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NED Status Report
Arnaud DevredCEA/DSM/DAPNIA/SACM
& CERN/AT/MAS
CARE Steering Committee MeetingLPNHE
11 April 2006
CARE/NED JRA
• The Activity 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 involves 7 institutes (8 laboratories)
• Total budget: ~2 M€; EU grant: 979 k€ (over 3 years).
Management & Communication (1/2)
• Steering Committee meetings– 23 February at CERN
1 June at CIEMAT
• HHH/AMT meeting– WAMDO: 3-6 April at CERN
• ESAC meeting next fall, at the end of Step 2 of Conductor
Development.
Management & Communication (2/2)
• 4 papers at ICEC 21/ICMC '06 (17–21 July, Prague,
Czech Republic) – NED cryostat– Nano- and micro-hardness measurements– 2 papers on conventional insulation
• 6 papers at ASC (27 August–1 September, Seattle,
WA)– Overview– Heat-transfer measurements– Quench computation on slot design– Wire FE model– NED reference design V2– WGMDO comparison
NED/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
Nb3Sn conductor insulation
(CEA and WUT; Task Leader: B. Baudouy, CEA),
– quench protection computation
(INFN-Mi; Task Leader: G. Volpini).
Heat Transfer Measurement Task (1/2)
• The first part of the Task was to
design and build a new He-II,
double-bath cryostat.
• The cryostat was built by
Kriosystem in Poland under the
supervision of Wroclaw University
according to specifications written
by CEA.
• The cryostat was delivered to
CEA on 20 September 2005 and
has been rprepared for
commissioning.Miscellaneous views of NED cryostat
(Courtesy M. Chorowski, WUT)
Heat Transfer Measurement Task (2/2)
• The first cooldown was carried out on 14 February 2006 and
it took ~7 hours to reach 1.5 K in the He II pressurized
bath.
First cooldown of NED cryostat at CEA
(Courtesy B. Baudouy, CEA)
• The test was suspended
due to a problem with a LHe
level sensor that is a critical
element of the control
system.
• A new sensor has been
ordered and the test is
expected to resume in June
2006.
• Extensive measurement
campaigns will follow.
08 AM 09 AM 10 AM 12 PM 01 PM 02 PM 03 PM 04 PM 06 PM 07 PM
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TT1 TT3 TT5bis TT2bis TT5 TT6 TT7 TT4 TT2
Temperature (K)
Time
February 14th first cooldown, 9:20 AM
NED Quench Computation Task
• INFN-Mi has carried a detailed
analysis of the thermal and
electrical behaviors of NED-like
magnets during a quench.
• The computations were
focused on the Reference 88-
mm-aperture, cos, layer design
and show that, magnets up to 10
m long can be operated safely,
thereby justifying the choice of
conductor parameters made
early on.
• The Task is completed and a
final report has been issued.
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Rd=15 mOhmRd=25 mOhmRd=35 mOhmRd=45 mOhmDelay=30 msDelay=40 msDelay=50 ms
I=15 kAI=22 kAI=29 kA
Hot spot temperature (K)
QLASA
QUABER
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Rd=15 mOhmRd=25 mOhmRd=35 mOhmRd=45 mOhmDelay=30 msDelay=40 msDelay=50 ms
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Total voltage (V)
QLASA
QUABER
Quench simulations for 10-m-long, 88-mm-aperture, cos, layer design
(Courtesy M. Sorbi, INFN-Mi)
Complementary NED/TSQP Efforts
• Since the start of NED, two complementary efforts have been
launched at CERN
– Analysis of available LHC magnet test data at high
ramp rate to determine how well the heat-transfer
measurements at CEA correlate with actual magnet data,
– Review of magnet cooling modes to estimate, on the
cryogenics system point of view, what are the limitations
on power extraction and to provide guidance on how to
improve cooling of magnet coils
(preliminary conclusions indicates that NED-like magnets
may have to be operated in superfluid helium).
NED/CD Work Package
• The CD Work Package includes three main Tasks
– conductor development
(under CERN supervision; Task Leader: L. Oberli),
– conductor characterization
(CEA, INFN-Ge, INFN-Mi, and TEU; Task Leader: A. den
Ouden, TEU),
– FE wire model (to simulate cabling effects)
(CERN and INFN-Mi; Task Leader: S. Farinon, INFN-Mi).
• It is the core of the Program and absorbs about 70% of the
EU-allocated funding.
