Bakingg and TiN Coatingg Equipmentsq p
Mt Tsukuba
Mt.

SuperKEKB

Linac

KEKB Oho Lab.
The 17th KEKB Accelerator Review Committee
2012 02 21
2012.02.21
Kyo Shibata (on behalf of KEKB Group)Introduction• What should we do before the installation of new beam pipes?
– For HER (e‐) : Baking at the laboratory in Tsukuba site(not in‐situ)– For LER (e+) : Baking & TiN coating at the laboratory in Tsukuba site

• How many beam pipes should be processed?
– For HER (e‐) : ∼180
– For LER (e+) : ∼1000 (of which ∼ 25 have electron clearing electrodes andthey are not coated. )•Topics discussed in this talk
– New baking equipment by hot‐air
hot air method, output estimation– TiN coating equipment, preliminary experiments, production status andoutput estimation– Working Schedule

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Baking equipment 1
Conventionall bbaking
k methodh d• Breaking away from the conventional style– Sheathed heaters or tape heaters were usually used in KEKB’s era.
– However, the process was laborious, requiring putting the heaters,
covering the beam duct with aluminum foil and thermal insulators,uncovering them after the baking, and so on…
Simple and convenient process is required.

Tape heater

Conventional baking style with tape heaters and Al foils
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Baking equipment 2
New baking
b k method
h db
by h
hot air hheating• Hot‐air heating method is adopted.
– Two beam pipes are mounted up and down in one hot‐air oven.
– Hot‐air oven consists of movable insulated walls and insulated frame.
– Hot air is circulated in the hot‐air oven.
– Each pipe is evacuated by a turbo molecular pump (0.3 m3/sec) during thebaking.

FramePumpingunit

Beam pipe
Movable walls

Hot‐air oven for baking of beam pipes

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Hot‐air duct
Hot‐air circulator (7.5 kW)

4Baking equipment 3
Procedure
dffor bbakingk• We can save a great deal of time by avoiding the trouble ofhaving to cover and uncover the aluminum foils and insulators.
– What we have to do are• Opening the insulated walls,• Mounting the beam pipes on the frame,• Connecting the beam pipes to the pumping units,• Closingg the insulated walls,• Turning on the vacuum pumps and hot‐air circulators.

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5Baking equipment 4

Baking station for long beam pipes.

Insulated walls can be jointed easily
using Velcro fastenings or latch clamps.

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Baking equipment 5
Bakingk conditionsd•Baking conditions– Temperature : ∼150150 °C ((∼120
120 °C for beam pipes with electrodes)– Duration : ∼24 hours• It was confirmed that the temperature of the beam pipes in theoven became ∼150 °C within a several hours if the temperature
settingg of the hot‐air circulator was ∼175 °C.

– Targeted pressure after baking : < 10‐8 Pa– NEG pump activation is performed at the same time.

•Before baking

Clean room (Oho lab.)– TiN coatingi (if necessary))– Installation of NEG pumps and BPM electrodes at Oho cleanroom.

•After baking– Filling with dry nitrogen up to atmospheric pressure.
– Isolating the beam pipe and putting a blank flange on the beampipe.
– Keeping the beam pipe in the stockroom until the installation.
Stockroom (Oho lab.)

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Baking equipment 6
Estimation off output off bbakingk• 4 baking stations will operate in the Japanese fiscal year of 2012.
– 2 stations
t ti
hhave alreadyl d bbeen iinstalledt ll d att KEKB Oh
Oho llaboratory.
b t• One is for short pipes (∼2.5 m) and another is for long pipes (∼5 m).

– More 2 stations are now in production.

• Output estimation:– One baking process will take 2 days frommounting to dismounting the beam pipes.
– Up
p to 24 ppipes
p can be baked p
per one week byy
our baking stations.
– 3.4 pipes/day, 544 pipes/year assuming 160
working days/yearSun.
8 pipes(2 pipes x 4 stations)

Mon.

Tue.

Wed.
dMounting,baking

Baking, cool
down

Dismounting
Mounting,baking

8 pipes
8 pipesThu.
hBaking, cool
down

Sat.

Dismounting
Mounting,baking

Dismounting

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Fri.

the 17th KEKB Accelerator Review Committee

Baking, cool
down

8TiN coating 1
Preliminaryl
experiment• For SuperKEKB LER, it is an important issue to mitigate the electron
cloud instability.
– In order to reduce the electron cloud, inner surfaces of almost all LER beam
pipes are coated with TiN (except beam pipes with clearing electrodes).

