Permanent Magnet Option for ILC Final Doublet Quads

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Permanent Magnet Option for ILC Final Doublet Quads and Tail Folding Octupole Y. Iwashita, T. Mihara, S. Nakamura, M. Ichikawa, Y. Tajima, Kyoto University M. Kumada, NIRS C. M. Spencer, SLAC 1 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Adjustable Permanent Magnet Quadrupole Prototype for 20 mr X’ing Angle Permanent Magnet (NEOMAX 38 AH) 2 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Prototype Magnet Bore radius Inner ring radii In 3. 3 cm out 5 cm Outer ring section length Physical length 1 cm, 2 cm, 4 cm, 8 cm 23 cm Pole material Permendur Magnet material (inner ring) NEOMAX 38 AH Magnet material (outer ring) NEOMAX 44 H Integrated gradient (strongest) 24. 2 T Integrated gradient (weakest) 3. 47 T Int. gradient step size Inner Ring In 1 cm out 3 cm Outer ring radii Inside View of Outer Ring 1 cm 1. 4 T Extra beam hole Before assembly 3 Base plate 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Magnetic Center Movement The cm values show the Switched-On-Length The center moves several µm for 20% strength change. See http: //accelconf. web. cern. ch/Accel. Conf/l 04/PAPERS/TUP 81. PDF (LINAC’ 04) 4 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Recent Modification Demonstrate a higher field gradient by reducing the bore size from ø 20 mm down to ø 15 mm. Temperature compensation of the inner ring; 1 mm (left) and 1. 6 mm (right) MS-1 trapezoidal plates are seen in a 2 cm space between magnets. 5 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Longitudinal Distribution Vertical component By measured along Z by a Group 3 Tesla meter. dz = 2 mm, z = 0 ~ 380 mm dx, dy = ± 2 mm Bore: ø 15 mm 6 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Longitudinal Distribution T/m All ON Bore ø 15 mm T/m All OFF Centroid Z [mm] Almost flat: Gmax ~１９０ T/m Gmin ~ ２９ T/m 7 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

SWL = 4 cm T/m Centroid SWL = 8 cm T/m Centroid Z [mm] Gradient is high at ON region. Magnet gaps of the inner ring affects the distribution. 8 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Integrated Strength (GL): ∫G dz [T] 40 35 GL value is proportional to the SWL: GLmax ~ 38 T GLmin ~ 5. 9 T @ø 15, L=23 cm 30 25 20 15 10 15 SWL [cm] 9 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Magnetic field centroid 50 Cases of only ８ｃｍ (entrance) ON or only ４ｃｍ(exit) ON mm shows the maximum and minimum. -50 0 5 10 15 Centroid location as a function of SWL The excursion of the centroid is almost half of its length; it can be reduced by using a couple of PMQ’s back to back. 10 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Required spec’s for Final Focus Eff. L Radius Poletip. B Gradient m m k. G/m QF 1 QD 0 QDEX 1 2. 0 2. 2 1. 1 0. 010 0. 015 8. 0 -14. 2 -15. 0 803 -1416 -1000 Int. G. dl k. G 1605 -3116 -1060 Variable PMQ will generate 1400 k. G/m, but 14 mrad. case needs more study. Brett Parker's sketch of how they be placed as sc. quads 11 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Demagnetization by Radiation Energy deposit Demagnetization by 14 Me. V neutron Si. D (by neutron Takahashi) Beam. CAL 17 m. W 13 m. W 29 m. W GLD Si. D QD 0 94 m. W 97 m. W 147 m. W SD 0 11 m. W QF 1 16 m. W 18 m. W 15 m. W SF 1 0. 4 m. W 0. 3 m. W 105 [n/cm 2 s] 1 m. W T. Kawakubo, et al. , The 14 th Symposium on Accelerator Science and Technology, Tsukuba, Japan, November 2003, pp. 208 -210, in Japanese, http: //conference. kek. jp/sast 03 it/Web. PDF/1 P 027. pdf very preliminary results by T. Abe (university of Tokyo), in private communication Continuous 1 mo. (2. 6 x 106 s) operation may cause about 0. 01[%] of (reversible? ) demagnetization on NEOMAX 32 EH. (1% for 10 years). . . needs more info. 12 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

PM-Octupole for Tail Folding 13 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

14 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

PM-Octupole for tail-folding Bore ø 32, Size ø 150 for ATF 2 ILC: Baseline Sc design: 0. 5 T@pole tip, 1 Te. VCM PMO can be strong; shorter in length. 15 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Mutlipole components Rotation of the ring may be analog not digital way. 16 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Reduced skews Skew components can be canceled if two outer rings are incorporated and rotated in opposite direction. 17 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

Summary Adjustable PMQ realizes 140 T/m@ø 20 mm The excursion of lens center was measured. New config. may be possible for smaller cross section (Needs more idea and study including lattice design) Demagnetization seems small (1% for 10 years? ) maybe OK even if 10 times more, but needs more info. Octupole for tail folding? Will fabricate one model (Quad or Octupole) — may be tested in ATF 2 18 9 th ACFA ILC Physics and Detector Workshop & ILC GDE Meeting

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