SRリング用超電導電磁石の偏向磁界の傾き測定法の提案と測定結果 [in Japanese] Measurement of the Gradient between the Bending Field and the Vertical Line at the SR Magnet [in Japanese]
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We developed SR compact superconducting magnets which are used for X ray lithography. If the vertical axis of the superconducting coil of SR magnet is out of the vertical line the horizontal field Bx will be appeared. The electron beam is kicked toward vertical direction by this field and this causes a large electron beam orbit distortion in the horizontal coordinate. From the beam optics, the gradient of the coil axis needs to be less than 1 mrad. We developed a magnetic field distribution measurement system of the horizontal magnetic field <i>Bx(s)</i> in the high bending magnetic field <i>By<sub>0</sub></i> which is 3.5T at the center of the SR (Synchrotron Radiation) magnet and measured the distribution of <i>Bx(s)</i> . Where, <i>s</i> is the beam direction. From the horizontal magnetic field <i>Bx(s)</i> and vertical dipole field <i>By<sub>0</sub></i>(=3.5T), we can evaluate the gradient of bending field from the vertical direction. The average gradient along S direction was 0.55mrad. This value satisfies our requirement which is less than 1mrad.
- IEEJ Transactions on Sensors and Micromachines
IEEJ Transactions on Sensors and Micromachines 118(9), 1056-1062, 1998-09
The Institute of Electrical Engineers of Japan