Conductor Development (1/2)
• Conductor specifications were derived from preliminary
design studies carried out in 2003-2004 at CERN; salient wire
parameters are
– 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 (funded by CARE/NED)
were awarded in November to 2004 to
– SMI in The Netherlands (“Powder in Tube” Process) for
290 m of 40-strand cable,
– Alstom/MSA in France (“Enhanced Internal Tin”
process) for 580 m of 40-strand cable.
• After discussion with CERN, the two companies have 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.
• Note that, since then, CERN has awarded in April 2005 a third
contract for 580 m of 40-strand cable to Outokumpu OY (which
is internally funded by CERN).
SMI Status (1/6)
• SMI STEP 1 was devoted to iterations on an existing 1-mm-ø
strand design with 192 (NbTa)3Sn filaments.
• Several billets were produced with different powder
compositions (B179 & B201) or outer Ta tubes around the Nb
tubes to act as on anti-diffusion barrier.
• The best critical current
results were obtained on
B179Diameter: 1.00 mmFilaments: 192 (50 m)
Cu-to-non-Cu ratio = 0.73IC = 1105 A at 12T (with 84 h at 675
°C)
Non/Cu JC = 2410 A/mm2 at 12 T
SMI Status (2/6)
• Following STEP 1, it was decided to produce another billet
(B207), aimed at NED diameter, but keeping the same NbTa
tubes and the same powder composition as for B179.
• The resulting wire is pretty good in terms of overall critical
current but Cu-to-no-Cu ratio and critical current density are
below expectations.
Diameter: 1.255 mmFilaments: 288 (50 m)
Cu-to-non-Cu ratio = 0.955IC = 1313 A at 12T (with 84 h at 675
°C)
Non/Cu JC = 2077 A/mm2 at 12 T
SMI Status (3/6)
• The critical current of wire B207 has been fully characterized
at INFN-Mi (7-13 T) and University of Geneva (15-19 T).
Non-Cu JC = 2077 A/mm2 at 12 T
= 1118 A/mm2 at 15 T
• INFN-Mi also performed stability current measurement, which
did not show any instability up to 1800 A (14 to 18 mT/s).
SMI Status (4/6)
• INF-Mi also performed measurements on 2 deformed samples
(0.35-mm deformation) yielding ~15-17% IC degradation.
(Courtesy G. Volpini, INFN-Mi)
øNb = 55 m øNb3Sn = 44 mm
• Shielded volumes derived from m(T)
4.5 K, transverse field
SMI Status (5/6)
• Magnetization measurements performed at INFN/Ge have
confirmed the expected filament outer diameter.
(Courtesy M. Greco, INFN-
Ge)
SMI Status (6/6)
• The next step agreed upon by CERN is to produce a 10-kg
billet similar to B207 (which was only 3 kg) with proper Cu-to-
non-Cu ratio and a proper powder preparation (aimed at
achieving a non-Cu critical current density greater than 2500
A/mm2 at 4.2 K and 12 T)
should be ready by mid-June.
Alstom/MSA Status
• Alstom/MSA is developing the so-called enhanced internal-tin
process based on a double-stacking billet design and cold
drawing.
• STEP 1 has been devoted on optimizing billet design and
assembly to obtain good workability.
• Workability problems have appeared more severe than
anticipated and require a systematic study of main design and
assembly parameters.
• Good progress, no show stoppers.
NED Conductor Characterization
• NED conductors are characterized by performing
critical current and magnetization measurements.
• Critical current measurements represent a real
challenge, given the expected performances (e.g.,
~1600 A at 4.2 K and 12 T on a 1.25-mm-Ø wire,
compared to ~200 A presently achieved on 0.8-mm-
Ø ITER wires).
• To validate sample preparation and measurement
processes, CEA, INFN-Mi and Twente University have
carried out an extensive cross-calibration program
and have now achieved a reasonable convergence.
FE Wire Model
• INFN-Ge has been working on
a mechanical FE model (based
on ANSYS®) to simulate the
effects of cabling on un-reacted,
Nb-Sn wires.
• To feed the model, CERN has
supervised and/or carried out a
series of nano-indentation and
micro-hardness measurements
to determine the mechanical
properties of the materials
making up the wire in the cold-
work state where they are prior
to cabling.
