1. A new QF1 magnet for ATF3 Alexey Vorozhtsov
International Workshop on Future Linear Colliders September 2011

2. Requirements for QF1 and QD0
Magnet Name
QF1FF
QD0FF
Units
Gradient Nom. / Ultra low
6.772 / 6.791
12.45 / 12.46
T/m
Magnetic length
475 mm
Nom. Integrated gradient
3.226
5.919 T
Tuning range ±5 %
Aperture radius
> 35
Good Field Region radius 20
Space constrains
Not specified
Field quality requirements
Harmonic №:
Skew an=An/B2
Normal bn=Bn/B2 3
0.124
0.748 4
0.344
4.12 5
0.665
2.76 6
1.57
9.82
Reference
H. Garcia, E. Marin. R. Tomas. “ATF2 QD0FF and QF1FF specifications”, CERN, 26/07/2011.
LCWS11, 28/09/2011
Alexey Vorozhtsov

3. Model 1: Electromagnetic Quadrupole
Parameters
UNITS
Magnet name
QF1
QD0
Aperture radius
[mm] 40
Good Field Region radius 20
Effective length
475
Field gradient
[T/m]
6.791
12.46
Pole field
[T]
0.272
0.498
Yoke length
455
COIL
Conductor dimensions mm
10 × 10 , Ø=5
12 × 12 , Ø=6
Number of turns per coil 13 16
Number of pancakes per coil 1
Average turn length
[m]
1.2
1.25
Total conductor length
57.2 80
Electrical parameters
Ampere turns per pole
[A]
4560
8350
Current
351
522
Current density
[A/mm2]
4.42
4.54
Total resistance
[mOhm]
12.3 12
Voltage
[V]
4.3
6.3
Power
[kW]
1.5
3.26
COOLING
Cooling circuits per magnet
Coolant velocity
[m/s]
1.1
1.6
Cooling flow per circuit
[l/min]
1.28
2.75
Pressure drop
[bar]
2.3 5
Reynolds number
7771
13877
Temperature rise
[K] 17
Yoke consists of 4 pieces: Assembling errors
Water cooled coils: Magnet vibration
Power consumption: 1.5kW - QF1, 3.3kW -QD0
LCWS11, 28/09/2011
Alexey Vorozhtsov

4. QF1 Model 2: Permanent Quadrupole Magnet (PMQ) with adjustable strength
P.M. blocks -as a flux generators
Aluminum ring (made in a single piece) -as a support structure, p.m. blocks and pole nose will be mechanically clamped by this ring.
Pole tip made of soft iron material- to smooth the effects of possible differences, among the p.m., in terms of easy axis orientation.
Tuning blocks (movable mechanically at 10 mm (max), independently per pole) - to compensate the possible p.m. inequalities and to set the field gradient (max at 12.5% from the nominal value), the exact position of the block will be regulated by the non-magnetic spacers of different thickness.
Magnet name
QF1
Aperture radius
40 mm
Magnet height ×width × length
220 ×220×455 mm
Effective length
474 mm
Field gradient
6.8 T/m
Integrated field gradient
3.225 T
Tuning
12.5 %
LCWS11, 28/09/2011
Alexey Vorozhtsov 4

5. Field computation 2D model
Opera 2D/ST code –to design the pole profile, yoke cross-section, permanent block size and position.
Pole tip-profile: Hyperbolic shape was replaced by the arc segments – to simplify the machining of the poles.
Harmonic amplitudes were obtained by Fourier analysis of the radial field component Br on a circle r=20 mm (GFR boundary): b6, b10 < 0.2 r=20mm
LCWS11, 28/09/2011
Alexey Vorozhtsov

6. p.m. easy axis orientation errors
LCWS11, 28/09/2011
Alexey Vorozhtsov

7. Field computation: 3D model
Opera 3D Tosca code –to study the end effects
LCWS11, 28/09/2011
Alexey Vorozhtsov 7

8. Integrated field quality
Chamfer of 8 mm × 450 – to minimize the integrated dodecapole field component B6
Harmonic amplitudes were obtained by Fourier analysis of the integrated radial field component Br :
integrated b6, b10 < 0.4 r=20mm for selected chamfer height
LCWS11, 28/09/2011
Alexey Vorozhtsov

9. Example of similar magnet : LINAC 4 PMQ prototype ( constructed at CERN in 2011 )
Magnet Name
QF1FF
Linac 4(Proto)
Gradient
6.791 T/m
~16 T/m
Aperture radius
40 mm
22.5mm
GFR radius
20mm (50%)
15 mm (67%)
Harmonic N
Required mm
mm(50% ) an bn 3
0.124
0.748
8.5
-5.2
6.38
-3.90 4
0.344
4.12
0.5
6.1
0.28
3.43 5
0.665
2.76
-1.3
-0.3
-0.55
-0.13 6
1.57
9.82
0.8
-2.2
0.25
-0.70
Reference
D. Tommasini, M. Buzio, P. A. Thonet, A. Vorozhtsov. “Design, manufacture and measurements of permanent quadrupole magnets for Linac4”, Presented at MT-22, September 2011
LCWS11, 28/09/2011
Alexey Vorozhtsov 9

10. QF1 Model 3: Hybrid quadrupole (based on PMQ)
Aperture radius
40 mm
Magnet length
512 mm
Yoke height ×width × length
290 ×290×455 mm
Effective length
474 mm
Nom. field gradient
6.9 T/m
Nom. Integrated field gradient
3.27 T
Tuning range
± 4.6 %
Coil parameters
Number of turns per pole 35
Conductor size
4 mm x 4 mm
Current
± 20 A
Max. current density
1.2 A/mm2
Cooling
Air, natural convention
LCWS11, 28/09/2011
Alexey Vorozhtsov

11. P.M. material High remnant field Br=1.12 [T]
Sm2Co17 Recoma 30S from “ARNOLD Magnetic Technologies”
High remnant field Br=1.12 [T]
The smallest deviation ~3% of the magnetic characteristic (Br,Hc) from the typical values.
±2[deg] error of easy axis orientation
Radiation and corrosion resistant
Reversible temperature coefficient of Br = %/0C
LCWS11, 28/09/2011
Alexey Vorozhtsov