KEKB Review030211

C-band R&D
S. Fukuda
Content(1) Introduction
Ř Plan for C-band Linac for Super KEKBĦGeneral)Ř EachýComponent(2) Status of Developments(3) Schedule up to the Accelerator Installation inSummer of 2003

KEKB Review030211

Super KEKB Requirements to Injector
1. e+ Beam Energy

3.5 -> 8.0 GeV(for Charge Switch
8.0 GeV e-/3.5 GeV e+ -> 8.0 GeV e+/3.5 GeV e-)

2. Injection Charge

1.0 -> 5.0 nC (e-)
0.6 -> 1.2 nC (e+)(for Larger Stored Current
1.1A e-/2.6 A e+ -> 9.4 A e-/4.1 A e+ )3. Simultaneous Injection (both e+/e-)
4. Smaller e+ emittanceKEKB Review030211

Higher Acceleration Field scheme
for 8 GeV e+✵✰❅s❧❛❢❝q✣❞mp✣◗❣❦s❥r❧❝msq✣G❧❤❝❛r❣m❧✣✣✣✴✰qr✣s❧❛❢✣✰❁✣❝✰✣G❧❤❝❛r❣m❧✣✣✣✵✰❧❜✣s❧❛❢✣✰❁✣❝✮✣npm❜s❛r❣m❧❅❄❝✮✣❇❦n❣❧❡P❣❧❡✣❞mp✣❥m✉❝p❝❦❣rr❧❛❝eGunDamping
Ring

1.7-GeVJ-arc for e–◗✰❧❜✣❛❛❥✱✣s❧❣rq✣p❝✣p❝n❥❛❝❜✉❣r❢✣❆✰❧❜✣s❧❣rq✱❄❛❛❥✱✣❉❣❝❥❜✣✣✵✴✣✰❁✣✷✴✣❑❚✲❦

E(e+)=1.0 GeV
Q(e+)=1.2nC

e+ target❆✴

E(e–)=3.5 GeV,Q(e–)=10 nC
to target
Q(e–)=5 nC
for Injection✵✶✷

L❝✉✣❆✰❧❜✣s❧❣rq✸E(e+)=8.0 GeV,
Q(e+)=1.2 nC
HERLERE(e–)=3.5GeV,
Q(e–)=5 nC

KEKB Review030211

Accelerator’s Scheme•Frequency is C-Band (2856MHz X 2 =5712MHz)•įPositron Energy Up to 8GeV with Using C-band RF Source,which Comprises 3 Sectors of ċ3➵ċ4➵ċ5.
•C-band Accelerator Design and Parameters were follows,•į2m-long Waveguide x 2➵42MV/Ż•Attenuation Factor 0.676, Filling➳Time➳0.365ɕs•Usage of SLED Type Energy Doublers•įHigh Q SLED Cavity Using the TE038 Mode•įPulse Width 2ɕsec,
Field Multiplication Factor 1.84áat Q=130000â
Then Operating Required Klystron Output Power is 40MW.

KEKB Review030211

RF Block Diagram for C-bandfrom #3 to #5 Sector
RFSystemDiagramC-bandPlan(example)
MAINDRIVE LINECounterC-band Waveguide Driving Line

2856MHzCW
571 MHz

Ref. Signal Generator(FMD-30)

MR

E/O

O/E

508 MHz114 MHz571 MHz30m
15m

60kW S-band
Klystron
SUB DRIVELINE(39D)

100m
100m

Coaxial Lines
30m
40m
5m
5m
SB-A

SB-B

SB-C

IɆA

SB-1

114MHzSHB1ElectronGun

1 kWAmp.
System

571MHzSHB2IɆASB✭✧✬

50MW S-bandKlystronHigh Power
ATT/Phase
Shifter

10kW
AMP.

100kWC-band
Klystron
SUB DRIVE LINE(WG)

80m

1 kWAmp.
Systeme-5712MHz

Optical Lines
DriverTrigger
System20m

SUB-BOOSTER3-1

SUB-BOOSTER 2

10 MHz

SB✮✧✫

SB✮✧✬

SB5-1

SB✯✧✬

50MC-band
Klystron

SLEDSLED

Sector 2

Sector 3-1

TargetPrebuncher Buncher ACCGuide

SectorA

Sector B

SectorC Sector 1

e+ e-ACC

ACC
Sector 3-2

Sector 4-1 Sector4-2 Sector 5-1 Sector5-2

Np❝q❝❧r✣❏✇msr✣m❞✣❙❧❣r✣◗❝❛rmp

KEKB Review030211❍✼✧✭✕✭✧✫✭✧✬✭✧✭✭✧✮✭✧✯✭✧✰✭✧✱

Gallery Layout Plan✭✧✲Npmnmq❝❜✣❏✇msr✣m❞✣❆✰ ❧❜✣❙❧❣r✣◗❝❛rmp

❍✼✧✭✕

✭✧✫

✭✧✬✭✧✭✭✧✮

✭✧✯

✭✧✰

Proposed Klystron Gallery
Layout (Up)✭✧✱Compact Modulator using
Inverter DC Power Supply(Below)✭✧✲

