7 March 2011 Toshi yasu Higo
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Transcript of 7 March 2011 Toshi yasu Higo
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日米協力 US/Japan cooperation
Research of High Gradient Acceleration Technology for Future Accelerators
2008-2010 progress report2011-2013 New proposal
7 March 2011Toshiyasu Higo
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Progress in previous collaboration and proposal in new application
• Progress– 2008-2010– Target– Result and progress
• New application– 2011-2013– Next target– Proposals
2011/3/7 US/Japan application Toshi Higo 2
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US/Japan cooperation is a key for worldwide collaboration
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KEKStructure fabrication
Infrastructure & test @ Nextef
CERN financially supports for Structure fabrication High power test System expansion
SLAC conductsStructure fabrication
High power testBasic research
US-Japan CERN/KEK
collaboration
CLICUS-HG
TsinghuaStructure design
Structure test and analysis @ Nextef
and others
Asian collab.SLAC/KEK benefit is very large through US/Japan cooperation and it makes the base for overall framework!
Recent test target comes from CLIC
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Three year progress• Collaboration framework was reinforced.• Many twin prototype structures have been made in work
sharing mode. • Each one of these pairs were high-gradient tested at both
laboratories. 80MV/m in copper structure is in our hand.• Basic studies in simple setups were extensively conducted
in close collaboration.• Pulse surface temperature rise, one of the most important
parameters in the high gradient realization, was identified. • An advanced design of acceleration unit is in progress.
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Who are contributing in what areaJapan• Main lab = KEK
– Accelerator high gradient test• Nextef
– Mechanical engineering center
• Structure cell production• Test sample production
• Discussion and information exchange is important
US• Main lab = SLAC
– NLCTA high gradient test• Station 1, 2
– ASTA high gradient test• Single-cell• Pulse heating
– Klystron shop• Structure fabrication
• US-HG collaboration
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SLAC/KEK prototype test flowDesign for
CLIC (CERN)
Fabrication of parts (KEK)
Bonding (SLAC)
CP (SLAC)
VAC bake (SLAC)
High power test (NLCTA-
SLAC)
High power test (Nextef-
KEK)
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Toward 100MV/m
0 2 4 6 8 10 12 14 16 180
50
100
150
200
250
iris number
P [M
W] (
blac
k), E
s (gre
en),
Ea (r
ed) [
MV/
m],
T
[K] (
blue
), S
c*50
[MW
/mm
2 ] (m
agen
ta)
8.1 12.5
148
232
2.7
4.4
76
126
53.0
37.4
Pinload = 53.0 MW, Pout
load = 37.4 MW Eff = 0.0 % tr = 0.0 ns, tf = 0.0 ns, tp = 100.0 ns
P (M
W),
Es (
MV
/m),
Ea (M
V/m
), T
(C),
Sc*5
0 (M
W/m
m2)
T
Iris number
P
Ea
Sc
EsT18 unloaded
100MV/m
0 2 4 6 8 10 12 14 16 180
50
100
150
200
250
iris number
P [M
W] (
blac
k), E
s (gre
en),
Ea (r
ed) [
MV/
m],
T
[K] (
blue
), S
c*50
[MW
/mm
2 ] (m
agen
ta)
29.1
47.0
155
226
3.2
4.4
79
120
57.5
34.3
Pinload = 57.5 MW, Pout
load = 34.3 MW Eff = 0.0 % tr = 0.0 ns, tf = 0.0 ns, tp = 100.0 ns
P (M
W),
Es (
MV
/m),
Ea (M
V/m
), T
(C),
Sc*5
0 (M
W/m
m2)
Iris number
P
Ea
Sc
Es
T
TD18 unloaded 100MV/m
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High Eacc and Es High Eacc and Es and T
T18
undamped
TD18Damped
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Electric field and magnetic field
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Hs/EaEs/Ea
Undamped cell
Damped cell
High
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T18_Disk for test at KEK and SLAC
TD18_Disk for test at KEK and SLAC
Test structures made as twins
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To meet BDR requirement for CLIC
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Damped
Undamped
Undmaped > 100MV/mDamped up to 80MV/m
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Breakdown rate vs T TD18 BDR versus T (pulse temperature rise)
BDR closely correlates to pulse temperature rise even at various accelerator gradient levels
Undamped Damped
T
BDR
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Faya Wang
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Breakdown rate in double pulse
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時間
Pulse temperature rise
Equal BDR even with higher pulse temperature rise at latter pulse.BDR does not depend on instantaneous temperature rise.
