KEKB Status
since Feb. 2005
Y. Funakoshi
March 21, 2006 @ KEKB Review

KEKB PerformanceKEKB History

Last Review

KEKB Performance Feb. 2005 - Mar. 2006
HERLER
High
Current
Trial

Bellows
TroubleBelle
SVD

Luminosity

Belle
SolenoidCrab
opticsSpec.
Lum.

16.27/nb/s

Luminosity Performance• Both peak and integrated luminosities havebeen improved.
Lpeak= 15.16 ! 16.27/nb/s!"/day, /7days, /30days= 1083/6242/23995 # 1183/7358/29018 /pb• Annual integrated luminosity
158.9(2004) !"188.7(2005)/fb/year• Total luminosity 363.4 !"563.3/fb

The Best Day 1182.5/pb

History of Daily Luminosity
Last Review

History of Weekly Luminosity
Last Review

Machine parametersDate

2/15/2005

RingLER

Horizontal Emittance

HER

18

Beam current

12/19/2005

241636

Number of bunches

LER
18

1261

1.27

0.975

1.8 or 2.4 (3.77sp)

Bunch trains

1103

116

Vertical size at IP

2.1

2.1

#*x/#*y1347

mA

1.23

0.970

mA

1.8 or 2.4 (3.5sp)

m1

Horizontal size at IP !*x

Betatron tune "x/"ynm

1388

Bunch spacing!*y24
1719

1293

Bunch current

HER45.506/43.535

44.510/41.577

59/0.54

103
2.1

116
2.1µm

45.506/43.531

44.512/41.578

56/0.62

59/0.65

56/0.620.074/0.056

0.117/0.096

0.073/0.055

160 @1503 mA 195@1132 mA

135@1719mA

222@1347mAcm

Beam-beam parameters$x/$y
Beam lifetime at collision
Luminosity (Belle CsI)
Luminosity records
per day/7 days/30 days

0.118/0.081
15.16

16.27

min/nb/s(total)1083/6242/23995 (363.4/fb)

1183/7358/29018 (560/fb)/pbµmMachine Parameters (cont’d)• Bunch fill pattern/bunch spacing– 3.77 (49/13) (April 2005~): physics run– 3.5 (49/14) (~April 2005): physics run– 3.27 (49/13) Test run in June 2005
– 3.06 (49/16) Test run in Dec. 2005

• Stored currents– LER ~ 1674 #$~<1750 mA~ 2000mA (short-term trial)– HER 1270 #$1350 mA world’s highestwith SCC• RF Voltage– LER 8 MV
– HER 15 MV

Progress of Specific Luminosity
3.5 spacing (Dec. 19 2005)

3.77 spacing (Feb. 15 2005)

4.08 spacing (May09 2003)

3.77 spacing (June03 2004)

Methods for higher luminosityMethods for higher luminosity
Items

Limitations or Methods
HER

Available RF power
Tolerance of vacuum components

LEREffects of electron clouds
Tolerance of vacuum components

Higher beam currents

PeakLuminosity

Crab cavities
Search for better machineparameters-> in preparation
Tune

Dynamic apertureIP #x,yHourglass effect

FB GainIntegrated
Luminosity

Reduction of downtime due totroubles-> Show statistics

Reduction of beam aborts-> Show statistics

Luminosity recovery after breaks Pursuit for effective tuning procedure
Shortening of injection time

Electron 2 bunch injection

Other operation stabilities

Countermeasure against day-night effects

Higher beam currents• Request from vacuum group– When we increase the beam currents, it is strongly
requested to increase the number of bunches to protect
vacuum components against high HOM power.
– At KEKB, the increases of the beam currents and thenumber of bunches are a set of procedures.

• Trial– 3.77 -> 3.5• Luminosity increased.

– 3.5 -> 3.27
• Luminosity decreased.

– 3.5 -> 3.06
• LER high current trial. No increase of luminosity.

2005 4/1 - 5/11

3.5 spacing

3.77 spacing

D7E Detune

Lower beam current
Due to frequent X Aborts

D4C in operation

Day-night effect

Maintenance

Belle Solenoid Down

MaintenanceInstall thermal insulator
Sheet for BPM cables

No Day-night effectNikko Refrigerator TroubleComparison of Specific Luminosity
3.5 spacing (May13 2005)
3.27 spacing (June01 2005)
3.77 spacing (Mar. 19 2005)

4.08 spacing (May09 2003)

3.77 spacing (June03 2004)

Fill pattern• Constraint from 2 bunch injection– The same fill pattern must be repeated every 49 RF buckets.
2 bunches from Linac49 RF buckets(~92n sec)

• Fill pattern– 3.77 (49/13)spacing (4444434443443): Physics Run (~April 2005)– 3.5 (49/14)spacing (34343434343434): Physics Run (April 2005~)– 3.27 (49/15)spacing(333433343334334): Test pattern– 3.06 (49/16)spacing(3333334333333333): Test patternBeam current dependence ofluminosity (HER)

L vs HER beam current

LER : 1800 mA (fixed)
HER : 1300 #$1000 #$1300 mA

2005 June 08

3.5 bucket spacing

Beam current dependence ofluminosity (LER)
L vs. LER beam current

LER : 1800 #$1500 #$1800 mA
HER : ~1300 mA (fixed)

2005 June 08

3.5 bucket spacing

Single beam: current dependence of beam size!LER"Sidebands

J. Flanagan

3.5 spacing

Tunechanger test

3.27 spacing

HER B2E
Oho water

HER IR Downstream
Vac Water

MaintenanceBase fill pattern: 3.27 spacing

3.5 spacingBunch-by-bunch specific luminosity~5%

Difference in averaged specific luminosity: ~5%

Bunch-by-bunch Luminosity by ZDLM
Average of all bunches in the equivalent
buckets in the train.

