SPring-8の磁気分析装置 (Window-Frame magnet at SPring-8)

SPring-8 のホームページ

経過 (introduction)


I had a chance to give my suggestion concerning the spectrometer to be constructed at the SPring-8 facility.

窓枠型電磁石 (window-frame magnet)


This picture show the spectrometer while magnetic field distribution was being measured. A manufacturer proposed an ordinary H-type magnet whose structure is shown below with the calculated magnetic field lines.


If the coil is wound like this, it will occupy spaces at the entrance and exit of the spectrometer. We had to save the space for counters.


Although we can save the space by changing the coil aspect like this figure, the magnetic field strength decreases a little.


I proposed a window-frame structure instead of the H-type one. The coils are bent up or down at the entrance and exit of the magnet and later traverse horizontally, saving the free space there. More importantly, the uniformity of the magnetic field is much better than ordinary H-type one because there is no pole. In order to obtain the same volume of good uniformity, we have to increase the width of the poles. Even the following example is inferior to the window-frame type.