Transcript S2 Progress Report for EC H. Padamsee and Tom Himel For the S2 Task Force.

S2 Progress Report for EC
H. Padamsee and Tom Himel
For the
S2 Task Force
Review S2 Goals (1)
• Review TRC R2 recommended tests and revise list
• Determine generic lessons learned from the
operation of TTF and other SRF based accelerators
– How are these lessons applicable for S2 tests and ILC
• Assess number of RF units needed for planned
activities
• Assess if beam is needed
• See what assemblies and tests are presently done or
planned at
– FLASH (TTF-II), SMTF (ILCTA@FNAL), STF
• Assess their timelines
– compare with S0, S1, TDR
• Evaluate impact of XFEL plans on S2 needs
Review S2 Goals (2)
(Relationship to Industrialization/Production Scenarios)
• The Plan should show how the transitions from
proof-of-principle to the S2 Milestone and to the
start of main linac production should be
accomplished.
– Look at how previous high tech projects have been industrialized
– Make model (s) for the cavity/cryomodule industrialization
plan(s) to prepare for ILC construction
– Work backward to determine where R&D needs to be over
intervening years between now and construction
– Do we need a phase 2 (longer string test of many RF Units)
Discuss Tests Needed
Examples Under Discussion
• Tests with < 1 RF Unit
– (e.g. at cryomodule test stand)
• Tests with 1 RF Unit
• Tests with a few RF Units
• Tests with N >> 1 RF Units
Example Tests With < 1 RF Unit
e.g. at cryomodule test stand
• Test reliability of components.
– Of particular concern are components with long MTTR such as
tuners, piezos, and couplers.
• Use ILC design piezos, tuners, HOM, and cryomodule
• Measure dark current in cryomodules
– cryo load
– radiation
• Important for electronics and personnel in tunnel with RF on.
• Check for cavity and quad vibration due to use of piezo
tuners
Tests Which Can Be Done With <1 RF Unit (con’t)
e.g. at cryomodule test stand(s)
• Test transportability of cryomodules
• Test compatibility of cryomodules from mixing
those of different regions
• Try a dirty vent on some cryomodules and
evaluate extent of damage and recovery
• Do above with a fast acting valve to see effects
both of valve and of the dirty vent
• Provide a test bed for evolving industrially
produced cryomodules.
– desire to test preproduction cryomodules before full
production released
One RF Unit Tests
(y = with beam)
•
Demonstrate that we can make an RF unit to ILC spec for gradient, Q, dark
current
– Evaluate cavity quench, coupler breakdown rates and recovery times at 31.5
MV/m for long-term operation
– Check static and dynamic cryo heat loads at spec (y)
– Are these commensurate with the operational expectations
•
Test RF fault recognition and recovery software (y)
– Insure that adequate instrumentation is available to sense likely faults. (coupler
breakdowns, cavity quench, broken tuner motor, broken coupler motor, defective
sensor…
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Check for trapped HOMs including between the cavities using final cavity
spacing
Check beam phase and energy stability (y)
Provide an RF unit for LLRF tests for several years (y)
Determine capability of LLRF, tuners, and couplers to deal with gradient
spread in cryomodules..how much spread can be dealt with?
Tests Needing More than One RF Unit
• Measure dark current
– effects cryo load
– how much dark current is accelerated/captured from module to
module
– How much radiation
• Important for electronics and personnel in tunnel with RF on.
• Check cryo control (maintain liquid levels, feedback time
response etc.) and vibrations due to cryogen flows
• Mock up actual tunnel layout to explore installation,
maintenance, and repair issues prior to large scale
construction of ILC
– could influence civil designs
Tests needing N >> 1 RF Units
(probably not practical)
• Check for emittance growth due to cavity
misalignments
• Check for emittance growth before and
after DFS steering
Next Steps
• Which system tests are done at TTF, SNS…
– (e.g next slide)
– What have we learned?
• What tests from previous lists can be done at
TTF-II/FLASH?
