magnetic horn design for cngs program

NBI 2002, 15 march Sandry Wallon (CNRS-IN2P3-LAL) 1

MAGNETIC HORN DESIGNfor CNGS PROGRAM

Workshop ‘’Neutrinos Beam and Instrumentation’’CERN, GenevaMarch 2002

Sandry WALLON

CNRS – IN2P3 – LAL

(Laboratoire de l’Accélérateur Linéaire)

Orsay, France


CONTENTS

1. Project and magnetic horn : overview

2. Inner conductor : design, manufacturing, checking

3. Electrical connection

4. Next steps of project

MAGNETIC HORN DESIGNfor CNGS PROGRAM


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


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

Fully 3D design(1) (Catia CAD)

soil

adjustable supports

electrical connection

HORN(1) : Sébastien Blivet, Alexandre Gonnin (CNRS-IN2P3-LAL)



Horn on its supports


• 7 m length (approx.)

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


inner conductor



Current input / output

• double pulse every 6 sec.• 150 kA (peak), 5000 ARMS

• toroidal B field : 1.9 T max.


drive current to inner conductor

drive current to outer conductor

How to have electrical insulation and water-tightness between red plate and yellow one?



Water-tightness with respect of electrical insulation glass ring between 2 metal seals (Sn-Ag)

Centring function with respect of electrical insulation Arclex washer



2. Inner conductor

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

2 flanges

Main part of magnetic horn


2. Inner conductorDesign and manufacturing constraints

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


Stress field & spectrum

2. Inner conductor / Design and manufacturing constraints /

Cyclic load

t

magnetic pressure vs. time

t

150 kAcurrent vs. time


Volume heat flux 1


Heat load

t

particles flux vs. time

t

150 kAcurrent vs. time

Volume heat flux 2


A B

Warning B/A > 3


Corrosive environment

example of metal consumptionA : DI waterB : DI water + radiation



Geometrical constraints

Real outer surface at 0.5 mm max. from nominal outer surface (theoretical outer surface)



Geometrical constraints

Expected deformation after welding

Weld


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?


good compromise : aluminium alloy 6082 (AlSiMg)

• Electrical resistance (6082 vs. Cu : 42 vs. 17 nΩ.m)

• Thermal conductivity (174 vs. 400 W/m.K)

• Transparency to particles• Radioactive half lifetime• Corrosion resistance• Mechanical strength (heat treated)• Machining• Welding

2. Inner conductor / Design and studies /

Material


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

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


Heat transfer study

Is it hot? What about thermal expansion?


forced convection coeff. vs. flow rate


Heat transfer study

Fortunately, some experimental results

water curtain

working zone


Enabled by thin flange

Results from heat transfer simulation (FEM / SAMCEF)(for cooling water at 20°C [inlet])


Heat transfer study

DeltaT < 10°C for 95% of conductor Thermal expansion < 1.5 mm


3 sets of wires (spiders) reduce inner conductor deformationMax. displacement without spiders: 0.8 mm (weight effect)


Static study

do it keep straight (after mounting)?


Global buckling (magnetic forces) : No (tensile force)

Global buckling (thermal expansion) : No (thin flange [flexible])

Local buckling (magnetic forces) : No (analytical calculation)


Buckling study


Mode 1 : conductor moves like a wiper

Mode 2 : local deformation of thin flange

How inner conductor can move? modal analysis (FEM / SAMCEF)

axisymmetric model


Fatigue-corrosion study

do it resist to cyclic magnetic forces, during 4 years?


Natural vibrationmode 1 : 140 Hz

Natural vibrationmode 2 : 310 Hz




Capacitor mounted onto flexible end cap



Experimental results (W. Coosemans, Cern)

Monitoring the thin flange of a similar inner conductor, under double pulse excitation


m i n : s

3 : 1 5 3 : 2 0 3 : 2 5

6 . 4 0

6 . 3 5

6 . 3 0

6 . 2 5

6 . 2 0

6 . 1 5

6 . 1 0

6 . 0 5

m i n : s

3 : 2 0 3 : 2 1 3 : 2 1 . 1 3 : 2 1 . 1 3 : 2 1 . 2 3 : 2 1 . 3 3 : 2 1 . 3 3 : 2 1 . 4 3 : 2 1 . 4 3 : 2 1 . 5

6 . 3 0 0

6 . 2 7 5

6 . 2 5 0

6 . 2 2 5

6 . 2 0 0

6 . 1 7 5

6 . 1 5 0

6 . 1 2 5

6 . 1 0 0

1st pulse 2nd pulse



Experimental results (W. Coosemans, Cern)


(1) : test conductor & experimental results

(2) : new conductor & results from calculations

Basically, fatigue analysis should focused those 2 frequencies

Axisymmetric model for dynamic analysis is good



Experimental results vs. simulation

Response under excitation (1)

Calculated response (2)

Mode 1 110 Hz 140 Hz

Mode 2 390 Hz 310 Hz


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)

Method to solve problem



(1) : Guy Le Meur (CNRS-IN2P3-LAL)

(2) : Marek Kozien (Cracow University of Technology, Poland)


vibration mode 1

vibration mode 2

Pt 2 (mode 2; 1+2)

Pt 1 (mode 1; 1+2)

Pt 3 (mode 1+2)



High stress zones

SFpt2, mode 2= 1.49


From Marek Kozien’s analysis



Safety factor


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

2. Inner conductor / Manufacturing


Inner conductor is made up of 11 parts

welding specs

geometrical specs

Constraints conditions to check that flexible part

2. Inner conductor / Manufacturing /

Dimensioning following ISO standardsInner

conductor drawing


local shot penning to improve fatigue behavior


Dimensioning following ISO standardsThick flange

drawing


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)


Machining


• Electrons beam welding• Only 2 casts of Al alloy low deformationExpected axis straightness : 0.9 mm


Welding


D2 ref. checking

Checking each parts before weldingD1 ref.

checking

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

alignment error / D1-D2

axis D1-D2


Checking


Checking procedure1. settle conductor on testing bench2. clamp flanges3. use 3 V supports modelling spiders4. check outer surface axis / D1-D2

(thank to laser tracker or interferometer)5. extra task : put probe inside

conductor and record it position / D1-D2

Checking the inner conductor


Checking


Checking the inner conductor (after mounting inside outer conductor)

Adjustment procedure1. put self-centring probe inside

inner conductor (at spider position)2. check probe position / D1-D23. adjust wires tensile force until to

find correct alignment4. repeat previous tasks for 2 others

spiders


Checking


Quick remove electrical connection

Strip lines



Strip lines



Remove and vertical displacement enabled

Lateral displacement enabled



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)

magnetic horn design for cngs program

Documents

sandry wallon cnrsin2p3

overview horn

in2p3cnrs french contribution

alexandre gonnin cnrsin2p3

inner conductor design

horn axis height

magnetic hornnbi

cngs programfully