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Basic studiesMany of the test assemblies were
supplied by KEK and tested at SLAC
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Prepared in clean environment
Using pure material
Single-cell test
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Geometries of four single-cell-SW structures
1)1C-SW-A2.75-T2.0-Cu 2) 1C-SW-A3.75-T1.66-Cu 3) 1C-SW-A3.75-T2.0-Cu 4) 1C-SW-A5.65-T4.6-Cu
V. Dolgashev, AAS 2010
2011/3/7 14US/Japan application Toshi Higo
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0 100 200 300 40010 -2
10 -1
10 0
10 1
10 2
10 3
P eak E lec tric Field [M V /m ]
Allb
reak
dow
nR
ate
[#/h
our]
0 100 200 300 400 500 60010 -2
10 -1
10 0
10 1
10 2
10 3
P eak M agnetic Field [kA /m ]
Allb
reak
dow
nR
ate
[#/h
our]
80 100 120 140 160 180 200 22010 -2
10 -1
10 0
10 1
10 2
10 3
Gradient [M V /m ]
Allb
reak
dow
nR
ate
[#/h
our]
20 30 40 50 60 70 80 9010 -2
10 -1
10 0
10 1
10 2
10 3
P eak P uls e Heating [deg . C ]
Firs
tbre
akdo
wn
Rat
e[#
/hou
r]
Breakdown rate for 5 single cell SW structures 1C-SW-A2.75-T2.0-Cu-SLAC-#1 (green empty diamond), 1C-SW-A3.75-T1.66-Cu-KEK-#1 (black solid circle),
1C-SW-A3.75-T2.6-Cu-SLAC-#1 (blue empty triangle), flat part of the pulse 200 ns, and 1C-SW-A5.65-T4.6-Frascati-#2 (red empty circle), and 1C-SW-A5.65-T4.6-Cu-KEK-#2 (red full diamond) ), flat part
of the pulse 150 ns
V. Dolgashev, AAS 2010
Magnetic field
Pulse surface heating
Surface electric
field
Accelerator gradient
Peak pulse heating plays an important role, rather than geometry.2011/3/7 15US/Japan application Toshi Higo
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20 40 60 80 10010 -2
10 -1
10 0
10 1
10 2
10 3
P eak P uls e Heating [deg . C ]
Firs
tBre
akdo
wn
Rat
e[#
/hou
r]
6 N H IP C u K E K 17 N C u K E K 1C u S L AC 1
V. Dolgashev, AAS 2010
Peak pulse heating plays an important role, rather than material property and treatments.
Breakdown rate vs. pulse heating for three A3.75-T2.6 copper structures, one OFC copper, 6N copper treated with HIP, and 7N large grain copper
2011/3/7 16US/Japan application Toshi Higo
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Flat side of high gradient cell
Photo John Van Pelt
V. Dolgashev, AAS 2010
In addition to discharge pits is seen the crystal pattern due to crystal orientation induced by pulse surface heating. 2011/3/7 17US/Japan application Toshi Higo
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Toward new application• We think it necessary to understand the physics which
triggers breakdown for future application.• Surface pulse heating seems to play an important role.• Further basic studies should be pursued in this respect.• In this respect, our new application is presented in the
following pages. Here the effective usage of facilities, human resources and experience of both laboratories are essential.
• Actually some are already launched but we want new items to be funded under US/Japan to proceed effectively, extending and expanding the previous collaboration framework.
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On-going and future activities for new target
• Target– Understand basic physics governing breakdowns– Realistic design at higher gradient
• On-going activities– SLAC made mode launchers for KEK to study with simple
setup.– KEK is preparing a new shield room “B”.
• Future activities– Various trials to understand the breakdown mechanism are
planned.– Unique accelerator unit design is going based on SW
configuration.
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Nextef expansion
KT-1X-band
NextefX-band
A
B
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Nextef another shield room “B” was being established.
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Reusable coupler: TM01 Mode Launcher
Surface electric fields in the mode launcher Emax= 49 MV/m for 100 MW
S. Tantawi, C. Nantista
SLAC made these launchers for KEK basic tests.KEK will prepare single cell test setups.
2011/3/7 21US/Japan application Toshi Higo
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Systematic study on surface treatment is planned in collaboration
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Cutting, HIP, purity, heat treatment, CP, EP, etc.
with using LG (high purity large grain material)
in coupon or single cell setup
VAC furnace
Hydrogen furnace
Crystal orientationSEM & X-ray
Field Emission Microscope
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A. D. Yeremian et al., “RF Choke for Standing Wave Structures and Flanges,” THPEA065, IPAC 2010, Kyoto, May 2010.
Solid model by David Martin
V. Dolgashev, AAS 2010
KEK is preparing in-situ inspection device for single-cell test setup at SLAC.
2011/3/7 23US/Japan application Toshi Higo
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1C-SW-A3.75-T2.60-Cu/Mo-clamped
Test with other materials than copper, such as stainless steel and molybdenum, are being tried for higher gradient.
KEK supplies the test setups.2011/3/7 24US/Japan application Toshi Higo
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Approach*
• Individually fed p mode cavities
US/Japan application Toshi Higo
RFsource
Directional Coupler Sc = (1 – i + N)-1/2
Accelerator Cavity
Nth Accelerator Cavity
Load
*S. Tantawi,” RF distribution system for a set of standing-wave accelerator structures”, Phys. Rev., ST Accel. Beams,vol. 9, issue 11
J. Neilson, US HG collaboration workshop, SLAC, Feb. 2011
SLAC is designing a SW cavity system, each cell fed independently for higher gradient than present prototypes in TW.
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RF Feed Using Biplanar Coupler
US/Japan application Toshi Higo
~ 7 cm
~ 3 cm ~ 24 cm
J. Neilson, US HG collaboration workshop, SLAC, Feb. 2011
SLAC made a mechanical design and will be tested experimentally.
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US/Japan application Toshi Higo2011/3/7 27
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Milestone in summary• 2011
– KEK start basic study with simple setup– Both continue prototype fabrication and evaluation
• 2012– Expand the study to application of other material– Evaluate the feasibility of Cu-based TW prototype
• 2013– Hopefully understand the trigger mechanism– Design a possible higher gradient section for such
as linear collider
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Conclusion• Three year progress were presented.• 80MV/m was found feasible in copper TW.• Pulse surface heating was found as one of the most
important parameters, especially when going to higher gradient.
• Basic studies are proposed to be conducted at SLAC and KEK in a very close collaboration.
• This opens the way to understand the physics triggering the breakdowns.
• This makes a realistic accelerator design possible at higher gradient than 100MV/m.
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