Transcript Document 7275733

BNL - FNAL - LBNL - SLAC
LARP Collaboration Meeting 13
Port Jefferson
Nov. 4-6, 2009
Magnet Radiation Issues
Giorgio Ambrosio
Fermilab
Outline:
- Summary of Radiation Hard Insulation Workshop
- Updates and other programs
- Options
Rad-Hard Insulation Workshop
FNAL April 07
AGENDA:
1:30
3:30
Introduction
LARP Magnets Mechanical Analysis
Radiation Environment in the LARP IR Magnets
and Needs for Radiation Tests
Radiation Effects to Nb3Sn, Copper and Inorganic
Materials
Break
Current Knowledge of Radiation Tolerance of
Epoxies
Radiation-Resistant Insulation for High-Field
Magnet Applications
New Wind-and-React Insulation Application
Process
Discussion about test needs, samples, and available
test facilities
Summary and plans
20
20
30
G. Ambrosio
I. Novitzky
N. Mokhov
20
A. Zeller
20
20
R. Reed
30
M. Hooker
10
M. Hooker
All
All
Talks on the LARP plone at:
2
https://dms.uslarp.org/MagnetRD/SupportingRD/Rad_Hard_Insul/Apr07_workshop/
Questions
Develop plan to arrive to these answers:
“Can this magnet withstand the expected radiation dose?”
 We should be able to reply either:
- “Yes it can, and we have data to demonstrate it”
- “No it cannot, but we have tested a TQ with an
insulation/impregnation scheme that can withstand the expected dose”
3
Rad-Hard Workshop
Fermilab
Radiation Environment in the LARP IR
Magnets and Needs for Radiation Tests
Nikolai Mokhov
Fermilab
Original slides,
I added comments
and underlines
Rad-Hard Insulation Workshop
Fermilab, Batavia, IL
April 20, 2007
Rad-Hard – Fermilab, Apr. 18-20, 2007
OUTLINE
•
•
•
•
•
IR Energy Deposition-Related Design Constraints
Basic Results for LHC IR at Nominal Luminosity
Dose in IR Magnets at 1035 for 3 Designs
Particle Energy Spectra etc.
Radiation Damage Tests
Rad-Hard – Fermilab, Apr. 18-20, 2007
LHC IR QUENCH LIMITS AND DESIGN CONSTRAINTS
Quench limits and energy deposition design goals:
NbTi IR quads: 1.6 mW/g (12 mJ/cm3) DC (design goal 0.5 mW/g)
Nb3Sn IR quads: ~5 mW/g DC (design goal 1.7 mW/g)
Energy deposition related design constraints:
Quench stability: keep peak power density emax below the quench limits,
with a safety margin of a factor of 3.
Radiation damage: use rad-resistant materials in hot spots; with the
above levels, the estimated lifetime exceeds 7 years in current LHC
IRQ materials; R&D is needed for materials in Nb3Sn magnets.
Dynamic heat load: keep it below 10 W/m.
Hands-on maintenance: keep residual dose rates on the component outer
surfaces below 0.1 mSv/hr.
Engineering constraints are always obeyed.
Rad-Hard – Fermilab, Apr. 18-20, 2007
Quad IR: Power Density and Heat Loads vs L*
The goal of below the design limit of 1.7 mW/g is achieved with:
Coil ID = 100 mm. W25Re liner: 6.2+1.5 mm in Q1, and 1.5 mm in the rest
Total dynamic heat load in the triplet:
1.27, 1.47 and 1.56 kW for L*=23, 19.5 and 17.4 m
Peak dose in Nb3Sn coils 40 MGy/yr at 1035 & 107 s/yr
Rad-Hard – Fermilab, Apr. 18-20, 2007
Peak Dose & Neutron Fluence in SC Coils
IR magnets
Luminosity,
1034 cm-2s-1
D (MGy/yr)
at 107 s/yr
Flux n>0.1 MeV
(1016 cm-2)
70-mm NbTi
quads
1
7
0.3
100-mm Nb3Sn
quads
10
35
1.6
Block-coil Nb3Sn
quads
10
25
1.2
Dipole-first IR
Nb3Sn
10
15
0.7
Both
increase
5 times
Shell-coil quads at 1035:
Averaged over coils D ~ 0.5 MGy/yr, at slide bearings ~ 25 kGy/yr
Rad-Hard – Fermilab, Apr. 18-20, 2007
Radiation Damage Tests (1)
1.
