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Damage Levels - Comparison of
Experiment and Simulation
V. Kain AB/Co
Contents …
• Introduction
• Assumed damage levels – TT40 accident
• Controlled damage test
• FLUKA results
• Comparison with experiment
• Conclusion
Scope …
• Comparison of predicted damage limits with
experiment
• Damage limits for the LHC will not be defined
1/21/2005
Verena Kain, AB-CO
1
Introduction
The damage limit of equipment has to be known for …
•
•
•
•
•
•
•
design of machine protection procedures
design of protection elements (robustness,…)
settings of protection systems
thresholds of monitoring systems (BLMs,…)
“safe” beam condition
design of operational procedures
…
Knowledge on damage levels based on simulations…
• especially for LHC energies and intensities
~25cm•long
hole in
chamber
mostly
static
energy deposition calculated (FLUKA,…)
of QTRF
TT40. Both
• indynamic
effects (shock waves,…)?
Chamber and magnet had to
• simulation vs. experiment?
be exchanged.
10 cm
• simulation vs. experiment!
Inside, damage visible over ~1m (melted steel)
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Verena Kain, AB-CO
2
Assumed damage levels
• 450 GeV
• ~ 2x1012 protons ≈ 5% of full ultimate batch
• 7 TeV
• ~1010 protons
Damage limit at 450 GeV:
1 full nominal batch » damage limit
25th of October: MSE trip during high intensity extraction. Damage of QTRF pipe and magnet.
~25cm long hole in chamber
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10 cm
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3
Reconstitution of Scenario and
Comparison with Simulation
•
Analysis of logging data:
– MSE tripped due to EMC of LHC
beam 11ms before extraction
– in 11ms field changes by 5%
– number of extracted protons:
[email protected]
Reconstructed trajectory according to screen
shots.
Input for FLUKA simulation (x, x’).
max. Temp. 1350°C
stainless steel: 314L
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The energy deposition result is very
sensitive to accurate input parameters.
Difficult to reproduce the observed damage.
Meaningful comparison with
simulation:The melting point of 314L: 1400°C.
Slit due to
heat + stress, rather than
CONTROLLED
EXPERIMENT
melting?
Verena Kain, AB-CO
4
Controlled Damage Test
– Stack of high-Z metal
plates
• 4 predefined 450GeVbeam intensities (A, B,
C, D)
6 cm
• Low-tech target, no
extra instrumentation
(no temperature
sensors,…)
• Simple target geometry:
Double Confinement
Screen
– Intensities chosen to see
certain effect on plate:
melting/not melting
Motor
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5
Target Description
• Materials:
– Zn, Cu, Stainless Steel
(316L, INCONEL)
• Special order of materials:
– packages of 3 materials
– Zn, Cu, 316L (INCONEL), Zn,
Cu, 316L (INCONEL),…
• plates 6cm x 6cm x 2mm
• place-holders between
plates (0.5mm) → avoiding
molten plates sticking together
FLUKA model of target geometry
Every plate has unique longitudinal position:
→ number on each plate
→ 3D experiment: longitudinal position + damaged area on plate
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Verena Kain, AB-CO
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FLUKA
Results…
plate 11
plate 15
Heat of fusion
not taken into account…
Cu
Predicted observations…
Intensity
protons
[1012]
Melting starting in plate (nr.)
Zn
Cu
316L
INCONEL
A
1.3
-
-
-
-
B
2.6
17
-
-
-
C
5.3
9
18
-
-
D
7.9
6
12
23
-
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Verena Kain, AB-CO
Results taking heat of
fusion into account…
¼ of a nominal batch
7
Damage test in TT40
• Target was installed in
TT40 in front of TED in
air.
• Target irradiation:
8th of November.
• 4 shots: intensities A, B,
C, D
TED – TT40
Screen
Ti entrance window
• Opened box: 5th of January → no full analysis yet!
• Took pictures of some plates (will take pictures of
ALL plates)
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Results …
Observations when we opened the box…
–
–
–
–
outer confinement: no damage
first plates no damage as expected
after 6 packages more and more damage
no stress related damage (buckling,
twisting, cracks, …), mostly very clean
results…
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Verena Kain, AB-CO
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Results…
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Results…
Plate 1, Zn
Impact locations
for the different
intensities…
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A
☼
B
☼
D
☼
Verena Kain, AB-CO
C
☼
11
Results…
Plate 7, Zn
Marks of melting
for intensity D…
A
B
D
C
Prediction:
melting @ D
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Results…
Plate 8, Zn
Marks of melting
for intensity D only…
A
B
D
C
Prediction:
melting @ D
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Results…
Plate 9, Zn
Marks of melting
for intensity D & C
A
B
D
C
Prediction:
melting @ D & C
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Results…
Plate 20, Zn
Melting
for intensity
D&C&B
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A
B
Verena Kain, AB-CO
D C
15
Results…
Plate 10, Cu
Marks of heating
for intensity D
A
B
D C
Prediction:
no melting
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Verena Kain, AB-CO
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Results…
Plate 12, Cu
Marks of melting
for intensity D
A
B
D C
Prediction:
melting @ D
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Results…
Plate 17, Cu
Marks of melting
for intensity D & C
A
B
D C
Prediction:
melting @ D
(plate nr. 18:
melting @ D & C)
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Results…
Plate 36, Cu
Melting
for intensity D & C
Marks of heating
for intensity B
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A
B
Verena Kain, AB-CO
D
C
19
Results…
None of the stainless steel plates
shows holes.
•INCONEL: as predicted
•316L: predicted melting from
plate 23… not observed.
Needs further investigation…
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Conclusions
• First examinations show good agreement with simulations
– Zn, Cu, INCONEL as predicted
– 316L still unclear
• Melting as predicted by FLUKA
– transverse size of damage still to be checked
• Gives confidence that damage limits could be adequately
simulated…
•
•
•
•
geometry has large effect
sensitive to details of beam impact
full modelling on case-by-case basis is essential
no simple scaling
• Establishing generic damage limits seems to be difficult…
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Thanks to …
K. Vorderwinkler, J. Ramillon, F.
Loprete, G. Ferioli, R. Schmidt,
B.Goddard, J. Lettry, F. Decorvet, J. Vo
Duy, R. Harrison, W. Weterings, S.
Sgobba, S. Calatroni, A. Dorsival, H.
Vincke, M. Mueller, D. Forkel-Wirth, A.
Desirelli
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