Update of KEK X-band Research Activity March 3, 2009 Shuji Matsumoto Accelerator Laboratory, KEK...

Update of KEK X-band Research Activity

March 3, 2009Shuji Matsumoto

Accelerator Laboratory, KEK

2009/3/3 1US High Gradient Workshop

Contents

•We are running two X-band high power test stands. Status and JFY2009 Schedule of these stations are given.

•We are working for the high gradient accelerator structures in close collaboration with SLAC and CERN as well as the fundamental researches on high gradient RF field and RF breakdown.


Those two X-band high power stations we are operating.

KT-1 (50MW)

Klystron Test,Small experiments (in Lead shield box)

Test area in Shield-A

Nextef (100MW)

Modulator and twin klystrons


KEK X-band High Power Stations

•Reassembled old XTF in 2007. •A 100MW high power station for the X-band accelerator structure tests.•We use Nextef for the collaboration work with SLAC and CERN on developing high gradient accelerator structures of 100MV/m by 2011.•Currently, the high power test of T18_VG2.4_Disk#2 is ongoing.

Nextef stands for NEw X-band TEst Facility.

KT-1stands for Klystron Test stand #1. •For small size fundamental studies on high gradient and RF breakdown tests such as narrow waveguides are done at KT-1 50MW station.


Nextef Configuration

A: Modulator B: Klystrons C: Circular Waveguide D: Accelerator Structure in Shield-A. The control hut is not shown explicitly in the figure.

Frequency 11.424GHz

Max power production

100MW

Max power for test*

75MW

Pulse width 400ns

Repetition rate

50pps

* 25% power loss in the waveguide.


Nextef layout and information• Present layout of the facility

– Two klystrons with power combiner.• Future layout

– Pulse compression to obtain 150MW.– Swich the combined power into Shield-A or/and

Shield-B.• Relevance to

– warm-LC R&D, close collaboration with CLIC structure developments and Nextef serves to get basic high gradient understanding and to develop components.

• Note that – The facility can run 24 hr/day closely linked with KEKB

Injector operation (KT-1 also).


T18 trend

0

20

40

60

80

100

120

0

500

1000

1500

2000

2500

3000

0 500 1000 1500 2000 2500

T18_VG2.4_Disk #2 Processing Historypower history at breakdown

(power meas. from DPO Top value by Ushimoto)

<Eacc> 51nsec Ushi

<Eacc> 113ns Ushi

<Eacc> 173n ushi

<Eacc> 213n Ushi

<Eacc> 253ns Ushimoto

Eacc keep 253ns Ushi

Eacc 51ns Ushi

Eacc 113ns Ushi

Eacc 173ns Ushi

Eacc 213ns Ushi

Eacc 253ns Ushi

Total BD

<Eacc> MV/m

Total# BD

RF-ON integrated (hr)

090221

80MV/mFor 1 month

252ns


T18_VG2.4_Disk#2 Test at NextefBD’s and BDR during 27 days in December 2008

at 80MV/m (35MW).

BDR

~17 str. BD / 566 hr

~0.030 BD/hr/str

~0.75 x10-6 BD/Pulse/m0

10

20

30

40

50

0 100 200 300 400 500 600

BD power vs RF-ON period from Nov. 28-Dec. 25

Power MW Excessive power relatedPower FC-UP

Pow

er

M

W

(cal

ib. n

eede

d)

RF ON Period (hours)

Total 20 BD's/585hrs (3 BD's are over pulse driven)

Power is calculated from DPO with a background subtraction

Finished at 9:00 on Dec. 25

Started at 10:00 on Nov. 28

566 hrs run / 643 hrs= 88% ON


200hr

Basic high gradient study at KT-1Narrow Waveguide

Please refer to Kazue Yokoyama’s presentation.


E=125MV/mSUS003

RF

KT-1 50MW Station

Damage due to BDs is clearly seen.

Nextef / KT-1 Schedule as of March 3.2008 2009


8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12

T18_VG2.4_Disk #2

TD18_VG2.4_Quad

TD18_VG2.4_Disk

C-band test

?

NWG SUS003NWG CU005

KLY PPM6BSolenoid Kly retest

Nextef Sheid-A

Shield-B

KT-1Construction Pulse Compression

(Schedule will be fixed)

Then, I should explain C-band high power test…

•C-band R&D project is ongoing in KEK for upgrading the positron injection energy in future Super KEKB project.

•Four 1m-long C-band Accelerating structures are (series CKM) working in KEKB Injector. Additional two, CKM005 and CKM 006, are to be installed in 2009 and 2010 (one per each year).

•Their high power tests are necessary before their installation into KEKB Injector. CKM005 test is planned in June 2009.

•We finally made a decision to make a new concrete shield (Shield-B), next to the existing one (Shield-A), for the C-band tests. This enables us to run our X-band and C-band programs simultaneously. Shield-B can be used by X-band test if C-band test does not occupy it.

•The C-band RF power is produced by the klystron at KT-2 and transferred into Shield-B. The waveguide is used as the delay line of the X-band pulse compression.


2009 Configuration of X-Band High Power Test Area

Nextef Modulator and Klystrons

Nextef Control Hut

Shield-A

Shield-B

KT-1

KT-2(Loaded C-Band Klystron)

Phi-80 Circular Waveguide


Shield B

Shield A

Nextef (X-band)Modulator and Klystrons

Almost fully packed!

