Transcript Operation of niobium cavities in the TTF Linac

ILC Main Linac Design Status
[email protected]
-MPY-
Bangalore 9.3.2006
• General layout
– Cryogenic layout
• Module layout
• Segmentation
– Tunnel sizes
ILC
Lutz Lilje DESY -MPY-
17.07.2015
Main Linac: Towards an Reference Design Report (RDR)
• Since Frascati and the appproval of the BCD several things
happened in the main linac layout to get the RDR done
– Must-link by C. Adolphsen:
• Main Linac RDR Wiki:
– http://www.linearcollider.org/wiki/doku.php?id=rdr:rdr_as:main_linac_home
– Cryomodule & Cryogenics Groups are defining cryomodule length and cryoplant
layout
• First pass generated at Jan 16-17 CERN meeting, has since been updated
– RF Group to work with Civil Group to define the size/layout of support tunnel
• Some detailed analysis is under way – diameter is going down again…
• Alternate cross section?
– Magnet group with specifying the linac quad and corrector package
• Reviewing issues
• Seperated corrector design
Lutz Lilje DESY -MPY-
17.07.2015
RDR Linac Definition (Cont)
• LET Group has been working resolving beam
dynamics related issues at Feb 8-11 CERN meeting
• Work with Instrumentation Group to define
diagnostics
– List of instruments and issues generated at Jan 17
FNAL meeting
• Discussing implications of MPS and availability
requirements with Himel et al.
Lutz Lilje DESY -MPY-
17.07.2015
• Must-read by T. Peterson:
Cryogenics
– http://tdserver1.fnal.gov/peterson/tom/SRF/ILC-cryo-8Feb06.ppt
– Cryogenics is not only the main linac….
• Heat load revisited
– More conservative estimates of static heat leak than in TDR
• based on TTF measurements (where all module have a warm-cold transition)
– Higher dynamic load due to higher gradient
– Keeping the plant sizes below 25 kW total equivalent 4.5 K capacity leads to
maximum plant spacing of ~2.3 km
• Cryo-segmentation every 560 m – warm or cold?
– Use segments to isolate insulating vacuum sections
• Not necessarily a warm-cold transition
– Introduction of a cold-warm transition could be used for shortening regions that are
warmed up for repair work
• Faster cooldown
• Could be used for Instrumentation and MPS
– From the beam dynamics standpoint not absolutely needed
– Main disadvantages are
• cost
• contamination issues
– e.g. need to add fast valves at very short distance from cavity surface
• increased vulnerability to insulating and beam pipe vacuum failures
– MPS issue
Lutz Lilje DESY -MPY-
17.07.2015
BCD Description -500 GeV Layout(Slide lifted from “Positron Source Configuration”
by KURIKI Masao and John Sheppard, January 2006.
Cryogenic device description in red added by Tom Peterson)
Primary esource
Up to about 500 MeV via special SRF cavity/magnet modules totaling about 25 m x 20 MV/m
Then up to 5 GeV with 21 standard SRF modules
650 MHz SRF, about 10-15 cavities plus 200 m of CESR-c type SC wigglers, all 3 damping rings
eDR
Standard modules (starting at 5 GeV)
150 GeV
Beam Delivery SC magnets and crab cavities
System
(no quatities yet)
Positron Linac
100 GeV
Helical
Undulator
In By-Pass
Line
RTML includes
SC solenoids
plus 61 SRF modules
Photon
Collimators
IP
Target e- Dump
250 GeV
Standard modules
Photon Beam
Dump
200 m of SC undulators
Auxiliary
e-
Source
Photon
Target
Adiabatic
Matching
Device
RTML includes
SC solenoids
plus 61 SRF modules
e+ pre-accelerator
~5GeV
Up to about 500 MeV via special SRF cavity/magnet modules totaling about 25 m x 20 MV/m
Then up to 5 GeV with 21 standard SRF modules
e+
DR
Lengths and Packing Factor
(from spreadsheet originated by Chris Adolphsen and revised by Tom Peterson)
Cry omodule with quad
Cry omodule without quad
12543
11271
number of modules
RF unit
35085
number of RF units
Extra Length at End of String (mm)
