Next European Dipole (NED) Status Report

Arnaud DevredCEA/DSM/DAPNIA/SACM & CERN/AT/MAS

on behalf of the NED Collaboration

CARE Steering Committee Meeting5 September 2005

Some very good

news…

• The DOE has agreed to fund the US-LHC Accelerator

Research Program (LARP) with a budget of 11 M$ for FY06

(approved by Congress but not yet signed by the President.

• This budget level should be kept constant for a few years

(until 2009?)

• For FY06, it will be divided up into 5 M$ for magnets, 4 M$ for

accelerator-related R&D and 2 M$ for management (shared

between FNAL, BNL, LBNL and SLAC).

• The goal of the magnet part of LARP is to build by 2009 one

or two 4-m-long, 90-mm-aperture, 200 T/m quadrupole magnet

prototypes.

…for our American

colleagues!

Some pretty sad

news…

• The EUROMAG NEST Adventure proposal has been turned

down by the EU on the ground that it was not “adventurous”

enough…

• Hence, we are back to square one regarding the funding of

the model magnet manufacturing and test…

…for the NED

collaboration!

NED Programme

• The NED Programme is articulated around four Work

Packages and one Working Group

1 Management & Communication (M&C),

2 Thermal Studies and Quench Protection (TSQP),

3 Conductor Development (CD),

4 Insulation Development and Implementation (IDI),

5 Magnet Design and Optimization (MDO) Working

Group.

• It is carried out by a collaboration made up of 8 institutes:

CCLRC/RAL, CEA, CIEMAT, CERN, INFN/Genova and INFN/Milano,

Twente University (TEU) and Wroclaw University of Technology

(WUT).

M&C Work Package

• We have held three Steering Committee (SC) meetings since

the beginning of the year– 20 January at CERN– 14 April at CERN– 7 July at WUT

• Next SC meeting will be held at CERN during the CARE

general meeting; next ESAC meeting will be held at CERN

before or after the planned HHH/WAMDO (April 2005).

• Second quarterly report will be completed by the end of the

week.

• All relevant documents are stored into EDMS and posted on

the NED website

http://lt.tnw.utwente.nl/project.php?projectid=9

TSQP Work Package

• The TSQ Work Package includes two main Tasks

– development and operation of a test facility to

measure heat transfer to helium through conductor

insulation

(CEA and WUT; Task Leader: B. Baudouy, CEA),

– quench protection computation

(INFN-Mi; Task Leader: G. Volpini).

Heat Transfer Measurement (1/3)

• The first part of the Task was

to design and build a new double

bath cryostat.

• CEA wrote detailed

specifications that were handed

out to WUT in June 2004.

• WUT performed a call for

tender in the Summer of 2004

and selected Kryosystem in

Poland to manufacture the

cryostat.

Radiation shields

Vacuum container

Heat exchanger piping

Heat exchanger

Expansion valve

Pumping

He IIp

He IIs

LHeGHe

Insert

Cryogenic vessel

He I

Experimental volume

Schematic of NED cryostat(courtesy F. Michel, B. Baudouy and B. Hervieu, CEA)

Heat Transfer Measurement (2/3)

• A first reception test of the cryostat was carried out on

Kryostem’s premises the 3rd week of April 2005, which

revealed a few problems.

• WUT reacted very promptly and worked in close collaboration

with CEA to correct these problems.

• A second reception test was carried out the 2nd week of July

2005 (including thermal and leak tests in liquid helium at 4.2

K), which was deemed successful.

• The cryostat will be delivered to CEA/Saclay on 19

September, for final implementation and commissioning.

• The 6-month delay with respect to the initial schedule is not

expected to any deleterious impacts on the overall NED

Programme.

Heat Transfer Measurement (3/3)

Lambda plate

He II heat exchanger

Cryostat with thermal

shields

Inner view of cryostat with Instrumentation (Courtesy M. Chorowski, WUT)

Quench Computation (1/3)

• INFN-Mi has undertaken a detailed analysis of the thermal

and electrical behaviors of NED-type accelerator magnets

during a quench.

• The computation was started considering the “conservative”,

88-mm-aperture, cos, layer design developed by D. Leroy.

• It studied the influence of

– magnet length (1, 5 and 10 m),

– operating current (15, 22 and 29 kA),

– external dump resistance (15, 25 and 35 m),

– quench detection delay (30, 40 and 50 ms),

– quench protection heater length.

• It also compared the results obtained by two different codes:

QLASA at INFN-Mi and QUABER at CERN.