Peak dose in the LHC Phase-2 Nb3Sn coils will be about
200 MGy over the expected IR magnet lifetime. Seems
OK for metals and ceramics, not OK for organics. It is >
90% due to electromagnetic showers, with <Eg> ~ 7 MeV
and <Ee> ~ 40 MeV: test coil samples (and other magnet
materials) with electron beams.
2. Hadron flux seems OK for Tc and Ic, but needs
verification for Bc2. Hadron fluxes (DPA) are dominated
by neutrons with <En> ~ 80 MeV, the most damaging are
in 1 to 100 MeV region. Very limited data above 14
MeV for materials of interest (e.g., APT Handbook).
Rad-Hard – Fermilab, Apr. 18-20, 2007
Radiation Damage Tests (2)
3. Propose an experiment with Nb3Sn coil fragments (and
other magnet materials) at a proton facility with emulated
IR quad radiation environment (done once with MARS15
for the downstream of the Fermilab pbar target). Look at
BLIP (BNL), Fermilab, and LANL beams.
4. One of the important deliverables: a correspondence of
data at high energies to that at reactor energies (scale?).
5. Do we need beam tests at cryo temperatures?
6. Analyze if there are other critical regions in the quads
with the dose much lower than all of the above but with
radiation-sensitive materials. For example, is it OK 10
kGy/yr
on end parts, cables etc.?
Rad-Hard – Fermilab, Apr. 18-20, 2007
Radiation Effects on Nb3Sn,
copper and inorganic insulation
Al Zeller
NSCL/
MSU
General limits for Nb3Sn:
Nikolai:
Dose: 200 MGy
Neutrons: 1021 n/m2
5 X 108 Gy (500MGy) end of life
Tc goes to 5 K – 5 X 1023 n/m2
Ic goes to 0.9 Ic0 at 14T – 1 X 1023 n/m2
Bc2 goes to 14T 3 X 1022 n/m2
NOTE: En < 14 MeV
Damage increases as neutron energy increases
Important Note
All of the radiation studies on
Nb3Sn are 15-25 years old and
we have lots of new materials.
Need new studies
But I may be able to help.
Have funding for HTS irradiation, so may be
able to irradiate Nb3Sn
Hot samples 
Need place to test samples
transp/handling isuess
-Should we do it?
- Can we use results of
other programs (ITER, …)?
Copper
Radiation increases resistance
Should check if
From the Wiedemann-Franz-Lorenz
law
this may affect our
magnets:
at a constant temperature
flux is smaller but
energy is higher
λρ = constant
Thermal conductivity decreases
Minimum propagating zone decreases:
Lmpz = ((Tc-To)/j2)
So Lmpz -> λ
This is 40 cm3/g
in one year!
Problem:
Gas evolution
Ranges from 0.09 for Kapton to
>1 cm3/g/MGy for other epoxies
Gas is released upon heating to room
temperature
Can cause swelling, rupture of
containment vessel or fracturing of epoxy
Big caution: Damage in inorganic materials
is temperature dependent.
Damage at 4 K, for some properties, is 100
times more than the same dose or fluence
This is
absorbed at room temperature.
concerning!
Since Nb3Sn has a useful fluence limit of
1023 n/m2, critical properties of inorganic
insulators should be stable to 1025 n/m2
at 4 K.
Note that electrical insulation properties are
10 times less sensitive than mechanical ones.
Radiation Tolerance of Resins
We need epoxy
resin or
Rad-Hard Insulation Workshop equivalent
Fermilab, April 20, 2007
material for coil
impregnation
Dick Reed
Cryogenic Materials, Inc.