number of modules
String
number of strings
Extra length at end of segment (BCD)
Extra length at end of segment (ACD)
number of modules
Segment
number of segments
Extra length at end of cry o unit
number of modules
Cry ogenic unit
number of cry ogenic units
Modules installed in 15-250 GeV region
# Required f or Acceleration (15-250 GeV)
Length of 15-250 GeV region of linac
Length occupied by cry o boxes
Linac Packing Fraction (%)
Packing Fraction w/o Extra Lengths (%)
Lutz Lilje DESY -MPY-
2000
140342
1757
9271
563123
20785
2273279.2
1 per RF unit
2 per RF unit
3 modules per RF unit
35.1 meters long RF unit
4 RF units per string
1 end box per string. Add back the 850 since separate box means secon
12 modules per string
140.3 meters long string
4 strings per segment
Take 1/3 module length f or v acuum-only segmentation as BCD -- repla
Take f ull module length f or warm-up/cool-down segmentation as ACD 48 modules per segment
563.1 meters long segment (BCD)
4 segments per cry o unit
Take one module length f or f eed box and one f or turnaround box -- rep
192 modules per cry o unit
2273.3 meters long cryo unit
5 cry o units per linac f rom 15-250 GeV
960
931
3% Ov erhead
5 degree of f -crest
11366396
11.4 km long linac (15 - 250 GeV) w/o diag, undulator,
139068
139.1 meters of cry o boxes in 15 - 250 GeV part of lina
70.0 % packing f raction
70.9 % packing f raction f or modules alone
17.07.2015
Cryoplant Layout in e- Linac
Tom Peterson
For ILC 500, total of ten 25 kW @ 4 K plants requiring 52 MW of AC power.
Lutz Lilje DESY -MPY-
17.07.2015
Towards an ILC Cryomodule
(4th generation)
• International Effort between the three
regions
• Design changes are towards nailing down
slot length of components
– Costing should be straight-forward from TTF
(and possibly XFEL) experience
Lutz Lilje DESY -MPY-
Slides from Talks by Don Mitchell, Tom Peterson and Others
at Jan 16-17 CERN Meeting
17.07.2015
ILC Cryomodule Design Considerations
• Move quad package to middle of cryomodule to
achieve better support and alignment.
• Shorten cavity-to-cavity interconnect and simplify
for ease of fabrication and cost reduction.
• Overall improved packing factor.
• Simplify the assembly procedure.
• MLI redesign to reduce hands-on labor costs.
• More robust design for shipping.
• Reliability of tuner motors in cold operation.
• Revaluate cryogenic pipe sizes
– partially done for the XFEL already
Lutz Lilje DESY -MPY-
17.07.2015
Increase
diameter
beyond
X-FEL
Increase
diameter
beyond
X-FEL
Review
2-phase pipe
Size and
effect of slope
Lutz Lilje DESY -MPY-
17.07.2015
E.g.: Module pipe sizes increase
(T. Peterson – CERN Meeting)
P ipe funct ion
BCD
designat ion
TTF inner
diameter
(mm)
XFEL plan
inner
diameter
(mm)
ILC BCD
proposed
minimum
(mm)
2.2 K subcooled supply
A
45.2
45.2
60
Major ret urn header,
st ructural supp’t
5 K shield and intercept
supply
8 K shield and intercept
return
40 – 50 K shield supply
B
288
288
288
C
57.5
71
70
D
50.0
71
70
E
57.5
71
100
75 - 80 K shield ret urn
F
50.0
71
100
2-phase pipe
72.1
72.1
Helium vessel to 2-phase
pipe cross-connect
54.9
54.9
72.1
(review)
54.9
Lutz Lilje DESY -MPY-
17.07.2015
Inside an ILC cryomodule
• Cavity package
– Cavity
– High power RF coupler
– Tuner
– Magnet package
– …(time won‘t permit)
Lutz Lilje DESY -MPY-
17.07.2015
Cavity with Frequency Tuner
•
No BCD Tuner, some designs are very close to requirement
–
–
•
E.g Bladetuner
–
•
Issue with cavity’s magnetic shielding
Could be also another tuner that does not need inter-cavity
space
–
Lutz Lilje DESY -MPY-
Generic issue to all designs: motor and piezo reliability
Deemed to be feasible, but some R&D needed
Just watch out for the cryo-lines…
17.07.2015
Existing DESY Interconnect Design
Interconnect:
Tesla TDR: 283mm
