eddy current septum magnet optimization
DESCRIPTION
Eddy Current Septum Magnet Optimization. Powering Options of SMH42 and the Influence of the Septum T hickness on the Fringe Field. Zsolt SZOKE (TE/ABT/SE). Outline. Eddy Current Septa Magnets Our Goal Baseline Design Performance Analysis in Time Domain - PowerPoint PPT PresentationTRANSCRIPT
Eddy Current Septum Magnet Optimization
Powering Options of SMH42 and the Influence of the Septum Thickness on the Fringe Field
Zsolt SZOKE (TE/ABT/SE)
LIU-PS Meeting 2
Outline
• Eddy Current Septa Magnets• Our Goal• Baseline Design Performance• Analysis in Time Domain• Comparing Full Sine and Half Sine Excitation• Comparing 5mm and 3mm Septum Blades• Comparing 2ms and 7ms Wavelength
19/08/2014
LIU-PS Meeting 3
Eddy Current Septa Magnets
• Different types of septa:– direct drive (DC, pulsed)– eddy current (only pulsed)
• Eddy current type - advantages:– coil dimensions are not critical– the pulsed coil has such a
magnetic field which induces eddy currents in the septum counteracting the fringe field
– septum can be very thin19/08/2014
LIU-PS Meeting 4
Our Goal
• Optimize different eddy current septum magnet parameters.
• 3 comparisons made with the baseline design.• Baseline: 2ms, full sine, 5mm septum.
• Examination of the fringe field: By and ∫Bydl.
19/08/2014
7ms half sine 3mm septum
LIU-PS Meeting 5
Baseline Design Performance
• ʃBy,gapdlmax = 502.67Tmm
• By,gap,max = 542mT
• ʃBy,fringedlmax = -1.37Tmm (after the current pulse)
• By,fringe,max = -1.4mT (after the current pulse)
• Idriving,max = 30251A• Gap fringe
field shape:
19/08/2014
LIU-PS Meeting 6
Analysis in Time Domain (1/2)• Opera finite element simulation, spanning 3×
the excitation time• Discrete moments interpolation in MATLAB• 2 types of interpolation:
– PCHIP: for plotting– SPLINE: for peak
determination
19/08/2014
LIU-PS Meeting 7
Analysis in Time Domain (2/2)
• 6 values for each simulated moment:– t [ms]– I [kA]– By (gap)
– ∫Bydl (gap)
– By (fringe)
– ∫Bydl (fringe)
19/08/2014
“gap”: the middle of the aperture
“fringe”: 5mm from the septum
LIU-PS Meeting 8
Comparing By of Full Sine and Half Sine
• Fringe field extents after excitation.
• Full sine: By = -1.4mT
• Half sine:By = 15mT
19/08/2014
0 1 2 3 4 5 6-40
-30
-20
-10
0
10
20
30
40
Cur
rent
[kA
]
Time [ms]0 1 2 3 4 5 6
-2
0
2
4
6
8
10
12
14x 10
-3
Mag
netic
flu
x de
nsity
[T
]
0 1 2 3 4 5 60
20
40
Cur
rent
[kA
]
Time [ms]0 1 2 3 4 5 6
0
0.01
0.02
Mag
netic
flu
x de
nsity
[T
]
LIU-PS Meeting 9
Comparing ʃBydl of Full Sine and Half Sine
• Integrated fringe field extents after excitation.
• Full sine: ∫Bydl = -1.37Tmm
• Half sine:∫Bydl = 14.28Tmm
19/08/2014
0 1 2 3 4 5 6-50
0
50
Cur
rent
[kA
]
Time [ms]0 1 2 3 4 5 6
-20
0
20
Fie
ld in
tegr
al [
Tm
m]
0 1 2 3 4 5 60
20
40
Cur
rent
[kA
]
Time [ms]0 1 2 3 4 5 6
0
10
20
Fie
ld in
tegr
al [
Tm
m]
LIU-PS Meeting 10
Comparing Full Sine and Half Sine
• Huge time constants in both cases:– 1 or 2ms excitation time (half or full sine)– time constant: >4ms
• Fringe field peak values are 10.4-10.7 times lower using full sine wave instead of half sine.
• Using ‘direct damping’ of the fringe field (full sine excitation) proves to be very effective.
19/08/2014
LIU-PS Meeting 11
Comparing By of 5mm and 3mm Septa
• Fringe field extents after excitation.
