First st field ld qualit lity y measurem suremen ents ts of a - - PowerPoint PPT Presentation

▶
first st field ld qualit lity y measurem suremen ents ts
SMART_READER_LITE
LIVE PREVIEW

First st field ld qualit lity y measurem suremen ents ts of a - - PowerPoint PPT Presentation

Mar 12, 2024 486 likes •735 views

Click to edit Master title style FERMILAB-SLIDES-19-056-TD First st field ld qualit lity y measurem suremen ents ts of a 15 T Nb3Sn n Dipole ole Demo monst nstrat rator or September 24, 2019 Thomas omas Straus uss, E. Barzi, J.

slide-1
SLIDE 1

Click to edit Master title style

1

US Magnet Development Program

First st field ld qualit lity y measurem suremen ents ts of a 15 T Nb3Sn n Dipole

  • le Demo

monst nstrat rator

  • r

September 24, 2019 Thomas

  • mas Straus

uss, E. Barzi, J. DiMarco, V.V. Kashikhin, I. Novitski, M. Tartaglia, G. Velev, A.V. Zlobin

Tue-Mo-Or7-02

FERMILAB-SLIDES-19-056-TD This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.

slide-2
SLIDE 2

Click to edit Master title style

2

  • Data collection
  • Magnetic Measurement System
  • Measurement sensitivity
  • Centering Corrections
  • Measurement discussion
  • Transfer Function (magnitude of the field)
  • Loop (Dynamic effects, eddy current)
  • Z-scan (behavior along magnet length)
  • Harmonics from Stair Step (geometric harmonics)
  • Comparison with Simulation
  • Decay and Snapback
  • Summary

Outline

slide-3
SLIDE 3

Click to edit Master title style

3

Magnetic Measurement System

  • Rotating Coil Measurement System at Fermilab Vertical Magnet Test Facility

– 0.75 – 1 Hz rotation – Rref set to 17 mm (56% of aperture)

  • Shaft with attached probe to scan ‘warm bore’ of the magnet, 3 m stroke
  • Two probes, offset by 130 mm (16 layers, 2 Loops, 13 Windings each)

– 130 mm x 22.25 mm PCB probe – 26 mm x 22.25 mm PCB probe – Dipole bucked signal

slide-4
SLIDE 4

Click to edit Master title style

4

0.01 0.1 1 10 100 2 4 6 8 10

bnin units harmonic order

Probe sensitivity bn vs n (26 mm probe)

1500 A Stair step 2000 A Stair Step 4000 A Stair Step 6000 A Stair Step 8000 A Stair Step 9000 A Stair Step 0.01 0.1 1 10 100 2 4 6 8 10

an in units harmonic order

Probe sensitivity an vs n (26mm probe)

1500 A Stair step 2000 A Stair Step 4000 A Stair Step 6000 A Stair Step 8000 A Stair Step 9000 A Stair Step

26 mm Probe sensitivity

~ 0.1 units ~ 0.1 units Ignore Allowed terms Sensitive to ~ n=7 130 mm probe sensitivity similar

𝑪𝒛 + 𝒋𝑪𝒚 = 𝑪𝟐𝟐𝟏−𝟓 ෍

𝒐=𝟐 ∞

ሺ𝒄𝒐 + 𝒋𝒃𝒐) 𝒚 + 𝒋𝒛 𝑺𝒔𝒇𝒈

𝒐−𝟐

slide-5
SLIDE 5

Click to edit Master title style

5

Centering Correction

  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 0.5 3000 4000 5000 6000 7000 8000 9000 10000

bn, an in units Current [A]

Higher order units versus current

b8 stair step (26 mm probe) b9 stair step (26 mm probe) a8 stair step (26 mm probe) a9 stair step (26 mm probe) b8 loop (26 mm probe) b9 loop (26 mm probe)

  • 40
  • 30
  • 20
  • 10

10 2000 4000 6000 8000 10000

bn, an in units Current [A]

Hysteresis feed-down from b3

b2 stair step (26 mm probe) a2 stair step (26 mm probe) b2 loop (26 mm probe)

Data indicates probe is well centered for this position

slide-6
SLIDE 6

Click to edit Master title style

6 1.4 1.5 1.6 1.7 1.8 1.9 2 2.1 2.2 1000 2000 3000 4000 5000 6000 7000 8000 9000 TF [T/kA] Current [A]

Stair step 26 mm Loop 20 A/s (26 mm probe) Loop 20A/s (130 mm probe) Loop 40 A/s (26 mm probe) Loop 40 A/s (130 mm probe) Loop 80 A/s (26 mm probe) Loop 80 A/s (130 mm probe) Acc Cycle (26 mm probe)

Transfer Function for multiple measurements

All MDPCT1 measurements overlaid Iron Saturation above 2.5T

slide-7
SLIDE 7

Click to edit Master title style

7

1.45 1.5 1.55 1.6 1.65 1.7 1.75 1.8 1.85 1.9 1.95 2000 4000 6000 8000 TF [T/kA] Current [A]

