MAGNETIC HORN DESIGN for CNGS PROGRAM

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MAGNETIC HORN DESIGNfor CNGS PROGRAM
Workshop Neutrinos Beam and Instrumentation CE
RN, Geneva March 2002
Sandry WALLON CNRS IN2P3 LAL (Laboratoire de
lAccélérateur Linéaire) Orsay, France
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CONTENTS
MAGNETIC HORN DESIGNfor CNGS PROGRAM

1. Project and magnetic horn overview
2. Inner conductor design, manufacturing, checking
3. Electrical connection
4. Next steps of project

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1. Project and magnetic horn overview

• ? Collaboration between Cern and IN2P3-CNRS
• (French contribution to CNGS Program)
• ? Design manufacturing of magnetic lenses
• (2 horns, 1 reflector) and some others
  facilities
• ? Provided by Cern inner conductors profiles
  and lot of advises
• IN2P3 National institute for particles and
  nuclear physics (CNRS dep't)
• LAL Laboratory specialized in particles physic
  research,
• detector accelerator design and
  manufacturing

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1. Project and magnetic horn overview Horn
designed for CNGS program
Fully 3D design(1) (Catia CAD)
HORN
(1) Sébastien Blivet, Alexandre Gonnin
(CNRS-IN2P3-LAL)
soil
adjustable supports
electrical connection
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1. Project and magnetic horn overview Horn
designed for CNGS program
Horn on its supports
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1. Project and magnetic horn overview Horn
designed for CNGS program

• 7 m length (approx.)
• horn axis height 1.6 m
• 1 ton (approx.)

inner conductor
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1. Project and magnetic horn overview Horn
designed for CNGS program

• double pulse every 6 sec.
• 150 kA (peak), 5000 ARMS
• toroidal B field 1.9 T max.

Current input / output
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1. Project and magnetic horn overview Horn
designed for CNGS program
drive current to inner conductor drive current
to outer conductor
How to have electrical insulation and
water-tightness between red plate and yellow one?
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1. Project and magnetic horn overview Horn
designed for CNGS program
Centring function with respect of electrical
insulation ? Arclex washer
Water-tightness with respect of electrical
insulation ? glass ring between 2 metal seals
(Sn-Ag)
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2. Inner conductor
? Main part of magnetic horn

• length 6.65 m
• min. thickness 1.8 mm
• diameter 30.8 to 136 mm
• made up of 9 conical parts and 2 flanges

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2. Inner conductorDesign and manufacturing
constraints

• Cyclic load
• Heat load
• Corrosive environment
• Geometrical constraints

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2. Inner conductor / Design and manufacturing
constraints /Cyclic load
Stress field spectrum
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2. Inner conductor / Design and manufacturing
constraints /Heat load
Volume heat flux 1
Volume heat flux 2
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2. Inner conductor / Design and manufacturing
constraints /Corrosive environment
example of metal consumption A DI water B DI
water radiation
A
B
Warning ? B/A gt 3
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2. Inner conductor / Design and manufacturing
constraints /Geometrical constraints
? Real outer surface at 0.5 mm max. from nominal
outer surface (theoretical outer surface)
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2. Inner conductor / Design and manufacturing
constraints /Geometrical constraints
Weld
Expected deformation after welding
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2. Inner conductorDesign and studies

1. Material more important than usually!
2. Heat transfer study is it hot?
3. Static study do it keep straight (after
   mounting)?
4. Buckling study do it collapse?
5. Fatigue-corrosion study do it resist to cyclic
   magnetic forces, during 4 years?

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2. Inner conductor / Design and studies /Material

• ? good compromise aluminium alloy 6082 (AlSiMg)
• Electrical resistance (6082 vs. Cu 42 vs. 17
  n?.m)
• Thermal conductivity (174 vs. 400 W/m.K)
• Transparency to particles
• Radioactive half lifetime
• Corrosion resistance
• Mechanical strength (heat treated)
• Machining
• Welding

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2. Inner conductor / Design and studies /Heat
transfer study
? Is it hot? ? What about thermal expansion?

• Heat load
• 13 kW (electrical resistance)
• 5 kW (radiation)