Micro-hardness measurements on a X-cut of internal tin wire
(courtesy C. Scheuerlein, CERN)
FE model of internal tin wire(courtesy S. Farinon, INFN-Ge
NED/IDI Work Package (1/2)
• 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/RAL; Task Leader: S. Canfer),
– studies on “innovative” insulation systems
relying on pre-impregnated fiber tapes and
eliminating the need for a vacuum
impregnation
(CEA; Task Leader: F. Rondeaux).
NED/IDI Work Package (2/2)
• CCLRC/RAL is evaluating a polyimide-sized glass
fiber tape that is able to sustain the required Nb3Sn
heat treatment without degradation and which
seems a promising solution to conventional
insulation.
• The Innovative Insulation Task is built upon an
ongoing R&D program at CEA which has
demonstrated the feasibility of such a system, but
which has been on hold for a year due to a lack of
human resources; the program has now restarted
and is gearing up to speed.
NED/MDO Working Group (1/4)
• The MDO Working Group is made up of representatives from
CCLRC, CEA, CERN and CIEMAT
(Chairman: F. Toral, CIEMAT).
• Its main charge is to address the following questions
– How far can we push the conventional, cos, layer
design in the aperture-central-field parameter space
(especially when relying on strain-sensitive conductors)?
– What are the most efficient alternatives, in terms of
performance, manufacturability and cost?
• A number of magnetic configurations have been selected and
are presently being evaluated.
NED/MDO Working Group (2/4)
Common coil(CIEMAT)
Ellipse-type(CEA/Saclay)
Double helix(RAL)Cos layer
(CERN & RAL)
Motor-type(CIEMAT)
Cos slot(CERN)
(Courtesy F. Toral, CIEMAT)
NED/MDO Working Group (3/4)
(Courtesy N. Schwerg, CERN)
• CERN has pursued the electromagnetic optimization of 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).
NED/MDO Working Group (4/4)
(Courtesy P. Loveridge, CCLRC/RAL)
• CCLRC/RAL is developing a comprehensive (ANSYS®-based)
mechanical model of the baseline, 88-mm-aperture, cos layer
design throughout the various steps of manufacturing,
cooldown and energization.
STAINLESS-STEEL COLLAR LAMINATION LOWER COIL
UPPER COIL
IRON YOKE
STAINLESS-STEEL SHRINKING CYLINDER
INFN/CANDIA Project (1/2)
• INFN has approved on 30 November 2004 a
research project called CANDIA (Italian acronym for
CAvi in Niobio-stagno per DIpoli ad Alto campo or
niobium-tin cables for high field dipoles), involving
teams from INFN-Frascati (LNF), INFN-Genova and
INFN-Milano (LASA).
• The main goal of CANDIA is the development of a
Nb3Sn conductor according to NED-like
specifications.
• A call for tender was issued in the Fall of 2005 and
a contract for the manufacture of 1500 m of wires
was awarded on 15 December 2005 to Outokumpu
Copper Superconductor Italy (OCSI).
INFN/CANDIA Project (2/2)
• The chosen technology is Internal Tin process.
• The expected delivery is Fall of 2006.
• Of course, close ties are maintained between
CANDIA and NED.
What’s next? (1/2)
• 10 European Group Leaders/Managers and 2 US-
LARP Managers have cosigned a contribution to the
CERN Council Strategy Grouphttp://council-strategygroup.web.cern.ch/council-strategygroup/
• This document outlines a strategy for European
superconducting accelerator magnet R&D aimed at
LHC luminosity upgrade, promoting the
manufacturing of NED (in complement to LARP) and
some well-focused R&D on cycled NbTi accelerator
magnets.
What’s next? (2/2)
• The document will be extended to outline a world-
wide strategy (with US and Japanese partners)
should be ready by mid-June.
• The strategy document will serve as a basis for a
letter of intent to the European Strategy Group on
Accelerator R&D (ESGARD) for FP7 proposals (due on
28 April 2006).
Letter of Intent for FP7
• Transnational Access
Test facilities for conductor characterization.
• Topics for JRA
– NED manufacturing and test,
– focused R&D on cycled NbTi accelerator
magnets (conductor, supercritical helium
study, quench protection study, extended test
of FAIR-type prototype).
• Strategy on one or two JRA’s to be determined
when the details of the call for proposal will be
known.
Conclusion
• All NED Tasks are making good progress.
• The Activity will come to an end at the end of the
year (first semester of 2007?).
• How to bridge the gap with FP7?