Proposed C-band Modulator Configuration
Present Configuration ofModulator and KlystronI❥✇qrpm❧❑m❜s❥rmp
G❧t❝pr❝p

Modulator✰✪✪P❉✣❧❜✣❆m❣❥✣N✲◗

Control✯✰✪❑m❜s❥rmp✰✪✪❆m❧rpm❥✲✪✪I❥✇qrpm❧

Proposed Configuration

Beam

40 MW
Klystron

Modulator

Control

40 MW
KlystronKEKB Review030211

Items for Developments• RF-Source•••••(50MW Klystron was already developed)(1) Compact Modulator’s Development(2) Driver 100kW Klystron Development(3) Development for an RF Window Capable to feed 50MW with one window.
Need to Construct Resonant Ring to test.
(4) Total Performance Test for 50-MW Operation• Accelerator Guide•••••(1) Design and Manufacturing the half-scale c-band 1-m long acceleratorguide.
(2) Design and Manufacturing a CERN-LIPS type SLED.
(3) Development of necessary waveguide components, such as the Beathe-hole
coupler, waveguide with vacuum port, 3 dB hybrid, SiC dummy load etc..
(4) High-power test in the test bench(5) Installation to the beam line and acceleration test

KEKB Review030211

Modulator Design
Basically the same pulse-forming circuit is applied to the newmodulator.
The rectifier and charging circuits are replaced to the compact inverterdc power supply.
R1L

1K

1 V0✾✧❤❡❣

1.3uL01.55uL91.55u❆❜✐❣

❃❝❦❣✐❣
✾✽ ❊✩❍❊❀❈✫✮ ❥❝✐❤
✬ ❡❣❛❛❛

L1

1.55u

X0 V
01.55u

L2

L11

1.55u

0 C
. 00
155u

L12

1.55u

0 C. 10
155u

1.55u

0 C. 90
155u

L4L51.55uL131.55u

0 C. 20
1
55u

1.55u

0 C
. 10 0155u

L140 C
. 30
1
55u

1.55u

0 C
. 10 1155u

0 C. 10 2
155u

L6

L7

1.55u

L15

1.55u

0 C
. 4
0
1
55u

1.55u

L160 C
. 5
0
1
55u

1.55u

0 C
. 1
0 3
1
55u

L8

1.55u

L170 C
. 60
1
55u

1.55u

0 C
. 1
0 4
1
55u

L21

1.55u

L220 C. 70155u

1.55u

0 C
. 10 5
1
55u

0 C
. 1
0 6155u

L23

1.55u

L24

0 C
. 10 8
155u

1.55u
0 C
. 10 9
1
55u

L25

1.55u

L26

0 C
. 20 0
155u

1.55u
0 C
. 20 1
155u

L27

1.55u

L28

0 C
. 20 2
1
55u

1.55u

L29

1.55u

L30

0 C
. 20 4155u

0 C. 20 6
1
55u

1.55u

0 C
. 20 31
55u

0 C. 20 51
55u

0 C. 20 7155u

PFNý14 steps 2-parallel, with Rp=5ʎ

1L. 1
497u5 R0I❞ ❊❥❛❤I❣❝❤❞❣❜❣

L3

1.55u

0 C. 80155u

1L. 1
38uIVm

L100 C.
0155u❊❀❈❚✽#✐✧I❣❝❤❝✐✧✬(V)+3.0000.0+2.000u+4.000u+6.000u+8.000u+10.000u

Time (s)+12.000u+14.000u+16.000u+18.000u+20.000u+2.000+1.000In❣✐❣❞❝

0.0

4.8ʚs

-1.000-2.000G❦❣❤ ❍❥❝✐✾❞

-3.000-4.000Flat top 2ʚs-5.000-6.000TIME+5.032u

V(IVM)-4.971

D(TIME)+1.700u

D(V(IVM)) -349.045u

Circuit Diagram
Simulation of output pulse

KEKB Review030211

Klystron Assembly Using Old 60-MW Klystron Tank•••

50MW Klystron(left)
Coil ODý 600ʣCore Window Size for330kV
ý-We have an experience, butreliable? Maybe OK• For test in this year, old60MW klystron tank isusable at first.
ýýýTank ODý 700ʣýýýFlange ODý850ʣ
ýý (ExampleŴcenterdrawingħ
• Existing Tank ODý 600ʣ
ýýFlange of tank ODý750ʣýýŴRedesign of tank or try
to fit the coil to old tank

