

Some studies can be possible.

Risk to Belle II

Maybe we can avoid the risks
by adiabaDc tuning (start fromsmall beam currents, withdetuned opDcs).

Less risk

Comparison of two scenarios (cont’d)during commissioning phase 2
Scenario A (w/ solenoid)
Works for accelerator Less works.
setup
Cosmic‐ray run w/VXD

Scenario B (w/o solenoid)
One more QCS ﬁeld measurement.
(heavier load to QCS group)Less Dme before phase 3. Can
More Dme before phase 3.
also be done in the beginning ofphase 3.

Expected Dme for the Earlier (maybe during phase 2).
ﬁrst target luminosity(1 x 1034 cm‐2s‐1)

Later (3~5 months aRer phase 3start).

Commissioning III : More sophisDcated tuning• OpDcs measurements and correcDons (1) : squeezing IP beta funcDons at IP– We will squeeze the IP beta funcDons with observing the beam lifeDme, the injecDon rate and theBelle II background. This study can be done with small beam currents (~30mA).
– QCS’s are vital for this study. We can do something without solenoid (Belle II). However, we need tostart tuning with solenoid (Belle II) almost from scratch.
– This tuning is most important for the luminosity at SuperKEKB. A factor 20 of the luminosity gain is
expected by squeezing beta funcDons.
• The ﬁrst target of verDcal beta funcDon at IP (βy*) is 10 Dmes larger values of the design values.

• OpDcs measurements and correcDons (2) : achieving a small value of x‐y coupling– We need to measure the beam size with x‐ray monitor.
• The beam size measurements will be possible with small beam currents with relaDvely high bunch currents.
• We do not need the solenoid winding for clearing the electron clouds.

– Although it is worthwhile to do this study w/o Belle II solenoid, we also need to do the study alsowith Belle II solenoid.

• Collision tuning– We have no experience on the beam collision with Nano‐beam scheme.
• Finding beam collision, establishing orbit feedback system（including dithering system）• Luminosity tuning like at KEKB (this kind of tuning will conDnue many years.)– It is worthwhile to do this tuning w/o solenoid. However, there is a possibility that the beam collision
will not be possible w/o Belle II solenoid.

• Belle II (Beast II) background study, tuning

Revised on April 1st 2012

27

M. OnoFaciliDes••Storage and staging areas needed for magnet and vacuum
components.
Need increased cooling water for klystrons and magnets:––•24 klystrons for ARES caviDes, 8 klystrons for SCC
Magnet cooling water needs double (4 plants ‐> 8)

Electricity:

Electricity ConsumpDon: June‐09

KEKB/KEK total(Design option)

KEKB:MWΔMW

Present(Average)

45

Nano Beam: June-09

70.7

24.3

96

32

Upgrade: Feb.-09

94.8

49.8

120

56

Super: ‘07-July

102.6

57.6

128

64

KEK:MWΔMW64

Recent Design(Feb.‐10): Add 2 ARES units‐‐> +(3~4)MW