Quench Computation (2/3)

• The results show that, for the entire parameter space, the

magnet is quite safe to operate, thereby justifying the choice of

wire and cable parameters made early on.

0

50

100

150

200

250

300

Rd

=15

mO

hm

Rd

=25

mO

hm

Rd

=35

mO

hm

Rd

=45

mO

hm

De

lay=

30

ms

De

lay=

40

ms

De

lay=

50

ms

I=15

kA

I=22

kA

I=29

kA

Ho

t sp

ot

tem

pe

ratu

re (

K)

QLASA

QUABER

0

200

400

600

800

1000

1200

1400

Rd=

15 m

Ohm

Rd=

25 m

Ohm

Rd=

35 m

Ohm

Rd=

45 m

Ohm

Del

ay=3

0 m

s

Del

ay=4

0 m

s

Del

ay=5

0 m

s

I=15

kA

I=22

kA

I=29

kA

Tota

l vol

tage

(V)

QLASA

QUABER

Quench simulation results on 10-m-long, 88-mm-aperture, cos, layer design

(Courtesy M. Sorbi INFN-Mi)

Quench Computation (3/3)

• Similar computations have now been started on the more

“innovative”, 160-mm-aperture, slot design also proposed by D.

Leroy.

• The quench computation task is near completion.

88-mm-aperture, layer design

(Courtesy D. Leroy, CERN)

160-mm-aperture, slot design

(Courtesy D. Leroy, CERN)

CD Work Package

• The CD Work Package includes two main Tasks

– conductor development

(under CERN supervision; L. Oberli has now taken over

D. Leroy as the official Task Leader),

– conductor characterization

(CEA, INFN-Ge, INFN-Mi, and TEU; Task Leader: A. den

Ouden, TEU).

• It is the core of the programme and absorbs about 70% of

the EU allocated funding.

Conductor Development (1/2)

• As a conclusion of preliminary design studies carried out in

2003 and 2004 under the supervision of D. Leroy, the following

specifications were derived for NED Nb3Sn strands

– diameter 1.250 mm,

– eff. filament diameter < 50 m,

– Cu-to-non-Cu ratio 1.25 ± 0.10,

– filament twist pitch 30 mm,

– non-Cu JC 1500 A/mm2 @4.2 K & 15

T,

– minimum critical current 1636 A at 12 T,

818 A at 15 T,

– N-value > 30 at 4.2 K and 15 T,

– RRR (after heat treatment)> 200.

(It is also requested that the billet weight be higher than

50 kg.)

Conductor Development (2/2)

• Based on these specifications, a call for tender was issued by

CERN in June 2004 and two contracts were awarded in

November to 2004 to Alstom/MSA in France (“Enhanced

Internal Tin” process) and SMI in the Netherlands (“Powder in

Tube” Process).

• After discussion with CERN, the two companies agreed to

work out their development program into two successive RD

Steps (referred to as STEP 1 and STEP 2) followed by final cable

production.

• A tentative schedule was established as follows

– STEP 1: Summer 2005,

– STEP 2: Summer 2006,

– Final production: December 2006.

Conductor Characterization (1/2)

• The NED-type conductor characterization represents a real

challenge, given the unprecedented performances that are

expected (e.g., a critical current of ~1600 A at 4.2 K and 12 T

on a 1.25-mm wire, to be compared to the timid ~200 A

presently achieved on 0.8 mm ITER wires).

• To validate sample preparation and measurement processes,

the laboratories involved (CEA, TEU and INFN) have launched a

cross-calibration program reminiscent of the ITER/EDA cross-

calibration program carried out in the mid-1990’s.

• Since the Summer of 2004, three rounds of calibration wires

have been prepared and circulated among the various partners.

Conductor Characterization (2/2)

SMI (billet 179)

500

700

900

1100

1300

1500

1700

1900

6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0

B [T]

Cri

tica

l cu

rren

t [A

]

TU, sample 1

TU, sample 2

LASA, sample 1

LASA, sample 2

SMI/Toshiba Test Wire

(results are within 2%)

• TEU and INFN have now achieved a good convergence.

• The problems at CEA have been identified and are being

solved.

• All 3 partners should be ready when the first wires become

available.

(Courtesy T. Boutboul,

CERN)

FE Wire Model

• In Parallel, INFN-Mi has started to develop an ANSYS model of

an “un-reacted,” Alstom/MSA-type wire so as to simulate

cabling effects.

• Running such a computation requires a detailed knowledge of

the mechanical properties of the materials making up the wire

(in the cold work state where they end up prior to the cabling

operation).