KEKB Review030211

SB Klystron
Existing C-band 200kW klystron for weather
observation station (MELCO) :5.3GHzŴRetune to 5.712GHǍ
Similar operating scheme performed by thepresent sub-boosterĦ100kW at the30kV) is expected.
It is possible to feed C-band klystrons if therectangular waveguide (WRJ-5) is used.
ýýý ŴGood cost performance
Constant-temperature water is necessary tokeep the drive line constant.
(±0.1 degree fine controlled water)
Phase stability, Minimum phase jitter isrequired for the C-band case.
ŴIt is necessary to study the phase stability
intensively.

KEKB Review030211

Design Guide of C-band AcceleratorĦ❅q❣❛✣❇❝q❣❡❧✣m❞✣❆✰ ❧❜✣❙❧❣rħ
Msrnsr✣Nm✉❝p✣❞pm❦✣❆✰ ❧❜✣I❥✇✱✣✷✳✣❑✣Œ❏mqq✣❣❧✣r❢❝✣t❝❡s❣❜❝Ħ✴✷#ħŒ❑s❥r❣n❥❣❛r❣m❧✣❉❛rmp✣m❞✣◗❏❈❇
Ħ
✶✱✷✴
ħŒ
❇❣t❣❜❝✣r❢❝✣nm✉❝p✣rm✣r✉m✣✵❦✰ ❄❛❛✱Ħ✴✲✵ħ❀P❝os❣p❝❜✣Nm✉❝p✰ ❣❧✣❞mp✣❧✣❄❛❛✱✣❊s❣❜❝✣✸✻✱✻✣❑Ħ❉mp✣❅❝❦✣◗rs❜✇✣❣❧✣◗s❦❦❝p✣m❞✣ħ
Msrnsr✣Nm✉❝p✣❞pm❦✣❆✰ ❧❜✣I❥✇✱✷✳✣❑Œ❏mqq✣❣❧✣r❢❝✣t❝❡s❣❜❝Ħ✴✷#ħŒLm✣◗❏❈❇✣❣❧✣◗s❦❦❝pĦ✴✱✳✳
ħŒ❙q❝✣m❧❥✇✣m❧❝✣✴❦✰ ❄❆❆✱Ħ✴✲✴ħ❀G❧nsr✣Nm✉❝p✣❞mp✣m❧❝✣❄❆❆✱✣❊s❣❜❝✶✷✱✷✣❑❘❝❧rr❣t❝✣❆✰ ❧❜✣✵❦✰ ❄❛❛✱✣❊s❣❜❝✣❇❝q❣❡❧❄✰ r✇n❝✣✴✲✵✰ q❛❥❝✣❇❝q❣❡❧

✵
❘mn✣
✴✷✱✳✳
❑❣❜❜❥❝ ✴✵✱✵✺
❈❧❜✣
✴✳✱✸✴

t❡✲❛
✵✱✻#
✴✱✻#
✴✱✳#p✳
✹✺✱✸✺✸✱✹✻✷✱✻

Nm✉❝p✸✻✱✻✶✷✱✻✴✷✱✷❄❛❛❥✱✣❉❣❝❥❜✣❀✣✷✵✱✹✣|✣✶✻✱✴✣❑❚✲❦❉❣❥❥❣❧❡✣❘❣❦❝✣r❉ ❀✣✶✻✳✣❧q❝❛❄rr❧✣❆m❧qr❧r✣τ ❀✣✳✱✺✳✶✵❘mn✣❈❧❜✣t❡✲❛✴✵✱✷✷ ✴✱✼#✴✳✱✷✴ ✴✱✳#p✳

