Analysis of MBXW and MBW

Per Hagen (TE/MSC)29.09.2009

Acknowledgements:R. Wolf (2008 analysis), G. de Rijk (ROXIE model),

B. Auchmann (ROXIE support), E. Todesco (discussions),BINP (Novosibirsk) and CERN personnel involved in measurements

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Function in LHC• Classical NC-magnets needed where SC-magnets would quench due to radiation• MBXW (2 beams in one aperture) are used for separating / combining the beams in ATLAS and CMS (194 – 224) mm. 6 MBXW = optics element D1. MBXW=29.• MBW (2 separate apertures) are used for changing the beam separation (194-224 mm) in cleaning regions where we have collimators (IR3, IR7). IR3: 3 MBW = optics elements D4 + D3. IR2: 2 MBW = D4 + D3. MBW=24.• Designed by CERN. Produced by BINP (Budker Institute of Nuclear Physics)

MBXW MBW

3

CERN

> 5000 KMBINP

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Measurements

• First magnet measured with NMR for absolute calibration• Each magnet measured at BINP with HALL probe array• 19 probes along horizontal axis • Calibrated with NMR* measurement to give the B*L integral• Longitudinal scan step: 2 cm• MBXW aperture measured: ± 45 mm• MBW each aperture measured: range ± 60 to ± 148 mm

(center 194 mm sep = 97 mm, 224 mm = 112 mm) • FiDeL REFPARM: Use only BL from center of each aperture

Could have taken actual slot into account (center of beam as function of s)

• Rotating coil measurements after delivery to CERN giving B(I) and harmonics in central position: MBXW 1, 9, 20 + MBW 1, 9, 15

* NMR = Nuclear Magnetic Resonance. Constant magnetic field affects nuclear E + spin states. Measure wavelength of emitted photons in measuring device which is scales with B field.

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How results are presented

• Geo-gamma @ 100 A is removed• All data points converted to units of geo-gamma• Why? Compare and fit shapes of B(I), BL(I) curves

Facts• We use only the FIDEL residual magnetisation and saturation components for the “warm” magnets

• Assume local B(I) curves from “middle of magnet” have same shape as BL(I) curves

• LHC operational ranges: MBXW 41 to 643 A (0.08 – 1.3 T) MBW 43 to 685 A (0.08 – 1.3 T)

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MBXW TF

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0

100

0 200 400 600 800

MB

XW

1 T

F (u

nits

)

Current (A)

TF local NMRTF local RC3TF local RC5TF HALL INT

All 4 measurements of MBXW 1

Modest, flat “resmag” around 30, 40AGeo-gamma 100A

RC with 50 units less saturation

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Statistics of 3 RC measurements Statistics of 29 HALL measurements

Individual geo-gamma per circuit

Conclusion:Less difference in saturation RC wrt HALL!

I (A) TF ave (units) TF sigma (units)30 6.49 3.9440 -2.80 13.36

100 0.00 0.00150 7.06 3.01200 5.70 2.86300 5.42 1.60400 -0.53 2.33500 -11.98 2.28600 -42.99 7.65650 -107.05 21.96700 -229.19 33.21750 -397.25 38.69800 -593.39 39.97830 -718.41 38.90

I (A) TF (Tm / A) TF ave (units) TF sigma (units)100 0.00655273 0.00 7.32500 0.00653464 -27.60 3.84750 0.00627223 -428.06 14.05830 0.00606208 -748.77 15.80

CIRCUIT TF (Tm / A) TF (units)RD1.LR1 0.00655124 -7.9RD1.LR5 0.00655370 -4.1RBXWH.L8 0.00656430 12.0

Average 0.00655641Stdev 10.6

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MBXW resmag (2009 feature)• The RC measurements include measurement of remanent field at 0 A as 1st measurement after pre-cycles to stabilise B(I) curve, B(0) = 10 G• Assume TF(I) at low current given by “geometric” + remanent allows to make an initial resmag table (expressed in units of geometric)• Assume remanent field measurement contains an absolute error, and the condition that resmag @ I_geo_gamma vanishes• Use the 2 “calibrated” values for TF fit @ 30, 40 A

I (A)uncalibrated calibrated

10 524 47220 262 21030 175 12240 131 7950 105 5260 87 3570 75 2280 66 1390 58 6

100 52 0

TF resmag (units)

Used for FIDEL resmag fit

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MBXW TF fit

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0

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0 200 400 600 800

TF (u

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Current (A)

TF FiDeLTF ROXIEave local measAVG HALL INT

ROXIE has much less saturationbased on residual magnetization

FIDEL fit where HALL measurements given more weight

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MBXW TF REFPARM and fit error

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30

40

0 200 400 600 800

Res

idua

l err

or (u

nits

)

Current (A)

Component Parameter ValueSaturation sigma 0.00073092

I0 790.3871s 4.4855Inomref 690

Residual mag rho 0.00002553r 3.3434Iinjref 43

Component Parameter ValueSaturation sigma 0.00077631

I0 791.7549s 4.2487Inomref 690

Residual mag rho NAr NAIinjref NA

2008

2009

Conclusion:Resmag only essentialdifference!