TF vs current for varying ramp rates

Loop 20 A/s (26 mm probe) Loop 40 A/s (26 mm probe) Loop 80 A/s (26 mm probe)

Near identical shape at high fields, very small variation in the magnetization at low

Loop measurements

Conductor uses 11 mm width stainless core (nearly full width of cable) Pre-cycle and ramp to 9 kA

slide-8
SLIDE 8

Click to edit Master title style

8

Loop harmonic b3 vs current for various ramp rates

  • 100
  • 50

50 100 150 200 2000 4000 6000 8000 b3 in units Current [A]

Loop 20 A/s (26 mm probe) Loop 40 A/s (26 mm probe) Loop 80 A/s (26 mm probe)

Near identical, no large eddy current or coupling between strands likely due to core. Large persistent current/hysteresis effect.

slide-9
SLIDE 9

Click to edit Master title style

9

20 A/s Loop measurements normal harmonics

  • 50
  • 30
  • 10

10 30 50 2000 4000 6000 8000 bn in units Current [A]

b3, b5, b7 and b9 vs current for Loop measurements

b3 Loop 20 A/s (26 mm probe) b5 Loop 20 A/s (26 mm probe) b7 Loop 20 A/s (26 mm probe) b9 Loop 20 A/s (26 mm probe)

b3 ‘drift’ is due to iron saturation (see previous talk, wait for comparison with calculation later)

slide-10
SLIDE 10

Click to edit Master title style

10

20 A/s Loop measurement skewed harmonics

  • 10
  • 8
  • 6
  • 4
  • 2

2 4 2000 4000 6000 8000 an in units Current [A]

a3, a5, a7 and a9 vs current for Loop measurements

a3 Loop 20 A/s (26 mm probe) a5 Loop 20 A/s (26 mm probe) a7 Loop 20 A/s (26 mm probe) a9 Loop 20 A/s (26 mm probe)

a3 offset points to small misalignment between coils, hysteresis origin could be from b3 contribution

slide-11
SLIDE 11

Click to edit Master title style

11

Z scan TF along magnet bore

0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

  • 0.5
  • 0.3
  • 0.1

0.1 0.3 0.5 TF [T/kA] z position around magnet center [m]

z scan 26 mm probe (26 mm step) z scan, 130 mm probe (130 mm step) z scan 26 mm probe (130 mm step)

Measured at 9kA Lead end Return end

slide-12
SLIDE 12

Click to edit Master title style

12

1.46 1.462 1.464 1.466 1.468 1.47 1.472 1.474 1.476

  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 TF [T/kA] z position around magnet center [m]

z scan TF along center axis

z scan 26 mm probe (26 mm step) z scan 130 mm probe (130 mm step)

Z scan TF, zoom

Measured at 9kA Lead end Return end Variations due to end field contributions

slide-13
SLIDE 13

Click to edit Master title style

13

Z scan harmonics

  • 30
  • 25
  • 20
  • 15
  • 10
  • 5

5 10 15 20

  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 bn in units z position around magnet center [m] b2 b3 b5 Errors smaller than symbols Measured at 9kA, 26 mm probe Lead end Return end

  • b3 in center is consistent with loop

and stair case measurements

  • Oscillatory pattern likely due to

cable transposition pitch (~12 cm)

slide-14
SLIDE 14

Click to edit Master title style

14

Z scan harmonics

  • 15
  • 10
  • 5

5 10 15

  • 0.4
  • 0.3
  • 0.2
  • 0.1

0.1 0.2 0.3 0.4 an in units z position around magnet center [m] a2 a3 a5 Errors smaller than symbols Measured at 9kA Lead end Return end

  • a3 depends on z-axis (possible

misalignment), and value in center is consistent with loop and stair case measurements

  • Oscillatory pattern likely due to cable

transposition pitch (~12 cm)

slide-15
SLIDE 15

Click to edit Master title style

15

  • Stair step, 26 mm probe
  • Loop, 20 A/s, both probes, 130 mm offset in between

Geometrical Harmonics

current B main TF b2 b3 b4 b5 b6 b7 b8 b9 a2 a3 a4 a5 a6 a7 a8 a9 7003 10.599 1.514 1.4

  • 7.4
  • 0.9

0.1

  • 0.1

1.3 0.1 0.1

  • 1.3
  • 3.4

0.6 0.1 0.1 0.0 0.0 0.0 Loop 20 A/s 26 mm 6996 1.512 1.4

  • 7.6
  • 1.0

0.2

  • 0.2

1.4 0.1

  • 0.2
  • 1.4
  • 3.7

0.8 0.2 0.2 0.1 0.0 0.0 Loop 20 A/s 130 mm 6996.030 1.514

  • 1.2
  • 7.2
  • 1.8
  • 1.3
  • 0.1

0.7 0.2 0.0

  • 1.5
  • 3.0

2.4 1.2 0.1 0.1

  • 0.1

0.0

Geometric harmonics nearly identical in stair step and loop, small except for a2,a3,b2, and b3