Nm✉❝p✺✷✱✻
✻✸✱✶

✶✷✱✷
✴✷✱✸

❄❛❛❥✱✣❉❣❝❥❜✣❀✣✷✴✱✵✣|✣✶✼✱✳✣❑❚✲❦❧q❝❛❉❣❥❥❣❧❡✣❘❣❦❝✣r❉ ❀✣✵✶✷✣❄rr❧✣❆m❧qr❧r✣τ ❀✣✳✱✷✶✷KEKB Review030211✣Manufacturing Principle for a C-band
No.1 Accelerator Guide• ◗❛❥❣❧❡✰ ❜m✉❧✣m❞✣❈✈❣qr❣❧❡✣◗✰ ❧❜✣❄❛❛✱✣❊s❣❜❝✣✫❇❣q✐✰ ❏m❜❝❜✣◗rps❛rsp❝✬✣rm✣❢❥❞✣q❣x❝❙r❣❥❣x❣❧❡✣r❢❝✣r❝❛❢❧m❥m❡✇✣❛❛s❦s❥r❝❜✣❣❧✣r❢❝✣◗✰ ❧❜✣npm❤❝❛r❈❞❞❝❛r❣t❝❥✇✱G❞✣◗❛❥❣❧❡✰ ❜m✉❧✣❣q✣❧mr✣❝❧ms❡❢✯✣❜❜❣r❣m❧❥❦m❜❣❞❣❛r❣m❧✣❣q✣❛p❝❞s❥❥✇✣❣❧rpm❜s❛❝❜✱✣• ❑❧s❞❛rsp❝✣✣❆✰ ❧❜✣✴❦✰ ❥m❧❡✣❄❛❛✱✣❊s❣❜❝✯✣
q❝❜✣m❧✣I❈I✣◗✰ ❧❜✣❄✰ r✇n❝✣✵❦✰ ❥m❧❡✣❄❛❛✱✣✵❦✰ ❥m❧❡✣❄❛❛✱✣❊s❣❜❝✣❣q✣❜❝q❣p❝❜✣❣❧✣❞srsp❝✯✣sr✣r✣❞❣pqr✣✴❦✰❥m❧❡✣❄❛❛✱✣❊s❣❜❝✣✉❣❥❥✣❝✣❦❧s❞❛rsp❝❜✣❛m❧q❣❜❝p❣❧❡✣r❢❝✣❦❧s❞❛rsp❣❧❡✣npm❛❝qq✱✣❘❢❝p❝✣❣q✣✣nmqq❣❣❥❣r✇✣r❢r✣✵❦✰ ❥m❧❡✣❄❛❛✱✣❊s❣❜❝✣❀✣✴❦✮✴❦✱❝✣❢t❝✣✣p❣❛❢✣❦❧s❞❛rsp❣❧❡✣❇m❛s❦❝❧rq✣m❞✣◗✰ ❧❜✣✵❦✰ ❥m❧❡✣❄❛❛✱✣❊s❣❜❝✱✣KEKB Review030211

RF Pulse Compressor• Parameter Comparison between KEKBSLED and Proposed LIPS-type SLEDKEKB-SLEDLIPS-type

Resonant Mode

TE015

TE038

Diameter

20.51cm

22.17cm(Scaled)

Length

33.59cm

29.8cm(scaled)2856.00 MHz

5712MHz

Cavity Q(theory)

107000146970(Expected)

Cavity Q(Mes)

97000

127800(Expected)

Coupling β6.49ĝ11Frequency

Both sizes are almost the same and previous experiences are
utilized to this new compressor. Install to Gallery is easy.

KEKB Review030211

C-band components R&D status•Toward 2003 Summer Beam test at KEKB Linac(1 Pulse Modulator + 1 Klystron + 1 Accl. structure 1m-long)

••
•

•

•
•

Klystron (Toshiba 50 MW C-band Klystron )Pulse Modulator (Compact type)Sub-booster klystron (weather observation 200 kW Klystron ismodified to 5712 MHz)
Already FabricatedAccelerating structure #1 (2pi/3-mode, scaled down from Sband)
Under Engineering design (parameter tuning)Wave guides, RF Window, Flange
Under fabrication, partly finished
3-dB Hybrid, Dummy load
Under Engineering design (parameter tuning)KEKB Review030211

ýýCurrent StatusĦƑħ(at Feb. 5,2005ħ

ŘCompact Modulator with aninverter DC power supply wasinstalled and the test was started
from Feb. 3, 2003. Ħright top
photoħÿResistive load test first
and then klystron load test.
Running and Durations for noise
will be evaluated.
Ř100kW SB-Klystron for C-band
was tested at beam voltage of28.5ƾV.Ħright bottom photoħ.
Output power of 1.5kW ( factorydata was 4kW) was obtained and
it is enough at the first test.
Transistor 8W amplifier of NEC
was also tested in this operation.
ýýModulator
Coaxial resistive load

Inverter PS

Klystron and magnet

SBK modulator

KEKB Review030211

Current Status(2)Ħat Feb.5,50-MW C-band klystron2003ħ

Ř Heater test and low voltage emission
test of the 50MW C-band klystronĦTop of right photoħ, and magnetic
field measurement of focusing coil ofthe klystron (Bottom of right photoħ
were finished.
Ř From Feb. 10, 2003, assembling theklystron on the pulse transformer tankand beam test will be started.
Then reassembling and rf-test will bescheduled from Feb. 17, 2003.
ýFocusing CoilPulse and heater transformer
for calibration