Sprinklers works at low pressure ? gentle
water curtain expected It looks like heat
transfer for heat exchanger working with liquid
film falling onto horizontal tube
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2. Inner conductor / Design and studies /Heat
transfer study
Fortunately, some experimental results
forced convection coeff. vs. flow rate
water curtain
working zone
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2. Inner conductor / Design and studies /Heat
transfer study
Results from heat transfer simulation (FEM /
SAMCEF) (for cooling water at 20C inlet)
? DeltaT lt 10C for 95 of conductor ? Thermal
expansion lt 1.5 mm
? Enabled by thin flange
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2. Inner conductor / Design and studies /Static
study
? do it keep straight (after mounting)?
? 3 sets of wires (spiders) reduce inner
conductor deformation Max. displacement without
spiders 0.8 mm (weight effect)
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2. Inner conductor / Design and studies
/Buckling study
? Global buckling (magnetic forces) No (tensile
force) ? Global buckling (thermal expansion) No
(thin flange flexible) ? Local buckling
(magnetic forces) No (analytical calculation)
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2. Inner conductor / Design and studies
/Fatigue-corrosion study
? do it resist to cyclic magnetic forces, during
4 years?
How inner conductor can move? ? modal analysis
(FEM / SAMCEF) ? axisymmetric model
Mode 1 conductor moves like a wiper
Mode 2 local deformation of thin flange
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2. Inner conductor / Design and studies
/Fatigue-corrosion study
Natural vibration mode 1 140 Hz
Natural vibration mode 2 310 Hz
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2. Inner conductor / Design and studies
/Fatigue-corrosion study
Experimental results (W. Coosemans, Cern)
? Monitoring the thin flange of a similar inner
conductor, under double pulse excitation
Capacitor mounted onto flexible end cap
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2. Inner conductor / Design and studies
/Fatigue-corrosion study
Experimental results (W. Coosemans, Cern)
1st pulse
2nd pulse
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2. Inner conductor / Design and studies
/Fatigue-corrosion study
Experimental results vs. simulation
Response under excitation (1) Calculated response (2)
Mode 1 110 Hz 140 Hz
Mode 2 390 Hz 310 Hz
? Basically, fatigue analysis should focused
those 2 frequencies ? Axisymmetric model for
dynamic analysis is good
(1) test conductor experimental results (2)
new conductor results from calculations
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2. Inner conductor / Design and studies
/Fatigue-corrosion study
Method to solve problem

1. Calculation of magnetic pressure field
   ? full analytical calculation is
   OK (1)
2. Making FEM model (2)
3. Looking for high stress zones (step by step) (2)
4. Calculation of stress amplitude and mean stress
   for a multiaxial stress (2) (see Sines formula)
5. Calculation of the Equivalent Completely Reverse
   Uniaxial Stress (2) (see Goodman formula)
6. Calculation of theoretical safety factor (2)

(1) Guy Le Meur (CNRS-IN2P3-LAL) (2) Marek
Kozien (Cracow University of Technology, Poland)
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2. Inner conductor / Design and studies
/Fatigue-corrosion study
High stress zones
vibration mode 1
Pt 1 (mode 1 12)
vibration mode 2
Pt 3 (mode 12)
Pt 2 (mode 2 12)
SFpt2, mode 2 1.49
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2. Inner conductor / Design and studies
/Fatigue-corrosion study
Safety factor
From Marek Koziens analysis
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2. Inner conductor / Manufacturing

• Dimensioning following ISO standards
• Machining
• Welding
• Geometric checking

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2. Inner conductor / Manufacturing /Dimensioning
following ISO standards
Inner conductor drawing
Inner conductor is made up of 11 parts
geometrical specs
welding specs
Constraints conditions to check that flexible part
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2. Inner conductor / Manufacturing /Dimensioning
following ISO standards
Thick flange drawing
local shot penning to improve fatigue behavior
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2. Inner conductor / Manufacturing /Machining
? All part are machined from - bars for
conical parts - cylinders for flanges
? Only two kind of alloy compositions used
(1st cast for bars, 2nd cast for cylinders)
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2. Inner conductor / Manufacturing /Welding

• Electrons beam welding
• Only 2 casts of Al alloy
• ? low deformation
• Expected axis straightness 0.9 mm

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2. Inner conductor / Manufacturing /Checking
? Checking each parts before welding
D1 ref. checking
D2 ref. checking
alignment error / D1-D2
axis D1-D2

• Mid. section checking
• shape
• alignment / D1-D2

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2. Inner conductor / Manufacturing /Checking
? Checking the inner conductor

• Checking procedure
• settle conductor on testing bench
• clamp flanges
• use 3 V supports modelling spiders
• check outer surface axis / D1-D2 (thank to
  laser tracker or interferometer)
• extra task put probe inside conductor and
  record it position / D1-D2

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2. Inner conductor / Manufacturing /Checking
? Checking the inner conductor (after
mounting inside outer conductor)

• Adjustment procedure
• put self-centring probe inside inner conductor
  (at spider position)
• check probe position / D1-D2
• adjust wires tensile force until to find correct
  alignment
• repeat previous tasks for 2 others spiders

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3. Electrical connection
Quick remove electrical connection
Strip lines
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3. Electrical connection
Strip lines
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3. Electrical connection
Strip lines
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3. Electrical connection
Lateral displacement enabled
Remove and vertical displacement enabled
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4. Next steps of project

1. Finish inner conductors manufacturing (Qty 2)
   ? final checking within June 2001
   
   ? testing at Cern of one of two
   conductor (1 million double pulses)
2. Manufacture others parts in progress
3. Finish design of others facilities soon
4. Start production (mounting)
   ? shipping to Cern
   within 2003 2 horns 1 reflector
5. Electrical checking at Cern (2003-2004)