– Start a dialog between S2 and TTF-II to make a list
– List tests that must be done elsewhere
• Compare time lines
Down time weeks 16-32
Total downtime: 370.8 h (13%)
Water: 1%
Magnets: 2%
Protection: 2%
Controls: 3%
Other: 3%
Photonline: 5%
Laser: 6%
Kly/Mod
LLRF
24.2 h (7%)
Laser
20.5 h (6%)
Photonline
17 h (5%)
Controls
10 h (3%)
Protectionsystems
LLRF: 7%
Klystrons / modulators:
71%
We urgently have to detail this; about 50% was one
single event (bouncer circ. capacitor)
9 h (2%)
Magnets
7.6 h (2%)
Water
4.2 h (1%)
Diagnostics
Operator
Klystrons / modulators is the sum of both plus
waveguides, pre-amplifier, interlocks….
264.7 h (71%)
1.5 h (<1%)
1 h (<1%)
Vacuum
0.8 h (<1%)
Other
10.3 h (3%)
Do we need a longer string test (phase 2)?
(Relationship to Industrialization/Production Scenarios)
• The Plan should show how the transitions
from proof-of-principle to the S2 Milestone
and to the start of main linac production
should be accomplished.
– Look at how previous high tech projects have been
industrialized
– Make model (s) for the cavity/cryomodule
industrialization plan(s) to prepare for ILC
construction
– Work backward to determine where R&D needs to be
over intervening years between now and construction
Examples Studied
• LEP-II SC system evolution
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–
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350 MHz, Nb-Cu Technology
288 cavities, 500 meters
Total 72 modules over 6 years
3 years initial @ 4 modules per year
Start-up 12 modules/year
Final rate 25 modules/year
• LHC evolution
– 1250 magnet modules, 15 m long
• Need to compare with XFEL scenario as it develops
>120 modules
6 modules tested in TTF-II (string test)
6 years total
29/year
24/year
12/ year
4/year
Brief Remarks for LEP Lessons
– 4 modules installed in LEP for initial system
tests with beam
– Many lessons learned
• Couplers need to be improved
• pondermotive oscillations, controls
• Optimize RF distribution
LHC: R&D, Pre-Series and Production
Phases, Total CM
10000
Series
Series1
LHC
String
Test 1
100
1m
10
10m
PreSeries
LHC
Project
Approval
15 m
1
19
91
19
92
19
93
19
94
19
95
19
96
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
Modules
1000
R&D With Industry Phase
Before LHC Approval
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Initial R&D with industry, 1991 – 1994
7 x 1.3m magnets/modules ordered from 5 firms
7 x 10 m long magnets/modules ordered from 4 firms
LHC string test first reached design field in Dec 1994
– 2 dipoles (10m) and 1 quadrupole
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•
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LHC approved in Dec 1994
LHC String test 1 complete Jan 1999 (4 year test)
String test 2/1, 3 D (15m), 1Q , 98 – 01
String test 2/2, 6 D (15 m), 1 Q, 02 - 06
LHC String Test
•
•
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The String has been an invaluable test-bed for
LHC systems such as cooling, vacuum and
magnet protection and has also served as a
training ground for the String team and operators
The String began operation in December 1994,
just before the … LHC project was approved.
Since then five experimental runs have been
carried-out. The first runs were aimed at
validating the design choices for the individual
systems. The emphasis then shifted towards
optimisation of the design, while later
experiments were designed to highlight any weak
points through artificially induced fatigue on
components and the interconnections between
them.
Many Scenarios Still Under Discussion in S2
One Possible Example
• An Evolutionary Picture
• Learning : Stage 0
– 1 RF unit
• Stage 1: 1 – 2 RF Units
– Reach spec
– Make modules regionally compatible
• Stage 2 : Many RF units together in one location
• Need to examine each relative to ILC timeline,
XFEL plans & timeline,
N= 1 - 2
Conclusions
• We are defining goals for S2
– Phase 1, carry out needed RF unit tests,
• keep it small to have minimal impact on funding decision
– Phase 2
• longer string of RF units to get good statistics on cavities, cryomodules, RF,
LLRF…(industrial?)
• After approval ?
• We try to make S2.1 consistent with S0, S1
– Number of cavities, timeline…
• We need to adapt the plan to available funding
– phase 1 and 2
• What is clear so far:
– It is a large effort
– Parts of Phase 1 can be done in TTF-II (define how much)
• Push for Plan formulation by Valencia
• We need your advice on our phased approach !