Mag. Field measuring tool
Power supplyFocusing Coil

KEKB Review030211✣✣✣❑❣✈✰❑m❜❝✣P❉✣❣❧❜m✉Ħ✣❅✇Ix✐mt✬• Reduced Electric-field at the edge combing a TE11-mode
and a TM11 mode.
• Possible to use the large diameter ceramic, though structure
is more complicated. (Diameter of 53mm for X-band).
• One window configuration for 50 MW output power.

✣✣✣✣✣❆❆❥❛s❥r❣m❧✣❧❜✣❑❝qsp❝❜
P❝qs❥rq❇❝q❣❡❧❝❜✣❣❧❜m✉✣❧❜✣❆m❥❜❑❝qsp❝❦❝❧r✣✫❏❝❞r✣rmn✣❧❜mrrm❦✬✫ ✮ ✱ # ✬❏❁✮✪✱✩❏✢❀❏✻G✮✲✣✮✧✪#✲Ǩȥ✮✧✪#✭Ǩȥ✮✧✪#✭Ǩȥ✮✧✪#✲Ǩȥ‫܉‬՘ҧౖȂǞǴǪLG❃✧✮✲✢LG❄✧✯✣ɞ✫✭✲✭ ✮ # ✮ɞ✳✬#✬✯❄❧❥✇q❣q✣m❞✣❊❢mqr✣❑m❜❝✣❣❧✣❣❧❜m✉✫❅❝❥m✉✬✯ ✮✬ ✱ ✫ # ✬✵✶❦❦✯✵✳✱✺❦❦✷❦❦✯✴✼✱✺❦❦✷❦❦✯✵✳✱✵❦❦✷❦❦✯✵✳✱✵❦❦Ħ‫ܭב‬✴✱✼✴✱✻❚◗P✴✱✺✴✱✹✴✱✸✴✱✷✴✱✶
✴✱✵

8✴✱✴
✴
✸✸✳✳

✸✹✳✳

✸✺✳✳
✸✻✳✳
❉p❝os❝❧❛✇✣❑❋x✸✼✳✳

KEKB Review030211

Test Layout of C-band Accelerator Processingin Accelerator Construction HallNew Modulator

Klystron Load

Shield RoomKEKB Review030211

RF Measurement of Standard Cavity
for the Acc. Guide in KEK
Left photo shows the standard cavity to givethe standard frequency for other manufactured
Cavity.

KEKB Review030211

Accelerator Manufacturing Status inMHI and KEK
Due to the super-fine lathe troubleof MHI, final machining of thedisks will be finished in KEK.
Left: first machined disks in MHI
Below:Coupler and measuring jig

KEKB Review030211✣✣✣✣✣✣✣Schedule up to Summer
We have a schedule to install an 1mlong accelerator guide in the beam lineof S-band KEKB linac making use ofthe summer shut-down (only a chanceto install it in this year). Necessary
tests are planed with this schedule.
50-MW Klystron test will be started fromFebruary 17, 2003 for 2 weeks.
Evaluate the modulator performance, checkthe tank assembly and waveguidecomponents. Evaluate the driving systemfrom the master oscillator to SB klystron.
Resonant Ring Test will be started fromend of the March for about a month.
Evaluate the capability of a Kazakov
window with 50-MW power.

High-power test of 1m-longaccelerator guide up to 40MV/m will
be started from the beginning of Julyfor 1 month.
SiC-dummy load and hybrid are also
planed at the same time.
Then 1m-long accelerator guide isinstalled in the #4-4 unit of theKEKB linac.
All test stand components are moved
to #4-4 in the Klystron gallery.
Beam acceleration test will beproceeded in this fall.

KEKB Review030211

Toward 2004 Spring Beam test at KEKB Linac(1 Pulse Modulator + 1 Klystron + 1 RF compressor + 2 Accl. structures 1m-long)and new RF test stand•Accelerating structure #2 (New power coupler design)
Under basic design• RF pulse compressor (LIPS-type TE038-mode)
Under basic design• New RF test stand construction(Because all components of the test stand are moved to #4-4 in KlystronGallery)
Demanding the budget for new bench• High Power test of accelerator structure #2 in the new RF test stand• High power test of pulse compressor in the new test bench?
Or directly install in the klystron gallery?
•Beam test using the pulse compressor in 2004 spring.