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Federico Carra – EN-MME

Expected damage on TCTA collimator during HRMT09-LCOL experiment in

HiRadMat facility

Collimation Working Group30.7.2012

F. Carra

A. Bertarelli, A. Dallocchio, L. Lari, N. Mariani

30.07.2012

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Federico Carra – EN-MME

Scope of the study performed

FEA 3D model

Damage classification

Accident simulation results Test 1 Test 2 Test 3

Conclusions

Outlook

30.07.2012

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Federico Carra – EN-MME

Three different tests on the TCTA will be performed in HiRadMat facility :

Test 1: to reproduce LHC asynchronous dump (single bunch setup, 1 bunch at 7 TeV energy impacting tungsten jaw)

Test 2: to assess the threshold damage on the collimator, in terms of beam energy and intensity (damage not imposing collimator replacement)

Test 3: to reproduce a destructive scenario and benchmark simulations (“Limits for Beam-Induced Damage: Reckless or too Cautious?“, A. Bertarelli et al. , Chamonix 2011)

Scope of the study presented

30.07.2012

How many SPS bunches (and at which intensity) are necessary to reproduce the 3 different scenarios, identified for the LHC?

1) FLUKA simulations – L. Lari: Equivalence of the energy peak

+2) Autodyn FEA – F. Carra: Equivalence of the damage produced on the jaw

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Federico Carra – EN-MME

Equivalent damage: LHC vs. SPS

30.07.2012

Preliminary analyses – FLUKA (L. Lari) Equivalence of the energy peak Equivalence of the maximum temperature

(considering adiabatic conditions, constant specific heat)

Input for successive Autodyn FEA

Autodyn FEA Equivalence of the damage produced on the jaw Shockwave is propagating during the time

between two successive bunches → pressure waves are not linearly superposing!

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Federico Carra – EN-MME

Material EOS Strength model Failure model

Tungsten Tabular (SESAME) Johnson-Cook Plastic strain/ Hydro (Pmin)

Copper OFE Polynomial Johnson-Cook Johnson-Cook

Stainless steel AISI 316 Shock Johnson-Cook Plastic strain

Water Shock - Hydro (Pmin)

Jaw block (x5)(W(95%)-Ni(3.5%)-Cu(1.5%)partly modelled as pure W)

Block Support(OFE-Copper)

Water

+/-10 mm through 5th

axis

Cooling Pipes(Cu(89%)-Ni(10%)-Fe(1%) modeled

as OFE-Cu)

Screw (x40)(Stainless Steel)

Stiffener(Glidcop

modeled as OFE-Cu)

FEA: 3D Model

30.07.2012

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Federico Carra – EN-MME

Three different damage scenarios, with increasing severity, were identified:

• Level 1 (Collimator need not be replaced). Limited jaw damage, an intact spare surface can be found relying on the 5th axis movement (+/- 10 mm). (Provided this movement is possible). Permanent jaw deformation is limited.

• Level 2 (Collimator must be replaced). Damage to collimator jaw is incompatible with 5th axis travel (H > 8 mm). Other components may also be damaged (e.g. Screws).

• Level 3 (Long down time of the LHC). Catastrophic damage to collimator leading to water leakage into beam vacuum (pipe crushing, tank water circuit drilling ...)

Damage classification

30.07.2012

Jaw Damaged Area (red)Level 1 : H ≤ 8 mmLevel 2: H > 8 mm

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Federico Carra – EN-MME

Test 1: beam parameters

30.07.2012

Preliminary estimation with FLUKA: 20 SPS bunches to have an equivalent energy peak

Energy peak in the axial coordinate, courtesy of L. Lari

LHC scenario

7 TeV 1 bunch 1,5E11 p/b σ = 0.5x0.5 mm2

Impact parameter (test): x = 2 mm y = 10 mm

SPS (HiRadMat) scenario

440 GeV X bunches 1,5E11 p/b σ = 0.5x0.5 mm2

Impact parameter: x = 2 mm y = 10 mm

Bunch spacing: 50 ns

???

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Federico Carra – EN-MME

Test 1: expected damage provoked by 1 LHC bunch, 7 TeV

30.07.2012

Maximum pl. strain on pipes ~ 2.1%

Tungsten damaged zone ~ 9 mm + plastic deformation of copper beam

1 bunch, 7 TeV: cooling pipes

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Federico Carra – EN-MME

Test 1: equivalent SPS bunches

30.07.2012

20 SPS bunches are necessary to provoke the same damage which is expected for 1 LHC bunch on the tungsten jaw

For an LHC equivalent damage on the cooling pipes, 30 SPS bunches are necessary! Scratch on the W jaw vs. Damage on cooling pipes: which one to use as a reference?