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MBXW harmonics (3 magnets)I (A) b2 a2 b3 a3 b4 a4 b5 a5 b6 a6 b7 a7 b8 a8 b9 a9 b10 a10 b11 a11

ave 40.0 -0.2 -0.2 0.1 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0stdev 0.1 0.2 0.3 0.0 0.0 0.0 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

ave 500.0 -0.2 0.0 0.0 -0.1 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0stdev 0.1 0.1 0.3 0.1 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

ave 750.0 -0.2 0.0 -0.4 -0.1 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0stdev 0.1 0.1 0.3 0.1 0.0 0.0 0.2 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

ave 830.0 -0.3 0.0 -0.9 -0.1 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0stdev 0.1 0.1 0.3 0.1 0.0 0.0 0.2 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Conclusion:Only b2 visible but -0.2 units is too small and uncertain for REFPARM

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MBW TF

All measurements of MBW 1

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MB

W 1

TF

(uni

ts)

Current (A)

TF local NMRTF local RC3 ap1TF local RC5 ap2TF HALL INT

Modest “resmag” around 30, 40A

Geo-gamma 100A

All 4 measurements of MBW 1

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Statistics of 2x3 RC measurements Statistics of 24 HALL measurements

Individual geo-gamma per circuit

Conclusion from HALL:No difference between apertures

I (A) TF ave (units) TF sigma (units)30 12.01 4.9140 -3.14 5.45

100 0.00 0.00150 4.08 2.98200 5.83 4.78300 5.95 3.90400 1.04 1.19500 -11.42 2.82600 -38.33 3.51650 -82.23 6.43700 -184.03 9.41720 -244.10 14.13750 -347.41 17.37810 -589.74 20.17

Conclusion:RC always less saturation similar to MBXW

Aperture I (A) TF (Tm / A) TF ave (units) TF sigma (units)1 100 0.00692104 0.00 4.141 500 0.00690243 -26.90 3.831 720 0.00672390 -284.84 14.151 810 0.00648078 -636.13 20.682 100 0.00692110 0.00 3.852 500 0.00690242 -27.00 3.312 720 0.00672368 -285.26 14.282 810 0.00648070 -636.33 20.42

CIRCUIT TF (Tm / A) TF (units)RD34.LR3 0.00692176 0.3RD34.LR7 0.00692141 -0.3

Average 0.00692158Stdev 0.4

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MBW TF fit

FIDEL fit where HALL measurements given more weight

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0 200 400 600 800

TF (u

nits

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Current (A)

TF FiDeLave local measAVG HALL INT

Based on residual magnetization like for MBXW

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MBW TF REFPARM and fit error

2008

2009

Conclusion:Resmag only essentialdifference!

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30

30 230 430 630 830

Res

idua

l err

or (u

nits

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Current (A)

Component Parameter ValueSaturation sigma 0.00161642

I0 896.2477s 3.5510Inomref 720

Residual mag rho 0.00004589r 2.4698Iinjref 41

Component Parameter ValueSaturation sigma 0.00167790

I0 900.9500s 3.5982Inomref 720

Residual mag rho NAr NAIinjref NA

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MBW harmonics (3 magnets)

Conclusion:Use geometric for b3, b5, b7 same sign both apertures

Ap I (A) b2 a2 b3 a3 b4 a4 b5 a5 b6 a6 b7 a7 b8 a8 b9 a9 b10 a10 b11 a11

ave 1 40.0 0.3 0.1 1.5 0.0 0.0 0.0 -0.4 0.0 0.0 0.0 -0.3 0.0 0.0 0.0 -0.1 0.0 0.0 0.0 0.0 0.0stdev 1 1.8 0.1 0.4 0.1 0.4 0.0 0.3 0.0 0.4 0.1 0.2 0.0 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0

ave 1 600.0 0.7 0.1 1.3 0.0 -0.1 0.0 -0.3 0.0 0.0 0.0 -0.3 0.0 0.0 0.0 -0.1 0.0 0.0 0.0 0.0 0.0stdev 1 1.6 0.3 0.4 0.1 0.5 0.0 0.3 0.1 0.4 0.1 0.2 0.1 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0

ave 1 810.0 1.5 0.2 -0.5 0.0 -0.2 0.1 -0.6 0.0 0.1 0.0 -0.3 0.0 0.0 0.0 0.0 0.0 -0.1 0.0 0.1 0.0stdev 1 1.3 0.2 0.8 0.2 1.0 0.1 0.3 0.1 0.4 0.1 0.2 0.1 0.2 0.0 0.1 0.0 0.1 0.0 0.1 0.0

ave 2 40.0 -0.5 0.0 1.4 0.0 0.0 0.0 -0.4 -0.1 0.1 0.0 -0.3 -0.1 0.1 0.0 -0.1 0.0 0.0 0.0 0.0 0.0stdev 2 1.8 0.1 0.5 0.1 0.5 0.1 0.2 0.1 0.5 0.1 0.2 0.1 0.2 0.1 0.0 0.0 0.0 0.0 0.0 0.0

ave 2 600.0 -0.7 0.0 1.3 0.0 0.1 0.1 -0.3 0.0 0.0 0.1 -0.3 -0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0stdev 2 1.6 0.1 0.5 0.2 0.5 0.1 0.2 0.2 0.4 0.2 0.2 0.1 0.2 0.1 0.1 0.0 0.1 0.0 0.1 0.0

ave 2 810.0 -1.4 0.2 -0.4 -0.1 0.3 0.1 -0.5 -0.1 0.0 0.0 -0.2 -0.1 0.1 0.0 0.0 0.0 0.1 0.0 0.1 0.0stdev 2 1.1 0.2 0.8 0.3 0.8 0.2 0.2 0.1 0.3 0.2 0.2 0.1 0.2 0.1 0.2 0.0 0.2 0.0 0.1 0.0geo 1.4 -0.4 -0.3