QXF Magnetization

VERY preliminary analysis

Susana Izquierdo Bermudez07/05/2013

2

QXF. Main Parameters

Susana Izquierdo Bermudez

• Napa Cross-Section

• Iron yoke updated (remove bus-bar slot)

6 7 8 9 10 11 12 13 14 15 160

500

1000

1500

2000

2500

Round wire Ic versus applied magentic field at 4.2 K

RW, Bapplied RW XS, Bapplied XS

Applied magnetic induction [T]

Criti

cal c

urre

nt [A

]

6.00 7.00 8.00 9.00 10.00 11.00 12.00 13.00 14.00 15.00 16.000

5001000150020002500300035004000

Wire Je versus applied magnetic field, Summers

4.2, aplied magnetic induction 1.9, aplied magnetic induction4.2, total magnetic induction 1.9, total magnetic induction

Magnetic induction [T]Wire

curr

ent d

ensit

y [A

/mm

^2]

• Jc fit

https://plone.uslarp.org/MagnetRD/DesignStudies/QX-CD/Magnetic/Study%20of%20the%20QXF%20cross-section/folder.2013-04-15.9119834501/

• 2650A/mm2 at 12T, 4.2K• 1400A/mm2 at 15T, 4.2K• Degradation: 5 %

3

QXF. Cable parameters 

XF150HTA (ref. 1, nov 2012)

XF150HTA1 (ref. 2, march 2013)

XF150HTA2 (ref. 3, may 2013)

Bare Cable after reaction

Width (mm) 18.638 18.3 18.3Thickness in (mm) 1.459 1.454 1.454Thickness out (mm) 1.676 1.66 1.66

Other cable parameters

# strands 40 40 40transposition pitch (mm) -- 109 109Degradation (%) 5 5 5

Insulation thickness

Radial (mm) 0.15 0.125 0.125Azimuthal (mm) 0.15 0.125 0.125

Jc Summers fit

(sf no included)

Data2650A/mm2 at 12T, 4.2K1400A/mm2 at 15T, 4.2K

2650A/mm2 at 12T, 4.2K1400A/mm2 at 15T, 4.2K

2650A/mm2 at 12T, 4.2K1400A/mm2 at 15T, 4.2K

C 3.82E+10 3.82E+10 3.82E+10Bc20 28.075 28.075 28.075Tc0 18 18 18

FilamentName OST RRP 108/127 OST RRP 108/127 OST RRP 108/127Outer diameter (um) 50 50 56Inner diameter (um) 0 0 0

StrandDiameter (mm) 0.85 0.85 0.85Cu/SC 1.13 1.13 1.15RRR 150 150 150

Susana Izquierdo Bermudez

Parameters used for all the calculations shown in this presentation

WRONG!Reference?

4

Magnetization models implemented in ROXIE

• Scalar model

(nested ellipse model)

Identical to the scalar model, but takes into account that, in the case of an applied rotating field, the orientation of the magnetization that is produced by a filament de-couples from the direction of the source field. It has never been validated experimentally

• Critical state model

(beam model)

• Vector model

REFERENCES:1. Superconductor Magnetization Modelling for the Numerical Calculation of Field Errors in Accelerator Magnets2. Magnetization Measurements of High-Jc Nb3Sn strands

5

Strand Magnetization

Susana Izquierdo Bermudez

0.0 0.5 1.0 1.5 2.0 2.5 3.0-300

-200

-100

0

100

200

300

400

Strand magnetization, OST RRP 108/127 1.9 K (QXF)

Scalar model Critical State ModelB [T]

M [k

A/m

]

Significant differences at low field

Analysis for 11T Magnet (Bernhard Auchmann)

First Guess for QXF

• Summers fit• Deff = 50 µm (should be 56 µm!)

6

Impact of Strand Magnetization in b6

Susana Izquierdo Bermudez

Persistent Currents not Considered

Persistent Currents Considered Δb6

Iron yoke not considered -5.86 -7.10 -1.24

Non-linear iron yoke 0.36 -0.52 -0.88

b6 @ Rref = 50 mm, I = Inom (17 kA)

0 2000 4000 6000 8000 10000 12000 14000 16000-300.00-200.00-100.00

0.00100.00200.00300.00400.00500.00600.00700.00

b6 (Rref = 50 mm)

PC considered (non-linear iron yoke)PC not considered (non-linear iron yoke)PC considered (no iron yoke)PC not consider (no Iron yoke)

I (kA)

b6 (u

nits

)

10000 11000 12000 13000 14000 15000 16000 17000-10.00

-8.00-6.00-4.00-2.000.002.004.006.008.00

10.00

I (kA)

b6 (u

nits

)

0.01Inom -> Inom ->0.001Inom->Inom

Current cycle:

Data for second up-ramp:

-0.62 for Deff = 56 µm

Scalar magnetization model

zoom

7

Proposals and Open Questions• Compare magnetization calculations

between Opera and Roxie• Reference design?

• Should we incorporate the impact of coil deformation in the design of QXF cross section?

• Would be very nice to do the analysis in HQ and see how magnetic measurements correlate with ROXIE calculations

Susana Izquierdo Bermudez

Additional slides

Susana Izquierdo Bermudez

9

Nested ellipse model

Susana Izquierdo Bermudez

Superconductor Magnetization Modelling for the Numerical Calculation of Field Errors in Accelerator Magnets

ROXIE magnetization modelo Summers fit, o Deff = 55 µm, o Aleksa/Russenschuck/Völlinger scalar model.

Strand magnetization model consistent with measurements at CERN and FNAL.

Strand magnetization model

Aug. 31, 2012 10B. Auchmann TE-MSC-MDT

Courtesy E. Barzi

11

Algorithm for the calculation of persistent currents as incorporated in the field computation program ROXIE.

1. Superconductor Magnetization Modelling for the Numerical Calculation of Field Errors in Accelerator Magnets

12Susana Izquierdo Bermudez

I=Inom