Energy Deposition in the New IRs

31/07/08 Review new IRs: Energy Deposition

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Energy Deposition in the New IRs

Francesco Cerutti, Marco Mauri, Alessio Mereghetti, Ezio Todesco, Elena Wildner

AB/ATB and AT/MCS

With contributions from: Frank Borgnolutti, Jens Bruer, Alfredo Ferrari, Christine Hoa, Vasilis Vlachoudis and others


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Outline

Triplet Upgrade Parametric approach

The Art of Binning Results

Peak energy deposition Influence of interconnections Total loads Particle Fluences

Conclusions (Part 1)

110 mm aperture case: power deposition and dose in TAS Triplet and corrector package D1 TAN D2

Part One:General aspects triplet

Part Two:A Shielding Option: thick Liner in Q1

Part Three:Particle fluences in electronics locations

UJ56 Conclusions (Part 2 and 3)


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The Triplet, Parametric Approach

Aperture(mm)

Gradient(T/m)

L(Q1,Q3)(m)

L(Q2a,b)(m)

Total length (m)

90 156 8.69 7.46 36.2

115 125 9.98 8.42 40.7

130 112 10.81 9.04 43.6

140 104 11.41 9.49 45.7

Total Length

Q1 Q2a Q2b Q3

“Symmetric”

IP1

TAS

No Corrector in tripletHalf Crossing angle 225 rad, vertical TAS aperture 55 mm

Max (cable length)

Actual gradient: 215 T/m

TAS at 19 m, Q1 at 23 m (like actual)


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The Magnet Cross Section


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Parameter Space for Parametric Study

Q1 Positioned at 23 m from the IP

Gaps between magnets 1.3 m Impacts the peak in energy deposition we get on the

following magnet

Symmetric triplet All magnets have the same aperture All magnets have the same gradient Q1 and Q3 have the same length Q2 is split in two parts of equal length

Magnets have “costheta” design Two layers

We get one family of solutions:(Aperture, gradient, length linked)

Different from latest “New Triplet” layout, small effect


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Beam pipe/Beam Screen Dimensioning

For the Cold Bore Tube (Beam Pipe): Relation thickness (t) and diameter (D), valid for stainless steel (pressure vessel

code, 25 bar ): t = 0.0272D For the Beam Screen:

Calculations gave the same minimum thickness for all cases (1 mm) we have used 2 mm (similar as for the previous simulations of the upgraded triplet)

Courtesy:G. Kirby, C. Rathjen

Cold Bore Tube and Beam Screen act as shielding. For parametric study: get the minimum necessary thicknesses for the different cases chosen

Aperture [mm]

BP thickness [mm]

BS thickness [mm]

90 2.4 2.0

115 3.0 2.0

130 3.4 2.0

140 3.7 2.0


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The Scoring for the Triplet Peak power in cable (quench)

We make the binning for the scoring so that it corresponds to a minimum volume of equilibrium for the heat transport (cable transverse dimensions, with a length corresponding to the twist pitch of the cable)

Total power deposited in the magnets (cryogenics) The outer diameter of the magnets (cold mass) is the same

The power deposited per meter of magnet Azimuthal and radial integration of the power in the longitudinal bins

Particle fluence/dose

Transverse area of cable (A)

Scoring volume: A*L

Length (L) 10 cm (twist pitch)


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The Bins and the Results The indicative value 4.3 mW/cm3 (P. Limon, private

communication) is valid for Rutherford cable in LHC main magnets, including contingency of a factor of 3!

Cable bin

For other cables and magnet designs, this value has to be revised.