Boulder, CO
Estimate of Radiation-Sensitive
Properties
Resin
Gas Evolution
(cm3 g-1MGy-1)
(4,77K)
DGEBA,
DGEBF/
anhydride
amine
cyanate ester
blend
Cyanate ester
TGDM
BMI
PI
Swelling
(%)
25% reduction:
dose/shear strength
1.2
0.6
~0.6
1-5
1.0
~1.0
5 MGy/75 MPa
10 MGy/75 MPa
~ 50 MGy/45-75 MPa
~0.5
0.4
0.3
0.1
~0.5
0.1
<0.1
<0.1
100 MGy/40-80 MPa
50 MGy/45 MPa
100 MGy/38 MPa
100 MGy
Other Factors Related to
Radiation Sensitivity of Resins
Radiation under applied stress at low
temperatures - increases sensitivity
(US/ITER/model coil)
Higher energy neutrons (14 Mev) are more
deleterious than predicted (LASL)
Irradiation enhances low temperature creep
(Osaka U.)
Radiation-Resistant Insulation
For High-Field Magnet Applications
Presented by:
Matthew W. Hooker
Presented at:
Radiation-Hard Insulation Workshop
Fermi National Accelerator Laboratory
April 2006
NOTICE
These SBIR data are furnished with SBIR rights under Grant numbers DE-FG02-05ER84351 and DE-FG02-06ER84456 . For a period of 4 years
after acceptance of all items to be delivered under this grant, the Government agrees to use these data for Government purposes only, and
they shall not be disclosed outside the Government (including disclosure for procurement purposes) during such period without permission
of the grantee, except that, subject to the foregoing use and disclosure prohibitions, such data may be disclosed for use by support
contractors. After the aforesaid 4-year period the Government has a royalty-free license to use, and to authorize others to use on its behalf,
these data for Government purposes, but is relieved of all disclosure prohibitions and assumes no liability for unauthorized use of these data
by third parties. This Notice shall be affixed to any reproductions of these data in whole or in part.
2600 Campus Drive, Suite D • Lafayette, Colorado 80026 • Phone: 303-664-0394 • www.CTD-materials.com
Proposed
substitute for
epoxy resin
CTD-403
100
CTD-403@50°C
• CTD-403 (Cyanate ester)
- Excellent VPI resin
- High-strength insulation from
cryogenic to elevated temperatures
- Radiation resistant
- Moisture resistance improved over
epoxies
Viscosity (cPs)
80
60
40
20
0
0
10
20
30
40
50
60
70
80
90
Time (hrs)
• Quasi-Poloidal Stellarator
-
Fusion device
Compact stellarator
20 Modular coils, 5 coil designs
Operate at 40 to >100°C
Water-cooled coils
QPS
24
Radiation-Resistant Insulation for High-Field Magnets
Braided Ceramic-Fiber
Reinforcements
Proposed
substitute for
S2 glass
• Minimizing cost
- Lower-cost fiber reinforcements for
ceramic-based insulation (CTD-CF-200)
- CTD-1202 ceramic binder is 70% less than
previous inorganic resin system
• Improving magnet fabrication efficiency
- Textiles braided directly onto Rutherford
cable (eliminates taping process)
- Wind-and-react, ceramic-based insulation
system
• Enhancing magnet performance
- Insulation thickness reduced by 50%
• Closer spacing of conductors enables higher
magnetic fields
- Robust, reliable insulation
• Mechanical strength and stiffness
• High dielectric strength
• Radiation resistance
25
Radiation-Resistant Insulation for High-Field Magnets
Use or disclosure of the data contained on this page is subject to the restriction on the cover page of this document.
