A new QF1 magnet for ATF3 Alexey Vorozhtsov International Workshop on Future Linear Colliders 26-30 September 2011

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 units@rGFR 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

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

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

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 [Units]@ r=20mm LCWS11, 28/09/2011 Alexey Vorozhtsov

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

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

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 [Units]@ r=20mm for selected chamfer height LCWS11, 28/09/2011 Alexey Vorozhtsov

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 MSRD@15 mm Scaled@11.25 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

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

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 = -0.035%/0C LCWS11, 28/09/2011 Alexey Vorozhtsov