J. Flanagan

Sideband measurement with single beam

Electron clouds still restrict the KEKB
performance severely!
3-bucket bunch (c)J. Flanagan
3-bucket bunch (b)3-bucket bunch (a)4-bucket bunchTotal length of solenoid
preliminary (very rough estimation)

3200
circumference• Almost all parts of the drift
space have been covered withsolenoids.

total drift length•In summer 2005, we installedsolenoids in 88 quadruple
magnets out of 461.

2800
2400

4thTotal length(m)

2000

5th

•However, the e!ectiveness ofthe solenoids was not observed.
(-> Fukuma’s talk)1600
2nd3rd1200
1stBz > 20 G

800
4000
Sep. 00

Jan. 01

Apr. 01

Sep. 01
DateJan. 02

Specific Luminosity vs FB Gain
HER vertical size enlarged.

+30-3-2-1+1.5+3+3+3

original gain

FB gain of the LER vertical affects the specific luminosity.
The other gains (LER H, HER H/V) bring no effects.

Methods of luminosity tuning
after regular maintenance• Magnet standardization (~30min.)• Optics Correction (~2h)– Global x-y coupling– Global dispersions– Beta beat

• Collision tuning (~30min.)– Orbit FB parameters• Fine tuning(knob tuning) (always during physics run)
– IP Knobs– Tunes– SX strengthOptics Correction#y*(LER) 12% smaller than design

MG Standardize(MG Cooling waterTrouble)MS

off-resonance

MG Standardize
Optics Correction

LER SX

Optics Correction

MSOptics Correction

Recovery of luminosity• After a short break such as a regular maintenance– Optics corrections are important.
– Knob tunings are also important.
– However, the best performance is not always reproducedby the above tunings.
• It seems that there are some unknown sources which affect theluminosity.
• It is critically important to identify such sources, if there are any.
– Candidate: mechanical position shift of BPMs due to heating by SR.

• After a long shutdown– It takes very long time to recover the best performance
before the shutdown.
• We feel that the recovery time became longer with higher specificluminosity.

– Usually we don’t proceed to other subjects before therecovery of the best performance.

Peak Luminosity• Beam-Beam Blowup– Tune– Single beam emittance– IP Optical parameters• IP knobs (14 parameters)– Waist– X-Y coupling parameters– Vertical dispersion– Chromatic parameters• Linear chromaticity etc.

– Feedback Gain

• IP #-functions• Effects of electron clouds• Beam Currents

Tuning in a typical shift!"#$!%The knob tuning is always done during the physics run by operators and/or shift crews.

!"#$!&

X-Aborts (Frequent beam aborts due tomysterious beam loss in LER)
Beam phase•Frequent beam aborts•Typically 15 aborts/week•Lost more than 1 shift every week!!
•LER Loss Monitor or Belle SVD Abort•Beam loss of LER is observed.
•Change of beam phase is observed.
•Energy loss side
•No transverse oscillation•No vacuum pressure change at the beginning•We found anomalous behavior of a bellow(temperature and vacuum pressure).
•The beam aborts disappeared after replacing thebellows.

Broken bellows
We experienced this kind of troubles
twice with different bellows (Marchand May 2005).

'($(%"")&($(%"")'"%($(%"")@8907$($(%"")><?

$%($(%""#;<=$$($(%""#$"($(%""#61789:,($(%""#/0123455+($(%""#*($(%""#-.

)($(%""##"#($(%""#&#'($(%""#&($(%""#%($(%""#36-!D00EFC!<G478!! "#("%(%*!HI")("&("$!
M. Tanaka

A48! -01BC'#

X AbortX Abort

&"

%#%"

$#

$"

#"

20

91812//6

7/71812//6

H.B&-

21812//6

81812//6

F*G

821812//0

D*E

881812//0

8/1812//0">-.BC;1812//0:1812//0=&>?@,AA

31812//061812//0#<01812//0

0/91812//0

71812//0

21812//0!"#$ %&&'()$ *+,-.$$ /01/2123$ 45/61/71/8
M. TanakaI,.$ #&>J)

909/70

X Abort2/80
8/0/

Operation
Statistics

FY 2005

FY 2004
T. Kawasumi

Operation
Statistics(Troubles)

FY 2005

FY 2004

T. Kawasumi

Trouble Statistics (except Belle)
TroubleVacuumMagnetBT
RF
SafetyFacility
ControlBeam Monitor
Linac
Cryogenic
Others