X-band High Power station in KEKB Injector Structure Test Hall

Feb. 20, 2009


Nextef JFY20081. 100MW power production is established with 250ns RF width, 50pps and

70MW power available for the structure test. We may go somewhat beyond this power level if necessary. The machines work basically fine.

2. Test of T18_VG2.4 #2 is ongoing at (or slightly beyond of) its design spec (Eacc 100MV/m, 250ns, 50pps). Test will continue till the end of March.

3. Every breakdown in the accelerator structure is believed to be detected and recorded. Need some effort for the better measurement and analysis of data.


List of works at High Power Stations in JFY2009

Nextef

Shield-AContinue the tests of X-band High Gradient Accelerator structures:T18_VG2.4_Disk #2 test ongoing till end of March.A quad structure, T18_VG2.4_Quad #5, will be installed in April. TD18_VG2.4_Disk will be the next.

New Shield: Shield-B will start to work.Condition C-band Structure (CKM-005) in June.

Phi 80 Circular waveguide will be ready.It is used for C-band power transmission from KT-2 to Shield-B.It is planned to be switched to the delay line of the X-band pulse compression after C-band test. First test of PC will be in autumn.


List of works (cont)

KT-1

Continue the Narrow Wave Guide High Gradient experiment.Condition a PPM klystron, PPM6B (One of our four PPM klystrons).Start to (re)test of our old solenoid klystron (XB72K).(The operation of a solenoid-focused klystron (named XB72K) at KT-1 is planned to see its performance with longer (1 us) RF pulse length as a study of future version of our pulse compression system.)


X-band Pulse Compressor Plan

One-Channel Delay Line Traveling Wave Typeutilizing 22m C-band Low Loss Line

・ X-band PPM Klystron : Expected to be stable at 30 MW. If this is true,→ ×2(Klystrons)= 60MW ×3(Compression) = 180MW→ we expect the peak power of 150MW (taking into account of the compression efficiency).


M. Yoshida, S. Kazakov, H. Matsushita

・ Easy Phase Flip compared with Cavity Type・ Only One Phase Shifter.・ Utilizing C-band Low Loss Line (φ80).・ No need to adjust phase difference of different mode.

KlystronAccelerator

SLED-II Traveling WavePulse Compressor

One-ChannelDelay LineTraveling WavePulse Compressor

KlystronAccelerator

TE11R

TE11L

Delay Line Type: Principle

Iris

20 1 00 ( 1)

2( 2) 1 0 0 0

( 3) 020 0 10 ( 4)

20 1 0

k jkV a

V b k jk

V bjk k

V ajk k

2 lines Single line

3-dB


Strategy for Nextef

Klys

tron

Acce

lera

tor

TE11R

TE11L

750ns → 150nsGain = 3.6 @ 3dB

22m - One ChannelKl

ystr

onAc

cele

rato

r

1500ns → 300nsGain = 3.3 @ 3dB.Meets solenoid klystron Spec?

TE11R

TE11L

TE12LTE12R

TE11 ModeConverter

TE11-TE12

Reflector

Upgrade using higher mode

25 MW×2 Klyston×gain=3→ 150MW

2009 version


Future version

Φ80 Circular Waveguide for Delay Line

← MO Flange - Fine alignment pin for gasket. - Keep straightness because flanges are tightly closed.

2.5m × 9 = 22.5 m

Assembled using EBW- Keep solidness.


□TE10→○TE11 Mode Converter

(by S. Kazakov)


Horn (matches to Phi 80 circular WG)

Linear

Cos

Cos(divided by each100mm)

TE11

Other modes2009/3/3 22US High Gradient Workshop

Fabrication of structures for high gradient study

• Target– Extend SLAC/KEK X-band legacy to recent CLIC approach.

• Framework– Electrical design by CERN– Mechanical design and fabrication by KEK and SLAC– Assembly and tuning at SLAC and/or KEK– High power tests at SLAC and KEK (until CERN station is established)• Four T18_VG2.4_Disk in collaboration with CERN and SLAC– Assembly and testing are being done by SLAC and KEK– These structures serve as a cross referencing.• Quadrant-type CLIC structure T18_VG2.4_Quad– Final fabrication process at KEK. Expected to be installed in Nextef in

April.


T18 #1~#4 disks and couplersproduced by KEK


T18_VG2.4_Disk #1 & #2 Assembly at SLAC

Parts for Input/Output Couplers

Cooling Blocks under brazingAccelerator Body under Diffusion Bonding


T18_VG2.4_Disk #1 & #2

#1 tested at NLCTA, SLAC

#2 being tested at Nextef, KEK


TD18 disks for damped cavity

Cells are being made based on SLAC/KEK HDDS technology.

Surface treatment and assembly is to be made at SLAC, following our standard technology to date.


Yasuo Higashi, KEK

Single-cell test samples production by KEK, tested at SLAC


Pulse heating samples

Some of the samples were prepared and provided by MEC, KEK.

Lisa Laurent, (SLAC)


Activities in JFY 20091. High power test of a CLIC type quad accelerator structure (T18_VG2.4_QUAD

#5, collaboration of SLAC, CERN and KEK) will start from April. We use Shield-A. The structure, TD18_VG2.4_Disk.

2. Fabrication of accelerator structures under the CKS collaboration will continue.3. X-band RF pulse compression in this autumn. Use the phi-80 circular

waveguide. Goal peak power 150MW.


Update of KEK X-band Research Activity March 3, 2009 Shuji Matsumoto Accelerator Laboratory, KEK...

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