IN20 with 15T

158OXHV26 (15T)

Stray Magnetic Field and Siting Issues on IN20

We present the magnetic forces measured on IN20 with the 15T symmetric split-pair coil magnet 158OXHV26. The results obtained in 2007 revealed the presence of strong forces, mostly with the manochromator shielding and the A3 motor block. The results of the measurements shown on the right have been obtained after these modifications.

We can see that the 15T can be used up to nominal field whatever are the positions of the sample table and analyser arm. This is mostly thank to the extension by 10cm of the A2 arm.

The larger forces observed for A2 = 12° are explained by the fact that the spectrometer table is exactly on top of the left hand railway track in the marble floor. This corresponds to the worst case for vertical forces, and also to the lower limit of A2 for IN20.