CFY 2004

VacuumMagnet
BTRF
SafetyFacility
ControlBeam Monitor
Linac
Cryogenic
OthersTroubleB
FY 2005

FY 2004

FY 2005

Total operation Time [h]56084527.5

Trouble Total except Belle [h]

255

258.5

Trouble Rate [%]4.55.7

#$QCS system is included#$FB is included

More detailed information:
http://accmac-server.kek.jp:8080/kekb/commissioning/statistics/Statistics/Statistics.html

2005 4/1 - 5/11

3.5 spacing

3.77 spacing

D7E Detune

Lower beam current
Due to frequent X Aborts

D4C in operation

Day-night effect

Maintenance

Belle Solenoid Down

MaintenanceInstall thermal insulator
Sheet for BPM cables

No Day-night effectNikko Refrigerator TroubleInstallation of thermal insulator sheets
Tejima%2005/04/22

LC4D06

D03LC2Υ(5S) Luminosity Run＠10.87GeV
Lpeak = 14.66 /nb/s, Lint = 1.817 /fb (corrected values)

Energy scanΥ(3S) Luminosity Run＠10.35GeV
Lpeak = 14.48 /nb/s, Lint = 3.279 /fb (corrected values)

Energyscan

O!-resonanceSummary and Plans
Electron cloud• Electron cloud e!ects still restrict severely the KEKB
performance.
• It is important to find where the e clouds exit and how
we can remove them.
• In this year,– We will buy 16 power supplies of 5A which replace theexisting 3A power supplies for the solenoids in thestraight sections.

Recovery of luminosity performance afterbreaks• To avoid losses of the integrated luminosity and keep
the opportunities to go for the other subjects, it isimportant to identify unknown sources which a!ect theluminosity.

Summary and Plans (cont’d)Higher luminosity• Optimization of machine parameters– Optimize "x/y* in both rings– Better choice of tunes and chromaticity corrections• Larger dynamic aperture• Weaken the e!ect of the synchro-betatron resonance• Higher HER beam currents– There remains some room to improve the luminosity withhigher HER current and larger number of bunches.

We will install crab cavities in both ringsin summer 2006.
• Achieve $y >.1 with crab cavities

D8-C ARES TunerCooling water leakage

Maintenance

Maintenance

X AbortOff-resonance(!(4S))!(3S)+off-reonance
Machine Study

Spare slides

Electron cloud density simulation
4343

4333

4342

K. OhmiBPM consistency

Recent progress•3 electrodes -> beam position-> 4 sets of beam position•BPM consistency•RMS of 4 beam position data• Recent observations– The BPM consistency also shows day-night difference.
– A part of BPM cables go through the outside of buildings and isaffected by the temperature change.
– Orbit corrections based on inaccurate BPM readings (or changingoffset) bring the optics deformation and may result in the luminosity
degradation.

• Countermeasure– Installation of thermal insulator sheets for the BPM cables in theoutside.
– The BPM consistency error was reduced by 30 or 50 %.
– The day-night difference in the luminosity almost disappeared.

3.06 sp

3.06sp3.5sp v.s. 3.06sp

HER(blue) 3.5 sp 12/19 4:35 - 7:39
(red) 3.06sp 12/25 5:39 - 23:04(cyan) reference 2003/5/9

LER

'(")"*!+,-./!

Optics Correction•••&'()*+,LER dispersion -./0,1*2345678LER XYcoupling -./0,1*2
LER "y*90:;<=>+*?@ABCXYcoupling

LER#yLER"y*Day-night effect• The KEKB luminosity degrades in the daytime by about
20% at the worst.
• The luminosity degradation seems to depend on
temperature difference between day and night.
• The effect is not remarkable in winter or on a rainy day.
• When the luminosity degrades, the HER beam blowup isobserved.
• Tuning on the x-y coupling parameters at IP is somewhat
effective to mitigate the degradation, although its
effectiveness is insufficient.

Effectiveness of thermal insulator sheets
LER D03 BPM consistency

DEF

LER D06 BPM consistency

DEF

HER D03 BPM consistency

DEF

HER D06 BPM consistency

DEF

Upgrade plan (short term)•Before the summer shutdown•Target beam currents•HER: 1400mA (We need to fix the D4C problem.)•LER: 2000mA•Target peak luminosity•17 /nb/s•During the next summer shutdown (2005)•Install one more RF station for ARES cavity (a klystron, low levelcontrol …) in HER (to be named as D5E)
•Increase of the HER beam current by about 150mA•One RF station costs about 2 Oku-yen.
•Movable masks in LER: Cu head -> Ti head

•Solenoids for electron cloud•Upgrade the 50 power supplies for solenoid coils (3A -> 5A)•Test for winding thin coils inside quadrupole magnets•Crab cavity•A crab cavity for the purpose of raising the beam-beam parameters
is scheduled to be installed in each ring at the beginning of 2006.

0%1!23)45"-!$-66#7/,-.8-95,(9-:;<<=:;>

Shibata, Suetsugu