HEP
CTD Irradiation Timelines
Epoxy-Based Insulations
SBS
E-beam Irradiated at 4 K
Proposed
Ceramic/Polymer Hybrids
SBS & Gas Evolution at 4 K
1992-93
SSC
GA
2008-2009
DOE SBIR
NIST
Not
completed
Fusion
1988
CTD Founded
1992-1998
ITER
Garching/ATI
Epoxy-Based Insulations
SBS, Compression
Shear/Compression at 4 K
26
2000-2003
DOE SBIR
ATI
Epoxies & Cyanate Esters
SBS, Compression
Gas Evolution
2005-2007
DOE SBIR
MIT-NRL
Resins & Ceramic/Polymer Hybrids
SBS, Compression
Adhesive Strength
Gas Evolution
Gas evolution , irradiation at:
70
C
80forCHigh-Field Magnets
Radiation-Resistant
Insulation
Insulation
Is this low shear
strength acceptable
Irradiations in a “small” area?
- CTD-101K (epoxy)
- CTD-403 (cyanate ester)
- CTD-422 (CE/epoxy blend)
• Insulation performance
- Shear strength most affected
by irradiation
- Compression strength largely
un-affected by irradiation
• Ongoing irradiations
-
Ceramic/polymer hybrids
CTD-403
20, 50, & 100 MGy doses
Expect to complete by 8/07
CTD-101K
100
CTD-403
CTD-422
80
60
40
20
Test Temperature: 77 K
0
0
20
40
60
80
100
120
Radiation Dose (MGy)
2000
Compression Strength (MPa)
• Fiber-reinforced VPI systems
Short-Beam-Shear Strength (MPa)
Nikolai:
120
Peak dose in 1 year
1500
1000
CTD-101K
CTD-403
500
Test Temperature: 77 K
CTD-422
0
0
27
20
40
60
80
Radiation Dose (MGy)
100
120
Radiation-Resistant Insulation for High-Field Magnets
2009 data
Radiation Resistance
• Insulation irradiations at Atomic
Institute of Austrian Universities
(ATI)
77 K
- CTD-403 (CE)
- CTD-422 (CE/epoxy blend)
- CTD-101K (epoxy)
• CTD-403 shows best radiation
resistance
• CTD-422 is improved over epoxy,
but lower than pure CE
• Irradiation conditions
- TRIGA reactor at ATI (Vienna)
- 80% gamma, 20% neutron
- 340 K irradiation temperature
28
77 K
Radiation-Resistant Insulation for High-Field Magnets
Radiation-Induced 2009 data
Gas Evolution
• Gas evolution testing
- Irradiate insulation specimens
in evacuated capsules
- As bonds are broken, gas is
released into capsule
- Breaking capsule under
vacuum allows gas evolution
rate to be determined
Irradiated at ATI, Vienna, Austria
• Test results
- Cyanate esters show lowest
gas evolution rate of VPI
systems
- Epoxies have higher gasevolution rates
- Results consistent with
relative SBS performance
29
Radiation-Resistant Insulation for High-Field Magnets
Proposed 4 K Irradiation
• Low-temperature irradiations
- Linear accelerator facility
- CTD Dewar design
• Insulation characterization
Dewar
Specimen
Position
Window
- Short-beam shear
- Gas evolution
- Dimensional change
• Insulations to be tested
- Ceramic/polymer hybrids
- Polymer composites
- Ceramic insulations
30
Radiation-Resistant Insulation for High-Field Magnets
Use or disclosure of the data contained on this page is subject to the restriction on the cover page of this document.
Discussion
 We need to optimize absorbers from a radiation damage point of view:
– Detailed map of damage by Mokhov,
– Effects on mechanical design by Igor (acceptable or not?)
– If not, increase liners and iterate
 We need to assess damage under expected dose:
– Test under conditions as close as possible to operation conditions
 Start testing CTD-403 (cyanate ester) or other alternative material:
– Ten stack for testing: impregnation, mechanical, electrical and thermal
properties
 Generate table with all materials (in magnet) and compare damage
threshold with expected dose
31
Other Programs (incomplete list)
• NED-EuCARD: RAL started R&D on radhard insulation for Nb3Sn magnets
– Initial focus on binder/sizing mat.