For dose calculations (for example cable, insulation and spacers) the bins have to be chosen to get the dose that in reality would damage the bulk material in the object (mechanical and electrical properties)

Insulation


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Peak Power Deposition I

0

5

10

15

20

25

20 25 30 35 40 45 50 55 60 65 70Distance to IP (m)

Peak

ene

rgy

(mW

/cm

3) 90 mm

110 mm

130 mm

140 mm

Pow

er

100% increase 140 -> 90115


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Peak Power Deposition IIRescaling longitudinally shows that the pattern is similar! Large effect for Q1 & Q2a

0.0

5.0

10.0

15.0

20.0

Peak

pow

er [

mW

/cm

3 ]

90 mm

115 mm

130 mm

140 mm

Q1 Q2a Q2b Q3


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Between the Magnets (1)

0.0

5.0

10.0

15.0

20.0

Pea

k p

ow

er [

mW

/cm

3 ]

90 mm

115 mm

130 mm

140 mm

Q1 Q2a Q2b Q3

The gaps between magnets cause a accumulation of non intercepted particles: peaks at the entrance of magnets (particles from IP collisions)

Smaller gaps or shielding of interconnection region interesting

Magnet1 Magnet2

IP

The more smooth pattern is due to the magnetic field (spectrometric effect)

Over all the magnet:Cable 1(red) twice the peaks of cable 2 (blue) => for correctors, for example, use inserts in aperture


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Between the Magnets (2)

0.0

5.0

10.0

15.0

20.0

Pea

k p

ow

er [

mW

/cm

3 ]

90 mm

115 mm

130 mm

140 mm

Q1 Q2a Q2b Q3


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0

5

10

15

20

25

80 90 100 110 120 130 140 150Aperture (mm)

Pea

k en

ergy

dep

ositi

on

(mW

/cm

3)

Q1

Q2a

Q2b

Q3

Peak Power Deposition IIILarge effect in Q1 & Q2a small in Q2b and Q3

Pow

er


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Total Heat Load

0

50

100

150

200

80 90 100 110 120 130 140 150Aperture (mm)

Hea

t loa

d/m

agne

t (W

)

0

125

250

375

500

Tot

al h

eat l

oad

(W)

Q1 Q2aQ2b Q3Beam screen Total

Choice of beam screen thickness: redistribution of heat loads


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Horizontal/Vertical Crossing

Can we use our results to scale without re-computing?


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Particle type Distribution, all 4 Magnets Fluence scored in the first cable over each magnet.

Interactions from material inside aperture (Beam Screen and Beam pipe)

Smallest (90mm) and largest (140 mm) aperture will be shown

Particle Fraction [%]

90 mm 140 mm

photons 87.0 86.0

neutrons 6.0 7.8

electrons 3.5 3.3

positrons 2.5 2.3

pions 0.4 0.4

protons 0.15 0.15


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Neutron Fluence 90mm/140mm

Calculated for 300fb-1 integrated Luminosity


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Neutron Spectra 90mm/140mm

> 1 MeV neutrons most critical for damage


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The Triplet Layout as of 30/07/08

110 mm aperture

Parametric study


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Summary, General Part (1)

The deposited peak power (quench) decreases with the triplet length. Shorter triplets (smaller apertures) need more shielding (takes more aperture).

The decrease with length is largest in Q1 and Q2, where we also have the highest peaks.

The total heat load on the triplet is decreasing (up to 140 mm at least) with length: between 90 and 130 mm aperture we have 16 % less, including the beam screen.

Pattern of energy deposition is similar for all lengths however not identical for the two insertions (1 and 5).


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Summary, General Part (2)

The distribution of particle types in Q1 is very similar for 90 and 140 mm.

Spectra similar, ~1.5 time higher fluence for 90 mm than for 140 mm aperture

Great care has to be taken for binning in cables for power deposition (quench) and for longevity of objects (dose calculations), studies ongoing


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ENERGY DEPOSITIONIN THE TAS-D2 REGION

FOR A TRIPLET SHIELDING OPTION(THICK LINER IN Q1)

power values referred to a 2.5 1034 cm-2 s-1 luminosity

time integrated values referred to a 100 fb-1 total luminosity


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80 MGy/100fb-1

r=1cm x =2o x z=2cm scoring grid

45mm TAS aperture -> 110mm triplet coil aperture

TAS


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TAS


peak power 114 mW/cm3

total power 325 W



total power 385 W

34mm TAS aperture


total power 184 W

present LHC (L=L0) N.V. Mokhov et al.,

LHC Project Report 633


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TRIPLET AND CORRECTOR PACKAGE