Currently 344mm
344
Flange/Bellows Design Specs:
• Bolted flange (12 bolts/flange)
• Convoluted SS Bellows (10 waves, 54mm free length, ±25mm)
-Length of bellows dictated by bolt length, old elastic parameters
• Bellows elastic requirements: ±4mm (~1mm thermal + ~3mm tuning)
• Aluminum Alloy 5052-H32 Diamond Hex Seal
• 7 Ton clamping force, 35 N-m torque/bolt
• Mechanical analysis done @ Desy, INFN (Cornelius Martens, Roberto Paulon)
Lutz Lilje DESY -MPY-
17.07.2015
Proposed Cavity Layout
Flange-to-Flange Cavity Spacing = 1319 mm
Lutz Lilje DESY -MPY-
17.07.2015
BCD assumes use of
XFEL Main Coupler
Graphics from Terry Garvey
Lutz Lilje DESY -MPY-
17.07.2015
BPM / Quad / Corrector Package
887
66
BPM
77
666
QUAD and
Correctors
78
TDR
ILC
Preliminary
Lutz Lilje DESY -MPY-
17.07.2015
Shell Type ILC Dipole Corrector
Vladimir Kashikhin, Fermilab
Magnet Parameters
Integrated field
0.02 T-m
Center field
0.2 T
Winding ampere-turns 18kA
Current
90 A
Superconductor
NbTi
SC diameter
0.5 mm
Outer diameter
140 mm
Magnet length
~ 200 mm
Flux density and flux lines at max
current in both dipole coils
Lutz Lilje DESY -MPY-
17.07.2015
ACD: Seperate Quad Cryo-section
1530 mm
Lutz Lilje DESY -MPY-
17.07.2015
ACD: Pros / Cons for a Separate Quad/BPM Cryostat
• Pros
– Allows for a common cryomodule design
– Flexibility
• Accommodation of different magnet packages, upgrades, etc.
• Independent adjustments to the quad/BPM position
– Handling
• Allows independent cold testing and measurement of the magnet package
• Schedule, resources, and fabrication facilities not tied to mainstream
cryomodule production
– Precludes the need for independent quad movers inside the
cryomodule (ACD)
• Cons
– Design issues
• Interconnect forces due to bellows could affect quad alignment
• Vibrations due to interconnect might need crosscheck
– Cost
• One extra interconnect required at each quad location
– Potentially requires more longitudinal space required in the lattice
Lutz Lilje DESY -MPY-
17.07.2015
Region between Cryomodules
• Assume 850 mm Flange-to-Flange length (TTF)
– 850 mm between flanges, 815 mm ‘free’ space
– Length partially defined by requirements of cryo tube welding
and beam tube assembly (local cleanroom)
• Includes
– 270 mm Broadband HOM absorber
• XFEL design could be used (but likely over-designed)
– Manual Gate Valves
– Pump-out Ports (integrated in absorber)
• Needs to be better defined
Lutz Lilje DESY -MPY-
17.07.2015
Some critical design issues
• ILC specific issues
– Quad/corrector/BPM package needs more work
• Implication for the next generation cryomodule (type 4) that is being
developed by FNAL/INFN
– Cavity-to-cavity interconnect design.
– Magnetic shield re-design.
• Issues for both ILC and XFEL
– Tuner reliability, slow and fast.
– Vibrational analysis, which will be compared to
measurements for verification of the model for future design
work.
– Development of module and module component tests.
– Design of test instrumentation for the module.
– Verification of cavity positional stability with thermal cycles.
– Robustness for shipping, analysis of shipping restraints and
loads, shipping specifications.
Lutz Lilje DESY -MPY-
17.07.2015
RF System: RF Unit
– Solid-state switched modulator with 1:12 step-up transformer
and bouncer droop compensator
– 10 MW 1.3 GHz multi-beam klystron
• Currently do not have a robust tube design
• Assume horizontal mounting (could be vertical depending on tunnel
height) – no such tube built yet.
– Waveguide distribution system with three way split to feed 24
cavities – each feed includes isolator and phase shifter / Qext
controller.
– 680 RF units for cold cavities in ILC 500
– Modulator, Klystron and three-way splitter in support tunnel,
rest in accelerator tunnel.