• CEA: ceramic insulation w/o impregnation
– I don’t know if it’s still in progress
• CERN: proposal of an irradiation test facility
that could accommodate a SC magnet (cold)
– Workshop in december
• …
LARP CM13 - BNL, Nov. 4-6, 2009
G. Ambrosio - Long Quadrupole
32
Options
1. Set acceptable dose with present ins./impregnation
scheme  optimize liners and absorbers
- Do we have enough info for this plan?
2. Perform measurement in order to set previous limit
- How much aperture do we expect to gain?
- What measurement should we perform?
3. Develop more rad-hard ins/impregnation scheme
- What measurement should we perform?
How do we want to proceed:
new task, WG, core progr.,… ?
LARP CM13 - BNL, Nov. 4-6, 2009
G. Ambrosio - Long Quadrupole
33
EXTRA
Quad IR: Fluxes and Power Density (Dose)
Q2B
Rad-Hard – Fermilab, Apr. 18-20, 2007
LARP Insulation Requirements
Design Value
CTD-1202/CTD-CF-200
Performance
200 MPa
650 MPa (77 K)
40-60 MPa
110 MPa (77 K)
Dielectric Strength
1 kV
14 kV (77 K)
Mechanical Cycles
10,000
Planned testing to
20,000+ cycles
1.00
0.20-0.30
Design Parameter
Compression Strength*
Shear Strength
Relative Cost**
*200 MPa is yield strength of Nb3Sn
**Relative cost as compared to CTD-1012PX
36
Radiation-Resistant Insulation for High-Field Magnets
Use or disclosure of the data contained on this page is subject to the restriction on the cover page of this document.
Enhanced Strain in
Ceramic-Composite Insulation
Stress (MPa)
200
Graceful Failure
Tensile Test, ASTM D3039
77 K
150
100
S-2 Glass Reinforcement
Brittle Failure
50
CTD-CF-200 Reinforcement
Graceful Failure
0
0
0.2
0.4
0.6
0.8
Brittle Failure
Percent Strain (%)
37
Radiation-Resistant Insulation for High-Field Magnets
Use or disclosure of the data contained on this page is subject to the restriction on the cover page of this document.
Radiation-Induced
Gas Evolution
• Gas evolution testing
- Irradiate insulation specimens
in evacuated capsules
- As bonds are broken, gas is
released into capsule
- Breaking capsule under
vacuum allows gas evolution
rate to be determined
Irradiated at ATI, Vienna, Austria
• Test results
- Cyanate esters show lowest
gas evolution rate of VPI
systems
- Epoxies have higher gasevolution rates
- Results consistent with
relative SBS performance
38
Radiation-Resistant Insulation for High-Field Magnets
Fabrication of Test Coils
• Successful test coils have been produced around the world using
CTD’s Cyanate Ester insulations for fusion and other applications
- Mega Ampere Spherical Torus (MAST) diverter coil – United Kingdom
- ITER Double Pancake test article – Japan
- Quasi Poloidal Stellarator (QPS) test coils – USA (Univ. of Tennessee)
• CTD-422 used to produce accelerator magnet for MSU/NSCL
• Commercial use of CTD-403 in coils for medical systems is ongoing
QPS Test Coil
USA
MAST Test Coil
UKAEA
ITER DP Test Article
JAEA
39
Radiation-Resistant Insulation for High-Field Magnets
Radiation-Induced Gas Evolution
Feed-through
• Gas evolution in polymeric
materials
Valve
Vacuum
gauge
- Attributed to breaking of C-H
bonds, releasing H2 gas
- Gas causes swelling of insulation
• Gas evolution measurements
- Composite specimens sealed in
evacuated quartz capsules
- After irradiation, capsule fractured
in evacuated chamber
- Gas evolution correlated to
pressure rise in chamber
- Dimensional change measured
40
Specimen
location
Radiation-Resistant Insulation for High-Field Magnets
Use or disclosure of the data contained on this page is subject to the restriction on the cover page of this document.