• Preliminary experiments were performed at atest stand to decide the coating parameters.
– The coating was done by a DC magnetron
sputtering of Ti in Ar and N2 atmospheres.
– A Ti cathode rod (‐400 V) was hung from the top
on the center axis.
– Gases were supplied into the test chamber
uniformly though the Ti rod.
– Magnetic field (16 mT) was supplied by asolenoid coilcoil.

M FlMass
Flow CControllerll
Ar gas (2.0 Pa)
N2 gas (0.5 Pa)

Discharge
PowerSource
Solenoid CoilSolenoid
Coil’sPowerSource

Sample Holder,
Film Thickness Meter,
Window

Ti Cathode Rod (-400 V)
16 mTGauge

Pumping System

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Gauge

TestSpectrometer
stand
Mass9Test standTiN coating 2Resultl off preliminarylexperiment• Results of preliminary experiments:– We made some samples varying the thickness of TiN and the temperatures ofsamples during process, and compared the adhesion strength and secondary
electron yield of them.
– It was found that parameter combination (200 nm‐150°C) is best from theview point of the SEY and adhesion strength.

SEY

1.4
1.2
135

Incident energy :250 eV

#1
#3
#4

Cu

#6
#2
#50.8

Results of nano‐scratch test

15 mm

#530

Loaad [mN]

1.6

200 nm25Cu sample(TiN‐coated, φ15 mm )

20

#2

#6

#41510100 nm#3

200

250sample #1

0.6 -66
1010-55-44-33-22101010Dose [C/mm2]

2012/2/2110-111005050100150

Temperature [degree C]
the 17th KEKB Accelerator Review Committee

300

ID number of thickness of TemperaturesamplesTiN [nm][deg. C]
#110025#2100150#3100250
#4200
25
#5200
150
#6200
250

10TiN coating 3
Test station forf KEKB b
beam pipe• To perform the beam test at KEKB LER, test coating station for long
beam pipe was built at KEKB Oho Laboratory.
PowerPSource

Coated pipe
Ar + N2Control Unit

PowerSourceChiller～7 [m]2012/2/21

B2 floorSole
enoid– One beam duct was set vertically.
– Ti cathode rod (4.2 m) was hung fromthe top on the center axis of the pipe.
– A movable solenoid coil with a lengthof 800 mm was mounted.
– To make an uniform TiN film with athickness of 200 nm all over the pipe,
the position of the coil was moved
200 mm step‐by‐step at an interval of
2 hours. (10 hours/m)– Baking heaters were put on the pipe
and the temperature of the pipeduring the coating process wascontrolled.
– Parameters (magnetic field, gaspressure,, dischargepg voltage)g ) wassame as those of the preliminaryexperiment.

B3 floor

Control Unit

the 17th KEKB Accelerator Review Committee

Elevator
MachinePumping
System11Heater

TiN coating 4
Pictures off test station
Gas inlet~4 m

SolenoidControl system
Movable solenoid coil

4.2 m

Beam pipe

Ti rodPumpingsystemNow processing

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Pumping System

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Titanium Rod (4.2 m)

12

TiN coating 5
Beam test at KEKB LER• Test chambers with/without TiN coating were installed into KEKB LER,
andd theh electronlcloudl dddensitiesi i iin themhwere measured.
d• Test chambers (circular duct with a diameter of 94 mm):
1. Copper chamber (Cu, OFC C10100)
2. Copper chamber with TiN coating (Cu+TiN)
3. Aluminum alloy chamber (Al, 5052)
4. Aluminum alloy chamber with TiN coating (Al+TiN)– Thickness of TiN coating : 200 nm

Cu

Cu + TiN

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Al + TiN

13

TiN coating 6
Beam test at KEKB LER (cont.)()• Result of beam test at KEKB LER:
– It was confirmed that our TiN coating is effective for both Cu and Al chambers.
K. KanazawaAlCu
Al + TiN––––––––Energy : 3.5 GeV
Beam current : ∼1600 mA
Number of bunch : ∼1585 (∼1 mA/bunch,∼1010 nC/cunch)
C/h)Bunch spacing : 6 ns
Bunch length : 6 mm
Number of photon : 3×1012 photons/s/m/mA
Drift space (straight section)
No solenoid field
Test chamber (Al)Cu + TiN

Electron monitor
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TiN coating 7
New coating stations forf SuperKEKB• New coating stations for large‐scale production are underconstruction now.
– 5 vertical stations for straight beam pipes.
– 3 transverse stations for bent pipes (of which one is test station).