  • 15
  • 10
  • 5

5 10 15 2000 4000 6000 8000 10000

harmonics in units Current [A] b2 b3 a2 a3 Harmonics averaged from up and down ramp

slide-16
SLIDE 16

Click to edit Master title style

16

1.40 1.50 1.60 1.70 1.80 1.90 2,000 4,000 6,000 8,000 10,000 TF [T/kA] Current [A]

MDPCT1 TF vs current

Stair Step (26 mm probe) Rubber NMR (2.5-5.5T) Comsol 3D Deuterium NMR (8-22T) ROXIE 2D

Transfer Function

Deuterium probe was loaned to FNAL by GMW

Vadim Kashikhin: 2% difference between the 2D Roxie and 3D COMSOL transfer functions at high field due to boundary condition in 2D setup while 3D is ok.

Large magnetization at low currents

slide-17
SLIDE 17

Click to edit Master title style

17

  • 150
  • 100
  • 50

50 100 2 4 6 8 10 12 14 b3 in units B1 in [T]

b3 Roxie 2D b3 Stair Step (26 mm probe) b3 20 A/s Loop (26 mm probe) b3 20 A/s Loop (130 mm probe)

b3 versus dipole field

Plotting against the main field resolve 2D simulation offset for fair comparison Persistent current is large, as expected

slide-18
SLIDE 18

Click to edit Master title style

18

b5 versus dipole field

  • 5

5 10 15 20 25 2 4 6 8 10 12 14 b5 in units B1 in [T]

b5 Roxie 2D b5 Stair Step (26 mm probe) b5 20 A/s Loop (26 mm probe) b5 20 A/s Loop (130 mm probe)

slide-19
SLIDE 19

Click to edit Master title style

19

Decay and Snapback

200 400 600 800 1000

  • 35
  • 30
  • 25
  • 20
  • 15
  • 10
  • 5

700 800 900 1000 1100 1200 1300 1400 Current [A] b3 in units time [s]

b3 versus time

B3 Current 100 A reset current 760 A plateau for 15 min 10 A/s

slide-20
SLIDE 20

Click to edit Master title style

20

Snapback

700 800 900 1000 1100 1200

  • 35
  • 33
  • 31
  • 29
  • 27
  • 25

1300 1320 1340 1360 1380 1400 Current [A] b3 in units time [s]

b3 versus time

B3 Current 100 A reset current 760 A plateau for 15 min 10 A/s

slide-21
SLIDE 21

Click to edit Master title style

21

Summary

  • Magnet TF and low-order field harmonics were measured using 26 mm and 130

mm long rotating coils in the field range up to ~14 T.

  • The measurements included geometrical components and contributions from the

coil magnetization and iron yoke saturation effects.

  • All the measured geometrical harmonics, except for a2, a3, b2, b3, are small, on the

level of 1 unit or less at Rref=17 mm.

  • The coil magnetization effect in MDPCT1 at low fields is large due to the high critical

current density and relatively large sub-element size in the contemporary Nb3Sn strands.

  • The iron yoke saturation effect in MDPCT1 starts at fields above 2.5 T and is also

large.

  • Both coil magnetization and iron saturation effects are in good agreement with

theoretical predictions for TF and b3

  • The eddy current effect in the cable on the TF and field harmonics in MDPCT1 was

suppressed by using a stainless-steel core inside the cables

  • A first glimpse at Decay and snapback showed no new surprises assuming an LHC

type accelerator profile

slide-22
SLIDE 22

Click to edit Master title style

22

Acknowledgment

  • We thank the technical staff of FNAL APS-TD for contributions

to magnet design, fabrication and test, and US-MDP Management Group and Technical Advisory Committee for the support of this project.

  • We thank GMW (www.gmw.com) for providing us with a

Metrolab 1226 8-22T NMR probe for our PT2026 Teslameter

slide-23
SLIDE 23

Click to edit Master title style

23

0.01 0.1 1 10 100 2 4 6 8 10

bn in units harmonic order

Probe sensitivity bn vs n (130 mm probe)

1500 A Stair step 2000 A Stair Step 4000 A Stair Step 6000 A Stair Step 8000 A Stair Step 9000 A Stair Step 0.01 0.1 1 10 100 2 4 6 8 10

anin units harmonic order

Probe sensitivity an vs n (130 mm probe)

1500 A Stair step 2000 A Stair Step 4000 A Stair Step 6000 A Stair Step 8000 A Stair Step 9000 A Stair Step

130 mm Probe sensitivity

~ 0.1 units ~ 0.1 units Allowed terms Sensitive to ~ n=8