• To determine these properties, CERN has carried out a series

of nano-indentation and micro-hardness measurements on

various wire samples, and compared the results with available

literature data.

• The next step is to apply this model and the appropriate

mechanical properties to the wire layouts presently considered

by Alstom/MSA.

IDI Work Package

• The IDI Work Package includes two main Tasks

– studies on “conventional” insulation systems relying

on ceramic or glass fiber tape and vacuum-impregnation

by epoxy resin

(CCLRC; Task Leader: E. Baynham),

– studies on “innovative” insulation systems relying on

pre-impregnated fiber tapes and eliminating the need

for a vacuum impregnation

(CEA; Task Leader: F. Rondeaux).

Conventional Insulation (1/2)

• CCLRC and CEA have developed in collaboration an

engineering specification (issued in July 2004) and a

coordinated test programme (issued in October 2004).

• Since then, CCLRC has carried out a number of screening

tests of candidate materials.

• The tests are applied to standardized laminates

representative of inter-turn insulation and include

– electrical breakdown test,

– short beam shear test,

– inter-laminar fracture test.

Precrack (release film)

Crack growth from test

Example of Double Cantilever Beam (DCB)

fracture test(courtesy S. Canfer, CCLRC)

Conventional Insulation (2/2)

• CCLRC has also investigated the issue of “sizing” (a lubricant,

usually organic, coated onto the fibers of tapes, that need to be

removed prior to conductor wrapping and winding, thereby

rendering the fiber tape fragile and easy to tear off).

• Very promising results have been obtained with an improved

polyimide sizing, produced by Hydrosize, NC, and applied by

JPS, SC, which seems to be able to sustain the required Nb3Sn

heat treatment without carbonization (thereby eliminating the

need for “de-sizing”).

• More complete evaluation tests are underway.

Innovative Insulation

• The work on innovative insulation has not started yet,

pending the hiring of a technician at the CEA chemistry

laboratory, which has been delayed until early next year.

• To compensate for this lack, it was decided last spring to

reallocate the EU funding of this task to hire a postdoc at CEA.

• A candidate has been identified, who is expected to start

working this fall.

• The timing of this task is now becoming critical with respect

to the overall NED program.

MDO Working Group (1/3)

• The MDO Working Group is made up of representatives from

CCLRC, CEA, CERN and CIEMAT, under the Leadership of F.

Toral, CIEMAT.

• Its main charge is to compare different magnet

configurations so as to assess their efficiency in terms of

manufacturability, performance and cost.

1.599814 MN/m

1.759376 MN/m

1.366123 MN/m

1.104555 MN/m

0.522062 MN/m

1.443344 MN/m

1.721069 MN/m

Coslayer design(courtesy D. Leroy,

CERN)

Intersecting-Ellipses design

(courtesy H. Felice,CEA)

Motor-type design(courtesy F. Toral,

CIEMAT)

MDO Working Group (2/3)

-80.00

-60.00

-40.00

-20.00

0.00

20.00

40.00

60.00

80.00

100.00

0.00 5000.00 10000.00 15000.00 20000.00 25000.00 30000.00

Shims

Variation Shims

Variation Without

Persistent Currents Without

Snapshot after 6 days of calculation

• In parallel, work is pursued at CERN so as to optimize the

baseline, 88-mm-aperture, cos layer design with respect to

– conductor geometry,

– iron shape (to reduce saturation effects),

– ferromagnetic shims (to compensate magnetization

effects).

(courtesy N. Schwerg, CERN)

MDO Working Group (3/3)

• CCLRC/RAL is also developing a 2D ANSYS model of the 88-

mm-aperture, cos layer design so as to optimize mechanical

support.

• This model includes “sub-models” of individual coil turns to

compute peak stresses in cable strands and cable insulation.

Von-Mises Stress in Cable

0 MPa < σVon-Mises < 180 MPa

Circumferential Stress in Insulation

-105 MPa < σθ < -35 MPa

Plane-stress with ½ unit thickness

Generalised plane-strain

Contact elements

(courtesy P. Loveridge, CCLRC)

Conclusion

• A great deal of progress has been made since my last

presentation (at the CARE general meeting in Hamburg last

year), leading to a number papers presented at various

conferences (1 at CEC/ICMC, 1 at EUCAS and 4 at MT).

• The cryostat for heat transfer measurements is completed

and will be delivered to CEA next week.

• The next few months will be critical for the Conductor

Development program with the results of the STEP 1 wires.

• The only Task that has not started is the Innovative Insulation

Task at CEA, but the hiring of a Postdoc should help.

• The funding of the model magnet manufacturing remains an

open question.