利用拉緊式導線快速量測磁通量密度之研究

Abstract

同步輻射研究中心(SRRC)擁有第三代同步輻射儲存環設施，專用於產生同步輻射光(synchrotron radiation)並且有效運用許多插入元件磁鐵(insertion device magnets)，可以有效地增加同步輻射光的強度與改變輻射光的偏極性。儲存環的磁格是由三個轉彎消能散磁格(triple bend achromat lattice, TBA磁格)所組成，可使電子的發散度更小，磁格磁鐵包含二、四與六極磁鐵等組合。為提高輻射光的品質並減少電子束的擾動，磁格磁鐵與插入元件磁鐵其磁場的品質就顯得很重要。為了解磁格磁鐵與插入元件磁鐵的磁場特性與修正磁鐵的磁場，所以需有一高準確度與精密度的磁場量測系統。 是故我們想建立一簡易而快速的自動量測系統－拉緊式導線系統(stretched wire system)，此量測系統相較過去一些傳統的磁場量測方式，如霍耳探針(hall probe)、翻轉線圈(flipping coil)及旋轉線圈(rotating coil)而言，可以減少量測時間，也可提高磁場量測的準確度。對於量測磁格磁鐵如二極、四極和六極磁鐵其多極諧和項(multipole field harmonic terms)和插入元件磁鐵的一次場積分(first field integral)與二次場積分(second field integral)的方法，具有較高的選擇彈性。而量測磁格磁鐵的多極諧和項及插入元件磁鐵的一次場積分與二次場積分的分佈情形，可研究分析磁鐵的缺陷(defect)並修正有缺陷的磁場。

SRRC is a third generation light source storage, which accommodate many insertion device magnets to produce the high intensity photon flux and varying polarization light of synchrotron radiation. The SRRC magnet lattice is a triple bend achromat that can minimize the electron emittance. The lattice magnet includes dipole, quadrupole and sextrupole magnets. In order to improve the synchrotron radiation quality and decrease electron perturbation. The qualities of lattice magnet and insertion device magnets are very important. Therefor we need a high precision and accuracy measurement system to understand magnet characteristics of lattice and insertion device magnets and to correct and shim the defect magnets. Herein, we want to set up a simple and high-speed automatic measurement system with stretched wire method. This method compare to traditional measurement methods, such as hall probe, flipping coil and rotating coil, it can reduce time consummation on the field measurement. The measurement results of harmonic field strength of lattice magnets and the first and second field integral strength of insertion device magnets that can analysis magnet defects and correct them.