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TY - CONF AU - Kitahara, R. AU - Fuwa, Y. AU - Iwashita, Y. ED - Petit-Jean-Genaz, Christine ED - Arduini, Gianluigi ED - Michel, Peter ED - Schaa, Volker RW TI - Magnetic Field Evaluation of Multipole Permanent Magnets by Harmonic Coil with Novel Calibration Technique J2 - Proc. of IPAC2014, Dresden, Germany, June 15-20, 2014 C1 - Dresden, Germany T2 - International Particle Accelerator Conference T3 - 5 LA - english AB - Quadrupole magnets for ILC final focus should be strong enough with the restriction on the external radius to let the disrupted out-going beam pass by, while vibration of the magnetic center has to be highly avoided to keep the nm sized beam focusing stable at the interaction point a few meter downstream from the lens. Gluckstern's 5-ring PMQ singlet seems a good candidate for this point of view. In order to fabricate a good 5-ring singlet, property of each ring has to be good enough. A harmonic coil system, which has 24-bit ADC’s for high resolution, was developed. Current noise level of the system is less than 10⁻⁵, which is supposed to be improved by reducing mechanical vibration of the ball bearings. We demonstrated the evaluation method of coil wire position with magnetic field from pin point magnet, so that the accuracy of the method was comparable to um scale. We measured the prototype 5-ring PMQ singlet and evaluated harmonic components. This result was compared with the data measured at KEK. PB - JACoW CP - Geneva, Switzerland SP - 1259 EP - 1261 KW - permanent-magnet KW - multipole KW - focusing KW - sextupole KW - neutron DA - 2014/07 PY - 2014 SN - 978-3-95450-132-8 DO - 10.18429/JACoW-IPAC2014-TUPRO094 UR - http://jacow.org/ipac2014/papers/tupro094.pdf ER -