110mm coil aperture

Q1 Q2a

Q2b

Q310mm thick additional

liner

75mm residual aperture


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horizontal crossing

8.05 m from the IP face

0.25 m from the IP face


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vertical crossing

1.25 m from the IP face 9.55 m from the IP face


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r=2.5mm x =2o x z=10cm scoring grid

horizontal crossing


mW/cm3


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vertical crossing

mW/cm3


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BS includedBS only

BS included

BS only 101 W

+12.9 W in the interconnections

(where BS is supposed to

continue)

in the rest

402 W @ 1.9 K

BS includedBS only

BS included

BS only 98 W

+11.4 W in the interconnections

(where BS is supposed to

continue)in the rest

382 W @ 1.9 K


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D1

180mm coil aperture

in the warm bore tube

0.9 2.5 W

0.8 1.4 W


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(present) TAN187 MGy/100fb-1

x=2.5mm x y=2.5mm x z=5cm scoring grid

495 15 6

442 32 3

externaltube

inner Cuabsorber

internaltube


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(present) TAN

horizontal cuts at beam level


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no TCTV, TCTH

no TCLP

(present) D2

in the coils (80 mm aperture)

in the coils (80 mm aperture)


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OVERVIEW

mW/cm3

vertical plane


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mW/cm3

horizontal plane

OVERVIEW


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130mm coil aperture

8/13mm thick

additional liner

Q1 Q2a

Q2b

Q3DC

vertical crossing


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Concrete shielding blocks

IP5 TAS

Triplet D1

TAN

UJ57

UJ56

courtesy of M. Fuerstner (SC/RP) with contribution of C. Hoa (AT/MCS)

FLUKA model of IR5 (present LHC)

ESTIMATION OF PARTICLE FLUENCESIN ELECTRONICS LOCATIONS


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In UJ56, after a 2m concrete shielding, the high energy hadron fluence at beam level ranges from 1.3 109 up to 1.3 1010 cm-2/100fb-1

>20 MeV HADRON FLUENCE

vertically averaged over the -60cm < y< 60cm interval (beam axis at y=0)

cm-2/100fb-1

relevant to single event errors


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UPSTAIRS

vertically averaged over the 220cm < y< 420cm interval (beam axis at y=0)

Upstairs (sensitive electronics) high energy hadron fluence is in the range 1.2 - 3.6 109 cm-2/100fb-1

T. Wijnands

cm-2/100fb-1


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CONCLUSIONS

•The peak power deposition in the Phase 1 Upgrade triplet SC coils (110-130mm aperture) is expected to be decreased down to the design limit by a 10mm thick stainless steel liner all along the Q1 beam screen, if the interconnection lengths are not increased (unless the liner is extended along the interconnections too). The Q1 liner effectiveness is limited to the first half of the Q2a.Peaks lie on the crossing plane and change their position (up->down, outer->inner) in the Q2a.

•The larger the crossing angle, the higher the peak power density. A magnetic TAS can play a role closing the crossing angle.

•~400 W the triplet toal load + ~100 W in the beam screen (about one half in the Q1 liner).

•Peak dose in the coils to be evaluated over a volume relevant to possible damage to the insulator.

•A corrector package on the non-IP side of a FDDF triplet is more significantly impacted for vertical crossing (peak at -90o in the transverse plane).

•A large aperture SC D1 is not expected to quench.

•TAS and TAN thermomechanical stress to be evaluated from the available power deposition maps.

•Expected high energy hadron fluence in UJ56 (triplet electronics) is worrying for the present LHC at nominal luminosity (with ideal shielding without holes).

Documents

Energy Deposition in the New IRs