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.
2009/3/3 2US High Gradient Workshop
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
2009/3/3 3US High Gradient Workshop
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.
2009/3/3 4US High Gradient Workshop
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.
2009/3/3 5US High Gradient Workshop
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).
2009/3/3 6US High Gradient Workshop
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
2009/3/3 7US High Gradient Workshop
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
2009/3/3 8US High Gradient Workshop
200hr
Basic high gradient study at KT-1Narrow Waveguide
Please refer to Kazue Yokoyama’s presentation.
2009/3/3 9US High Gradient Workshop
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
2009/3/3 10US High Gradient Workshop
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.
2009/3/3 11US High Gradient Workshop
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
2009/3/3 12US High Gradient Workshop
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
2009/3/3 13US High Gradient Workshop
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.
2009/3/3 14US High Gradient Workshop
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.
2009/3/3 15US High Gradient Workshop
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.)
2009/3/3 16US High Gradient Workshop
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).
2009/3/3 17US High Gradient Workshop
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
2009/3/3 18US High Gradient Workshop
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
2009/3/3 19US High Gradient Workshop
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.
2009/3/3 20US High Gradient Workshop
□TE10→○TE11 Mode Converter
(by S. Kazakov)
2009/3/3 21US High Gradient Workshop
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.
2009/3/3 23US High Gradient Workshop
T18 #1~#4 disks and couplersproduced by KEK
2009/3/3 24US High Gradient Workshop
T18_VG2.4_Disk #1 & #2 Assembly at SLAC
Parts for Input/Output Couplers
Cooling Blocks under brazingAccelerator Body under Diffusion Bonding
2009/3/3 25US High Gradient Workshop
T18_VG2.4_Disk #1 & #2
#1 tested at NLCTA, SLAC
#2 being tested at Nextef, KEK
2009/3/3 26US High Gradient Workshop
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.
2009/3/3 27US High Gradient Workshop
Yasuo Higashi, KEK
Single-cell test samples production by KEK, tested at SLAC
2009/3/3 28US High Gradient Workshop
Pulse heating samples
Some of the samples were prepared and provided by MEC, KEK.
Lisa Laurent, (SLAC)
2009/3/3 29US High Gradient Workshop
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.
2009/3/3 30US High Gradient Workshop
Top Related