• 5mm septum blade: By = -1.4mT
• 3mm septum blade:By = -3.6mT
19/08/2014
0 1 2 3 4 5 6-40
-30
-20
-10
0
10
20
30
40
Cur
rent
[kA
]
Time [ms]0 1 2 3 4 5 6
-2
0
2
4
6
8
10
12
14x 10
-3
Mag
netic
flu
x de
nsity
[T
]
0 1 2 3 4 5 6-40
-20
0
20
40
Cur
rent
[kA
]
Time [ms]0 1 2 3 4 5 6
-0.01
0
0.01
0.02
0.03
Mag
netic
flu
x de
nsity
[T
]
LIU-PS Meeting 12
Comparing ʃBydl of 5mm and 3mm Septa
• Integrated fringe field extents after excitation.
• 5mm septum blade : ∫Bydl = -1.37Tmm
• 3mm septum blade :∫Bydl = -3.51Tmm
19/08/2014
0 1 2 3 4 5 6-50
0
50
Cur
rent
[kA
]
Time [ms]0 1 2 3 4 5 6
-20
0
20
Fie
ld in
tegr
al [
Tm
m]
0 1 2 3 4 5 6-40
-20
0
20
40
Cur
rent
[kA
]
Time [ms]0 1 2 3 4 5 6
-10
0
10
20
30
Fie
ld in
tegr
al [
Tm
m]
LIU-PS Meeting 13
Comparing 5mm and 3mm Septa
• A thinner septum blade is advantageous for the beam: lower continuous losses.
• 3 mm septum blade has higher current density.• Fringe field peak values are 1.7-2.6 times lower
using 5mm septum instead of 3mm.
19/08/2014
LIU-PS Meeting 14
Comparing By of 2ms and 7ms Wavelength
• Fringe field extents after excitation.
• 2ms wavelength: By = -1.4mT
• 7ms wavelength:By = -15.6mT
19/08/2014
0 1 2 3 4 5 6-40
-30
-20
-10
0
10
20
30
40
Cur
rent
[kA
]
Time [ms]0 1 2 3 4 5 6
-2
0
2
4
6
8
10
12
14x 10
-3
Mag
netic
flu
x de
nsity
[T
]
0 5 10 15 20 25-40
-20
0
20
40
Cur
rent
[kA
]
Time [ms]0 5 10 15 20 25
-0.02
0
0.02
0.04
0.06
Mag
netic
flu
x de
nsity
[T
]
LIU-PS Meeting 15
Comparing ʃBydl of 2ms and 7ms Wavelength
• Integrated fringe field extents after excitation.
• 2ms wavelength : ∫Bydl = -1.37Tmm
• 7ms wavelength :∫Bydl = -15.14Tmm
19/08/2014
0 1 2 3 4 5 6-50
0
50
Cur
rent
[kA
]
Time [ms]0 1 2 3 4 5 6
-20
0
20
Fie
ld in
tegr
al [
Tm
m]
0 5 10 15 20 25-40
-20
0
20
40
Cur
rent
[kA
]
Time [ms]0 5 10 15 20 25
-20
0
20
40
60
Fie
ld in
tegr
al [
Tm
m]
LIU-PS Meeting 16
Comparing 2ms Wavelength and 7ms
• 3.5 ms pulse half sine shape would be a pulse length similar to present SMH42.
• Shorter pulse length (w.r.t. baseline design) wasn’t investigated, since it will be very difficult to build a compatible magnet.
• Fringe field peak values are 3.2-11.1 times lower using 2ms full sine wave instead of 7ms.
19/08/2014
LIU-PS Meeting 17
Final Conclusion
Full sine vs. Half sineDirect fringe field cancellation very effective
5mm septum vs. 3mm septumThe thicker the septum, the lower the fringe field
2ms wavelength vs. 7ms wavelengthThe shorter the pulse, the lower the fringe field
The base line design appears a good compromise.
Next: the BMP42 septum bumper analysis.19/08/2014
LIU-PS Meeting 18
References• Full documentation: Z. Szoke: Eddy Current Septa Magnet
Optimization• M. J. Barnes, J. Borburgh, B. Goddard, M. Hourican, in Proceedings
of the CAS-CERN Accelerator School: Magnets, Bruges, Belgium, 16-25 June 2009, edited by D. Brandt, CERN-2010-004, pp. 167-184
• Finite element simulations: Cobham Opera 16• Data processing: MATLAB R2013b
19/08/2014
LIU-PS Meeting 19
Thank You for Your Attention!
Q&A
19/08/2014