Lutz Lilje DESY -MPY-
17.07.2015
Examples of RF three-way split
Leibfritz, FNAL
Fukuda, KEK
Lutz Lilje DESY -MPY-
17.07.2015
TTF Waveguide Distribution
Lutz Lilje DESY -MPY-
17.07.2015
Need more compact design
(Each Cavity Fed 350 kW, 1.5 msec Pulses at 5 Hz)
Two of ~ 16,000 Feeds
Lutz Lilje DESY -MPY-
17.07.2015
RF System Design
– Work so far on
• Understanding interface to LLRF system, which is in the
Control’s group domain
• Compiling list of actuators and signals to be monitored in
the linac
• Working with civil group on rf system layout in the
support tunnel
– Distribution system needs more design work to
lower cost
Lutz Lilje DESY -MPY-
17.07.2015
Example: RF System layout
Lutz Lilje DESY -MPY-
17.07.2015
Example: Implementation using ATCA standard
Lutz Lilje DESY -MPY-
17.07.2015
Lutz Lilje DESY -MPY-
17.07.2015
Civil Facilities: Tunnel Layout
• Distance between tunnels based on construction needs,
radiation protection is under investigation
• Water influx
• Tunnel Sizes
– Component lists with sizes generated
– The 4 m diameter support tunnel and 3.2 m diameter beam tunnel in
BCD are likely too small
– Would help to make components narrower – work in progress
• A lot of work underway on other details
–
–
–
–
–
–
Water and power distribution
Air supply and temperature regulation
Penetration size and access (e.g. crossover)
Transportation and stay clear
Personnel access and egress
Fire Safety
Lutz Lilje DESY -MPY-
17.07.2015
Tunnel layout: Component Lists
Lutz Lilje DESY -MPY-
17.07.2015
Example: 4.5 m Linac and 5 m Service tunnel
Lutz Lilje DESY -MPY-
17.07.2015
Service tunnel sizes under discussion: 4.5m, 5m and 5.5m
Lutz Lilje DESY -MPY-
17.07.2015
Installation Systems Concept Development
Step Installation Phases & Sequencing
Installation Systems Concept Development
Step Installation Phases & Sequencing
Installation Systems Concept Development
Step Installation Phases & Sequencing
Installation Systems Concept Development
Step Installation Phases & Sequencing
Crossovers between the tunnels
Lutz Lilje DESY -MPY-
17.07.2015
Diagnostics: Under discussion
•
Aim for BPM resolution of 0.3 micron at full charge and 3 micron at reduced
charge (10%) when running with keep-alive source. Want to achieve this bunchby-bunch with bunch spacing down to 185 ns.
– Accelerator Physics might be satisfied with less ambitious goals for full charge (~1um)
•
Do not implement HOM readout initially, but to bring signals just outside of the
cryomodules where they would be terminated.
•
Use beam coupling to HOM ports to monitor relative bunch intensity and bunch
phase relative to rf (use for rf phase control)
•
Optional: Include 6-12 m long warm sections after every 48 cryomodules (560 m)
• Use for beam line and insulating vacuum isolation.
• Each would contain a laser wire: with 21 wires, have 7 independent measurements of
emittance along each linac.
• Could contain other instrumentation such as beam halo and dark current monitors.
• Could contain spoilers for short-train beam abort.
• Could be used for cryo-segmentation as discussed earlier
• Penalties (as mentioned before): Cost; MPS issues, contamination
•
Within linacs, measure beam energy and energy spread only for the electron
beam in the undulator line.
Lutz Lilje DESY -MPY-
17.07.2015
Summary
• Many discussions on-going
– Interplay between Area systems and Technical systems is being
defined and starts to work
• Very detailed information becoming available
– Cryogenics
– Module layout
• More work needed
– Tunnel layout has changed and experts are working e.g. on the
component level to further reduce the tunnel size
– Costing details need more work:
• E.g. How to handle TESLA TDR or XFEL cost estimates?
• Is there a ‘common sense‘ to do the costing?
• Baseline design exists
– Some of the options need more thorough discussion e.g. cryo
segmentation
Lutz Lilje DESY -MPY-
17.07.2015
Thank you…
• … to the many colleagues who provided me with
transperencies!
Lutz Lilje DESY -MPY-
17.07.2015