Pulse characteristicsHeight of the damaged

W surface [mm]

1 bunch, 7 TeV 916 bunches, 440 GeV 7.518 bunches, 440 GeV 8.420 bunches, 440 GeV 9.224 bunches, 440 GeV 10.530 bunches, 440 GeV 12.2

Pulse characteristicsMax. plastic deformation

on cooling pipes

1 bunch, 7 TeV 2.10%16 bunches, 440 GeV 1.07%18 bunches, 440 GeV 1.26%20 bunches, 440 GeV 1.40%24 bunches, 440 GeV 1.70%30 bunches, 440 GeV 2.08%

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Federico Carra – EN-MME

Test 2: beam parameters

30.07.2012

SPS (HiRadMat) scenario

440 GeV X bunches → X = max. n. SPS bunches for which 80% of W melting temperature is

not exceeded (S. Redaelli) 1,5E11 p/b σ = 0.5x0.5 mm2

Impact parameter: x = 2 mm y = 10 mm

Bunch spacing: 50 ns

Inermet microstructure

Metallic matrixInermet: Cu/Ni

Densimet: Fe/Ni

W grains

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Federico Carra – EN-MME

Test 2: results

30.07.2012

6 bunches to stay below 80% of W melting temperature (unavoidable melting of Cu/Ni phase) No plastic strain of the tungsten active surface Scenario equivalent to 1 LHC bunch, 7 TeV, 4.5e10 p

6 bunches, 440 GeV – Temperature

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Federico Carra – EN-MME

Test 3: beam parameters

30.07.2012

Preliminary estimation with FLUKA: 50 SPS bunches to have an equivalent energy peak

LHC scenario

5 TeV 4 bunches 1,3E11 p/b σ = 0.5x0.5 mm2

Impact parameter (test): x = 2 mm y = 10 mm

Bunch spacing: 25 ns

SPS (HiRadMat) scenario

440 GeV X bunches 1,5E11 p/b σ = 0.5x0.5 mm2

Impact parameter: x = 2 mm y = 10 mm

Bunch spacing: 50 ns

???

Energy peak in the axial coordinate, courtesy of L. Lari

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Federico Carra – EN-MME

Test 3: expected damage provoked by 4 LHC bunches, 5 TeV

30.07.2012

Coarser mesh to reduce calculation times Change of density between each of the last

bunches is introducing an error > 10%

Calculation will be refined in the next weeks

4 bunches, 5 TeV: Vertical Displacement

Considerable vertical deformation of the copper beam

Extensive damage on the tungsten jaw

Plastic strain on cooling pipes ~ 10%!

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Federico Carra – EN-MME

Test 3: equivalent SPS bunches

30.07.2012

~ 65 SPS bunches are necessary to provoke the same damage which is expected for 4 LHC bunch (5 TeV) on the tungsten jaw

In the HiRadMat facility, an equivalent damage provoked on the cooling pipes by 4 LHC bunches (5 TeV) is not reproducible! (decreasing beam σ would have very limited effect )

N. bunchesHeight of the damaged

W surface [mm]

4 bunches, 5 TeV 19.240 bunches, 440 GeV 12.850 bunches, 440 GeV 15.460 bunches, 440 GeV 1880 bunches, 440 GeV 23

N. bunchesMax. plastic deformation

on cooling pipes

4 bunches, 5 TeV 9.63%40 bunches, 440 GeV 2.67%50 bunches, 440 GeV 3.33%60 bunches, 440 GeV 3.77%80 bunches, 440 GeV 4.35%

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Federico Carra – EN-MME

Conclusions

30.07.2012

Simulations were performed with FLUKA and Autodyn in order to evaluate the correct beam parameters for HRMT09 experience.

Test 1: 20 bunches proposed for an equivalent damage on W jaw; 30 bunches to have the same pipes plastic deformation. What part of the jaw to be taken as a reference?

Test 2: 6 bunches are proposed: Tmax < 0.8Tmelt(W), no plastic deformation of active jaw surface. Total beam intensity: 9e11 protons.

Test 3: 65 bunches are proposed: damage on W jaw is equivalent to the destructive case that should be reproduced. With current HiRadMat parameters, high plastic strain levels on cooling pipes cannot be reached.

TEST 1

N. bunches Pulse IntensityDamage extension

on W jaw [mm]Pl. Strain on

cooling pipes

1 bunches, 7 TeV 1.5e11 p 9 2.10%20 bunches, 440 GeV 3e12 p 9.2 1.40% 30 bunches, 440 GeV 4.5e12 p 10.5 2.08%

TEST 3

N. bunches Pulse IntensityDamage extension on

the W jaw [mm]Pl. Strain on

cooling pipes

4 bunches, 5 TeV 5.2e11 p 19.2 9.63%65 bunches, 440 GeV 9.75e12 p ~ 19 ~ 4%