• Modifications to improve efficiency of the coating work:– Two beam pipes can be mounted side‐by‐side in one station.
– One station have 8 fixed solenoid coils instead of one movablecoil.
– Combination of hot‐air oven and circulators are adopted toavoid the trouble of having to cover and uncover the aluminum
foils and insulators
insulators.

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TiN coating 8Layout off Ohoh llaboratoryb• Solenoid coils and hot‐air ovens for one vertical station and one
transverse station have been installed at KEKB Oho laboratory.
16m
Coating station (transverse type)Coating station (transverse type)stairwway

Coating station (transverse type)
Baking station (long type)2012/2/21

Coating stations(vertical type)

6.5 m

Bakking station (shortt type)

4.5mm

stairway

Bakking station (shortt type)16m

Baking station (long type)

Oho experimental
deck (top view)the 17th KEKB Accelerator Review Committee

16TiN coating 9

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17TiN coating 10

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TiN coating 11
Results of magnetic field measurement in solenoid coils

Target value

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TiN coating 12
Estimation off output off coating 1•

5 vertical stations will start operations from this spring.
– One vertical station is being started up now and operation test will be done in March.
– Transverse stations will start operations after the summer.

•Output estimation of straight pipes(vertical stations):––––

One coating process willll takek 4ddays ffrom mounting to ddismounting theh bbeam pipes.
By jointing two beam pipes, up to 4 pipes can be coated in one station simultaneously.
Up to 20 pipes (4 pipes x 5 stations) can be coated per one week by vertical stations.
2.8 pipes/day, 450 pipes/year (assuming 160 working days/year)
Sun.

Station 1
Max. 4 pipes

Mon.
Mounting,baking

Station 2
Max. 4 pipes
Station 3
Max. 4 pipes

Dismounting

Station 4
Max. 4 pipes

Cool down

Station 5
Max. 4 pipes

Tue.

Thu.

Fri.

Baking, coating(∼4 hours)

Cool down

Dismounting

Mounting,baking

Baking, coating(∼4 hours)

Cool down

Dismounting

Mounting,baking

Baking, coating(∼4 hours)

Cool down

Mounting,baking

Baking, coating(∼4 hours)

Dismounting
Cool down

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Wed.

Dismounting

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Sat.

Cool down

Mounting,baking

20TiN coating 13
Estimation off output off coating 2• Output estimation of bent pipes (transverse stations):– OneO coatingi process will
ill takek 4ddays ffrom mounting
i to didismounting
i theh b
beam pipes.
i– Up to 2 pipes can be coated in one station simultaneously.
– Up to 4 pipes (2 pipes x 2 stations) can be coated per one week by transversestations.
– 0.6 pipes/day, 90 pipes/year (assuming 160 working days/year)
Sun.
Station 1
Max. 2 pipes
Max

Mon.
Mounting,baking

Station 2
Max. 2 pipes

Tue.

Wed.

Thu.

Baking, coating(∼4 hours)

Cool down

Dismounting

Mounting,baking

Baking, coating(∼4 hours)

Cool down

Fri.

Sat.

Dismounting• Estimation of coatingg times for LER arc sections :– Assuming operation of 3/5 vertical stations and 1/2 transverse station, up to 12
straight pipes and 2 bent pipes can be coated per one week.
– It is possible to coat beam pipes of LER arc sections (∼1100 pipes) in 2 years.

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Schedule• Full‐scale
Full scale work will start from April.
• Baking and coating will be completed by the end of FY2013 (March2014).
LER

FY2011

Straight pipe withclearing electrode(wiggler section)

26

Straight pipe(wiggler section)

106

Straight pipe
(Arc section)

581

Bent pipe(Arc section)

106

Other pipes (Local
correction, Skew‐Q,Injection,jAbort, Fuji‐jcross)120

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FY2012FY2013bakingcoatingFY2014HER

FY2011

Straight pipe
(wiggler section)

34

Straight and bent pipes(Arc section)

24

Other pipes (Localcorrection, Skew‐Q,Injection Abort
Injection,Abort, FujiFuji‐cross)120

the 17th KEKB Accelerator Review Committee

FY2012FY201322

FY2014

END

Thank you very much for your attention.

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Backup2012/2/21

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