D23 with 12 and 15T cryomagnets

Stray Magnetic Field and Siting Issues on D23

We present the magnetic forces measured on D23 with the 15T symmetric split-pair coil magnet 158OXHV26. The measurements have been performed on the completely new non-magnetic secondary spectrometer for a distance of 855 mm.

Later, after the failure of the non-magnetic rollers located about 1 m below the magnet, the forces have been remeasured. The tests up to 13 T still showed very low forces. The minimum distance to be kept from the monochromator protection is 855 mm (between the aluminium piece at the beam exit and the center of the magnet). No additional magnetizable or magnetic items are authorized between magnet and monochromator.

D23 can use the 12T and 15T magnets up to nominal field, provided the distance of 855 mm is kept between the aluminum piece at the exit of the monochromator protection and the magnet axis.